Rim Question

cgk-<< Are all 700c rims the same? I have 30s on my bike for gravel roads but
find
I am riding more on asphalt paths. Will new tubes and tires in a 25 fit my
rims? Other than a smoother tread, what will such a change do? >><BR><BR>

Maybe make the ride 'feel' a bit 'faster'. Yes you can put 25c tires onto that
rim.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

cgk said:

Are all 700c rims the same? I have 30s on my bike for gravel roads but find
I am riding more on asphalt paths. Will new tubes and tires in a 25 fit my
rims? Other than a smoother tread, what will such a change do?

Chris

I think you know the answer to your first question is no.

Yes, new tubes and tires will "fit", but there is a chance, if you are using rims that are quite wide, that your ride quality will suffer.
From Sheldon Brown's web pages:
"Width Considerations
Although you can use practically any tire/rim combination that shares the same bead seat diameter, it is unwise to use widely disparate sizes.
If you use a very narrow tire on a wide rim, you risk pinch flats and rim damage from road hazards.

If you use a very wide tire on a narrow rim, you risk sidewall or rim failure. This combination causes very sloppy handling at low speeds. Unfortunately, current mountain-bike fashion pushes the edge of this. In the interest of weight saving, most current mountain bikes have excessively narrow rims. Such narrow rims work very poorly with wide tires, unless the tires are overinflated...but that defeats the purpose of wide tires, and puts undue stress on the rim sidewalls."

There is a chart on that page that doesn't copy and paste well here. The URL is:

<http://www.sheldonbrown.com/tire-sizing.html>

You will need to scroll down to near the bottom of the page for the chart.

cgk said:

Are all 700c rims the same? I have 30s on my bike for gravel roads but

find

Quoted message said:

I am riding more on asphalt paths. Will new tubes and tires in a 25 fit my
rims? Other than a smoother tread, what will such a change do?

No, some 700c rims are wider than others. See compatibility chart at:

http://www.sheldonbrown.com/tire_sizing.html#width

The 25s will be lighter, and may have slightly less rolling resistance.
You'll probably run higher pressure in the 25s which will give a somewhat
harder ride and be a bit less sure-footed on gravel.

Art Harris

Thank you all. This is just what I needed!

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

Quoted message said:

cgk said:

Are all 700c rims the same? I have 30s on my bike for gravel roads but

find

Quoted message said:

I am riding more on asphalt paths. Will new tubes and tires in a 25 fit

my

Quoted message said:

Quoted message said:

rims? Other than a smoother tread, what will such a change do?

No, some 700c rims are wider than others. See compatibility chart at:

http://www.sheldonbrown.com/tire_sizing.html#width

The 25s will be lighter, and may have slightly less rolling resistance.
You'll probably run higher pressure in the 25s which will give a somewhat
harder ride and be a bit less sure-footed on gravel.

Art Harris

My bike is a cross-bike. The rims are marked 15-622 and my tires are 30-622.
Looks like that's a match. If I'm reading the chart that you referred me to
correctly, I should be able to get 622 tires in widths from 23 to 32 that
will work with my rims. When I wear out these little knobby tires I think
I'll try 25s in a smoother style.

Chris

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

Quoted message said:

cgk said:

Are all 700c rims the same? I have 30s on my bike for gravel roads but
find
I am riding more on asphalt paths. Will new tubes and tires in a 25 fit
my
rims? Other than a smoother tread, what will such a change do?

Chris

I think you know the answer to your first question is no.

Yes, new tubes and tires will "fit", but there is a chance, if you are
using rims that are quite wide, that your ride quality will suffer.
From Sheldon Brown's web pages:
"Width Considerations
Although you can use practically any tire/rim combination that shares
the same bead seat diameter, it is unwise to use widely disparate
sizes.
If you use a very narrow tire on a wide rim, you risk pinch flats and
rim damage from road hazards.

If you use a very wide tire on a narrow rim, you risk sidewall or rim
failure. This combination causes very sloppy handling at low speeds.
Unfortunately, current mountain-bike fashion pushes the edge of this.
In the interest of weight saving, most current mountain bikes have
excessively narrow rims. Such narrow rims work very poorly with wide
tires, unless the tires are overinflated...but that defeats the purpose
of wide tires, and puts undue stress on the rim sidewalls."

There is a chart on that page that doesn't copy and paste well here.
The URL is:

<http://www.sheldonbrown.com/tire-sizing.html>

You will need to scroll down to near the bottom of the page for the
chart.

--
daveornee

Bicycling 1/2 century

cgk said:

Are all 700c rims the same? I have 30s on my bike for gravel roads but find
I am riding more on asphalt paths. Will new tubes and tires in a 25 fit my
rims? Other than a smoother tread, what will such a change do?

A 30 mm or larger tire may be of lower quality. When I switched from
27 x 1 1/4 tires to 27 x 1 1/8 tires, the change in road feeling was
tremendous. I think that half the change was from a smaller tire, and
half was from a better (finer weave, less material, optimized profile)
tire.

A 30 mm tire is probably not folding - its probably a wire bead. If
you have a rim with a "hooked" bead, then you can get a folding tire.
Today's highest quality folding tires of width XX in mm should weigh
about XX * 10 grams. Therefore, if you want to maximize the impact of
changing to skinnier tires, select a 700x25c folding tire that weighs
250g or less to see maximum benefit.

- Don Gillies
San Diego, CA