Wider Rims for Roadies ?

I have seen quite a few reviews extolling the virtues of wider clincher rims
for road use--23mm instead of the usual 19mm. The arguments generally
revolve around the "improved" tire cross-section, i.e. less of a
cinched-down light bulb shape as well as increased air volume. This is said
to improve ride feel, perhaps less squirm around corners and more forgiving
of rough roads. I would guess the aerodynamic penalties are minimal if any
and the rolling resistance moot. People mention a distinctly "tubular"
feel, but that is meaningless to me since I have never ridden on sew ups.

Unfortunately the claims above occur in the context of someone having spend
$$$$ for a new set of boutique wheels and is usually accompanied by drivel
about how "round" the wheel is and how wonderfully it "rolls". Is there any
test data to verify any of this?

Has anyone tried a direct comparison, perhaps with the same brand of tire?
If so, how does the improvement increment, if any, compare to going from
23mm tires to 25mm?

Cheers, Shawn

PS: My apologies if I have missed a recent discussion on the subject,
kindly point me at it.

RimaNeas wrote:
I have seen quite a few reviews extolling the virtues of wider clincher rims
for road use--23mm instead of the usual 19mm. The arguments generally
revolve around the "improved" tire cross-section, i.e. less of a
cinched-down light bulb shape as well as increased air volume. This is said
to improve ride feel, perhaps less squirm around corners and more forgiving
of rough roads. I would guess the aerodynamic penalties are minimal if any
and the rolling resistance moot. People mention a distinctly "tubular"
feel, but that is meaningless to me since I have never ridden on sew ups.

Unfortunately the claims above occur in the context of someone having spend
$$$$ for a new set of boutique wheels and is usually accompanied by drivel
about how "round" the wheel is and how wonderfully it "rolls". Is there any
test data to verify any of this?

Has anyone tried a direct comparison, perhaps with the same brand of tire?
If so, how does the improvement increment, if any, compare to going from
23mm tires to 25mm?

Cheers, Shawn

PS: My apologies if I have missed a recent discussion on the subject,
kindly point me at it.



I can't help specifically but the world is full of mountain
bikes with 23~25mm rims and 32~35mm slicks. Perhaps borrow
one and see if you can 'feel the magic' ?

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On 19 Oct, 00:04, "RimaNeas" wrote:
I have seen quite a few reviews extolling the virtues of wider clincher rims
for road use--23mm instead of the usual 19mm. *The arguments generally
revolve around the "improved" tire cross-section, i.e. less of a
cinched-down light bulb shape as well as increased air volume. *This is said
to improve ride feel, perhaps less squirm around corners and more forgiving
of rough roads. *I would guess the aerodynamic penalties are minimal if any
and the rolling resistance moot. *People mention a distinctly "tubular"
feel, but that is meaningless to me since I have never ridden on sew ups.

Tubs grip the road better, they steer quicker and are better in
isolating the rider from vibration. A good wired on tyre can do
almost ass good a job in a bigger section. Bigger sections need wider
rims else the tyre may become prone to lifting of the rim in or
following a hard corner.

Unfortunately the claims above occur in the context of someone having spend
$$$$ for a new set of boutique wheels and is usually accompanied by drivel
about how "round" the wheel is and how wonderfully it "rolls". *Is there any
test data to verify any of this?

Tape a depth gauge to the rim and hub of a wheel and measure the
movement of the rim at the ground with the wheel loaded at the axle
with all your weight and without. A digital 'vernier' caliper gauge
is pretty easy to set up and measure this.
The differences is usually more evident in attention to wheel build
than to components used.


Has anyone tried a direct comparison, perhaps with the same brand of tire?
If so, how does the improvement increment, if any, compare to going from
23mm tires to 25mm?

er, why not 25, 28?

Choice of tyre is necessarily subjective. If you want a faster tyre
for time trialling, then maybe a 23mm could be a good choice, it
depends on yourself and the road on which you are riding on how you
cope with the vibration, how it affects your output power or how it
fatigues you over the distance. 22/23mm is the standard tubular size
suitable for the average male adult racer. To attempt to give a
comparison in ride a wired on tyre must be bigger.

