Are narrower tires really more efficient?

[Dien Cai Dau]

I am riding the stock 700x38c tires that came on my road bike; right now
riding circuits of 20 to 30 or more miles, trying to work up to riding
century tours.

I have been told that if I changed to narrower tires (700x32c) I would
reduce rolling resistance and would be able to expend a little less energy
pedaling. Unless my math is wrong, the difference in circumference of the
two tire sizes in miniscule but over distance is does factor in -- for a
20-mile ride the narrower tire will have to make about 220 more revolutions
than the slightly wider one.

My question to the group is whether the energy savings of lower resistance
with the road exceed the energy expenditure of having to pedal the tires
through more revolutions?

 

[[email protected]]

On Oct 5, 11:06 pm, "Dien Cai Dau" <[email protected]> wrote:
> I am riding the stock 700x38c tires that came on my road bike; right now
> riding circuits of 20 to 30 or more miles, trying to work up to riding
> century tours.
>
> I have been told that if I changed to narrower tires (700x32c) I would
> reduce rolling resistance and would be able to expend a little less energy
> pedaling. Unless my math is wrong, the difference in circumference of the
> two tire sizes in miniscule but over distance is does factor in -- for a
> 20-mile ride the narrower tire will have to make about 220 more revolutions
> than the slightly wider one.
>
> My question to the group is whether the energy savings of lower resistance
> with the road exceed the energy expenditure of having to pedal the tires
> through more revolutions?

I really doubt that you'll notice much difference, probably not nearly
enough to make up for the cost of the new pair of tires.

Smokey

 

[[email protected]]

On Oct 6, 12:06 am, "Dien Cai Dau" <[email protected]> wrote:
> I am riding the stock 700x38c tires that came on my road bike; right now
> riding circuits of 20 to 30 or more miles, trying to work up to riding
> century tours.
>
> I have been told that if I changed to narrower tires (700x32c) I would
> reduce rolling resistance and would be able to expend a little less energy
> pedaling. Unless my math is wrong, the difference in circumference of the
> two tire sizes in miniscule but over distance is does factor in -- for a
> 20-mile ride the narrower tire will have to make about 220 more revolutions
> than the slightly wider one.
>
> My question to the group is whether the energy savings of lower resistance
> with the road exceed the energy expenditure of having to pedal the tires
> through more revolutions?

Unless you are riding a single speed bike, the slightly smaller
circumference doesn't mean you'll move the pedals any more, if that's
what you were thinking of. You'll ride in a slightly higher gear, on
average, and make up for the difference in circumference.

And you will have slightly less rolling resistance, despite the
difference in circumference. Don't worry about the circumference.
You'll see a net improvement.

For what it's worth, I'd never try a century on 38 mm tires. And
unless I was riding on super-rough surfaces, or carrying camping gear,
I probably wouldn't even use 32s. Most organized century rides are on
fairly smooth roads, where maybe 28s (or even narrower) are
appropriate.

- Frank Krygowski

 

[Tom \Johnny Sunset\ Sherman]

[email protected] aka Frank Krygowski wrote:
> ...
> For what it's worth, I'd never try a century on 38 mm tires. And
> unless I was riding on super-rough surfaces, or carrying camping gear,
> I probably wouldn't even use 32s. Most organized century rides are on
> fairly smooth roads, where maybe 28s (or even narrower) are
> appropriate.

Huh? I road a double-metric century in about 6-1/2 hours on 47-mm wide
tires, and my best century time was on 44-mm wide tires.

--
Tom Sherman - Holstein-Friesland Bovinia
A Real Cyclist [TM] keeps at least one bicycle in the bedroom.

--
Posted via a free Usenet account from http://www.teranews.com

 

[Stephen Harding]

[email protected] wrote:

> For what it's worth, I'd never try a century on 38 mm tires. And
> unless I was riding on super-rough surfaces, or carrying camping gear,
> I probably wouldn't even use 32s. Most organized century rides are on
> fairly smooth roads, where maybe 28s (or even narrower) are
> appropriate.

