(5 MAR 2018)
We undertook a comprehensive project over the last 8 weeks to perform an unbiased, independent, full product and performance review, of the 3 major players in the Fat Bike suspension fork market.
In order to perform a fair and unbiased review, several BASELINES needed to be established, to make the test fair for all competitors.
RIDEFATBIKES.ca provided all necessary gear and suspension forks to independent riders and asked them to do all their independent testing offsite, while recording their results. If the product testers ran into component issues, found operating condition limitations, or product failures, the data was sent back to RIDEFATBIKES.ca to review and attempt to replicate these conditions using our own equipment. In every instance, we were able to duplicate and validate their findings on at least 2 or 3 bikes, so the results are vetted through multiple sources confirming the statistical and performance review data was accurate.
RideFATbikes.ca will publish the Lead Independent Tester's full review unaltered and in it's entirety.
Before and after the actual review article, RIDEFATBIKES.ca will introduce the background information and performance baselines for the test. We will only include supplementary comments, charts, pictures, and provide product and performance clarifications (like direct communications with the manufacturers or factories during testing), to help tell the story of this product review, and answer questions the Independent Testers ran into during the testing process.
The decision, of which suspension fork won the shootout review, is completely the decision of the lead independent tester.
We completely support their independent decision and will publish their complete report for the sake of transparency.
RIDEFATBIKES.ca is the only retailer in CANADA that sells *all three models* of the suspension forks in this test. We thought we owed it to our customers to perform this review, so they had the best buying options possible. RIDEFATBIKES.ca shares information, and our goal is three-fold :
If you have taken a moment to sit down and think about just how many versions of fat bike suspension forks are out there, it's over 20 makes/models...so let the selection process begin !!
First - we have to determine a number of factors that will go into this test. This criteria selection process needs to be fair, and the eligible product options need to be up to date with 2018 production standards and readily available in the marketplace. In addition, we need to baseline them in several ways, so that cross-platform testing can be done, where we are not randomly picking suspension forks by different vendors in random travel lengths and AC Heights. This all needs to be standardized through baseline criteria. Next, we have to establish, what product we are going to consider the "baseline" by which all others will be compared to. We need to do all that, and make sure the test bikes can accommodate those forks too, without any modifications needed to the installation (such as crown race extenders) and no conflicts with wider fork crowns hitting the down-tubes, when extended in a 90-degree turn from the centerline.
Once we determine which brands, or product lines we will test, we need to find the ACTUAL suspension fork, in EACH of those product lines that best meets the baseline criteria. As mentioned above, there are over 20 suspension forks to currently chose from. We need to narrow that down to 3 forks.
We had to look at all the suspension fork manufacturers, and choose the 3 brands that best met the acceptance of mass production standards, features and suspension travel, for all fat bikes in 2018. From those 3 manufacturers, we selected the best forks they had to offer, in their premium build lines, and installed them on industry-leading alloy and carbon fat bikes.
SUSPENSION FORK QUALIFICATIONS:
Often overlooked, and not always understood, is the AC HEIGHT specification of a fat bike frame. This Axle-to-Crown (AC) measurement is a very important specification, because manufacturers often base their warranties and frame durability ratings off that number. This is also closely tied to the "Suspension Correct" calibration number assigned to manufactured frames.
From our extensive research done on STACK and REACH (click for separate article review), our internal database found that the majority of quality hard tail fat bike frames, are suspension corrected to an Axle-to-Crown (AC) Height of 511mm.
If you try to install a suspension fork that exceeds this number - and your frame is rated to MAX AC=511, you are liable to :
The suspension fork shootout takes all the above facts and variables into consideration and has carefully prepared their fork selection, so that after applying the manufacturer-suggested amount of SAG to the fork, the final ready-to-ride AC Height will be <= 511mm.
NOTE : After applying factory-suggested SAG settings the available Travel is also reduced.
TRAVEL and AC HEIGHT Adjusted for SAG :
BLUTO RCT3 120
WREN ATK 110
MASTODON PRO EXT 100
Once the Suspension Forks for this test were selected, we then decided upon the best available fat bikes to perform the testing.
BIKE QUALIFICATIONS :
(If the first bike ran into a limitation or "feature" on any fork, this secondary bike would be used to replicate and verify that condition, using the same type of fork, or same fork, as needed.
(used as a verification platform, when testers on the first two bikes found issues or limitations of their WREN ATK or MASTODON PRO EXT test forks. This bike then tested that fork in the 150mm travel version only, to see if the issues/limitations persisted at that level too).
The Rockshox Bluto was the first suspension fork for fat bikes, entering the market in October 2013 and forever changed the way riders and manufacturers looked at fat bikes. The Bluto ushered in many technology changes for fat bikes, and made the sport a better. SRAM made two versions of the Bluto, the RL and the RCT3, in both 100mm and 120mm travel lengths. We are testing their final version, the RCT3 120mm, w/ tapered steerer, and accepts up to 26 x 4.8" or 27.5 x 3.8" tires, on standard 150mm hubs.
Inside the Retail Box :
The Wren Twin-Air suspension fork is an inverted design with keyed stanchions, and has gone through at least two major revision upgrades in the last 3 years. This version has an adjustable rebound, compression, and air-side control, along with full lockout mode. There are only two versions of this fork, and both use a tapered steerer. The "110" covers travel increments of 80, 90, 100, and 110mm. The "150" covers travel increments of 120, 130, 140, and 150mm. Both accept up to 26 x 5.0" or 27.4 x 4.5" tires on most standard 150mm hubs. We are testing the latest Twin-air version, in the 110mm travel length. The model number is WSF150-110ATK.
