Wren Suspension Fork for Fatbikes

While the Rockshox Bluto fork I’ve been using on my Salsa Bucksaw since day 1 has been effective, it’s been a bit underwhelming. It worked fine on my local xc trails and winter rides, but when I’d ride more rowdy trails, it really began to show its limitations.

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It’s a little flexy, and I could deal with that under most conditions. Burping air out of the fork was a problem, though. Finding that halfway down a long, gnarly downhill that your fork has suddenly lost air and that it’s now mush and bottoming out far too easily isn’t good. Thankfully I had my shock pump when that happened, but that initiated a drive to look for other options.

Wren Sports acquired the old FOMN (Fork of Many Names) that was used/branded by Carver, 11nine, and others a few years ago. They’ve been making improvements to it pretty steadily. I have been aware of it for some time, but early issues kept me away. It seemed like Wren had made some pretty significant headway by making solid improvements recently, so I was willing to buy one to address the issues I had with the Bluto. Nobody else was really making an effort to address those issues. The Fox 34 plus fork would have worked for the Bucksaw, but would have required a new hub and a front wheel rebuild in order to use. If I was building a Bucksaw new today, it’s probably what I would have chosen. But I’m already invested in the 150mm front thru axle standard.

So far, I’ve been pretty pleased with that choice. For the Bucksaw, I got the 110mm travel, 150mm hub spacing version of the Wren with a tapered steerer. Salsa is pretty adamant about keeping the axle-crown at or below 511mm.

Currently available forks compatible with fatbikes and their dimensions:

Manufacturer Model Travel (mm) Axle-Crown (mm) Rake/Offset (mm) Stanchion Dia. (mm) Weight (g)
Wren 150 150 570 45 36 2259
Fox 34 27.5+ 140 545.5 51 34 1805
RockShox Bluto 120 531 50 32 1796
Wren 110 110 530 45 36 2154
Fox 34 27.5+ 120 525.5 51 34 1805
RockShox Bluto 100 511 50 32 1796
Cannondale Lefty Olaf 100 unknown 60 36 2290
Wren 110 80 505 45 36 2154
RockShox Bluto 80 491 51 N/A 1796
Lauf Carbonara 60 494 45 36 <1100
Cannondale Lefty (older) 70-110 480-520 45 32-36 varies

 

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The Fox 34 would keep the A-C closest without going too much shorter, but would require the aforementioned wheel rebuild. I opted for the Wren 110 as the next closest alternative. The Wren does add about a pound compared to the Bluto, but at least it’s not rotating weight. And, the inverted design of the Wren reduces unsprung weight, which should improve suspension performance.

I notice a couple things after a few rides on the Wren, with some pretty rocky terrain. The Bluto suffers from a fair bit of wheel deflection. I wasn’t aware of it at first, because I didn’t have a really good comparison on the same trails. But comparing the feel of the Wren to the Bluto, it’s definitely noticeable. That wheel deflection never caused me to crash, and it never ruined a ride, but I noticed once I rode the Wren that I was making a lot of small steering adjustments with the Bluto, and I had to learn to stop that with the Wren, because the bike tracked more precisely.

I also noticed improvements with small bump absorption with the Wren. I’m still playing around with suspension settings to get it exactly how I like it, but the Wren is much more sensitive to small bumps.

4 comments to Wren Suspension Fork for Fatbikes

  • I have a Wren 150/110 fork on my Fatboy (running it at 80mm currently to best match Specialized’s recommended/stock geometry). I agree entirely with your comments on the improvements in the ride over the Bluto.

    About the only thing that’s been a bit of a pain, however, has been that fitting the thru axle into place seems finicky. Sometimes it’s difficult to fit through the dropouts (both, or moreso the second dropout after having pushed it through the front hub). I always begin on the rotor side of the fork per Wren’s instructions; I’m using an I9 150mm front hub with the plastic adapters and a Surly Bud tire on a Nextie 65mm rim.

    I’ve also noticed that it’s possible to clamp the wheel into the fork with one side of the tire closer to the adjacent fork upper than the other (i.e., off-center), although I’m now very careful to center the wheel before closing the skewer. On several rides, even after clamping down the skewer with the wheel centered, the wheel has moved to that off-center position (sometimes indicated by a little chirping from the front rotor).

    It’s my understanding that Wren intends to offer an “improved” skewer in the coming weeks, although I don’t know if it was designed to address this issue. Have you noticed anything similar in your experiences? Any other thoughts? Thanks!

  • The GPS Geek

    Yeah, my skewer is a little iffy at times. I’m getting better at getting it in/out smoothly. What I don’t like about the skewer is that it can ONLY go in on the rotor side. I’ve been installing front QR levers from the other side for over a decade, and RS does their thru-axles that way. Fox and Wren do brake side, which I really dislike with disc brakes. There’s less space, increased chances of contaminating your rotor, increased chances of hurting yourself on a hot rotor or getting your fingers where they shouldn’t be, etc. I also have a nice DT RWS thru axle for 150mm spacing that I’d like to use, but cannot because of the hemispherical washers.

    I have not had issues with the hub going off-centered. I’ve got a Hope Fatsno 150mm hub that has machined aluminum endcaps and it always stays centered.

  • I had a long response to your note which basically mentioned how many of these new points you’ve made were things I’ve also noted. Unfortunately, the CAPTCHA Code said there was an error when I tried to submit the note — maybe I used CAPS for the characters when I shouldn’t have? — and it erased my note. Anyway, rather than recreate the note let me just thank you for your thoughts and mention that I hope the forthcoming “improved” skewer mentioned by Wren’s Russ Johnson in a recent email to me solves some of our concerns.

  • I own High Intensity Bike Shop in North Haverhill N.H. I am a rebuilder/service center for Wren.

    Prior to the Wren i used the Bluto..I switched to Wren about 8 months ago on my Personal Fat Bikes.I was so impressed with the Forks Performance i became a Service Center for Wren.

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