I think the only tire "inappropriate" for a century ride
would be something with a knobby tread.

If it's a road tire, 38 or 21mm doesn't make much of any
difference.

My joy bike has 25mm tires and my tourer has 37mm and I
can't really tell much performance difference between the
two on a century ride with the exception that the 37's
make for a generally more comfortable ride.

Now off course I'm not in a pace line or trying to keep
up with anyone. Just covering the distance. If you're
trying to stay with a pack, then you'd go for the higher
pressure skinny tires to help you out.

Why anyone would want to do a century ride in this way
is beyond me though.


SMH

 

[Roger Zoul]

"Stephen Harding" <[email protected]> wrote in message
news:qb3Oi.1869$pl2.399@trndny07...
> I think the only tire "inappropriate" for a century ride
> would be something with a knobby tread.
>
> If it's a road tire, 38 or 21mm doesn't make much of any
> difference.
>
> My joy bike has 25mm tires and my tourer has 37mm and I
> can't really tell much performance difference between the
> two on a century ride with the exception that the 37's
> make for a generally more comfortable ride.
>
> Now off course I'm not in a pace line or trying to keep
> up with anyone. Just covering the distance. If you're
> trying to stay with a pack, then you'd go for the higher
> pressure skinny tires to help you out.
>
> Why anyone would want to do a century ride in this way
> is beyond me though.

Which way? Seems as if you're saying the skinnier tires are faster and
fatter tires are more comfortable. So, if you want comfort, use fatter
tires, if you want faster, use skinnier. So, which way is "beyond" you?
Seems as if you appreciate both advantages. What seems to be the case most
often, in my POV, that ligher rides don't mind skinny and like to go fast
and get the ride done. Heavier riders take longer and appreciate the
comfort. Or, perhaps some older riders enjoy the comfort. Or, perhaps those
who enjoy looking at the scenery along the route enjoy the comfort...or
those who aren't pack riders. But I'm sure you can find those who like to
look but also like to go fast, so they might want skinny so they can look
when they want to and then "put the hammer down" when they need to worry
about getting home.

 

[Just A User]

Tom "Johnny Sunset" Sherman wrote:
> [email protected] aka Frank Krygowski wrote:
>> ...
>> For what it's worth, I'd never try a century on 38 mm tires. And
>> unless I was riding on super-rough surfaces, or carrying camping gear,
>> I probably wouldn't even use 32s. Most organized century rides are on
>> fairly smooth roads, where maybe 28s (or even narrower) are
>> appropriate.
>
> Huh? I road a double-metric century in about 6-1/2 hours on 47-mm wide
> tires, and my best century time was on 44-mm wide tires.
>
Double metric in six and a half. Pretty good. What were you riding? I
have done a single metric in 4 hours.

 

[Tom \Johnny Sunset\ Sherman]

Just A User wrote:
> Tom "Johnny Sunset" Sherman wrote:
>> [email protected] aka Frank Krygowski wrote:
>>> ...
>>> For what it's worth, I'd never try a century on 38 mm tires. And
>>> unless I was riding on super-rough surfaces, or carrying camping gear,
>>> I probably wouldn't even use 32s. Most organized century rides are on
>>> fairly smooth roads, where maybe 28s (or even narrower) are
>>> appropriate.
>>
>> Huh? I road a double-metric century in about 6-1/2 hours on 47-mm wide
>> tires, and my best century time was on 44-mm wide tires.
>>
> Double metric in six and a half. Pretty good. What were you riding? I
> have done a single metric in 4 hours.

See <http://www.ransbikes.com/Gallery/Archive/images/Sherman1.jpg>.

Tire were 47-406 Mitsuboshi Tioga Comp Pools.

--
Tom Sherman - Holstein-Friesland Bovinia
A Real Cyclist [TM] keeps at least one bicycle in the bedroom.