Inside the Retail Box :
The Manitou Mastodon PRO is the newest fat bike suspension for on the market, and has been in use for about a year now. This fork looks to improve on performance where the Bluto RCT3 left off and is claimed to be 25% stiffer. It is the widest, tallest, and heaviest of the bunch, and comes in a bewildering selection of 8 different retail versions capable of 100, 120 or 140mm travel, plus 2 additional OEM versions with 150mm travel. We are testing the MASTODON PRO EXT 100, with 100mm travel and accepts up to 26 x 5.0" tires.
In the Retail Box :
Author, Ryan Ellis
"I need / want to purchase a (new) suspension fork for my fat bike, but what fork should I buy?" It’s a common question but the answer is not as clear as I would like. With limited information and reviews online about many of the new forks consumers are forced to roll the dice with a $1000.00 suspension fork purchase and hope they choose well.
When I bought my fat bike one season ago the fork options were a rigid steel fork, a rigid carbon fork, or a RockShox Bluto. The Lauf was also an option but for my trail riding and four season needs it offers little useable travel, no spring damping and just looks goofy to me. I chose to go with a RockShox Bluto RL in 100mm of travel then changed it out for a Bluto RCT3 with 120mm of travel. After about 8 months of riding on the 120mm travel RockShox Bluto RCT3 the fork developed a knocking sound that my mechanic attributed to bushing play. The Bluto is going back to RockShox for warranty consideration and I’m going to take this opportunity to change it up for a different fork.
Thanks to www.ridefatbikes.ca in Burlington, Ontario I had the opportunity to perform an extended test ride with the top models from Wrensports and Hayes / Manitou.
At the conclusion of the test period I will be putting my money where my mouth is an ordering a new fork from RideFatBikes.ca.
Here are my impressions, findings, and thoughts from behind the handlebars with the RockShox BLUTO RCT3, the WREN 110 ATK inverted fork and the Manitou MASTODON Pro Ext 100.
I am neither a professional writer (you’ve probably already picked up on that) or the best fat biker out on the trails. I’m the average 40-year-old weekend warrior who gets 1-2 good fat bike rides in per week during the winter. I’m 6’3” and 200(ish) lbs and I am only a couple years into my fat bike riding career.
Prior to fat bikes, I do have more than 20 years of off road riding experience and currently enjoy a mid travel, full suspension 29er for most warm weather riding. My fat bike is primarily a winter ride and this review is based on testing during an Ontario winter with temperatures (usually) between +5 Celsius and -20 Celsius.
This fork review was based on six weeks of regular riding on the same bike. It required lots of late night fork swaps but it should provide a relevant comparison. The test mule was an XL Fatback Rhino Alloy with a SRAM XO1 11 speed drive train, SRAM Guide hydraulic brakes, and DT Swiss BR 710 wheel set.
Of particular note, this frame is a great platform for testing because it provides plenty of down tube clearance to accommodate all of the forks in this test. Please keep in mind that your frame may not provide the same down tube clearance.
This review took place on the trails and not in a laboratory. My impressions are based only on my own observations and experiences riding each fork. I did my best to subject each fork in a variety of trail conditions and environmental conditions.
Temperatures during testing were generally cold in the -10 to -15 degrees Celsius range with a couple opportunities to ride each fork closer to the freezing mark.
The trails were snow covered for most of the testing period. Although, I did manage to get one ride in on the new Mastodon Pro EXT 100 before the first snow of the season and one ride in on the Wren 110 ATK after a thaw and rain destroyed the snow cover.
As noted above, the fat bike suspension forks were all tested on an Alloy XL Fatback Rhino frame and tire pressures were maintained in the range of 6-7psi in the rear and 7-8psi in the front tire."
“We started with the features you’ve come to love from RockShox: Fast Black aluminum upper tubes, stout 15mm Maxle, remote or crown adjustable damping, tapered steerer tube, and the infinitely tunable Solo Air spring. Then, the chassis got the fat treatment by reengineering it to meet the unique needs of fat tires and wheels. Everything from crown, to arch, to axle has been optimized to tackle the increased torsional loads of its wide stance. With more traction and control than ever before, you’ll never be happier you went fat.”
The BLUTO is available in four (4) different versions.
The ROCKSHOX BLUTO RCT3 120 is the fork selected for this test review, and is highlighted in green in the chart below.
(by Lead Independent Tester)
"Having owned and ridden numerous RockShox products over a number of years, I have always found their fit and finish to be excellent. With the exceptions of a couple of very tiny paint imperfections, the fit and finish of the RockShox Bluto RCT3 was close to perfect."
"All damper and rebound controls are easy to access and operate and the sag setting indicators on the stanchions are a touch that I really appreciate when setting up the fork. The air pressure chart on the fork leg gets you into the ballpark quickly and it’s easy to add or remove a little air pressure to make your final adjustments."
"This particular fork has the bolt-on Maxel Lite15mm axle and after riding both the bolt-on and the quick release (QR) version, I would always choose the simplicity of the bolt on-axle. Even when using a rack that required me to remove the front wheel I found the bolt-on Maxel Lite to be easier to use than the quick release axle."
