Roadie tire sizes...

Alex Ravenel said:

Forgive me!

I have an old roadie in the basement I am rebuilding. Needs new tires. It has some pretty nice
mavic rims on it, 27". Will a 700 tire or tube fit this?

No.

700c's are 29 inch wheels.

Barry

B a r r y B u r k e J r . said:

Alex Ravenel said:

Forgive me!

I have an old roadie in the basement I am rebuilding. Needs new tires. It has some pretty nice
mavic rims on it, 27". Will a 700 tire or tube fit this?

No.

700c's are 29 inch wheels.

They're only called that because of some lame mtn bike marketeer, they were never called 29" until
a marketeer came up with the label so the public wouldn't recall the last round of 700c wheeled
mtn bikes. And just because some 700c mtn bike tires may be close to 29" in outer diameter doesn't
mean all will.

700c = 622 mm = 24.5" 27" = 630 mm = 24.8"

So close but no banana. But nowhere near the diff between 27" and 29". Some road bikes can even use
either rim if you have older long reach calipers with a lot of adjustment.

Greg

--
"Destroy your safe and happy lives before it is too late, the battles we fought were long and hard,
just not to be consumed by rock n' roll..." - The Mekons

Alex Ravenel <[email hidden]> wrote in :"]news:[email hidden]:

Quoted message said:

I have an old roadie in the basement I am rebuilding. Needs new tires. It has some pretty nice
mavic rims on it, 27". Will a 700 tire or tube fit this?

Tubes will fit, tires will not.

OK, what should I get width-wise? I dont want to go with an inch, a little narrow--should I go 1
1/8 or 1 1/4?

--
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Alex Ravenel theravenel.nettheravenel.netOpen ↗

Quoted message said:

Tubes will fit, tires will not.

Thats what I was thiking. Thanks much.

--
--------
Alex Ravenel theravenel.nettheravenel.netOpen ↗

Alex Ravenel said:

OK, what should I get width-wise? I dont want to go with an inch, a little narrow--should I go 1
1/8 or 1 1/4?

I'd go with the 1 1/4. The only benefit of narrow tires is the ability to run 110 psi and up. At a
given pressure fatter tires have less rolling resistance (due to less hysteresis).

Greg

--
"Destroy your safe and happy lives before it is too late, the battles we fought were long and hard,
just not to be consumed by rock n' roll..." - The Mekons

"G.T." <[email hidden]> wrote in :"]news:[email hidden]:

Quoted message said:

I'd go with the 1 1/4. The only benefit of narrow tires is the ability to run 110 psi and up. At a
given pressure fatter tires have less rolling resistance (due to less hysteresis).

While that partially is true, it is not a valid argument. If two tires have identical construction,
except that one is wider, you should *not* run them at the same pressure. The narrower tire will
have a higher optimal pressure and thus a lower rolling resistance. The wider tire will weigh more
and roll slower, but give you a plusher ride, especially on rough roads.

Ken

Ken said:

"G.T." <[email hidden]> wrote in :"]news:[email hidden]:

Quoted message said:

I'd go with the 1 1/4. The only benefit of narrow tires is the ability to run 110 psi and up. At a
given pressure fatter tires have less rolling resistance (due to less hysteresis).

While that partially is true, it is not a valid argument. If two tires have identical
construction, except that one is wider, you should *not* run them at the same pressure.

Why not? If the max pressure on a 1" tire is 140 psi and it's 100 psi on a 1 1/4" tire but you're
only planning on running 100 psi why can't you run the 1 1/4" at 100 psi?

Quoted message said:

The narrower tire will have a higher optimal pressure and thus a lower rolling resistance.
The wider tire will weigh more and roll slower, but give you a plusher ride, especially on
rough roads.

And the wider tire has less rolling resistance at the same pressure just like I said (due to less
hysteresis). The wider tire will roll faster than the skinnier tire at the same pressure. Did you
read what I said? "At a given pressure fatter tires have less rolling resistance".

Greg

--
"Destroy your safe and happy lives before it is too late, the battles we fought were long and hard,
just not to be consumed by rock n' roll..." - The Mekons

G.T. said:

Ken said:

"G.T." <[email hidden]> wrote in :"]news:[email hidden]:

Quoted message said:

I'd go with the 1 1/4. The only benefit of narrow tires is the ability to run 110 psi and up. At
a given pressure fatter tires have less rolling resistance (due to less hysteresis).