--
Posted via a free Usenet account from http://www.teranews.com

 

[[email protected]]

On Oct 7, 10:20 am, "Tom \"Johnny Sunset\" Sherman"
<[email protected]> wrote:
> Just A User wrote:
> > Tom "Johnny Sunset" Sherman wrote:
> >> [email protected] aka Frank Krygowski wrote:
> >>> ...
> >>> For what it's worth, I'd never try a century on 38 mm tires. And
> >>> unless I was riding on super-rough surfaces, or carrying camping gear,
> >>> I probably wouldn't even use 32s. Most organized century rides are on
> >>> fairly smooth roads, where maybe 28s (or even narrower) are
> >>> appropriate.
>
> >> Huh? I road a double-metric century in about 6-1/2 hours on 47-mm wide
> >> tires, and my best century time was on 44-mm wide tires.
>
> > Double metric in six and a half. Pretty good. What were you riding? I
> > have done a single metric in 4 hours.
>
> See <http://www.ransbikes.com/Gallery/Archive/images/Sherman1.jpg>.
>
> Tire were 47-406 Mitsuboshi Tioga Comp Pools.

Hmm. I wonder if there were any significant differences between your
bike and mine (and the OP's). What do you think?

FWIW, not only are my tires narrower than yours, they're also way
larger in diameter.

- Frank Krygowski

 

[Mike Kruger]

Tom "Johnny Sunset" Sherman wrote:
> [email protected] aka Frank Krygowski wrote:
>> ...
>> For what it's worth, I'd never try a century on 38 mm tires. And
>> unless I was riding on super-rough surfaces, or carrying camping
>> gear, I probably wouldn't even use 32s. Most organized century
>> rides are on fairly smooth roads, where maybe 28s (or even narrower)
>> are appropriate.
>
> Huh? I road a double-metric century in about 6-1/2 hours on 47-mm wide
> tires, and my best century time was on 44-mm wide tires.
>
I did a century earlier this year on my recumbent with 1.95 inch wide tires
(49.5 mm) -- Maxxis hookworms, that carry 110 psi. (slower than Tom did,
unfortunately)

I don't claim expertise, but I thought that tread pattern and PSI were more
important than width.

 

[[email protected]]

On Oct 7, 12:44 pm, "Mike Kruger" <[email protected]> wrote:
> Tom "Johnny Sunset" Sherman wrote:> [email protected] aka Frank Krygowski wrote:
> >> ...
> >> For what it's worth, I'd never try a century on 38 mm tires. And
> >> unless I was riding on super-rough surfaces, or carrying camping
> >> gear, I probably wouldn't even use 32s. Most organized century
> >> rides are on fairly smooth roads, where maybe 28s (or even narrower)
> >> are appropriate.
>
> > Huh? I road a double-metric century in about 6-1/2 hours on 47-mm wide
> > tires, and my best century time was on 44-mm wide tires.
>
> I did a century earlier this year on my recumbent with 1.95 inch wide tires
> (49.5 mm) -- Maxxis hookworms, that carry 110 psi. (slower than Tom did,
> unfortunately)
>
> I don't claim expertise, but I thought that tread pattern and PSI were more
> important than width.

I haven't made an in-depth study of the issue, but my impression is
that a) tread hurts rolling resistance; b) higher pressure helps,
provided the road is smooth enough. (You don't so much pressure that
the tire becomes effectively rigid at the roughness you encounter); c)
thick rubber and thick, low thread count fabric hurt, and d) width
wouldn't be a big problem (and might even be an advantage) if it
weren't for "c."

But my impression is that most wider tires also have thicker sidewalls
and coarser fabric reinforcement, which gives more hysteresis losses
and more rolling resistance. I've heard there are exceptions, but
that they're not easy to find.

BTW, the wide Conti Top Touring tires I passed on to a friend (37mm, I
think) were reputed to be wide tires with good rolling. But he told
me that their sidewalls had failed for him, just as their "sister"
pair failed for me. Too thin and supple for durability?

