MTB - Rim width vs. Tire width

Peder said:

At what point would I need to be concerned about increasing rim width as I
go to wider tires? I'm now using Maxxis High Rollers 2.35 on Mavic X-139
rims. Thanks for reading.

The ideal is something like 1.5x rim width, but MTBs break this rule by
a long way. It depends to some extent on the pressure - tyres at a high
pressure (say 80psi+) are more likely to be damaged against the sidewall
of the rim if they are too fat. Also, some tyres have much better
anti-chafing strips than others and will withstand this treatment.

Zog The Undeniable <[email hidden]> wrote in
news:40eadf1c.0@entanet:

Quoted message said:

Peder said:

At what point would I need to be concerned about increasing rim width
as I go to wider tires? I'm now using Maxxis High Rollers 2.35 on
Mavic X-139 rims. Thanks for reading.

The ideal is something like 1.5x rim width, but MTBs break this rule
by a long way. It depends to some extent on the pressure - tyres at a
high pressure (say 80psi+) are more likely to be damaged against the
sidewall of the rim if they are too fat. Also, some tyres have much
better anti-chafing strips than others and will withstand this
treatment.

Thanks for the reply. I managed to find a link to a doc somewhere on
Mavic's site showing "1,5 à 2,3" so I guess at 2.35, I'm just barely over
max. Interesting they recommend lower pressures at wider widths (like 45
psi). Suppose it would blow the wheel or blow off?

--
Peder (Please reply to group only, email invalid)

Peder wrote:

Interesting they recommend lower pressures at wider widths
(like 45

Quoted message said:

psi). Suppose it would blow the wheel or blow off?

don't wider tires generally run at lower pressures?

dave

Bay Area Dave <[email hidden]> wrote in
news:[email hidden]:

Quoted message said:

Peder wrote:

Interesting they recommend lower pressures at wider widths
(like 45

Quoted message said:

psi). Suppose it would blow the wheel or blow off?

don't wider tires generally run at lower pressures?

dave

I guess I didn't write that very well. What I meant was would the max
listed tire pressue of 65 psi break the wheel or tend to blow off.

--
Peder (Please reply to group only, email invalid)

Peder said:

Bay Area Dave <[email hidden]> wrote in
news:[email hidden]:

Quoted message said:

Peder wrote:

Interesting they recommend lower pressures at wider widths
(like 45

Quoted message said:

psi). Suppose it would blow the wheel or blow off?

don't wider tires generally run at lower pressures?

dave

I guess I didn't write that very well. What I meant was would the max
listed tire pressue of 65 psi break the wheel or tend to blow off.

oh, are you wondering if one installs a tire LARGER than is
recommended for a particular wheel, will it tend to come off
easily due in part to running it a lower pressure than the
correct tire would be run at? If that's your question, I
don't have an answer. 🙂

dave

Quoted message said:

I guess I didn't write that very well. What I meant was would the max
listed tire pressue of 65 psi break the wheel or tend to blow off.

No. I run a 2.4 on my Mavic X223 rim and they are just fine.

--
Phil, Squid-in-Training

In article said:

At what point would I need to be concerned about increasing rim width as I
go to wider tires? I'm now using Maxxis High Rollers 2.35 on Mavic X-139
rims. Thanks for reading.

There is a table listing recommended tire sizes for various rim widths at
http://tandem-fahren.de/Technik/Reifentips/
The text is in German, however.
The table is meant for tandem riders, but a lot of mtb riders seem to
use much wider tires than suggested by this table.

--
Ned Mantei
Department of Cell Biology, Swiss Federal Institute of Technology
CH-8093 Zurich, Switzerland

back in my weight-weenie days i ran 26" aero road rims (sun
something-or-others) on my mtb. 26x2.0 tires stayed on just fine, and the
wheels were surprisingly durable. brake adjustment was finicky
though...skinny kool-stops were required to prevent the pads from rubbing
the bulging sidewalls when the brakes were not being applied while
preserving reasonable lever travel.

fwiw,

dookie

"Peder" <[email hidden]> wrote in message news:[email hidden]...

Quoted message said:

At what point would I need to be concerned about increasing rim width as I
go to wider tires? I'm now using Maxxis High Rollers 2.35 on Mavic X-139
rims. Thanks for reading.

--
Peder (Please reply to group only, email invalid)

"dookie" <[email protected]> wrote in
news:[email hidden]:

Quoted message said:

back in my weight-weenie days i ran 26" aero road rims (sun
something-or-others) on my mtb. 26x2.0 tires stayed on just fine, and
the wheels were surprisingly durable. brake adjustment was finicky
though...skinny kool-stops were required to prevent the pads from
rubbing the bulging sidewalls when the brakes were not being applied
while preserving reasonable lever travel.

I've been wondering about this, ever since the topic came up.

I'm riding a '92(?) Trek Multitrack 7600 hybrid, converted to drop bars and
STI. I use it as a townie/light trail riding bike. I'm still on the
original 700c rims, which are Trek-brand "Journey", measuring about 14mm at
the gap across the top. The bike came with 38c tires from the factory on
these rims, and I've stayed in that 35-42c range ever since.

But I see from various sites online (including Sheldon's), that the
"recommended" range of tire widths for this width of rim is smaller. And
some of the aftermarket tires I've bought over the years do bulge out more
than the original Trek-branded 38c tires... like the IRC Metro II 38c
slicks I'm running now. The bulge just barely clears the canti brakes, but
it works.

Is there actually some danger or drawback in using wider tires on a
narrower rim like this? I have flats now and then, but nothing I'd
consider unusual. I'm thinking "if it ain't broke don't fix it"... but if
there is some catastrophic failure mode that could happen in the future,
I'd like to know about it.

--
Mike Barrs