MTB-width tyres on road rims

[Hawk]

Would I get away with a 2.25" tyre on a rim rated up to 28mm?

I've had no problems with a 1.5" on the same rim but want to upgrade my snow/ice tyre to a wider one; avoiding blowouts on snow/ice would be great.

 

[PpPete]

2.25" is twice as wide as rim is rated for. (28mm is a gnat's pubic hair away from 1.125")
You might get away with it, but I would suggest the combination is likely to more fragile than with 1.5" wide tyre.

 

[mickle]

Go for whatever fits between the stays/fork blades/ mudguards. The worst that can happen on a narrow rim is that the tyre will have a slightly greater tendency to roll sideyways under side loading - due to the slightly less rigid sidewall - but this is only ever a problem at very low pressures.

 

[Hawk]

It is unlikely that they aren't but the rims are hooked?

CXP22s, http://www.ekmpowershop25.com/ekmps...road-rims-700c-cxp22-black-mav081-19805-p.jpg

Hooked

Go for whatever fits between the stays/fork blades/ mudguards. The worst that can happen on a narrow rim is that the tyre will have a slightly greater tendency to roll sideyways under side loading - due to the slightly less rigid sidewall - but this is only ever a problem at very low pressures.

Think I'll get away with it, it's a TriCross. Will measure to verify.

I might be at fairly low pressure (30-40psi or so?) with this winter tyre - ice spiker pro. No risk of tyre coming off the rim in your opinion?

 

[mickle]

CXP22s, http://www.ekmpowershop25.com/ekmps...road-rims-700c-cxp22-black-mav081-19805-p.jpg

Hooked



Think I'll get away with it, it's a TriCross. Will measure to verify.

I might be at fairly low pressure (30-40psi or so?) with this winter tyre - ice spiker pro. No risk of tyre coming off the rim in your opinion?

None whatsoever.

 

[mickle]

The entire mountain bike community used to run 2.1 tyres on 23mm rims with no ill effects. I once had 2.3 Ritchey WCS kevlar beaded tyres in a very fetching pinky red on 19mm purple (aero!) rims. Those were the days! They didnt have the most rigid sidewalls but they never burped off the rim.

 

[mickle]

When you say 'rated up to 28mm',,,

 

[Rohloff_Brompton_Rider]

http://sheldonbrown.com/tire-sizing.html


I follow sheldon's advice, usually pretty good.....there's a chart at the bottom.

 

[mickle]

http://sheldonbrown.com/tire-sizing.html


I follow sheldon's advice, usually pretty good.....there's a chart at the bottom.

"Increased chance of sidewall wear?" Thats pretty lame.

 

[Rohloff_Brompton_Rider]

Not really, tyre flex = possible tyre rub on rim edge, same as underflated tyres. Not common, I suppose, but does happen..might be one of the reasons of the latest tubeless mtb ( as well as snake bite) fashion.

 

[mickle]

Not really, tyre flex = possible tyre rub on rim edge, same as underflated tyres. Not common, I suppose, but does happen..might be one of the reasons of the latest tubeless mtb ( as well as snake bite) fashion.

As a reason not to fit fat tyres to skinny rims it falls flat. One of the things you check when installing rim brake blocks is that they dont foul the tyre sidewall. Its obvious. And if a tyre is so soft that it hits the brake block it was already way too flat to ride on. Sheldon makes it up as he goes along sometimes.

 

[black'n'yellow]

Sheldon makes it up as he goes along sometimes.

I'm glad it's not just me that thinks that....

 

[Hawk]

When you say 'rated up to 28mm',,,

Measured an identical wheel (off the bike) just for you:

Braking surfaces to braking surface - 20mm
Internal width (between innermost parts of the "hook" - 14.9mm

The largest size the sticker on the tyre says to put on it is 28mm

 

[Rohloff_Brompton_Rider]

As a reason not to fit fat tyres to skinny rims it falls flat. One of the things you check when installing rim brake blocks is that they dont foul the tyre sidewall. Its obvious. And if a tyre is so soft that it hits the brake block it was already way too flat to ride on. Sheldon makes it up as he goes along sometimes.

Most mtb's are discs are they not? As I understand mtb'ers go tubeless so they can go narrower to tackle the issues that sheldon's page talks about ( not sheldon but an article on his page).

Re the narrow tyre sidewall failure, he only stated this issue for wide tyres.

Tbf he only gave his opinion, pretty much like you,I don't remember reading anything that says its gospel.

That said tho, I found his pages extremely helpful when I was a novice and I still refer to them today. Of course I'd would use yours too, but I can't find your knowledge kindly written down by googling....have you got a link please?

 

[Rohloff_Brompton_Rider]

Going back to the op's question.....on a disk bike I don't know why not, although having a high enough pressure to stop rollover negates the advantage of a large volume tyre (cushioning wise). With rim brakes I wouldn't, the rims could be at risk of failure sooner than with a correct size tyre....as the metal gets rubbed away.....not an issue on disks.