- Frank Krygowski

 

[Bob]

On Oct 7, 7:28 am, "Roger Zoul" <[email protected]> wrote:
> "Stephen Harding" <[email protected]> wrote in message
>
> news:qb3Oi.1869$pl2.399@trndny07...
>
>
>
>
>
> > I think the only tire "inappropriate" for a century ride
> > would be something with a knobby tread.
>
> > If it's a road tire, 38 or 21mm doesn't make much of any
> > difference.
>
> > My joy bike has 25mm tires and my tourer has 37mm and I
> > can't really tell much performance difference between the
> > two on a century ride with the exception that the 37's
> > make for a generally more comfortable ride.
>
> > Now off course I'm not in a pace line or trying to keep
> > up with anyone. Just covering the distance. If you're
> > trying to stay with a pack, then you'd go for the higher
> > pressure skinny tires to help you out.
>
> > Why anyone would want to do a century ride in this way
> > is beyond me though.
>
> Which way?

The way I read it he was saying he doesn't understand why anyone would
want to do a century in a paceline, just trying to keep up with other
riders, or just grinding out the miles. I can understand that
sentiment.

Regards,
Bob Hunt

 

[smn]

"Dien Cai Dau" <[email protected]> wrote in message
news:[email protected]...
>I am riding the stock 700x38c tires that came on my road bike; right now
>riding circuits of 20 to 30 or more miles, trying to work up to riding
>century tours.
>
> I have been told that if I changed to narrower tires (700x32c) I would
> reduce rolling resistance and would be able to expend a little less energy
> pedaling. Unless my math is wrong, the difference in circumference of the
> two tire sizes in miniscule but over distance is does factor in -- for a
> 20-mile ride the narrower tire will have to make about 220 more
> revolutions than the slightly wider one.
>
> My question to the group is whether the energy savings of lower resistance
> with the road exceed the energy expenditure of having to pedal the tires
> through more revolutions?
So you think you are sitting higher on 38's. No, cause they get less psi.
the resistance comes from having less air. My narrow width 26in MTB tires
would probably outperform yours cause they hold 100 psi

 

[Just A User]

Tom "Johnny Sunset" Sherman wrote:
> Just A User wrote:
>> Tom "Johnny Sunset" Sherman wrote:
>>> [email protected] aka Frank Krygowski wrote:
>>>> ...
>>>> For what it's worth, I'd never try a century on 38 mm tires. And
>>>> unless I was riding on super-rough surfaces, or carrying camping gear,
>>>> I probably wouldn't even use 32s. Most organized century rides are on
>>>> fairly smooth roads, where maybe 28s (or even narrower) are
>>>> appropriate.
>>>
>>> Huh? I road a double-metric century in about 6-1/2 hours on 47-mm
>>> wide tires, and my best century time was on 44-mm wide tires.
>>>
>> Double metric in six and a half. Pretty good. What were you riding? I
>> have done a single metric in 4 hours.
>
> See <http://www.ransbikes.com/Gallery/Archive/images/Sherman1.jpg>.
>
> Tire were 47-406 Mitsuboshi Tioga Comp Pools.
>
That's a tailwind correct? With dual 20's (406)? Interesting. That seems
like a pretty fast ride for that bike. I mean I am sure that the front
fairing and body soc helped with the speed. But from my limited
experience with small rear tires is that the overall speed seems to less
than with a larger tire. I think I am considerably faster with the 26
tire on my v2 than one my ez-1 with a 20 in back.

 

[Tom Sherman]

