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Im lucky enough to have several bikes with different wheel sizes.
Im currently spending a lot of time riding my Cube Stereo 650b, and my Orange Gyro 29er.
I have been looking at new wheels for one or both of these bikes. It seems that modern tech and manufacturing has made wide rims very popular. I like the idea that they can make a wheelset stiff, and make a tyre wider. However herein lies tge problem.
Surely a tyre is designed for an optimum rim width so the inflated tyre has the correct profile and all its exquisitely engineered knobs in the right place?
How will i know if a wide rim and tyre combo will fit between my chainstays? How can i predict quite what i will be getting in terms of a final width?
It makes less difference to width than you'd think based on all the hype.
I did a compare of the same Butcher 2.3 on a Lightbicycle 33mm vs a Roval Traversee, 22mm ID. Both tyres with Butcher Control 2.3s on 'em. So basiacally a traditional width and a modern wide-but-not-fat.
The important number for frame clearance is probably the tyre width at the knobbles, as that's where they frame's generally tightest. And the difference is .3 of a mm! 57.2 on the LB vs 56.9 on the Roval.
There's more difference to the actual carcass though. On the Roval, it's 55.8mm, actually narrower than the knobs. On the LB it's 58.2
Oh, and in terms of tyre shape, I can't actually see any difference. Couldn't think of any way to measure it. Perhaps height drop from the centre to the edge blocs? But that's a bit unintuitive. I can't personally feel any difference beyond what you get in small pressure variations.
(fattening the tyre is probably a bigger deal on badly designed tyres with roundy edges where it could get over the shortcomings a bit. No coincidence that the pinkbike article that raved about this was using Hans Dampfs I think!)
I found some pitchers. Do these help?
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Think of your tyre profile as a triangle with the contact patch as the peak. It's much harder to push over a triangle with a wider base than it is a taller, narrower one.
So no, not much visible difference to tyre width but a tangible effect on stability if you like to smash corners so hard you can hear your tyres trying to escape.
I borrowed some wheels with some wide ass rims and swore I couldn't tell the difference. Then I put my own wheels back on and could feel the tyres wiggling and squirming in hard corners.
Thanks for the replies. I understand the advantages, but was really concerned that i might fit a wider rim, and then have to fit a narrower tyre as i had broken some previously unconsidered law of physics.
All the hype seems to suggest that a tyre grows to galactic proportions and that you will struggle with frame clearance.
I will try some wider rims and post back, but in the mean time im still interested in pitfalls and clearance problems or gains.
thanks
All the hype seems to suggest that a tyre grows to galactic proportions and that you will struggle with frame clearance.
I found that there was quite a difference between my Mavic XM319 (19mm internal) and an EX729 (29mm internal)....that 10mm extra base on the tyre bulged the sidewalls out a ridiculous amount, tread width didnt change but i was far more conscious of roots and rocks tearing at the sidewalls that seemed to extend way beyond the knobbly parts of the tyre on the wider rim.
I have since gone to a happy medium and run a 23mm internal rim width.
You need to try 45mm rims & 29+ tyres for ultimate grip*
*second only to 4"+ tyres
Deviant, im currently running mavic 319s. Can you quantify how much wider the sidewalls went?
Did the tyre look more square in profile with the wider rim? It seems like it must have gone quite a bit wider on the wide rim if you were aware of catching the sidewall?
How can i predict quite what i will be getting in terms of a final width?
You need Weird Bike Tool No.27:
[url= https://farm8.staticflickr.com/7336/16517694651_33c83be444_z.jp g" target="_blank">https://farm8.staticflickr.com/7336/16517694651_33c83be444_z.jp g"/> [/img][/url][url= https://flic.kr/p/raBv9P ]Untitled[/url] by [url= https://www.flickr.com/people/10954782@N00/ ]Ben Cooper[/url], on Flickr
bencooper.....tell me more!
It's a special gauge for measuring rims and tyres to find the actual inflated width:
http://www.wheelfanatyk.com/blog/wheelbuilding-tip-17-understanding-tire-sizes/