[cjcrawford]

I've seen several articles stating that a wider rim yields better performance at a small weight penalty.

Does a wider rim help the bead sit better?
Does a wider rim change the profile of the inflated tire cross-section enabling a larger contact patch?

What is the ideal XC rim width from a performance point of view for hardpack, rocky,
Colorado trails if one doesn't care much about a few extra grams.

Thanks everybody.

Chris
Denver CO

 

[Vmax911]

Sorry, I've got no info for you. But I am interested in the answer to the question. So consider this a free bump.

 

[keen]

I have seen numerous veiw points on rim vs. tire width. I run a 21mm+ internal width for tires greater than 2.2", less and the rim width.can go smaller. Really depends on the tire size.

 

[Alias Pauly]

I'll have a go at answering this. I've got 2 wheelsets, a cheap set with 21mm rim width and a set of easton havocs with a 28mm rim. The wider havocs flatten the tires out alot, they increase the contact patch and the internal volume. I have the same tires mounted on both wheelsets at the moment and the ones on the havocs look a whole size bigger, ie, the 2.2 tires look like 2.35's on the havocs. So for the same weight of tire I get all the advantages of a bigger tire, ie, more traction, softer ride, etc..

So I can ride on a 2.1 race tire, and not have to worry about pinch flats because the tire is the size of a 2.2 or a small 2.3. This is good for me because I'm pretty heavy, for a lighter rider it may not matter as much.

One last consideration is the effect it has on the way a tire rides. I tried 2.35 high rollers on my skinny rims and hated them. The transition area from the centre to side knobs was huge, and it felt like I was washing out as I leant the bike over, until the side knobs caught and arrested the slide. Not very confidence inspiring. With the wider rim the tire is alot flatter on the tread, this means the side knobs engage a lot sooner when you start to lean the bike over. You can feel them grab as soon as you tip the bike in. Like a totally different tire.

Oh yeah, I think I actually measured the same tire to be 5mm wider at the tread with the wider rim.
Hope that helps.