"The set up of the RockShox Bluto RCT3 was very quick and easy. A pump up to the recommended air pressure and a couple small tweaks to set the sag was the bulk of the work. Rebound was set with the garage floor bounce test and compression always run wide open. I’m not one to fiddle with lock out switches and levers and would prefer some inefficiency in climbing, rather than futzing with my suspension fork. I didn’t change this setup for the duration of my time with this fork."
"If I had any volume reducing tokens I would have liked to try adding one or two to make the suspension a little more progressive but I didn’t have any on hand. I’m also not sure how many tokens were pre-installed by the factory, so I can’t tell you how many I was riding during testing." [see footnote (*1*) below]
"On the trail I was impressed with the RockShox Bluto RCT3. I found it to be supple over small bumps but not quite as progressive over larger hits as I would have liked. With 20% sag I would regularly use all 120mm of available travel and bottom out when riding moderate trails. I never experienced a harsh bottom out but additional bottomless token may have provided a more progressive suspension feel."
"Ride quality did not noticeably change with temperature fluctuations and the fork performed well at -15 Celsius and at +30 Celsius. I did not experience any of the temperature related issues such as leaking seals and stiffening damper with the RockShox Bluto RCT3 that I have read about in the online forums."
"I’ve read reviews and watched YouTube videos about the RockShox Bluto and the term “noodly” gets used a lot to describe the stiffness of the fork. Because almost all of my fat bike riding experience has been on a Bluto equipped bike, I therefore couldn’t compare the Bluto to a stiff rigid fork. When riding with the Bluto I did notice some handling characteristics of the bike that I initially attributed to fat tires and soft sidewall flex."
"After riding the Wren 110 ATK and the Mastodon Pro EXT 100 on the same bike, on the same trails, and with the same tires and tire pressure, I’m sure that the 32mm stanchion RockShox Bluto chassis was just overwhelmed and demonstrated enough flex to be noticeable in the handling of the bike."
"The 32mm stanchions on the Bluto look down right spindly (aka wimpy looking) installed on just about every fat bike out there. I’m old and a chicken, so hucking off large drops with my fat bike is not in the cards. The structural integrity of the Bluto was still in the back of my mind when making my line choices, because I would avoid some of the drops and features that wouldn’t give me any concern when riding my 29er full suspension trail bike. There are lots of videos online of great riders pushing their Blutos to the limit in demanding terrain, so I’m sure the fork is up for the challenge, but for me it just wasn’t confidence inspiring."
"When reading about the Bluto online I found numerous complaints about the fork performance deteriorating when riding below freezing. I didn’t experience this particular problem with the Rockshox Bluto RCT3 or with the RockShox Bluto RL under those conditions. Rebound and compression speed may be slower in colder temperatures but not enough that I found it noticeable on the trails."
"The flex of the fork identified above could be considered a problem, but the fork is essentially a widened cross country chassis. It doesn’t pretend to be anything else and does offer the lightest weight of the bunch (3.7 lbs). If you want a lightweight fork offering this much travel, some flex is the compromise you need to be willing to accept."
"The major issue that I experienced with the RockShox Bluto RCT3 is a knocking sound and play that developed inside the fork that has been attributed to worn bushings. This has occurred with less than a year of seasonal riding on the fork. This disappointed me after spending quite a bit of money on the RockShox Bluto RCT3, but I was willing to do the maintenance to get myself riding again. Unfortunately, with the RockShox Bluto the bushings are not a simple maintenance item. To replace the bushings you need to replace the entire fork lowers. This seems like a lot of waste and expense and hassle to perform a common repair. A quick search of the usual online retailers revealed new lowers without stickers for approximately $300.00. A new sticker kit will add another $50.00 to the cost, totaling $350.00 in repairs."
(*1*) - (Tokens) : The BLUTO RTC3 120 has the ability to add up to 4 tokens, and zero are pre-installed at the factory, in this configuration.
“The Inverted fork design simply works better. By inverting the fork so that the lighter stanchions are on the bottom, we reduce the mass of the moving part of the fork so that it will react quicker and easier to the trail. Inverting also anchors the stanchions into the stronger, larger upper tubes and crown making the overall chassis much stronger and stiffer. It also lowers the fulcrum point where the uppers join the stanchions compared to other fork designs decreasing the leverage factor. Inverting also positions the seals downward so that all kinds of bad stuff doesn't sit on them and get pulled into your fork.”
The Wren inverted fat bike suspension fork comes in two versions :
[see footnote (*1*) below]
You can adjust Travel only or Travel and AC together, on these models. The Wren 150 ATK version weighs about 100g more at 2208g.
The WREN ATK 110 was the suspension fork selection for this review test, and is highlighted in Green, in the charts below :
(By Lead Independent Tester)
"If I can believe what I’ve found on the net, the WrenSports inverted fat bike suspension fork is an evolution of the “Fork of Many Names” that was previously branded and sold under multiple brand and model names. My understanding is that WrenSports has undertaken a considerable redesign of the fork and the current iteration can’t really be compared to its predecessors." (*2*)
"Before this opportunity to test the Wren 110 ATK, I had never seen a WrenSports inverted fork in person and only had limited anecdotal information from riders who had. I honestly didn’t have the highest expectations of the Wren and anticipated a prototype look and feel."