"AMuzi" wrote in message
...
RimaNeas wrote:
I have seen quite a few reviews extolling the virtues of wider
clincher rims for road use--23mm instead of the usual 19mm. The
arguments generally revolve around the "improved" tire cross-section,
i.e. less of a cinched-down light bulb shape as well as increased air
volume. This is said to improve ride feel, perhaps less squirm
around corners and more forgiving of rough roads. I would guess the
aerodynamic penalties are minimal if any and the rolling resistance
moot. People mention a distinctly "tubular" feel, but that is
meaningless to me since I have never ridden on sew ups.

Unfortunately the claims above occur in the context of someone having
spend $$$$ for a new set of boutique wheels and is usually
accompanied by drivel about how "round" the wheel is and how
wonderfully it "rolls". Is there any test data to verify any of
this?

Has anyone tried a direct comparison, perhaps with the same brand of
tire? If so, how does the improvement increment, if any, compare to
going from 23mm tires to 25mm?

Cheers, Shawn

PS: My apologies if I have missed a recent discussion on the
subject, kindly point me at it.



I can't help specifically but the world is full of mountain bikes with
23~25mm rims and 32~35mm slicks. Perhaps borrow one and see if you
can 'feel the magic' ?
--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

He likely won't, if he's looking for a difference in "feel." The move to
wider rims is all about aerodynamics, not road feel. That "lightbulb"
profile mentioned is terrible for aerodynamics. I suspect this matters
to a very small number of people.

It's funny that this is suddenly coming up as a big thing. During the
earliest days of the US Postal team, Trek was building them a wider
tubular rim than what was generally available for sale. It wasn't long
before the wider rim came over to the consumer line as well, but with
some resistance, since you couldn't interchange tubulars with the
now-narrower clincher rim without having to adjust the brakes.

Why not make wider clincher rims as well? Probably due to added weight
without added strength. The aerodynamic argument just hasn't caught on
(nor is it likely all that relevant) for the typical rider.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

In article ,
"RimaNeas" wrote:

I have seen quite a few reviews extolling the virtues of wider
clincher rims for road use--23mm instead of the usual 19mm. The
arguments generally revolve around the "improved" tire cross-section,
i.e. less of a cinched-down light bulb shape as well as increased air
volume. This is said to improve ride feel, perhaps less squirm
around corners and more forgiving of rough roads. I would guess the
aerodynamic penalties are minimal if any and the rolling resistance
moot. People mention a distinctly "tubular" feel, but that is
meaningless to me since I have never ridden on sew ups.

I think in large part the "tubular" feel was because most people
inflated them to 100 psi, whereas most 23 mm clinchers are inflated to
110-120 and sometimes more. The harder tire gives a rougher ride.

Unfortunately the claims above occur in the context of someone having
spend $$$$ for a new set of boutique wheels and is usually
accompanied by drivel about how "round" the wheel is and how
wonderfully it "rolls". Is there any test data to verify any of
this?

I highly doubt it. There is, however, a pretty good body of evidence
that wider tires have less rolling resistance (up to a point, anyway).
There is more recent evidence suggesting that wider, softer tires result
in less energy being needed to get down the road due to reducing
suspension losses. Those findings have not, to my knowledge, been
replicated.

There are a lot of fairly low-cost rims that are of these dimensions.
The Sun CR-18, for one.

Has anyone tried a direct comparison, perhaps with the same brand of
tire? If so, how does the improvement increment, if any, compare to
going from 23mm tires to 25mm?

Hmm, wider tires versus wider rims are two different discussions.

There are a lot of bikes with wider tires, as Andrew mentioned in his
post. I'd add trying some cyclo cross bikes with 70 x 28 road tires.

I ride "fatter" tires- 25-32 mm and find them cushier but there's no
magic about it.

Mike Jacoubowsky wrote:

The move to
wider rims is all about aerodynamics, not road feel. That "lightbulb"
profile mentioned is terrible for aerodynamics. I suspect this matters
to a very small number of people.
[...]
Why not make wider clincher rims as well? Probably due to added weight
without added strength. The aerodynamic argument just hasn't caught on
(nor is it likely all that relevant) for the typical rider.

