Max tire size on "road" rim?

Paul Kossa wrote:
What's the largest size tire you can safely put on a road rim, such as
a Mavic Pro (or whatever they're called)? Do 'cross tires fit on them?

I've used 35mm studded tires on Open Pro rims for a few years now. I
typically run them around 70psi. I weigh 230.

In article ,
"James Thomson" wrote:

"Paul Kossa" a écrit:

What's the largest size tire you can safely put on a road rim,
such as a Mavic Pro (or whatever they're called)? Do 'cross
tires fit on them?

I've run 37mm hybrid tyres on Open Pro rims.

Many XC mountain bike rims are not much wider, and are routinely used with
2" tyres.

But, bear in mind that casing tension at a given pressure increases with
tyre width. Fat tyres at high pressures will put more strain on your rim
walls than slim tyres at high pressures.

Totally true. But in the real world, fatter tires are almost always run
at lower pressures than skinnier ones.

--
Ryan Cousineau http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."

James Thomson wrote:

What's the largest size tire you can safely put on a road rim, such
as a Mavic Pro (or whatever they're called)? Do 'cross tires fit
on them?

I've run 37mm hybrid tyres on Open Pro rims.

Many XC mountain bike rims are not much wider, and are routinely
used with 2" tyres.

But, bear in mind that casing tension at a given pressure increases
with tyre width. Fat tyres at high pressures will put more strain on
your rim walls than slim tyres at high pressures.

I am more concerned with the angle at which the tire casing departs
from the rim. An angle becomes more lateral as tire cross section is
increased. That angle increases the tendency to pop off the rim when
it gets hot from braking. Tire blow-offs are one of the worst
incidents when descending. They create and artificial "skating on
ice" condition, an aluminum rim having as good as no traction just for
staying upright on the bicycle, quite aside from trying to apply a
brake on that wheel, something that was most likely occurring at the
time of the blow-off.

Jobst Brandt

Ryan Cousineau wrote:
In article ,
"James Thomson" wrote:

"Paul Kossa" a écrit:

What's the largest size tire you can safely put on a road rim,
such as a Mavic Pro (or whatever they're called)? Do 'cross
tires fit on them?
I've run 37mm hybrid tyres on Open Pro rims.

Many XC mountain bike rims are not much wider, and are routinely used with
2" tyres.

But, bear in mind that casing tension at a given pressure increases with
tyre width. Fat tyres at high pressures will put more strain on your rim
walls than slim tyres at high pressures.

Totally true. But in the real world, fatter tires are almost always run
at lower pressures than skinnier ones.

Not for BMX freestyle (or for the recumbent riders that use rim and
tires originally intended for BMX). The highest inflation pressures run
from 6 to 9 bar for tires in the 44 to 53-mm width range.

--
Tom Sherman - 42.435731,-83.985007
If you are not a part of the solution, you are a part of the precipitate.

Hi,

DirtRoadie wrote:
True, despite using wheels on my 29er that used to be on my road bike,
I wouldn't begin to suggest that those same wheels would still fit on
the road bike with the 52mm tires. Not even close.

Sorry, I'm getting confused by the 29-figure - if I remember correctly,
27 was larger than 28 was larger than 29? These figures never really
compared well :-(

There should be an ISO measure on your tire, something like 23-622
(narrow 28" tire) or 28-630 (27" road tire) or something similar. The
first number is tire width in mm and the second is the tire seat
diameter in mm. Although I find the inch numbers easier to remember, the
ISO standard is easier to compare ;-) So if your bike had 28-630 tires
to start with, you should be able to fit 32-622 with only minor change
to the brake setup. But especially modern high-end road frames do not
have enough tire clearance for narrow rims and fenders. If you've got an
older frame or a "sensible" frame, there is enough clearance to mount
wider tires than commonly used for the type of bike (e.g. mount 32 mm
wide tires on road bikes, along with fenders, or mount 54mm wide tires
on a "city" bike along with fenders which was meant for 38mm tires ;-)

Good luck...

In article ,
Bernhard Agthe wrote:

Hi,

DirtRoadie wrote:
True, despite using wheels on my 29er that used to be on my road bike,
I wouldn't begin to suggest that those same wheels would still fit on
the road bike with the 52mm tires. Not even close.

Sorry, I'm getting confused by the 29-figure - if I remember correctly,
27 was larger than 28 was larger than 29? These figures never really
compared well :-(

An easy mistake. "29er" is a designation used by mountain bikers for
700c (ISO 622) wheels. When used with 2" mountain-bike tires, they are
in deed close to 29" dia.

--
Ryan Cousineau http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."