What’s the deal with the rim and tyre compatibility? Mavic has a page on their site about rim and tyre widths –http://engineerstalk.mavic.com/en/the-right-tyre-width-on-the-right-rim-width/

If you scroll down there’s a table showing a 25mm tyre shouldn’t be used on a rim with an internal width greater than 17mm, but I have seen company’s wheel spec’s saying that an internal width of 21mm width is fine with 23mm tyres.

Are the standards erring on the side of caution too much?

Some of it is probably down to ‘aero gainz’ matching tyre to rim size, I run 28’s tubeless on an 18mm internal dt swiss rim with zero tyre roll issues in hard cornering, 60 front, 65 psi rear. The tyre to rim shape probably isn’t perfectly aero, but that’s the least of my problems when road riding, lol.

Thanks wildc4rd, but I’m interested is tyres that are narrower than spec, rather than wider.

Sheldon is your friend.

Also bear in mind mavic are French, that means they will not stop doing things the traditional/old/outdated way, even if it’s patently wrong by modern consensus.

Wheel Mfrs are always going to err on the side of caution because they don’t want the liability and are unable to test every rim and tyre combo. I’ve successfully used tyres more than 2x rim width safely, but not all have worked i.e. the bead is too loose. I certainly would avoid putting a 23mm tyre on a 21mm rim – too much risk of railing on the rim

The Sheldon Brown table looks to be the same one that’s on the Mavic site.

I’m running 25c tyres on 19mm rims.

I’m running 25c tyres on 19mm rims.

That’s what I’m wanting to do – 25mm Schwalbe Ones on a 19mm inner width Mavic rim. I take it you’ve had no problems?

https://www.schwalbe.com/gb/reifenmasse.html

I’m running 25c tyres on 19mm rims.

commuted on this for a while. no issues.

Though it does provide the following advice underneath “Note: This chart may err a bit on the side of caution. Many cyclists exceed the recommended widths with no problem.”

All-new Mavic Ksyrium, Cosmic Pro Carbon SL Clinchers get full carbon construction & wider rims

25’s on Pacenti CL25 and SL25 rims. One is 20. something and the other is 21mm . Fine.
Think about MTB tyres. They are way wider than the rims.

Mavic creates UST Road Tubeless standard, presses it all across their wheel line

The new normal: the current thinking behind wide road wheel design

I use 23mm Conti tyres on 25mm wide rims. They’re the perfect width (the same as the rim when inflated). Matching the tyre and rim width gets you some good aerodynamic gains.