Yet Another Cycling Forum

Random Musings => DIY => Skip Bike and Bodge It => Topic started by: Brian G on 29 October, 2008, 08:01:45 pm

Title: wheel rims and tyre width
Post by: Brian G on 29 October, 2008, 08:01:45 pm
Hello out there.

I'm slowly building up a sort of MTB thingy from variously-acquired bits.  The wheels I have are 17-559, i.e., 26 inch wheels with an inner rim size of 17mm.  My LBS assures me that these rims will happily work with 2.1 inch tyres.  Now I've fitted such tyres to the rims and inflated them to the recommended pressure and they certainly work in that the tyres stay on the rims and look quite comfortable (in a fat, bloated sort of way) at least while the wheels are merely sitting in the shed.

Thing is, will they actually do the job when the bike is up and running?  Does anybody have experience of using such a combination?  For all I know, every mountain bike on the planet is equipped thus, for my ignorance of the type is broad and deep.

Any advice or experiences most welcome.

Brian
Title: Re: wheel rims and tyre width
Post by: Gus on 29 October, 2008, 08:11:20 pm

It is the same size as Mavic XC717 rims and they recommend tire widths from 1.00 - 2.10
so you should not have any problems with your wheels.
Title: Re: wheel rims and tyre width
Post by: rogerzilla on 29 October, 2008, 10:46:59 pm
It's fine.  If you were running the 2.1 tyre at 100psi it would probably blow off, but you're not.
Title: Re: wheel rims and tyre width
Post by: Chris N on 30 October, 2008, 08:34:46 am
Manufacturer's limits seem to be around 2:1 tyre:rim width, but the lower the pressure, the fatter the tyre you can get away with.  I'm currently running a 37mm tyre on a Mavic MA3 - so the tyre's almost 2.5x the rim width.  Seems ok so far, at 80 psi.
Title: Re: wheel rims and tyre width
Post by: Brian G on 30 October, 2008, 01:59:47 pm
Manufacturer's limits seem to be around 2:1 tyre:rim width, but the lower the pressure, the fatter the tyre you can get away with.  I'm currently running a 37mm tyre on a Mavic MA3 - so the tyre's almost 2.5x the rim width.  Seems ok so far, at 80 psi.

But a 2.1 inch tyre on a 17mm rim is a ratio of greater than three to one, so your advice seems to conflict somewhat with the others.  So are you saying I can't use the tyres, or I have to run them at way below recommended pressure (not good at my weight  :-[ ), or what?

Brian
Title: Re: wheel rims and tyre width
Post by: Chris N on 30 October, 2008, 02:11:17 pm
So are you saying I can't use the tyres, or I have to run them at way below recommended pressure (not good at my weight  :-[ ), or what?

Nope.  I'm saying that I use a tyre that is outside the range recommended by the rim manufacturer at a relatively high pressure and I think it's probably ok.
Title: Re: wheel rims and tyre width
Post by: Brian G on 30 October, 2008, 02:16:57 pm
So are you saying I can't use the tyres, or I have to run them at way below recommended pressure (not good at my weight  :-[ ), or what?

Nope.  I'm saying that I use a tyre that is outside the range recommended by the rim manufacturer at a relatively high pressure and I think it's probably ok.

Ah, thanks for the clarification.

And thanks to all for the helpful replies.  I may yet be back with other queries as the thingy develops.

Brian
Title: Re: wheel rims and tyre width
Post by: andygates on 30 October, 2008, 02:48:52 pm
I run 2.25's on skinny rims.  Works fine, though it looks balloony.  The manufacturer's spec is the "most restrictive case guaranteed to work".
Title: Re: wheel rims and tyre width
Post by: cc93 on 30 October, 2008, 03:41:21 pm
wot, no-one quoted Sheldon yet? (http://www.sheldonbrown.com/tire-sizing.html)

(scroll to the bottom for recommended rim/tyre combos)
Title: Re: wheel rims and tyre width
Post by: Chris N on 30 October, 2008, 03:43:05 pm
No, but:

Quote from: sheldon brown
Note: This chart may err a bit on the side of caution. Many cyclists exceed the recommended widths with no problem.
Title: Re: wheel rims and tyre width
Post by: Brian G on 30 October, 2008, 07:03:44 pm
Indeed, that's the very reason I sought the wisdom of this collective.  For once the late great Sheldon's site was unsatisfactory.  If I followed the chart shown I'd be limited to a 37mm tyre (if I remember it right).


Brian