32" Wheel impressions and who they are for

Everybody’s Talking 32”

Last April at Sea Otter (the big bicycle industry trade show in the US), I chatted with the folks at Maxxis about a new 32” tire size they would be producing. A few weeks later, I had a prototype set of tires and some parts to build wheels on the way. I was excited since a lot of my bicycle nostalgia centers around the time I got on my first 29er. It was a rigid steel frameset with one gear and mechanical brakes. I must have scraped it together for less than $1000  – all the money I’d made flipping old road bikes into colorful fixies back when those were hot – and I’ve been chasing the disproportionate amount of fun I had on that bike ever since.

Things got busy, though, and as I pondered the design more, I became a little less inspired. At the Made bike show, some fellow builders like Cameron Falconer, Btchn bikes and Neuhaus dropped their very cool 32” creations, but that moved the needle even a little further back. They just looked BIG. Still, there is always something to be learned, so the CAD file I had started in April got some updates and I started thinking more about the concept. As the year wound down, I had a little more time. I started setting some tubes aside for the build. I decided to use a PBJ fork since it has ample clearance for these big honkin’ wheels. I decided my use case would be a bike for riding the Marin Headlands. 

Use Case: XC for the Headlands

For those unfamiliar, the Headlands is the closest dirt riding area to San Francisco. After a couple miles of pavement, across the Golden Gate Bridge, and up a short but steep road climb, there are beautiful rolling dirt climbs and descents with some occasional ruts and fun singletrack cuts. For me, riding my MTB over all that road is a little annoying. I ride it more than anything on my SuperSomething Gravel bike with 700 x 50mm tires, but my favorite has been the rigid PBJ with a fast rolling 2.6” tire. 32” seemed to promise a faster-feeling road ride combined with the benefits of the 2.6” tire and a faster-rolling, narrower tread. Sounds pretty cool, yeah? A fast, rigid, XC bike. I finalized the design and started to build the frame.

Geo Talk

So I got to work building my frame. I hadn’t built one in a while and it was fun to watch the muscle memory kick into gear. When we moved the shop to San Francisco, I sold a few milling machines that made the process go quickly; I was back on the very basic and first machines I ever bought - My two Benchmaster Mills and the old Southbend Lathe. I was pleasantly surprised that it still went pretty quickly and things went together smoothly. In a lot of ways, building for 32” is not that special. Of course, the massive height of the axle requires a whole lot of bottom bracket drop, nearly maxing out my jig at 96mm, and a long rear end. I built this frame with 445mm chainstay length (with the dropouts slammed) or 460mm (with the dropouts all the way back). To accommodate the long rear end, the seat tube has a dramatic bend, as well as a pretty steep seat tube angle. 

I used the PBJ fork because, well, I have a bunch of them on hand and they are super nice. In an ideal world, 32” bikes would use a fork that has about 70mm of offset. The PBJ fork has 52mm. At least I am not totally insane like the suspension fork companies who are going to produce 32” forks with 44mm of offset. That doesn’t make any sense (but maybe that’s not a conversation for right now). Anyway, that left me with 120mm of trail after a 66.5º head tube angle. I think I could have gone with a little less trail, but it feels good. I do get a tiny bit of flop when riding really slowly, but that may also just be the nature of these gargantuan wheels. To keep the wheelbase in check, I went for a 772mm front center. I think that’s a pretty good number for a 5’11” rider like myself on a more XC-style bike. I had just been designing our new XC hardtail (coming later this year), and this geo is pretty similar. I am excited for that bike – more on that later. 

Okay, that is a lot of scattered geo talk. Thanks for sticking with me.

The Ride

So how does it ride? The short answer: this is a fun bike. Immediately you notice the way that the wheels spin up and really build momentum. I especially feel it going up on dirt. It feels like a lot more traction, but not in a dragging way, almost like I was on a Mario Kart magic carpet accelerating me up the hill. That is, until I was about 5 minutes into the climb. As my legs got more tired, I did notice a feeling of resistance – maybe the leverage of the big tires pushing back on me? Not hugely noticeable, but not invisible.

Rollover

One of the most surprising things about 32” wheels was the rollover. I expected to feel a big difference, like my first ride on a 29er when rocks felt invisible. I expected to feel nothing as the wheels glided over every rock and root, but that isn’t what I felt. Maybe there are diminishing returns? Maybe my expectations were too high? It rolled over stuff well. Quite similar to a 29er, plus maybe 10-15% smoother. This is all subjective, so what that heck, let’s throw in some percentages. I will say that descending on rough and rooty singletrack felt substantially rougher and less nimble than my 29 x 2.6” PBJ not to mention the humungous tire dangerously close to your butt when you push the bike over something. I do not love the 32er for technical descending.

Cornering

I am still trying to wrap my head around how this bike corners. My first few rides were on singletrack with some tight switchback-y singletrack, and the large wheels are absolutely bad at that stuff. There is no getting around that. They feel big, they hit your legs. I mean, I was still having fun because I was on a bike ride, but personally, I would not consider these wheels for a mountain bike for this reason alone. On flowy singletrack and wide-open dirt roads, I was impressed with the cornering. You can definitely feel the traction provided by the larger contact patch, and that was nice. When I leaned this bike over, it really did dig into the corner, but I also felt like I was pushing against some gyroscopic force that was holding the wheels upright.

The Elephant in the Room

Let’s talk about it: these wheels do not work for anyone under 5’8” ish. I was going to say more, but maybe that’s enough.

So who is it for?

Looking back on these words, I sound quite critical; however, I have had some really fun moments on this bike that had me dreaming of its perfect use case. For me, that would be smooth, flowy singletrack or mellow dirt road cruising. I think a lot of people who want to go explore their neighborhoods and local trails without worrying about suspension maintenance could enjoy a bike like this, since the big wheels are very stable and you wouldn’t need suspension, which just makes things simpler and lighter. I know someone is going to say “tHe PrOs ArE rAciNg On ThEm”, but for me I would never ever ever ever use this as my only mountain bike. It just isn’t as fun and nimble as smaller wheels, and I ride bikes for fun.

Takeaways from 32”

When I finally did work up the motivation to build this frame, my main drive was to learn more about bike geometry. A lot of the ideas behind modern MTB geo come from things that 29ers forced us to do, and I was hoping to push my perspective in a similar way. I think it was cool to see that the driving numbers I base my designs around do translate across wheel sizes, and despite my critical take on the wheels, this is a super fun bike.

Will there be a production 32er?

It’s not looking like it. As a designer, one of the biggest things I aim for is longevity. I hope that someday all the frames we make at Sklar will make their way to a bike co-op donation and get reimagined as someone's commuter. I want to design bikes that use standards so someone can reimagine their bike in 15 years with parts they can get at any bike shop. I don’t see that being the case for a 32” wheel bike. Maybe I’ll eat my words in a few years, but for now, it’s a fun novelty I am glad I tried. There is always something to learn from trying something new.

Happy trails,

Adam