"Upon opening the plainly packaged Wren I was surprised with the high quality feel and look of the fork. It was slightly less refined than the RockShox Bluto RCT3 or Manitou Mastodon Pro EXT 100. There are a couple sharp edges on the drop out casting, and the clamps that hold the stanchion guards on are a bit utilitarian. Overall, this fork feels like a solidly built and high quality suspension fork. Plus, it looks very cool!"
"After reading the manual in its entirety a few times to make sure I fully understood the twin air system, setting up the Wren to the recommended starting point proved to be fairly straight forward, save for a couple minor challenges."
"Step one is adding air to the top and bottom chambers equally until the recommended 20% sag is achieved. With the inverted Wren fork design, you can’t simply use your shock pumps pressure gauge when pumping up the top and bottom air chambers. Because of the floating piston design of the twin air Wren, the air pressure in the top and bottom chambers will always equalize. The equalized pressure is relevant because the pressure inside the air spring provides the correct sag and can be adjusted to control bottoming out or to allow the fork to achieve full travel. However, what is also important with the Wren’s twin air design is the relative air volume in the top and bottom chambers."
"When setting up the fork initially Wren recommends that you add the same volume of air in both chambers to provide a very neutral starting point for adjustment. The only way to do this is to count the number of pump strokes and add the same number of strokes to each chamber. If the sag is more than 20% you can add a couple pump strokes to the top and the bottom and try again. If the sag is less than 20% and you have too much air in each chamber the only option is to bleed all the air from the fork and start again. The inability to make small, accurate, and recordable decreases in air volume without fully bleeding the air out of the fork is a limitation of the twin air design." (*3*)
"Once the sag is set and the fork has equal air volume (and pressure by default) in both the top and bottom chambers of the fork it’s time to adjust the rebound. Wren has not provided detents or clicks to help you nor have they limited the range of adjustment that the user has access to. The red adjuster knob on the bottom of the right fork leg provides complete adjustability to go from pogo stick fast to molasses slow, and everything in between. It’s up to the user to select a speed that won’t allow the fork to pack up in the smallest bumps or eject them from the bike in larger bumps. With very little rebound damping (fast rebound speed) there is a noticeable top out clunk sound inside the fork. With a little more rebound damping dialed in, this sound completely disappears. With higher speed riding or more frequent hits it may not be possible to run the rebound fast enough and avoid the top out sound."
"With the sag set and rebound dialed I hit the trail and fine-tune the feel of the Wren. By increasing the volume of air in the top chamber relative to the bottom chamber the Wren 110 ATK will provide a softer, plusher and less progressive ride. And by decreasing the air in the top chamber relative to the bottom chamber the Wren will provide a more progressive feel. Decreasing the volume of the top chamber relative to the bottom chamber is similar to adding bottomless tokens to a RockShox fork or adjusting the IVA system on a Manitou fork but the twin air design allows you to achieve the same affect by only your shock pump and without opening up the fork. What can become confusing when making these adjustments is that the equalized air pressure in the top and bottom chambers will be influenced by adjusting the volumes of the upper and lower chambers and adjustments may have to be made to the sag. For example if you adjust the fork to your preferred sag setting but then decide you want a more progressive ride characteristic and add some air to the bottom of the fork you may also notice that your sag is now less than 20%. It can become slightly confusing! Once you have settled on an air pressure that provides 20% sag and the volume ratio that you like you will want to record this so that you can achieve the same result in the event that you bleed the air completely from the fork and start from scratch."
"The Wren 110 ATK that I was provided for testing came with a quick release axle and a bolt on axle. The design of each axle doesn’t feel as refined or sophisticated as the Axle system of the RockShox Maxle Lite or Manitou Hexlock SL but both do the job of holding the front wheel in place. Wren recommends the bolt on axel over the quick release axle for all fat bike applications. The bolt on axle provides more clamping force and rigidity to handle the forces generated by fat bike wheels." (*4*)
"The brake line management system on the inverted Wren is also different than a conventional fork. If you fix the brake line to the fork leg, the inverted design results in a loop of brake line close to the rotor growing as the fork compresses. The loop of brake line could find its way into the spokes or brake rotor. Wren ships with two cable management guides that are fixed to the upper stanchion with zip ties. These are essentially the same solution that is used with some externally routed dropper seat posts. This solution is not as tidy as the brake line management found on a conventional fork but it is completely effective and it does allow you to control placement of the guides to avoid brake line rub."
"Riding the Wren felt very much like riding any other high-end bicycle suspension fork. When tuned properly it provides excellent small bump sensitivity with the desired amount of ramp up as the fork progresses through its travel. Steering was precise and noticeably faster than the RockShox Bluto RCT3 or the Manitou Mastodon Pro EXT 100."
"I suspect the fast steering can be mostly attributed to the 45mm offset of the Wren vs. the 51mm offset of the Bluto and the Mastodon."
