Hi, I recently got a 1989 centurion le mans rather impulsively. I thought it would make a great winter bike to replace my crashed beloved bicycle, but there is NO clearance for 700c wheels and fenders. It's ugly but a surprisingly great ride! Anyway, I measured and put some ruined awful zac19 wheels with 38mm tires on the frame. It fits, but not at lot of space in the rear stays. I have read in many sources that 38mm is tight with the centurions (and many other frames). I have seen many photos online of similar era centurion 650b conversions with fenders but no details. So, those with experience, will fenders fit with 38mm tires or should I go with 32mm tires? I will be using Velocity A23 rims if it matters. I read that some tires are either wider or more narrow dependent on rims. I do not look forward to going to the bike shop and being lied to about how 32mm tires do not exist. I know the options are grand bois cypress or hutchinson 650b confederie, but if there are are any other options less than 38mm and are good I'd love to know. I'd also love to know if 38mm and fenders fit perfectly fine.

I have an '87 LeMans that I built up with 650B wheels just to see how it would work. My experience was similar to yours, 650x38 fit but it was tight.





It's been a couple of years, so the pictures are better than my memory at this point. Nothing in either of those pictures tells me that fenders would have worked well with those tires. You could probably squeeze them in. I ended up choosing a different frame for my 650B build.

FWIW, the pictures above are with 650x38 Panaracer Pari Motos on A23 rims. The A23 rims are likely to make your tires a little wider than spec. Mine are around 39mm.

650x32 tires certainly exist, but they might be hard to find. Curiously, the just announced Continental Grand Prix 5000 tires are being offer in 650x28. If you are going to be riding mostly on pavement that might be an awesome option.

I have a set of Gran Bois Cypres tires in 650B x 32mm if you're going to go that route. They're certainly not fatties, but their significantly fatter than 25mm tires that would be the max on lots of 80s road bikes. You can have 'em for cheap. Let me know.

Thanks!

Andy K, your past post was one that I referenced. And wow Continental are making 650b x 28mm and 25mm Grand prix 5000 tires!! I'm not sure that's my kind of tire as I ride on terrible paved roads, dirt roads and trails. I was hoping one of the main 650b tire brands would come up with a 28mm at least. As a tiny person tire width, cushiness etc are experienced differently and a 28mm tire might for me feel like a 38mm tire. 28mm an 25mm opens up options and could save me from having to consider 650c for some of my tiny road bikes.

jyl my husband did a 650b conversion with an 80's japanese bianchi and he cut, bent and spent hours on the honjo fenders to fit 38mm tires. It makes them a bit useless for my project because they've been custom hacked.

nlerner, I'd definitely be interested because I am having trouble finding the 650b x 32 cypress short of ordering from japan!