So wide rims are the latest trend in wheels, but I'm not sure I understand the advantages unless they are paired with particularly fat tyres. Surely a normal (say 2.3") tyre on a 35mm internal diameter rim will have a less 'pear shaped', more circular cross section, therefore exposing the sidewall to greater vulnerablity from sharp rocks, etc?

Anybody have experience of these contemporary wheels?

Yes. I run an ikon 2.35 on a 35mm rim on the front at between 12-15 psi. It's much squarer in shape and does seem likely to roll off the rim at those pressures like it would on a crest or arch rim.

Don't understand the idea that the dude walls are more vulnerable though.

I don't think it's as easy as just saying 'wide rims are better', as with most things in life, a balance is required.

Wider rims will generally support a tyre better but the tyre needs to be wide enough for the rim, otherwise (as you say), you end up with a squared off tyre profile. A couple of mm here and there isn't going to make that much difference but once you start to reach the 28mm - 35mm widths you really need a larger volume tyre to take advantage of the extra width. I've found 2.4" X Kings to be a prime example ... you can fit them to a 23mm rim and they'll be fine but fit them to a 35mm or wider rim and they come into their own.

I agree with stu, wider tyres seem to work better on wider rims.

I have 35mm rims and find a scwhalbe 2.35 gives a nice wide profile, slightly squared off. I also have a spesh 2.3 on the back and its come up very narrow and any perceived advatage from the wider rim is lost. But I've bought that tyre now so its getting used.

35mm upwards does mean you can fit up to 3" tyres should you see fit.

I've run the 2.4 x kings and the ikon a come up bigger. Both good tyres though

I use a 2.4" Ardent on the front - when I swapped from a Stan's Crest (25mm) to a WTB i25 (30mm) rim it made no discernible difference to the overall width of the tyre. Shoulda gone wider...

Remember when Keith Bontrager rose to fame as the bloke who re-rolled skinny road rims to 26" sizes so we could ditch our wide ones?

I'll get me coat....

Out of interest, how do you (collectively) find the side walls for 'fretting' of your chosen tyre.

I've never really had major problems with Maxxis but obviously havnt used every tyre ever. I have a racing ralph pacestar-evo--27-longname-TLR that seems to be holding up well and has been on the back and front.
The specialized fastrack 2.3 is showing the fret lines after a couple of hundred miles, not the best imo (it also came up like a 2.1)

I think Specialized tend to suffer this. They are relatively light and I quite like the way they perform (the ones I've used) but they are prone to cuts and sidewall tears IME.

Maxis Ikons (tubeless) are constantly puncturing on the rear with sidewall problems. Confusing number of variations in each model (why do you need 8 different types of 2.2 tyre?) and hard to get hold of at the moment. Might go back to Schwalbes; better value as well.