"It is possible that the rigidity of the fork also enhances the faster steering response. This is a very rigid fork - the most rigid of the bunch in my opinion." (*5*)
"During testing the effects of the fluctuating temperatures on the fork were a little frustrating as I tried to dial in the ride quality that I wanted. As the temperature fluctuated (below the freezing point) so did compression and rebound speed. Physics and the properties of air, oil and metal indicate that this effect should be noticeable on all suspension forks. The Wren 110 ATK is the only fork that I’ve found it to be significant." (*6*)
"Prior to riding the unique Wren 110 ATK I spent a few evenings scouring the Internet looking for whatever complaints I could find. I wanted to know what to watch out for when testing the fork. The two most common complaints that I could find were the fork “freezing up” in cold conditions, and rubbing of the tire on the upper fork leg. The rubbing was attributed to the inverted design that allows some independent movement of each fork leg. Interestingly, I didn’t find complaints about the Wren being more complicated to set up." (*6*)
"In my experience during testing the Wren was absolutely influenced by cold temperatures." (*6*) "As ambient temperatures decreased from 21 degrees in my work shop to -10 degrees at the trail head the Wren’s rebound and compression damping both became much heavier during the parking lot bounce test. The difference was more pronounced with rebound than compression. During actual riding and at about -10 and warmer, the increased rebound damping and compression damping effect was minimized as the cycling suspension generated heat. Rebound speed could also easily be increased to overcome the sluggish damper. At temperatures colder than about -10 Celsius the Wren did not generate enough heat to overcome the effects of temperature and the fork in the fully open compression setting felt almost the same as it did with the lock out engaged. This effect was more noticeable in riding conditions with a significant wind chill."
"While the early heavy snow falls this season quickly smoothed out the most demanding terrain I did my best to hit every rock, log, jump, and trail feature that I could during testing. Despite my best efforts, I was unable to duplicate any of the tire on upper fork leg rubbing that I’d read about online. It’s possible tire rub is only noticeable with the widest of wide tires. I have plenty of clearance with my 4.6” tires and the independent movement of the fork stanchions would have to be significant to ever result in rubbing. The owners who reported rubbing may have been using the quick release axle and not the bolt-on axle, or, may have used the quick release axle installed incorrectly." (*4*)
(*1*) - Response from RideFATbikes.ca : (True Fork Travel) - I bet almost no one realized this, but the WREN ATK 110 is really a 120mm travel fork, and the WREN ATK 150 is really a 160mm travel fork. They both sacrifice 10mm of usable travel, when the carbon bash guard clips are installed.
(*2*) - Response from RideFATbikes.ca : ("Fork of Many Names") - Previously marketed under the "Carver", "AEKO", "Muru" and "11nine" labels, and currently marketed under the "FATLAB" and "WREN" label.
(*3*) - Response from Wren : (Setting up Sag / Twin-Air Chambers) - "In terms of adding air to achieve sag, after initial setup and getting close to sag, we recommend small additions, not a couple of pumps at a time. Each pump stroke can make a significant change, as you are getting closer and closer to dialing in the fork. This would prevent having to start over. Yes, if you bleed there is no way to gauge accurately, but the advantages to the adjustability outweigh this in our opinion. We discussed this with our engineers during development, and the additional cost to equip the fork with digital gauges indicating where the sliding piston is located, was too expensive an option."
(*4*) - Response from WrenSports : (Axle Setup / Tire Rub) - "The QR and/or the Bolt-on axle should always be inserted first into the BRAKE side. The securing bolt should then be fastened (firmly and to torque spec) via the drive-side of the fork."
"Regarding tire rub - We have found that in those cases where we were contacted by customers about this issue, either the axle was installed backwards (not from brake side), or the two stanchions were not lined up evenly to allow the axle to slide in and seat evenly, which resulted in a loose condition that was not felt until riding. This caused the wheel/rim to deflect into the left upper stanchion of the fork."
(*5*) - Response from WrenSports : (Regarding Steering Response) - "The faster, more precise steering is mostly due to the rigidity. The 45mm offset does also make some difference. The main reason for the picking 45mm as the offset, is to allow the fork to fit more bikes with varied geometry and help balance the ride. We did not work with just one OEM in mind. The offset also matches well with our AC adjustability to be able to put our fork on much older bikes."
(*6*) - Response from WrenSports : (Cold Weather Performance) - "We have discussed this at length with everyone involved. We know there are Wren fork-equipped bikes out there that work great in temps much colder than the Bluto or the Mastodon can achieve (past -30c). We need to figure out why the particular test forks in this review did not perform for you."
(*6*) - Response from RideFATbikes.ca : (Cold Weather Performance) - The failure of the Wren suspension forks freezing up prematurely between -5c and -10c has been verified by :
This indicates it is not an isolated incident, but instead a manufacturing inconsistency where build specifications have differed from real-world testing on forks built throughout 2017. If the Wren fork was made in 2016, it appears to be more predictable and consistent than Wren forks made within the last 6-9 months. We had perfectly working Wren forks in early 2017, but not by end of 2017. Customers were starting to notice cosmetic and functional defects in the forks, by Fall 2017. We immediately notified WrenSports LLC of these issues so they could investigate.
(*6*) - Response from WrenSports : (Cold Weather Performance) - "The updated (1 MAR 2018) factory specification of the Wren fork is to function problem-free down to -15c."
(*6*) - Response from RideFATbikes.ca : (Cold Weather Performance) - Upon learning of our test results, WrenSports LLC asked for extra time to send out a new fork from the factory to beat/challenge the poor cold weather performance we were seeing in the forks we randomly pulled from current production runs. We waited almost 3 weeks. No fork arrived. As of publication date [5 MAR 2018] we still do not have a clear answer as to what is causing this problem. The review continues on...
“Real-world trail suspension for your fatbike! All-temperature performance soaks up chatter and big hits on freezing cold snow as well as it does on shimmering hot sand, and everywhere in-between.
The Manitou Mastodon is available in nine (9) different versions! There are the PRO (Durado Air) and COMP (Expert Air) model lines, divided into STD (standard) and EXT (extended) Ride Height configurations. Eight (8) of these models are Retail, while one (1) version is OEM only.
