Newbie query re rim width vs. tire width (longish)

I have had a new Trek 7.5 FX for about a week now. Stock wheels are
Bontrager SSR and tires are 700x32 Bontrager Race Lite Hardcase (road
slicks).

I bought this bike planning to ride about 95% pavement and 5% unpaved
(mostly smooth hardpack with/without minimal loose surface grit), and
with that in mind planned to get a wider tire with tread, something
like a Bontrager Invert or Continental Travel Contact, in a 35-37 mm
width.

So I get the bike and there's a clicking sound when using the rear
brake. Turns out there's a rim defect - a big misalignment where the
two ends of the formerly-straight piece of rim meet.. My LBS looked at
it, didn't like the front rims either, and got Trek to send
replacement wheels gratis, and they are the "Select" wheels, an
upgrade ... sweet..

But now the new wheels have arrived, and yesterday I got to measure
the interior rim width, which is 15mm (distance between the flanges).
And from what I could tell without removing the tires, the old SSR
rims had approximately the same exterior width.

Can I safely use the wider tires on these rims? According to the chart
at

http://sheldonbrown.com/tire-sizing.html#width (not sure this link
will go to the right
place, on the page, but just scroll down to the chart at the
bottom)

the 32s are about as wide as I can go. But Brown does say this chart
is rather conservative, and it comes from a site that appears to be
tandem-centric (thus more weight is a concern - I'm a Clydesdale at
215, but I imagine most mixed gender couples outweigh me 8-).

Trek has at least one bike which comes stock with SSR wheels and the
Bontrager Invert 700x35s. And the Trek rep assured my LBS I could put
37s on the stock wheels. Still, I'm a little nervous about this and
would like some reassurance.

I could look for a treaded tire in a 32, but I'm wanting to use the
guidelines at

http://www.rivbike.com/files/pick_tire.html ,

though these may be somewhat conservative as well.

Happy riding (and/or wrenching), and thanks for any advice ...
Don in Denver

Wrote:
I have had a new Trek 7.5 FX for about a week now. Stock wheels are
Bontrager SSR and tires are 700x32 Bontrager Race Lite Hardcase (road
slicks).

I bought this bike planning to ride about 95% pavement and 5% unpaved
(mostly smooth hardpack with/without minimal loose surface grit), and
with that in mind planned to get a wider tire with tread, something
like a Bontrager Invert or Continental Travel Contact, in a 35-37 mm
width.

So I get the bike and there's a clicking sound when using the rear
brake. Turns out there's a rim defect - a big misalignment where the
two ends of the formerly-straight piece of rim meet.. My LBS looked at
it, didn't like the front rims either, and got Trek to send
replacement wheels gratis, and they are the "Select" wheels, an
upgrade ... sweet..

But now the new wheels have arrived, and yesterday I got to measure
the interior rim width, which is 15mm (distance between the flanges).
And from what I could tell without removing the tires, the old SSR
rims had approximately the same exterior width.

Can I safely use the wider tires on these rims? According to the chart
at

http://sheldonbrown.com/tire-sizing.html#width (not sure this link
will go to the right
place, on the page, but just scroll down to the chart at the
bottom)

the 32s are about as wide as I can go. But Brown does say this chart
is rather conservative, and it comes from a site that appears to be
tandem-centric (thus more weight is a concern - I'm a Clydesdale at
215, but I imagine most mixed gender couples outweigh me 8-).

Trek has at least one bike which comes stock with SSR wheels and the
Bontrager Invert 700x35s. And the Trek rep assured my LBS I could put
37s on the stock wheels. Still, I'm a little nervous about this and
would like some reassurance.

I could look for a treaded tire in a 32, but I'm wanting to use the
guidelines at

http://www.rivbike.com/files/pick_tire.html ,

though these may be somewhat conservative as well.

Happy riding (and/or wrenching), and thanks for any advice ...
Don in Denver
You are at the upper edge of the tire/rim width with your 32 mm tire &
15 mm inner width on the rim. At 215 pounds you need to look at the
inflation issue and protection against pinch flats.
If it were me, I would push for a wider rim and wider tire.
Your idea of 35 or 37 mm wide tires sounds suitable for your weight and
riding applications...


