Rim Width and Tyre Width

[whitestone]

Is there a recommendation or formula that relates internal rim width to tyre width? Ideally I'd like a rim that will cope with tyres from 2.35" to 3". I realise that I might not get the best tyre profile at either end of the range.

[ianfitz]

I've used light bicycle 35 and 38mm rims with that sort of range.

Could go wider though. And no idea if there's a formula

[PJG]

Is there a recommendation or formula that relates internal rim width to tyre width? Ideally I'd like a rim that will cope with tyres from 2.35" to 3". I realise that I might not get the best tyre profile at either end of the range.

If in doubt, ask Sheldon Brown:

https://www.sheldonbrown.com/tyre-sizing.html#width

(Doesn't seem to work well on a mobile device)

[Richard G]

There are a few charts floating about / some articles. I'd personally say about 35mm for what you're looking for.

Edit - Depends on the tyre profile in reality though.

[Bearbonesnorm]

I'd say 30mm internal is as narrow as you really want to go. Fitting a 3" tyre to anything smaller and you're simply dragging a heavy tyre about for no real benefit.

[fatbikerbill]

surly rabbit hole's are perfect IMO at 50mm

Hugo's might be a good lighter option.

[whitestone]

I was thinking of building up a wheel with a dynamo hub. Given the likely cost I'd rather have a rim that could cope with both normal and plus sized tyres.

Looking at that chart on the Sheldon Brown site and a quick bit of work on the calculator it looks like a tyre width/rim width ratio of 1.75 is about right for the narrow end and 2.25 for the wide end. 2.35" is 60mm => 60/1.75 = 34.3mm, 3" is 75mm => 75/2.25 = 33.3 so Richard's 35mm looks about spot on, equally 30mm isn't too far away.

I think I'm right in saying that a narrow rim makes a given tyre have a very round profile whereas a wider rim gives it a squarer one.

Found an article on bikerumour where they've gone to various tyre manufacturers about this. They (Bikerumour) say this: "But, with some calculations of the ETRTO standards, we came up with a rough guideline suggesting your rim width should be between 32% to 70% of the tyre width."

[ianfitz]

I rode a chronicle on a 35mm rim for the borders350 attempt the other year.

It was still a bit lightbulb shaped but ran it at 10psi no trouble.

I'd not build up a dynamo wheel until you've tried the semi plus thing though bob. It's an acquired taste, great small bump absorption but odd 'square' steering.

Can lend you a 35/38 with a chronicle on if you want to try it.

[whitestone]

I've got a set of the Alpkit Rumpus wheels with a WTB Bridger 3" on the front, these are 650B+ rather than 29+ so I do have some feel for the sizing but those are 45mm rims.

If a 35mm rim was fine with the narrower tyre then I'd go with that, with the Chronicle on clearance at CRC I could try it and go back to the Bontrager XR4 if I didn't get on with it.

[Mart]

on my 29+ wheel i'm running a dually rim which i really rate - it's been good for me so far
think it's 45mm outside, 39mm internal

[In Reverse]

The Dually is perfect for that range of tyre width. I've run 2.35 Nobby Nics, 3" Dirt Wizards and various things in between.

[Mariner]

DT Swiss are doing some wider rims.
I think they are up to 40mm internal the last time I looked.