Rim Width and Tyre Width

Talk about anything.

Moderators: Bearbonesnorm, Taylor, Chew

Post Reply
User avatar
whitestone
Posts: 8032
Joined: Thu Dec 04, 2014 10:20 am
Location: Skipton(ish)
Contact:

Rim Width and Tyre Width

Post by 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.
Better weight than wisdom, a traveller cannot carry
ianfitz
Posts: 3642
Joined: Thu Jan 24, 2013 1:33 pm

Re: Rim Width and Tyre Width

Post by 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
Image
User avatar
PJG
Posts: 156
Joined: Thu Oct 06, 2016 9:09 am
Location: Stockport

Re: Rim Width and Tyre Width

Post by PJG »

whitestone wrote: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)
User avatar
Richard G
Posts: 5024
Joined: Sat Apr 04, 2015 9:09 am
Location: South Wales

Re: Rim Width and Tyre Width

Post by 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.
Last edited by Richard G on Thu Apr 27, 2017 8:45 pm, edited 2 times in total.
User avatar
Bearbonesnorm
Posts: 24077
Joined: Sun Jun 05, 2011 8:53 pm
Location: my own little world

Re: Rim Width and Tyre Width

Post by 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.
May the bridges you burn light your way
fatbikerbill
Posts: 351
Joined: Wed Dec 30, 2015 6:25 pm
Location: manchester

Re: Rim Width and Tyre Width

Post by fatbikerbill »

surly rabbit hole's are perfect IMO at 50mm

Hugo's might be a good lighter option.
User avatar
whitestone
Posts: 8032
Joined: Thu Dec 04, 2014 10:20 am
Location: Skipton(ish)
Contact:

Re: Rim Width and Tyre Width

Post by 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."
Better weight than wisdom, a traveller cannot carry
ianfitz
Posts: 3642
Joined: Thu Jan 24, 2013 1:33 pm

Re: Rim Width and Tyre Width

Post by 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.
Image
User avatar
whitestone
Posts: 8032
Joined: Thu Dec 04, 2014 10:20 am
Location: Skipton(ish)
Contact:

Re: Rim Width and Tyre Width

Post by 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.
Better weight than wisdom, a traveller cannot carry
User avatar
Mart
Posts: 1782
Joined: Wed Feb 15, 2012 9:57 pm
Location: Oot 'n' aboot

Re: Rim Width and Tyre Width

Post by 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
2924 miles per Gallon
User avatar
In Reverse
Posts: 1847
Joined: Mon Oct 12, 2015 9:08 pm
Location: Manchester

Re: Rim Width and Tyre Width

Post by 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.
User avatar
Mariner
Posts: 1793
Joined: Fri Feb 06, 2015 2:37 pm
Location: East Devon

Re: Rim Width and Tyre Width

Post by Mariner »

DT Swiss are doing some wider rims.
I think they are up to 40mm internal the last time I looked.
Zazen - nothing happens next this is it.
Post Reply