--
daveornee

On 8 Apr., 21:43, wrote:

I bought this bike planning to ride about 95% pavement and 5% unpaved
(mostly smooth hardpack with/without minimal loose surface grit), and
with that in mind planned to get a wider tire with tread, something
like a Bontrager Invert or Continental Travel Contact, in a 35-37 mm
width.

My recommendation would be to keep the wheels and slick tires. You
will be surprised on how well slicks perform
on unpaved roads like the ones you describe.

Can I safely use the wider tires on these rims? According to the chart
at http://sheldonbrown.com/tire-sizing.html#width
the 32s are about as wide as I can go.

I wouldn't do it. You will be better off with new rims if you want 37
mm tires.

I could look for a treaded tire in a 32, but I'm wanting to use the
guidelines at
http://www.rivbike.com/files/pick_tire.html,

I like Rivendell bikes, but forget about that chart.
People as heavy as you rides just fine on narrow 23 mm tires without
their wheels being destroyed. You don't _need_ 37 mm tires just
because you are a Clyde and do some light unpaved road riding.
Off course, only you can decide what tire with and what tire pressure
feels good for you. But at least try to gain some riding experience
on your present wheelset and tires before spending money.

--
Regards
Peter S.

On 8 Apr 2007 12:43:38 -0700, wrote:


But now the new wheels have arrived, and yesterday I got to measure
the interior rim width, which is 15mm (distance between the flanges).
And from what I could tell without removing the tires, the old SSR
rims had approximately the same exterior width.

Can I safely use the wider tires on these rims? According to the chart
at

http://sheldonbrown.com/tire-sizing.html#width (not sure this link
will go to the right
place, on the page, but just scroll down to the chart at the
bottom)

the 32s are about as wide as I can go. But Brown does say this chart
is rather conservative, and it comes from a site that appears to be
tandem-centric (thus more weight is a concern - I'm a Clydesdale at
215, but I imagine most mixed gender couples outweigh me 8-).

Trek has at least one bike which comes stock with SSR wheels and the
Bontrager Invert 700x35s. And the Trek rep assured my LBS I could put
37s on the stock wheels. Still, I'm a little nervous about this and
would like some reassurance.

I've been using Conti SportContact 700x37 on Shimano R500 rims, which
are only 13mm between flanges, for a couple of years. I'm 200+ and
ride about 70/30 road/hardpack. From my experience, I'd say don't
worry too much about fitting wide tyre to narrow rims, as long as you
don't plan to run low pressures where the wider base really does make
a difference to tyre stability. Also, don't bother with a tread unless
you ride in mud - if you can't see the tread pattern in the mark you
make on the ground, it's not doing anything other than reducing the
amount of rubber in contact with the road.

Kinky Cowboy*

*Batteries not included
May contain traces of nuts
Your milage may vary

On 8 Apr 2007 12:43:38 -0700, wrote:

I have had a new Trek 7.5 FX for about a week now. Stock wheels are
Bontrager SSR and tires are 700x32 Bontrager Race Lite Hardcase (road
slicks).

I bought this bike planning to ride about 95% pavement and 5% unpaved
(mostly smooth hardpack with/without minimal loose surface grit), and
with that in mind planned to get a wider tire with tread, something
like a Bontrager Invert or Continental Travel Contact, in a 35-37 mm
width.
[snip]
Trek has at least one bike which comes stock with SSR wheels and the
Bontrager Invert 700x35s. And the Trek rep assured my LBS I could put
37s on the stock wheels. Still, I'm a little nervous about this and
would like some reassurance.

I could look for a treaded tire in a 32, but I'm wanting to use the
guidelines at

http://www.rivbike.com/files/pick_tire.html ,

though these may be somewhat conservative as well.

Happy riding (and/or wrenching), and thanks for any advice ...
Don in Denver

Don,

FWIW: I ride a tandem and our combined rider weight is about 300 lbs,
and we have also pulled a loaded BOB trailer. (I would not be
surprised to discover that we have had as much as 200 lbs on the rear
wheel when we pulled our trailer.) We run slicks in a 1.25" (32mm)
size on a 26" wheel at about 90-100psi and have no complaints,
especially considering the price tag of under $20 a piece. I replace
these tires about every 3,000 miles.

We also ride mostly on pavement but occasionally ride on hard packed
gravel (such as the Katy Trail in Missouri) and have been happy with
the slicks. I have not felt the need to consider a treaded tire for
any of the conditions in which we have ridden.

Cheers,
Harry