Tire Width and Speed

smyrna45 said:

Is there a source on the net that shows any scientific data on speed
vs tire width, or failing that rolling resistance vs tire width?

Here are some rolling resistance test results:

http://bike.terrymorse.com/rolres.html

--
terry morse Palo Alto, CA http://bike.terrymorse.com/

smyrna45 said:

I am sure this has probably been answered here numerous times,
although I can't seem to find a definitive answer by googling the
newsgroups. I also find "Bicycling Science" to be lacking on the
subject, although its great on most other topics such as tire pressure
and diamter.

On my recently acquired Miele I have 700 x 32c tires. I am sure its an
improvement over my old 27 x 1 1/4 tires on my old Huffy and Schwinn.
I do most of my riding on a relatively flat paved muliti-use trail. I
am trying to decide whether it would make sense for me to get some
skinnier tires, such as 25c's. Most of what I read seems a bit vague,
using such terms as it will only make a minor difference in speed. I
don't know how much "minor" is. I do know skinnier tires are more flat
prone and not as easy to handle on the occasional sand or mud patches.

Is there a source on the net that shows any scientific data on speed
vs tire width, or failing that rolling resistance vs tire width?

Depends how fast you go. For riding over 20mph, narrow tyres will win
out because air resistance is far more significant than rolling
resistance. If you pootle, use the wider ones.

On Tue, 27 Jul 2004 09:31:18 -0400, smyrna45 <[email hidden]>

Quoted message said:

On my recently acquired Miele I have 700 x 32c tires. I am sure its an
improvement over my old 27 x 1 1/4 tires on my old Huffy and Schwinn.
I do most of my riding on a relatively flat paved muliti-use trail. I
am trying to decide whether it would make sense for me to get some
skinnier tires, such as 25c's. Most of what I read seems a bit vague,
using such terms as it will only make a minor difference in speed. I
don't know how much "minor" is. I do know skinnier tires are more flat
prone and not as easy to handle on the occasional sand or mud patches.

Is there a source on the net that shows any scientific data on speed
vs tire width, or failing that rolling resistance vs tire width?

Speed is a function of power input vs. power loss; tires contribute
only one part of the loss.

Tire construction and inflation pressure has more of a bearing on
rolling resistance than width; testing has shown that there is no
direct correlation between width and rolling resistance within the
range of road tires tested. There is no extensive database to consult
for information on the rolling resistance of tires currently on the
market, so it is difficult to state whether any given tire has high,
moderate or low resistance. The aerodynamic drag of the tire is
unlikely to be a significant factor for the casual rider.

One thing that is frequently reported, however, is that narrower tires
ride rougher than wider ones (which is most likely due to higher
inflation pressures being used in the narrower tires), and often are
reported to have a higher rate of punctures.

All things considered, given where you ride, I'd advise staying with
the 700x32.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

smyrna45 said:

Is there a source on the net that shows any scientific data on
speed vs tire width, or failing that rolling resistance vs
tire width?

Schwalbe has a little info on rolling resistance at
http://www.schwalbe.com/index.pl?punkt=265

John

smyrna45 wrote in message ...

Quoted message said:

On my recently acquired Miele I have 700 x 32c tires. I am sure its an
improvement over my old 27 x 1 1/4 tires on my old Huffy and Schwinn.
I do most of my riding on a relatively flat paved muliti-use trail. I
am trying to decide whether it would make sense for me to get some
skinnier tires, such as 25c's. Most of what I read seems a bit vague,
using such terms as it will only make a minor difference in speed. I
don't know how much "minor" is. I do know skinnier tires are more flat
prone and not as easy to handle on the occasional sand or mud patches.

Is there a source on the net that shows any scientific data on speed
vs tire width, or failing that rolling resistance vs tire width?

Road grip, rolling resistance and handling is all improved by a more
flexible casing.
If you can feel the difference manipulating the tyres with your hands,
there will also be a noticable difference on the road. Some tyres use a
low thread count, these would be expected to puncture more frequently and
wear out more quickly as the rubber has to do more work. A highly flexible
casing with fine thread laid flat, not woven, and a thin covering of rubber
is approaching the ideal of a pneumatic tyre.
I feel it is always best to go for the thin tyre, dependant on frequency
of debris, but not necessarily a narrow tyre. A narrow tyre, especially of
the wired-on type, requires extreme high pressure to avoid pinch punctures.
A consequence of this is a shortening of the tyre contact patch which makes
a bike skittish through corners in the dry and liable to side slip when the
road is wet.
Narrow tyres are not difficult to handle, they are different. Narrow
tyres with low pressure or excessively high pressure are compromised.
If you really want narrow tyres, you need to try tubular tyres which come
with a collection of perceived problems.
Recommendations are difficult. Testing is needed upon the roads that
you use, with pressures that give an acceptable level of comfort and grip
without compromising puncture risk.
TJ

smyrna45 <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

I am sure this has probably been answered here numerous times,
although I can't seem to find a definitive answer by googling the
newsgroups. I also find "Bicycling Science" to be lacking on the
subject, although its great on most other topics such as tire pressure
and diamter.

On my recently acquired Miele I have 700 x 32c tires. I am sure its an
improvement over my old 27 x 1 1/4 tires on my old Huffy and Schwinn.
I do most of my riding on a relatively flat paved muliti-use trail. I
am trying to decide whether it would make sense for me to get some
skinnier tires, such as 25c's. Most of what I read seems a bit vague,
using such terms as it will only make a minor difference in speed. I
don't know how much "minor" is. I do know skinnier tires are more flat
prone and not as easy to handle on the occasional sand or mud patches.

Is there a source on the net that shows any scientific data on speed
vs tire width, or failing that rolling resistance vs tire width?

If you want to compare tires of different widths, make sure you pick
tires of comparable quality. Your chances of getting a high quality
tire (i.e., fairly lightweight and supple) are probably better in the
25mm width (since many wider tires seem aimed at people who won't
tolerate flats).

I once had a pair of Specialized Armadillo tires in a wider size
(either 28mm or 32mm) and found them to be terrible -- heavy and
harsh-riding. For a while I stayed away from all wide tires because I
thought that was the nature of the beast. But then I discovered tires
like the Avocet FasGrip and the Panaracer Pasela (both available in
sizes bigger than 25mm).