I had to test this for myself, and I did a week ago. I have a Mavic MA2 13mm internal width wheel on hand, and I mounted a 35mm Marathon Racer tire on to the same 40 psi I ride on my road bike with Mavic A719 rims @19mm inner width. Yea sure, they mounted just fine, but glaringly apparent was the width, the lack of it. Only 30mm on the MA2, and it just looked all wrong as it was so skinny that the tread was rolling over the sides. It's 34mm on the A719 and the proper shape. While sure, on the MA2 it may be considered relatively "safe", but seeing how the tire wasn't capable of being shaped normally, I saw no point in it and no way I'd want to ride it. Just because it can be put on a rim doesn't mean it's a good idea. I tried this as I too was contemplating some Mavic road rims that are all 15mm inner, but after this, no thanks. A 17mm minimum for me with 35mm-45mm tires. So for another road bike w/130mm rear spacing I bought a set of Mavic Aksium wheels that come with a 17/23mm inner/outer rim. Mavic is so behind the times in regards to making retail rims for sale that are in the 17mm range. It's been 15mm for up to 28mm tires, or 19mm for 28-47mm tires since the 90's, at least ! On Thursday, October 9, 2025 at 5:06:17 PM UTC-4 Ben Miller wrote:
> 40 mm tyres on 15 mm inner rims all laced to a power meter hub?? I want to > see a photo of that! > > IDK, but I say if you can get a tyre seated on a rim, it doesn't really > matter what the rim width is at the lower end. Though at low pressures and > supple sidewalls you may have excessive tyre squirm when cornering. But if > you like the handling of them currently I wouldn't lose sleep over it. > Though I also don't know that I'd recommend rebuilding the rear wheel > either. Maybe sell the off to a weight weenie and acquire a new wheel set?? > > On Thursday, October 9, 2025 at 1:55:17 PM UTC-7 [email protected] > wrote: > >> I just acquired a soma san marcos with mavic open pro rims, inner rim >> width of 15mm. >> >> I immediately put 40mm tires on it, and have been riding it for a few >> weeks as I dial in the build. >> >> It has a cycle ops power meter rear hub, looks gross, so I was planning >> on rebuilding the rear wheel with a cuter hub, but then realized I was >> fully in violation of the acceptable range of tire width for this rim. >> Should I just get a different wheelset? >> >> the rim widths recommended by rene herse and sheldon seem to be >> conservative at 15mm but then generous at 17mm, idk, is anyone cheating and >> getting away with it? >> >> >> -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/rbw-owners-bunch/3a9e7a8c-b0f7-41b7-bf76-668f8b9f1d17n%40googlegroups.com.
