Wheel meat again

Getting a handle on Pacenti’s 650B mission

The meaty matter of wheel size seems to stir up all sorts of passion and emotion. I reckon there’ve been more derogatory comments about 29in wheels on bike forums in recent years than on any other subject. Those 26 v 29 battlers make mountain bikers and roadies seem like empathic twins in a fully functioning family.


Of course, much of the debate is simply light hearted banter. The rabid vitriole is just a front to disguise other personality issues. As far as I’m aware, no murders have been commited to back up arguments and most of us just get on with riding our bikes, regardless of how big, small or otherwise superior our wheels appear to be.

The funniest wheel size response I saw on a forum was when the idea of 650B wheels started to get coverage. A vociferous evangelist of 29ers chimed in, apparently without a hint of irony, with “Why the hell do we need another wheel size?”

650B wheels fall half way between 26in and 29in. In other words, tyre edge to tyre edge diameter is about 27.5in. An open mind may look at the much talked about pros and cons of 26in and 29in and conclude that 27.5in is a pretty good compromise in terms of comfy rolling rhythm without the problem of fitting bigger wheels into smaller frame sizes. US custom frame and lugs specialist Kirk Pacenti (http://www.bikelugs.com/) and other 650B evangelists are likely to tell you that this would be the wheel size we’d have gone for if we’d designed MTB wheels instead of going with what was already on those original clunkers.

Anyway, coming from cyclo cross in the days before MTB history began, I’ve always had a soft spot for bigger wheels. I like most 29ers, but I often get the feeling that other differences on the bikes are more significant than the wheel differences. So I asked Kirk Pacenti to build a frame to my own geometry specs. It’s designed for 650B wheels, but an eccentric (position adjustable) bottom bracket and different forks means I can mess with different wheels without unduly upsetting the geometry.


I currently have it built with a 29in wheel up front, wrapped with a 2.55in WTB Weirwolf tyre, in a 26in Pace rigid fork, and a 26in wheel at the back, again with a 2.55in WTB tyre. I have two sets of Pacenti’s own 650B tyres so I’m currently building a set of 650B wheels (Stans rims & Hope hubs) to accommodate the tyres. Over the next few months I’ll be trying every conceivable wheel, tyre and rigid fork combo. Hopefully I’ll be able to come to some sort of rational conclusion about which sizes I prefer, and why. There again, I may just end up concluding that other things are far more important than wheel size 😉