WRP Mullet yoke for Specialized Enduros
This review focusses on the Williams Racing Products (WRP) mullet yoke for the 2020/21Specialized Enduro. I do not want to debate the mullet (27.5 rear, 29 front) vs 29r because I already knew going into the test that I prefer the mullet set up on my Enduro. I devoted some time to why I prefer small rear wheel big front wheel, but mostly I'm going to focus on what this WRP link does and how it performs compared to the regular Specialized link in a mullet set up.
History of my mullets
My first mullet, other than grade 11/12 at Earl of March High School in Kanata Ontario, was a 26 front/24 rear on my Banshee Scream, many skinnies and flat drops ago. I don’t remember much about the set up other than not liking the climbs nor the unstable ride. In 2018 I put a 27.5 wheel on the back of my Enduro 29r while keeping the 29" wheel up front; I loved it right away. After one ride and a bit of research I slid the saddle forward in hopes of increasing the STA, I dropped the stack height by slamming the stem to the head tube and I decreased the stem length from 50 to 35. This gave me a much better ride with the MX wheel set up. The one thing I liked most about that mullet was how great it felt on steeps, both rolling in and turning at the bottom. The rollover was a treat because I did not have to worry about my seat getting buzzed by the rear tire; the turns were more aggressive, sharp and controlled which made me feel like I was accelerating out of them faster. After a few months I had to give the 27.5 wheel back and I rode the Enduro 29” front and back. This was the bike I used for my Ohlins air vs coil article. After about 30 minutes on the first ride I settled back into loving the bike in its original form and never missed the mullet except when my ass got knobbed.
When I got my hands on a 2020 Enduro, I rode it stock for about 35 rides before I obtained a 27.5” rear wheel. I put the smaller wheel on, made the same adjustments I performed on the 2017 Enduro and proceeded to the mullet love zone. The joys of mullet past were far surpassed on the new bike. I felt like I was able to ride my steep gnarly trails more aggressively since it felt like the bike tipped into corners on steeper lean angles and made tight corners easier and a lot more fun. I had more confidence knowing I wasn’t going to have to deal with tire buzz and I also felt like I was able to pop the bike up over rocks, logs and anything else in my way. It made me want to get more air off side hits than I normally would. I rode this set-up for about 30 rides before I got my hands on the WRP mullet yoke specific to 2020/21 Specialized Enduros.
Mic Williams is the W in WRP. After a few emails I know I wanna ride with this guy. He exudes passion and for some reason I think he rips. In addition to the Enduro mullet yoke, Mic and company manufacture stems, chain guides, drop outs , shock hardware, a centre hub device, a new centralized shock bushing, linkage yokes for mulleting Commencal Meta TRs and AMs, two turntables and a microphone - ok not that. In addition to the benefits of mulleting the Enduro here is what Mic claims will happen when his yoke is installed on the Enduro: it “maintains the stock progressive curve, however it sits in the higher leverage portion of the respective path. This results in slightly more beginning stroke with slightly less ending stroke. On the trail, this means a plusher feel off the top that handles the rough nicer than stock. Ending ramp can easily be maintained by adding a small amount more air pressure or by adding tokens, or a wind or two of coil preload.”
The 6061-T6 aluminum link increases the effective length of the shock so that the bike will sit higher in the leverage curve due to the smaller wheel size. The hand polished links have Enduro bearings hand pressed into the link. An extra set of bearings comes with the link.
This section is for the Tim Colemans, Mike Wallaces, Uncle Daves and all the other enginerds out there. I got Mic to give us (not me - you ya nerd ) an explanation and some graphs and some big words. Here ya go:
Regarding the graphs. These (like all my kinematic graphs) are modelled on Linkage software. We've found this to be most accurate and have the most utility. The stock bike can be modelled/found in the online library and from there we can tweak the coefficients depending on what the end goal is - in this case attempting to reinstate 29'r geo while running a 27.5 rear wheel. We can see mathematically and in visual real time how our design alters the bikes kinematics to ensure we're not designing in undesired effects. For clearance and kinematic reasons, the maximum length we could make the Enduro Yoke was 5mm longer than stock (or about 80% of what would be needed to reinstate total 29/29 geo).
- Axle Path (magnified): We can see from the graphs that we can achieve a 4mm of travel and an extra 2mm of rearward axle path when using our yoke. As noted, this graph is magnified; the best way to visualise this is, if the blue line was moved down ~16mm the two lines would overlap and the blue's starting point would be proportionally (~16mm) lower (to account for the lower axle of the smaller wheel). It also ends proportionally lower (less forward "hook" at the top of the travel) with the smaller wheel so less "hang-up" on the big holes. What this also means though is that a 65mm stroke shock can also be ran (instead of the stock 60mm) due to the extra clearance (it can keep following the pink line to its max value).
- Leverage ratio (magnified): The leverage ratio is proportionally higher throughout its range, hence why it feels a tad plusher with the same spring rate. Again, this is magnified (like the previous explanation), so if the blue line was moved over ~8mm the two would overlap (like a ven diagram analogy). Progressivity stays similar to stock, it just sits in the higher leverage portion. A couple of pro's who ride this set up left pressure the same and added 2 clicks of LSC, for any customers/readers looking for a reference.
-Anti-Squat: I have modelled this in a 34/50 gearing to give a real world example of the kinematics in a real world climbing situation (note: gearing does not affect the axle path or leverage ratio at all). What's also important to note in an anti-squat graph, is that when climbing/pedalling, the rider is usually at 0mm travel (climb switch on). Therefore, while our Anti-Squat value decreases throughout the travel more than the stock yoke, the important figure to look at is at 0mm travel; in this case they are identical (121.4% vs 121.6%, respectively).
Okay I'm back.
Additional gear for the set-up
After having a lot of success with the Race Face Turbine R35 in 29 inch from my wheel review, I got hold of a 27.5" version for my mullet and a Maxxis DD High Roller 27.5" anchor.
When I did a long-term review of the Santa Cruz Nomad V last spring, I loved how poppy and playful the 27.5 wheel bike rode. I really wanted to like it as my future bike but when I got back on my Enduro I liked the Enduro's plowing and tracking much better than the Nomad's ability to do the same. What I missed was the poppy playfulness. That's where the mulleting of the Enduro came in to give me what I wanted. I find the WRP link gives me a similar to plowing feeling that the 29'r gives more than mulleting without the link. I assume it is because the link is engineered to keep the 29'r characteristics very close when riding the linked mullet. I had to keep the BB flip chipped on high when I mulleted the Enduro without the WRP link which changed the ride in a subtle way. When climbing in high, I lost a bit of traction but I gained a clearer path with less BB shell and chainring strikes. With the WRP link I get all the traction on steep technical climbs a bit less BB/ring striking and a way better feel than the unlinked mullet gave me climbing. When descending the link makes the rear wheel stick to the corners better than when mulleted in high BB position. As for Mic's claim that the link gives a "plusher feel off the top that handles the rough nicer than stock" I can attest that I did notice this but I still think the 29'r stock set up can handle the rough stuff at high speed better than the WRP-linked mullet can. It is close but a little better in stock set up. That's my technical science-based term - a "little." For that small sacrifice I would choose mulleting everytime.
As a 29'r the Enduro is just fine but I want more than fine, I want finer so I will stay with the WRP mullet yoke set-up. All of the mullet pros outride the one high speed chunder con. If you are going to mullet your Enduro, I highly recommend getting the WRP link from Williams Racing Products.
Cost is $295 AUD or about $270 CAD/$220 USD.