The MANITOU MASTODON PRO EXT 100 is the suspension fork selection for this test review, and highlighed in green, in the charts below.
(by Ryan Ellis, Lead Independent Tester)
"The Manitou Mastodon Pro is the biggest, widest and heaviest fork of the bunch. It looks solid, it feels solid and the build quality is excellent.
"The Mastodon pro features a solo air style air spring as well as externally adjustable rebound damping, high speed compression and low speed compression via the standard anodized knobs on the top and bottom of the damper leg of the fork. Additionally the Mastodon pro offers the IVA (incremental volume adjust) system in the air spring leg of the fork. The IVA system is clever in that it doesn’t require any additional parts like the RockShox bottomless token system. After opening the air spring side of the fork with a 24mm socket the air spring position can be adjusted with a series of built in clips. Reducing the volume of the air spring with provide a more progressive ride that ramps up quicker to reduce bottoming. Increasing the volume of the air spring will provide a more linear ride that bottoms easier but provides a supple ride that is sensitive to small bumps throughout the stroke of the fork. During testing I rode with the IVA system at the factory settings and found it to be sufficient for riding snow covered trails, only bottoming out gently a couple of times. During more aggressive summer riding a slightly more progressive tune would probably be in order."
"Manitou provides an easy to read single page setup guide for the Mastodon Pro and I found the recommended settings to be a great starting place. For my weight around 100psi is recommended to achieve static sag in the 15-25% range. I settled on approximately 25% sag for myself. I adjusted the rebound speed to my liking and left high speed and low speed compression wide open."
"The only setup annoyance that I had when installing the Mastodon Pro was related to brake line routing. I found that the reverse arch and the placement of the brake housing attachment points on the rear of the leg resulted in some unusual routing of the brake line through the fork between the crown and the arch to minimize brake housing rub points on the fork and on my frame. My best solution still required me to protect the fork at two locations with tape. Brake line routing may be cleaner with your setup."
"The Mastodon Pro EXT 100 uses Manitou’s Dorado Air spring and top of the line MC2 compression damper. When combined with the stiff chassis of the Mastodon Pro the ride quality is as good as you would expect from any of the best mountain bike suspension forks on the market. The fork performed well in all conditions and felt very composed and not in any way challenged by the terrain. There is some noticeable stiction with the Mastodon that is more evident during the workshop bounce test than it is out on the trail. It is possible that this will improve but is still noticeable after 5-6 hours of riding."
"During testing of this fork I did not experience any noticeable influence of cold weather on the performance of the fork (within 5 Celsius to – 15 Celsius). The fork behaved in sub-zero temperatures just as it did when I set it up in my warm basement workshop." (*1*)
"The Manitou Mastodon was only recently released and I wasn’t able to find much information about the fork. The online forums were buzzing with anticipation of this new fork but I didn’t find any complaints. During my testing I identified a couple of small issues that a potential buyer should consider before purchasing."
SIZE - "Firstly, the Mastodon Pro is a huge fork with a very wide stance and an equally wide crown. The fork is so big that I suspect that the crown will not clear the down tube and may result in crash damage to the frame or the fork if installed on some fat bikes. Even many frames that were designed for use with a Bluto don’t always provide the down tube clearance required to use a Mastodon. The high speed and low speed compression knobs are also elevated above the right fork leg which will further exacerbate the problem for frames with already tight clearance. Anyone interested in the Mastodon should check for potential clearance issues if this is a concern." (*2*)
AC Axle-to-Crown Height - "Secondly, for the same 530-531mm axle to crown measurement and a few hundred grams more weight the Mastodon Pro provides only 100mm of travel (with the extended height fork tested) vs the 110mm of travel offered by the Wren 110 ATK vs. the 120mm of travel of the RockShox Bluto RCT3. I suspect that the Mastodon is short changing us on travel to accommodate the 27.5 x 4.5” fat tires found on the bikes of major OEM purchaser Trek." (*3*)
WEIGHT - "Up to half a pound more than a Wren and 1.2 lbs more than a Bluto" (*4*)
(*1*) - (Cold Weather Testing) - We completely agree. The Mastodon PRO EXT fork worked well down to its rated -18c without any problems, and continued working well down to -20c. Extended time outside, or in the wind, did get it to start acting sluggish as you went past -15c. It performed the best of all 3 forks tested in cold weather.
(*2*) - (Size) - This is a big fork! (Hence, I think, the reference to a Mastodon in the wild). This fork does have compatibility issues on older style frames, that were built with only the Bluto in mind. I think as time passes, frames (specifically down-tube shapes) will be updated, to accommodate this wider stance. The Mastodon is 23mm, or about 1 inch WIDER than a Bluto. Lucky for us, the MASTODON PRO and WREN ATK both fit perfectly on all the FATBACK and FOES RACING fat bikes we custom build.
(*3*) - (AC Axle-to-Crown Height) - OK, this one is frustrating. For two reasons. There are so many fork versions to choose from, plus, you need to second guess the charts that Manitou released. It seems that they did not test every tire combination with standard 80mm rims. Some tires rated as not being compatible with the STD version actually DO fit. This "error" or miscalculation causes customers to play it safe and go for the EXT version, versus the STD version. What that does is add 20mm to the AC Height, slackens out the frame geometry, and reduces the travel by 20mm. This gives the Mastodon the worst AC-to-suspension-travel ratio of the forks tested. If Manitou invests some time updating their charts on this rating... they might help customers gain 20mm of travel, for the same AC stack height, or, help them save 20mm of AC stack height, for the same travel rating. (Please refer to our charts at the beginning of the review for more info on general STD vs EXT stack and travel).
