Observations on 32” inch vs 29” after shakedown on local trails
[Wow, you guys have been sharing this post in places? Loads of reads!]
It's true what the people say: it rides like a bike, but better.
After previous experience with a Jeff Jones 29+ bike on 32" wheels, today I got some daylight riding on my own bike, local trails. I came up with a build that's a mix of budget, performance and weight.
Setup (pic in comments):
- Steel custom frame "Furlong Overdrive"
- Thrust rigid carbon fork, 500/51 mm + 10 mm crown race spacer.
- 210 mm OneUP V3 dropper, my first dropper
- ZIINO carbon bar, 20º, 20 mm drop, 740 mm. Old school Dimension cork grips +bar tape on top.
- Aspen 32x2.4 front, Aspen ST 32x2.15 rear (see unboxing post)
- Luther/Sapim CX-Sprint carbon rim wheels (long term test set, see article in highlight)
- 1X10 Saint shifters, XT M8000 rear derailleur
- XT M8100 180 mm cranks, 36t oval chainring
- Goldix light 11-46t 10 spd
- XT 8100/8120 brakes, 180/160 with aftermarket rotors.
- 440-455 mm chainstays set in 440 mm position
- 12.1 kg without bottles. With a carbon frame perhaps under 10 kg, including pedals.
General handling, front end: Still getting used to it. It’s my longest Trail/slowest handling bike ever, albeit quick compared to modern XC bikes. I seem to be steering in too late, could be a matter of adjusting my timing, I’ve had this before. Actually the overall feel (at least on the road) is very similar to the 2020 Canyon Lux FS loaner I had yesterday. Similar front end geometry.
Aspen 32x2.4” front tire appears to not want to turn in, unless leaned. Once leaned, it grips harder on loose over hardpack vs my best 29” front tire. It will take some time to trust the Aspen more and understand what it does when pushed to the limit. May need to apply more steering input sooner and harder. Never had a hint of too low pressure, need to explore lower ones.
Being new to the whole bike I had some minor wash outs but the tire caught itself and no drama.
I have the Aspen on, only because of a race on sandy trails next weekend and I may go and pre ride this week. After that I’ll put the Aspen AT on which is more grippy to go after Strava segments and the like.
Aspen ST 32x2.15” rear tire looks narrow in 32”, but it’s not actually all that narrow. Full nominal 55 mm casing width. Uphill traction is phenomenal. Better than a 29x2.25” Schwalbe Rick XC Speed, by some margin.
Braking traction feels oddly weak compared to the spectacular climbing traction. I’ve not had the rear slide out, but I only get that with rear brake on, across my various bikes. I used the rear brake to get my front wheel to bite. Also never a hint of too low pressure, need to explore lower ones.
Rolling is better than I expected. I’ve not run tubeless in recent years and these are mounted tubeless, so that helps. I feel it most, perhaps oddly, when…
Climbing. Perhaps it’s a characteristic of the rear tire, but this heavier bike feels lighter uphill. My guess is that the trail surface is disturbed less from the smooth long contact patch of the Aspen ST.
Front center is significantly longer than on my previous bikes, while still shorter than modern XL and even L bikes. 32” pulls the front axle 12-13 mm aft vs 29” for a given steerer axis placement
Losses in cornering. I never gave this much though, until the losses disappeared. These Luther prototype wheels are very solid feeling, they disappear from the equation. The bike just feels like going around corners on rail, even on the road. It feels like significant energy losses from wheel flax affected me earlier, but no more. Every little corner seems to shed less momentum. The tires have a role in that as well, no doubt.
Comfort is in most cases better than my 29”/100 mm hardtail, despite similar length or shorter rear end on the heavy steel 32”er. It does have seat stay bends and a low top tube which may help a bit for flex. Hands are not shaking worse than with the hardtail.
High speed on gravel, it’s just amazing how smooth it is. One little passage on gravel and you’re DONE dreaming about 700c Gravel bikes. That’s the past now, or for the vertically challenged. Who in their right might would pass on THIS rolling performance?
Pedaling, I can’t say much about, as I’m SQlab 511 XL pedals running 15 mm wider axle pedals, just to have my heels clear the awkwardly wide chainstays. I now appreciate more why roadies just want their narrow Q-factor cranks no matter what.The difference between Road and XC I just never really noticed in that respect. It’s tiresome on the legs to have the pedals so far out, and it feels goofy. Got a pedal strike in a new place on the trail as well. It happens with the 29” bike as well (lower BB even with the fork fully extended) but in a different way.
Braking. Coming off older M785 2-piston brakes, these are an upgrade. The hardtail has 203/160 mm rotors but on smaller wheels. Despite the larger wheel and same 160 mm rear rotor, the rear does feel more powerful, out of the box. The front now with 4-piston on 180 mm vs 203 on the 29” hardtail, has literal bigger shoes to fill. I’m OK with the performance for now and hope it will improve with use.
BTW, I’d like to harmonize XC and Gravel 32” wheels at MTB Boost, and then have the same rotor sizes as well. 203 mm on Gravel may be asking for trouble so I hope to keep it at 180 mm.
The acceleration thing. Everyone and their sister will tell you about how it’s such a huge downside that 32” wheels will get to speed slower. Somehow, with a short run between corners, I am arriving at corners faster than I’m used to. I don’t know which physics would cause the slight weight penalty of 32” over 29” to overpower the ~9% reduced rolling resistance. People say they “feel” it. Or know it before trying. I just see big numbers on my speedo.
Overall. What the heck took this long? I was definitely on the right path 20 years ago trying to get 32” conceived. It’s been around for a while, but these high-end tires for it make a real difference.
Is the cycling industry anti-science? What’s not understood about the invention, application and appropriate sizing of the wheels ?
Perfect size? For someone, no doubt.
I believe, and have been for decades, that for XC the ideal wheels are the largest that result in a more or less workable bike for you. In recent years, front ends got a lot longer and now S size riders can deal with 32” wheels just fine. When I get wrapped up in the local Strava KOM battles, I may want to go bigger still and find out what’s possible. All it takes is good tires.
This is one heck of an upgrade. Better in nearly almost every way, but no-one is more biased than yours truly, so take that as you will.