40mm with a 72 degree headtube angle
37mm with a 72.5 degree headtube angle
34mm with a 73 degree headtube angle
31mm with a 73.5 degree headtube angle
28mm with a 74 degree headtube angle
If you've converted an old road bike to fatter 650B tires but still have high trail steering geometry you're only getting half the joie. With fat tires, a front load, and a low-trail front end you can see what all the Frenchy fuss is about.
For those unfamiliar with the P/R forks, I've included some pictures below. They have double eyelets on the dropouts, mid-fork braze ons for low rider racks, and threaded fender mount underneath the fork crown (very handy), and braze ons on the top of the fork crown for rack Kogswell is developing specifically for the fork. The fork crown affords room for a 50mm fender. I've put both Gran Bois Hetres and Panaracer Fatty Rumpkins under a 50mm fender of this fork. Both fit, the Rumpkin was a little tighter than the Hetre.
Forks are $65. Shipping is $10 to the continental United States. I can have the forks threaded for $40, but I need to know the exact length of the headtube (plus any spacers you plan on using) for the bike the fork is destined for. I also can ship the fork directly to a good powdercoater or painter if you don't have one in your area.
Keep in mind 1" threadless headsets and stems are readily available, so don't dismiss the idea of changing your setup to threadless. The steerer tube on these forks is huge (400mm), so you won't have any problem putting your handlebars wherever you'd like should you decide to go threadless.
For those that can't wait for the Kogswell front racks I haven Nitto M-12's for $60.