kyselad

I have some new 700c x 45mm VO hammered fenders sitting around that I would love re-radius and mount on my commuter with 26 x 1.75" tires. Adjusting the radius seems pretty straightforward based on info in other posts here and elsewhere online, but what's not clear to me is how much the fender is widened during the process of reducing the radius. Are we talking 1-2 mm? Several mm? Based on the actual tire and fender widths I see when holding the fenders up to the tire, I would need to gain ~5 mm to get reasonable clearance.

I know this is a big jump from 700c to 26", but they're the fenders I have on hand, and I'm hoping the big jump will help me by translating to more width. Anyone have practical experience on how much widening I can expect?

lonesomesteve

I've re-radiused Velo Orange 700c fenders to 650b on a couple of occasions. I didn't measure the difference in width, but it was hardly noticeable. 26" isn't a lot different than 650b, so I highly doubt you're going to get the 5mm width increase you're looking for.

Also, I've had a couple of the VO hammered style fenders crack after heavy re-radiusing. Something about the stamped-in "hammered" pattern makes them a little more susceptible to cracking, me thinks. Granted, that was years ago. They may have since changed how they do the "hammered" look (it's certainly not done with a hammer). Since then I've always used either the Zeppelin or the smooth style fenders, and have never had cracking problems with those.

brooklyn_bike

IME you don't get much additional width from re-radiusing fenders. i've never gone from 700 to 26 but i have gone from 700 to 650b several times. the additional width gained is tiny (hard to estimate maybe 1 - 2mm) if you need 5mm you prob need dedicated 26" fenders or you can always try the 700c fenders you have on hand and run them a little higher off the wheel than usual - i've seen some bike riders do that to get some fenders to fit

kyselad

Hmm, I hadn't considered that the hammered fenders might be more prone to cracking with re-radiusing. Even if they've improved things lately, I've probably had these sitting around for 5+ years at this point, so maybe the same issue.

kyselad

Could definitely run them a bit high and make it work even if the width didn't increase at all, but not sure I want to sacrifice these fenders to this project if it's going to be a crap fit. The problem is 26" fenders are hard to find, especially up here in Canada. A local shop had 650b x 52mm Zeppelin fenders at some point, so maybe I'll see if they can get those since width is good from the start and it would require less drastic re-radiusing.

rhm

Changing the radius of a fender is pretty simple. If you want it to fit a smaller diameter wheel, you make it a little wider.

Measure the inner width of your fender, that is the inside diatance between the rolled edges at the sides of the fender. Cut a small stick of wood (like as big around as your finger) to a length just a little bigger than what you measured, and jam it into that space; and then slide it along from one end of the fender to the other. This will widen the fender evenly and reduce the radius. You may need to repeat the process with a series of longer sticks until you get it just right.

I did this with a pair of aluminum Velo Orange 700c fenders that i now use on a bike with 26” wheels. No problems yet after 7 years.