Just A User wrote:
> Tom "Johnny Sunset" Sherman wrote:
>> Just A User wrote:
>>> Tom "Johnny Sunset" Sherman wrote:
>>>> [email protected] aka Frank Krygowski wrote:
>>>>> ...
>>>>> For what it's worth, I'd never try a century on 38 mm tires. And
>>>>> unless I was riding on super-rough surfaces, or carrying camping gear,
>>>>> I probably wouldn't even use 32s. Most organized century rides are on
>>>>> fairly smooth roads, where maybe 28s (or even narrower) are
>>>>> appropriate.
>>>>
>>>> Huh? I road a double-metric century in about 6-1/2 hours on 47-mm
>>>> wide tires, and my best century time was on 44-mm wide tires.
>>>>
>>> Double metric in six and a half. Pretty good. What were you riding? I
>>> have done a single metric in 4 hours.
>>
>> See <http://www.ransbikes.com/Gallery/Archive/images/Sherman1.jpg>.
>>
>> Tire were 47-406 Mitsuboshi Tioga Comp Pools.
>>
> That's a tailwind correct? With dual 20's (406)? Interesting. That seems
> like a pretty fast ride for that bike. I mean I am sure that the front
> fairing and body soc helped with the speed. But from my limited
> experience with small rear tires is that the overall speed seems to less
> than with a larger tire. I think I am considerably faster with the 26
> tire on my v2 than one my ez-1 with a 20 in back.

Strictly speaking, the bike started life as a RANS Wave, but I purchased
a fork for a 406-mm wheel. The Wave and Tailwind frames at that time
were identical, with only the fork being different (the Wave used an ISO
305-mm wheel).

The Zzipper fairing and bodysock definitely helps with the speed.

I think a V2 with an ISO 406-mm rear wheel would still be considerably
faster than an EZ-1. The V2 would have a lower seat height, greater seat
recline, and lighter weight.

--
Tom Sherman - Holstein-Friesland Bovinia
Beer - It's not just for breakfast anymore!

 

[Tom Sherman]

[email protected] aka Frank Krygowski wrote:
> On Oct 7, 10:20 am, "Tom \"Johnny Sunset\" Sherman"
> <[email protected]> wrote:
>> Just A User wrote:
>>> Tom "Johnny Sunset" Sherman wrote:
>>>> [email protected] aka Frank Krygowski wrote:
>>>>> ...
>>>>> For what it's worth, I'd never try a century on 38 mm tires. And
>>>>> unless I was riding on super-rough surfaces, or carrying camping gear,
>>>>> I probably wouldn't even use 32s. Most organized century rides are on
>>>>> fairly smooth roads, where maybe 28s (or even narrower) are
>>>>> appropriate.
>>>> Huh? I road a double-metric century in about 6-1/2 hours on 47-mm wide
>>>> tires, and my best century time was on 44-mm wide tires.
>>> Double metric in six and a half. Pretty good. What were you riding? I
>>> have done a single metric in 4 hours.
>> See <http://www.ransbikes.com/Gallery/Archive/images/Sherman1.jpg>.
>>
>> Tire were 47-406 Mitsuboshi Tioga Comp Pools.
>
> Hmm. I wonder if there were any significant differences between your
> bike and mine (and the OP's). What do you think?

Most likely.
>
> FWIW, not only are my tires narrower than yours, they're also way
> larger in diameter.

butbutbut, you did not specify that in you post. A better statement
would have been, "I'd never try a century on 38 mm tires, on a bicycle
with wheel sizes ranging from ISO 571-mm to ISO 630-mm".

--
Tom Sherman - Holstein-Friesland Bovinia
Beer - It's not just for breakfast anymore!

 

[Tom Sherman]

Mike Kruger wrote:
> Tom "Johnny Sunset" Sherman wrote:
>> [email protected] aka Frank Krygowski wrote:
>>> ...
>>> For what it's worth, I'd never try a century on 38 mm tires. And
>>> unless I was riding on super-rough surfaces, or carrying camping
>>> gear, I probably wouldn't even use 32s. Most organized century
>>> rides are on fairly smooth roads, where maybe 28s (or even narrower)
>>> are appropriate.
>> Huh? I road a double-metric century in about 6-1/2 hours on 47-mm wide
>> tires, and my best century time was on 44-mm wide tires.
>>
> I did a century earlier this year on my recumbent with 1.95 inch wide tires
> (49.5 mm) -- Maxxis hookworms, that carry 110 psi. (slower than Tom did,
> unfortunately)
>
> I don't claim expertise, but I thought that tread pattern and PSI were more
> important than width.

And tire indestructibility (relatively speaking)? I have Hookworms on my
trike, since they allow me (combined with the rear suspension) to ignore
most road hazards.