The 24mm wide, 32mm tall Velocity Chukker should be just the thing for
OCD types whose cause du jour happens to be tire aerodynamics.
"Without added strength"? Yeah, right!

Chalo

On 19 Oct, 03:32, Tim McNamara wrote:

I think in large part the "tubular" feel was because most people
inflated them to 100 psi, whereas most 23 mm clinchers are inflated to
110-120 and sometimes more. *The harder tire gives a rougher ride.

110 about my limit, required overly careful riding to avoid bottoming
out at times. I run my tubs at around 90psi and falling. Nice to be
able to ignore tyre pressure until I do actually botttom out the
tyre. The pressure at this point is dead soft (under 30psi?). You
wouldn't dream of using such a low pressure on a narrow tyre if all
you're used to is wired on tyres.


Unfortunately the claims above occur in the context of someone having
spend $$$$ for a new set of boutique wheels and is usually
accompanied by drivel about how "round" the wheel is and how
wonderfully it "rolls". *Is there any test data to verify any of
this?

I highly doubt it. *There is, however, a pretty good body of evidence
that wider tires have less rolling resistance (up to a point, anyway). *
There is more recent evidence suggesting that wider, softer tires result
in less energy being needed to get down the road due to reducing
suspension losses. *Those findings have not, to my knowledge, been
replicated.

If the wheel is taken as a whole, and not separating the tyre as a
distinct entity then comparisons become valid. Precise method of
fitting of spokes and tyres significantly affects how a wheel performs
despite the use of same components. A standardised single wheel
trailer with load, springing and damping to represent a bicycle and
rider would be beneficial in determining different draw loads over
standard road surfaces with complete wheels at their best to
accomodate the test jig. It would be up to the wheel supplier to
specify tyre pressure for the jig intended. The wheel supplier
chooses and fits everything, only final running pressure to be
adjusted for comparison.

There are a lot of fairly low-cost rims that are of these dimensions. *
The Sun CR-18, for one.


I ride "fatter" tires- 25-32 mm and find them cushier but there's no
magic about it.

So which give the longest rollout for you at what pressure? You do
have records for your coasting race?

Chalo wrote:

The 24mm wide, 32mm tall Velocity Chukker should be just the thing for
OCD types whose cause du jour happens to be tire aerodynamics.
"Without added strength"? *Yeah, right!


Velocity Dyad often used by tandems gives tires an extra 2-3mm of
width compared to the same tire on an Aerohead 19mm? rim.
Great rim but keep an eye out for sidewalls contacting pavement on
tires 28mm and narrower.

Wayne

On Sun, 18 Oct 2009 21:32:30 -0500, Tim McNamara
wrote:

however, a pretty good body of evidence
that wider tires have less rolling resistance (up to a point, anyway).

And narrower tires have lower rolling resistance than wider ones down
to a point. A 1.5" tire rolls better than a 2" on roads for all but
the fattest fat boys,

I don't understand who you can make such simple statements as yours
above w/o reference to weight and what you are comparing.

PS: how much do you weigh?

JFT wrote:

Tim McNamara wrote:

however, a pretty good body of evidence
that wider tires have less rolling resistance (up to a point, anyway). *

And narrower tires have lower rolling resistance than wider ones down
to a point. *A 1.5" tire rolls better than a 2" on roads for all but
the fattest fat boys,

I've never seen any evidence to suggest that what you say here is
true. Wider tires have higher aerodynamic losses, and they lend
themselves to lower pressures (which in turn result in higher rolling
resistance), but the weight of experimental evidence suggests that for
a given tread thickness and pressure, fatter tires roll freer than
narrower ones regardless of width. This makes sense inasmuch as the
tread rubber flexes less to establish a given size footprint with a
fat tire than with a skinny one.

If you have data that suggest otherwise, please link to it.

The more I ride over poor pavement, the more I come to recognize that
gross rolling resistance is more a function of bump absorption and
restoration than it is a simple matter of hysteresis loss in the
tread. Few of us normally ride on roads so smooth that bumpiness is
not a major factor in rolling resistance. To mitigate this type of
energy loss, the size of the tire should be matched to the size of the
pavement asperities so that inflation pressure can be kept as low
enough to respond to the whole range of bump magnitudes.

Chalo