While that partially is true, it is not a valid argument. If two tires have identical
construction, except that one is wider, you should *not* run them at the same pressure.

Why not? If the max pressure on a 1" tire is 140 psi and it's 100 psi on a 1 1/4" tire but you're
only planning on running 100 psi why can't you run the 1 1/4" at 100 psi?

Quoted message said:

The narrower tire will have a higher optimal pressure and thus a lower rolling resistance.
The wider tire will weigh more and roll slower, but give you a plusher ride, especially on
rough roads.

And the wider tire has less rolling resistance at the same pressure just like I said (due to less
hysteresis). The wider tire will roll faster than the skinnier tire at the same pressure. Did you
read what I said? "At a given pressure fatter tires have less rolling resistance".

Greg

Not sure if I can get my head around that one. You're saying that if I had a 1 meter wide tire, and
a 1cm wide tire (assuming smooth tread), then the 1 meter wide tire will roll faster, not taking int
account weight and momentum? The tire is going to have a larger contact patch, which means more
deformity of the tire with the surface its on, which means more energy loss (hence more hysteresis).
Granted, it'll have massive grip, but not sure if I agree with your statement. I'm probably wrong,
and would love to be proved so, but I can't get my mind around that one.

Jon Bond

Jonathan Bond said:

G.T. said:

Ken said:

"G.T." <[email hidden]> wrote in :"]news:[email hidden]:

> I'd go with the 1 1/4. The only benefit of narrow tires is the ability to run 110 psi and up.
> At a given pressure fatter tires have less rolling resistance (due to less hysteresis).

While that partially is true, it is not a valid argument. If two tires have identical
construction, except that one is wider, you should *not* run them at the same pressure.

Why not? If the max pressure on a 1" tire is 140 psi and it's 100 psi on a 1 1/4" tire but you're
only planning on running 100 psi why can't you run the 1 1/4" at 100 psi?

Quoted message said:

The narrower tire will have a higher optimal pressure and thus a lower rolling resistance. The
wider tire will weigh more and roll slower, but give you a plusher ride, especially on rough
roads.

And the wider tire has less rolling resistance at the same pressure just like I said (due to less
hysteresis). The wider tire will roll faster than the skinnier tire at the same pressure. Did you
read what I said? "At a given pressure fatter tires have less rolling resistance".

Greg

Not sure if I can get my head around that one. You're saying that if I had a 1 meter wide tire,
and a 1cm wide tire (assuming smooth tread), then the 1 meter wide tire will roll faster, not
taking int account weight and momentum? The tire is going to have a larger contact patch, which
means more deformity of the tire with the surface its on, which means more energy loss (hence more
hysteresis). Granted, it'll have massive grip, but not sure if I agree with your statement. I'm
probably wrong, and would love to be proved so, but I can't get my mind around that one.

I interchanged "less rolling resistance" and "rolling faster" because I was talking about tires of
only 1/4" difference in width and assuming they would be constructed similarly. A 1 1/4" wide tire
at 100 psi (if it's rated for 100 psi) will roll faster than a 1" wide tire at 100 psi if they are
constructed similarly. This is tires 101.

draco.acs.uci.edu8b.14.htmlOpen ↗

The reasons narrower tires usually have less rolling resistance is that they are usually constructed
differently than wider tires. If you take a Conti Grand Prix 25mm and a 20mm and inflate them to 95
psi the 25mm is going to be faster. This isn't specifically mentioned in the r.b.t. FAQ but this has
been discussed at length on r.b.t. I was schooled on this long ago.

Greg
--
"Destroy your safe and happy lives before it is too late, the battles we fought were long and hard,
just not to be consumed by rock n' roll..." - The Mekons

"G.T." <[email hidden]> wrote in :"]news:[email hidden]:

Quoted message said:

And the wider tire has less rolling resistance at the same pressure just like I said (due to less
hysteresis). The wider tire will roll faster than the skinnier tire at the same pressure. Did you
read what I said? "At a given pressure fatter tires have less rolling resistance".

Sheldon Brown says "at the same pressure" is a bogus argument. See:
sheldonbrown.comtires.htmlOpen ↗