(*4*) - (Weight) - As a point of reference, for the weight weenies out there sifting through manufacturer's claimed weights - Here are some actual digital measurements, from the Park Tools digital scale in our workshop. The weights are "race-ready", meaning they include the axles, cut steerer tubes (230mm usable), star nuts installed, and in the case of the Wren, the carbon bash guards installed:
MASTODON PRO EXT 100
WREN ATK 110 (-0.2 lbs lighter)
BLUTO RCT3 120 (1.0 lbs lighter)
"If you’ve read this far or even scrolled to the end of this article you would probably like to know what fork I think is the best. Before we go any further let me remind you that what went into this article was not scientific testing. The observations and reports are based on one rider’s experience over an extended test ride in a variety of trail and environmental conditions. To be honest, I was expecting to be able to recommend a clear winner but these are all good forks. Each of these fat bike suspension forks has both strengths and weaknesses vs. their competition."
You are buying a new fat bike and it comes with a RockShox Bluto or you can upgrade to a Bluto for very little money. This suspension fork offers good performance at a relatively light weight and it will make your fat bike a versatile four season machine that is a lot more fun to ride than a rigid fat bike.
"Thank you again to RIDEFATBIKES.ca for the opportunity to participate in this extended test ride of the best fat bike suspension forks currently available. Even after multiple test rides with each fork choosing between the Wren and the Mastodon to replace my Bluto was not easy."
"The Wren was a lot of fun to ride, when it worked. The burly 43mm uppers and 36mm stanchions inspired confidence and encouraged me to ride features that I have previously avoided on my fat bike. I like the idea of supporting a small company like Wren Sports and the ability to easily contact customer service for parts and support is a significant benefit of riding the Wren.
The major downside of the Wren is poor cold weather performance. All of the three Wren forks used during testing suffered from the same heavy damping and rebound as the temperatures dipped below O degrees Celsius.
By -10 degrees Celsius each test fork stopped operating altogether, even with the installation of a cold weather damper."
"The Mastodon is a polished and composed fork that worked FLAWLESSLY during testing in ALL trail and environmental conditions. It is the biggest, widest and heaviest fork of the test but the extra heft is not noticeable while riding.
The wide crown will not be compatible with some frames but I didn’t have any issues with my Fatback Rhino.. For me the limited travel in the PRO EXT 100 as compared to the Wren or the Bluto is the most significant downside of the Mastodon.
But we are still going to do follow-up testing the Mastodon PRO STD 120 next with 4.8in tires on 82mm rims as we just got word from an Industry Guru, this may indeed work. If so, the downsides for this fork completely disappear."
"The Wren was a lot of fun and I wanted to love it, but the inconsistent performance was a deal breaker.
The PERFECT Fit and Finish, Quality of Construction and Consistent Performance of the Mastodon PRO across a range of temperatures were qualities that I could not live without.
At the conclusion of this review period I purchased a Mastodon PRO suspension fork from RIDEFATBIKES.ca and I look forward to many months of trouble free riding."
Author, Ryan Ellis.
TOTAL = 230 pts
Thanks again to Ryan Ellis for taking a few months during the Fall of 2017 and early winter 2018 to test all three suspension forks, compile his test results, and write his first online product review!
This 3-Fork Shootout Review was scored across a total score of 230 points, encompassing 6 main categories, and 36 sub-categories.
INNOVATION - 2014 belonged to the ROCKSHOX BLUTO because this suspension fork ushered in a whole new opportunity for fat bike riders, with its innovative suspension options. At the time of its release, the Bluto was probably the biggest revolution the sport had seen to date. This fork opened the door for more advanced frame and component designs, and Industry standardizations.
LIGHTWEIGHT - Weighing in at about 1 lb lighter than the competition, this cross-country inspired design is a good beginner fork to get into the sport, and comes in at a low price point. Downsides - The lighter weight comes at the expense of durability and fork flex, and this fork is more prone to bottoming-out than the other forks tested. The Bluto's ride quality was not expected to compete with the Wren ATK or Mastodon PRO on demanding trails, but it was the baseline for our test.
DURABILITY ISSUES - The most common repair issue is the bushings tend to wear out quickly, and create play in the fork. All-in-all, the Bluto RCT3 certainly is an improvement upgrade over using a rigid fork, for trail riding enthusiasts.
After owning a Bluto for several solid seasons of riding... riders that upgrade to either a Wren ATK or a Mastodon PRO for more gnarly, aggressive trail riding, should almost instantly see a boost in Ride Quality.
This fork is like a classic muscle car in a way... it can be a lot of fun to own, has its handling limitations when compared to the latest sports cars, might leak oil from time to time, and can require considerable wrenching to pull off that V8 performance. Yet it always has that "wow" factor for its unique look.