If it makes you feel better, I would be much slower on the trike than on
a bicycle with a front fairing and bodysock.

--
Tom Sherman - Holstein-Friesland Bovinia
Beer - It's not just for breakfast anymore!

 

[Tom Sherman]

Stephen Harding wrote:
> [email protected] wrote:
>
>> For what it's worth, I'd never try a century on 38 mm tires. And
>> unless I was riding on super-rough surfaces, or carrying camping gear,
>> I probably wouldn't even use 32s. Most organized century rides are on
>> fairly smooth roads, where maybe 28s (or even narrower) are
>> appropriate.
>
> I think the only tire "inappropriate" for a century ride
> would be something with a knobby tread.
>
> If it's a road tire, 38 or 21mm doesn't make much of any
> difference.
>
> My joy bike has 25mm tires and my tourer has 37mm and I
> can't really tell much performance difference between the
> two on a century ride with the exception that the 37's
> make for a generally more comfortable ride.
>
> Now off course I'm not in a pace line or trying to keep
> up with anyone. Just covering the distance. If you're
> trying to stay with a pack, then you'd go for the higher
> pressure skinny tires to help you out.
>
> Why anyone would want to do a century ride in this way
> is beyond me though.

I say a guy [1] on a full-suspension ATB with knobby tires on an
invitational ride. There was considerable pogo of the suspension as he
rode. That he was able to maintain almost 20 mph on the flats was most
annoying.

[1] Probably early 20's with sub 5% body fat.

--
Tom Sherman - Holstein-Friesland Bovinia
Beer - It's not just for breakfast anymore!

 

[Tom Sherman]

Cyclist Bob Hunt wrote:
> On Oct 7, 7:28 am, "Roger Zoul" <[email protected]> wrote:
>> "Stephen Harding" <[email protected]> wrote in message
>>
>> news:qb3Oi.1869$pl2.399@trndny07...

>>
>>> I think the only tire "inappropriate" for a century ride
>>> would be something with a knobby tread.
>>> If it's a road tire, 38 or 21mm doesn't make much of any
>>> difference.
>>> My joy bike has 25mm tires and my tourer has 37mm and I
>>> can't really tell much performance difference between the
>>> two on a century ride with the exception that the 37's
>>> make for a generally more comfortable ride.
>>> Now off course I'm not in a pace line or trying to keep
>>> up with anyone. Just covering the distance. If you're
>>> trying to stay with a pack, then you'd go for the higher
>>> pressure skinny tires to help you out.
>>> Why anyone would want to do a century ride in this way
>>> is beyond me though.
>> Which way?
>
> The way I read it he was saying he doesn't understand why anyone would
> want to do a century in a paceline, just trying to keep up with other
> riders, or just grinding out the miles. I can understand that
> sentiment.

It does seem rather odd behavior for an invitational ride. If one wants
to ride hard in a paceline, why not join a club that does "training" rides?

Similarly, there are people who skip rest stops so they can have better
overall times. Seems to miss the point of an invitational ride.

--
Tom Sherman - Holstein-Friesland Bovinia
Beer - It's not just for breakfast anymore!

 

[[email protected]]

On Oct 14, 9:05 am, Tom Sherman <[email protected]> wrote:
> [email protected] aka Frank Krygowski wrote:
>
>
> >> Tire were 47-406 Mitsuboshi Tioga Comp Pools.
>
> > Hmm. I wonder if there were any significant differences between your
> > bike and mine (and the OP's). What do you think?
>
> Most likely.
>
> > FWIW, not only are my tires narrower than yours, they're also way
> > larger in diameter.
>
> butbutbut, you did not specify that in you post. A better statement
> would have been, "I'd never try a century on 38 mm tires, on a bicycle
> with wheel sizes ranging from ISO 571-mm to ISO 630-mm".

Sorry, your logic is wrong.

My statement is correct as it stands. A smaller wheel diameter would
not tempt me to violate what I said.

- Frank Krygowski