The Wren ATK fork did place a respectable second overall, and placed first in the categories of :
That said, this fork has so much potential if quality control levels were maintained consistently. Unfortunately, we ran into several issues, which ranked the WREN ATK last in several categories including :
When you are dealing with a catalog product, like the WREN ATK series suspension fork, it can be tough to get engineering support, because the OEM manufacturer (MEKKEM SASO Industrial in Taiwan) owns the rights to the fork, and determines things like quality control procedures during production runs. The state-side manufacturer has very little control of QA (Quality Assurance). The creator of this suspension fork (the owner of FATLAB) apparently, by summer of 2017, stopped plans to produce the next updated version of this modular-designed fork. The latest design was version 5, called the "TWIN-AIR". You can read more about this on the Internet, at many places like THIS LINK , or if your Deutsch is not up to speed, throw it in Google translator and get a rough English equivalent here : THIS LINK . (scroll down to the "FATLAB01" entries... starting at 21 FEB 2017, and it goes on for several pages - from their you can pick up the full story of this fork through some Google searches...)
If you own a Wren ATK fork and purchased it prior to the summer of 2017, chances are it works quite well. If anyone had issues with their fork, we tried our best to swap it out for a replacement, and with a 2 year warranty, everyone is encouraged to contact WrenSports LLC if they have any issues, as Wren does a good job of fielding customer service issues and warranty returns.
HIGHEST SCORING AREAS :
LOWEST SCORING AREAS :
The poor cold-weather performance was found on both the 110 and 150 models we had set aside for this review, on bikes in multiple provinces, so the issue was not isolated to one location or source. Adding the "extreme" cold-weather damper, had no affect. Forks still froze up between -5c to -8c, as noted earlier in the review. Neither the factory that makes this fork, nor WrenSports LLC employees could explain why this was happening.
Update: (9 MAR 2018) The MEKKEM SASO factory initially told us that they were going to manufacture a fork to show us they can pass all the test criteria in this review, including cold weather testing. We received an email tonight from the Wren OEM factory, that after almost a month of waiting, they are not in a position to send us a fork to test.
Update : (9 MAR 2018) FATLAB has taken their own suspension fork off their website, and replaced it with the Manitou Mastodon PRO, in all their photos.
I suspect a lot of Wren owners have been caught by surprise at these results. I was too. As I said before, I own a WREN ATK, yet I voted for MASTODON PRO once we really got into the testing. The winner was emerging early on, and the MASTODON kept in the lead. MANITOU did their homework. The MASTODON PRO suspension fork was literally flawless from a consistent, reliable, performance perspective.
This WREN ATK fork lacks the latest tech advancements and refinements. It's also the most expensive fork in this competition.
People are willing to pay for a premium product, but they will demand premium results. As the most expensive fork in the competition, we expected better build quality, refinement, and consistency. I've owned several Wren forks and prior to summer 2017, they generally worked better out-of-the-box, than as of late.
Because of the inconsistencies WrenSports LLC is currently working through, we are offering a sale discount of 30% off on the the remaining forks in inventory. They carry a 2 year warranty directly through the manufacturer. You can order via our Contact page.
The decision Ryan and I had to make was a tough one, but we feel it was the correct one, and stayed true to what our goals were when we set out to perform this extended test.
REFINEMENT - "2018 belongs to the MASTODON PRO. With refined execution in build quality, that results in excellent fit and finish, along with consistent problem-free and sure-footed control, this is currently the fat bike fork to buy if you don't want to roll the dice with your money."
CONSISTENT - The ride quality of the MASTODON PRO was excellent. It consistently performed as expected, and worked down to -18c in cold weather riding with zero issues. The axle design and clamping system is fantastic. The MASTODON PRO offers both High and Low Speed compression, at the same time, and this is a difference maker for many riders.
On the MASTODON PRO, there were no issues with any 150mm TA hub designs. The dropouts measured exactly 150mm across when unbolted. The shipping box protects the fork well while in transit against scuffs and scratches, and arrives at the customer's door with good presentation and a nice collection of setup information guides and charts.
The main drawbacks on the MASTODON PRO would be :
I think Manitou could revisit their AC HEIGHT / TRAVEL charts and update for riders using 80-83mm rims from many popular wheelbuilding brands, on the most popular tire sizes. I think this update could save riders 20mm of AC height, and/or gain 20mm of travel, increasing the performance and handling of the fat bike it is installed onto. Many bikes with PRO EXT forks, just might have done fine with the PRO STD versions instead.
All in all, if this suspension fork can fit on your fat bike, and weight is not a deal-breaker, it is a safe bet, that offers very good performance and excellent build quality.
Comparing Control Dials and Axles
Comparing Control Dials and Axles
If you read this far, I will give you some very important information if you are still trying to figure out "Which fork will fit on my bike ??". The difference is much closer than you may think...
Some handy items to make this measurement easier :
It is very important to get the horizontal measurement precise.
NOTE : This measurement is to the lockout level switch, on the right side of the fork crown, which would be the first item on the WREN ATK that would hit a frame, should the clearance not be sufficient, in a 90-degree turn.
NOTE : BOTH of these items need to clear the frame down-tube, in a 90-degree turn, to the right.
We are in the process of making Autocad templates for this, that can be printed out via PDF, cut out on a piece of paper, and taped to the frame to see of there is collision or clearance. Once done, we would encourage people to contact us via email for a copy of these guides, and our only "ask" is that you email us back and give your Year, Make, Model, Size of fat bike and let us know of the forks would clear or collide with that frame. We will build a database from this information and post it online for everyone to use freely.
... time to go Riding !!
... time to go Riding !!
THANKS FOR READING OUR REVIEW...
CONGRATULATIONS TO ALL THAT GUESSED THE MASTODON PRO EXT 100 WOULD WIN.