Advice on Carbon wheels

Jamie Smith said:

I am looking at buying myself some carbon wheels and would like some
advice from the group.

Firstly I am not the lightest of cyclists at 13 stone (82 Kg), I will
be using them for time trialling and also road racing.

So I would be looking for a reliable set of wheels which will take the
abuse of my weight.

I have been looking at a set of Mavic Cosmic Carbons and before
spending my cash want to be sure I am getting the right set.

Any advice would be great.

Thanks

Jamie

My advice seems to be getting shouted down a lot at the moment but
here goes. I am heavier than you and have ridden a set of Carbones for
time trialling for that last two seasons. Next year I will be road
racing them as well. They are great with very smooth bearings. Because
they are a normal rim with a carbon fairing they still brake properly.
I have seen them advertised for about £550 over the last few weeks and
are a good deal at that price. They also come supplied with very nice
skewers and wheel bags.

Stan Cox

P.s. They look FANTASTIC as well 🙂

Stan Cox said:

My advice seems to be getting shouted down a lot at the moment but
here goes. I am heavier than you and have ridden a set of Carbones for
time trialling for that last two seasons. Next year I will be road
racing them as well. They are great with very smooth bearings. Because
they are a normal rim with a carbon fairing they still brake properly.
I have seen them advertised for about £550 over the last few weeks and
are a good deal at that price. They also come supplied with very nice
skewers and wheel bags.

Oi, Cox! SHUT IT!

:-)

Simonb said:

Stan Cox said:

My advice seems to be getting shouted down a lot at the moment but
here goes. I am heavier than you and have ridden a set of Carbones for
time trialling for that last two seasons. Next year I will be road
racing them as well. They are great with very smooth bearings. Because
they are a normal rim with a carbon fairing they still brake properly.
I have seen them advertised for about £550 over the last few weeks and
are a good deal at that price. They also come supplied with very nice
skewers and wheel bags.

Oi, Cox! SHUT IT!

:-)

Yes Sir!!, Sorry Sir 🙂

Stan Cox

in message <[email hidden]>, Stan Cox

(') said:

Jamie Smith said:

I am looking at buying myself some carbon wheels and would like some
advice from the group.

Firstly I am not the lightest of cyclists at 13 stone (82 Kg), I will
be using them for time trialling and also road racing.

So I would be looking for a reliable set of wheels which will take
the abuse of my weight.

I have been looking at a set of Mavic Cosmic Carbons and before
spending my cash want to be sure I am getting the right set.

My advice seems to be getting shouted down a lot at the moment but
here goes. I am heavier than you and have ridden a set of Carbones for
time trialling for that last two seasons. Next year I will be road
racing them as well. They are great with very smooth bearings. Because
they are a normal rim with a carbon fairing they still brake properly.
I have seen them advertised for about £550 over the last few weeks and
are a good deal at that price. They also come supplied with very nice
skewers and wheel bags.

885g front, 1090 rear. As against Ksyrium Equipe (which is what I'm
currently riding on) one third of the price, 835g front, 1000g rear, on
apparently the same hubs (all figures from Mavic's website). Forgive me
if I'm being very thick here, but what's the benefit of the Cosmic
Carbons which makes them worth 8% extra weight and 200% extra money?
(OK, the money I can understand, but paying more money for _more_
weight really hurts).

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; making jokes about dyslexia isn't big, it isn't clever and
;; it isn't furry.

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

Quoted message said:

885g front, 1090 rear. As against Ksyrium Equipe (which is what I'm
currently riding on) one third of the price, 835g front, 1000g rear, on
apparently the same hubs (all figures from Mavic's website). Forgive me
if I'm being very thick here, but what's the benefit of the Cosmic
Carbons which makes them worth 8% extra weight and 200% extra money?
(OK, the money I can understand, but paying more money for _more_
weight really hurts).

Don't more aero wheels tend to be heavier?

cheers,
clive

in message <[email hidden]>, Clive George

(') said:

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

[someone had recommended Mavic Cosmic Carbon wheels]

Quoted message said:

Quoted message said:

885g front, 1090 rear. As against Ksyrium Equipe (which is what I'm
currently riding on) one third of the price, 835g front, 1000g rear,
on apparently the same hubs (all figures from Mavic's website).
Forgive me if I'm being very thick here, but what's the benefit of
the Cosmic Carbons which makes them worth 8% extra weight and 200%
extra money? (OK, the money I can understand, but paying more money
for _more_ weight really hurts).

Don't more aero wheels tend to be heavier?

That's really what I'm asking, I suppose. Clearly there is some benefit
from a more aerodynamic wheel. But at the same time we're forever being
told that weight at the rim of the wheel is the worst place to have it,
and, clearly, a non-structural aero fairing (which is what the Cosmic
Carbon appears to have) is just that - weight in exactly the wrong
place.

So is there a realistic trade off here, and does it make sense?

And if the aero benefit of the carbon fairing is so much as to be worth
8% (or more) extra rotating mass, then what is the (purely aero)
benefit of 20mm tyres as opposed to 23mm? Surely it must be of the same
order?

I mean I know there has always been snake-oil and pseudo-science in kit
for time trial bikes (bent crank-arms, for one example)... Don't get me
wrong, I think the deep aero section carbon rims look extremely cool.
But if one is trying to get a bike to go fast, are they a benefit or a
hindrance?

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
;; If Python is executable pseudocode,
;; then Perl is executable line noise
-- seen on Slashdot.

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

Quoted message said:

Oi, Cox! SHUT IT!

Sounds as though The Sweeney have arrived on u.r.c - and they haven't
had any dinner!
Back to the wheels topic - conventional spoked wheels are generally
reckoned to be better than Cosmics or Ksyriums on cost and maintenance
grounds (no special tools/spokes needed for repairs); Record, Chorus
or Centaur (or Shimano equivalents for fans of that brand) hubs
combined with Mavic Open Pros and high-end Sapim spokes can often make
for a lighter - and certainly cheaper - wheel without compromising
durability; Oldham Cycle Centre is one shop worth contacting for
well-priced builds of such wheels. Admittedly, I have finally given in
and bought factory-built wheels myself, but only because they were a
cheap option for training; conventional wheels built with
off-the-shelf 32h hubs and Open Pros are still my choice for
competition. If the original poster is road racing as well as TTing,
they might be a better bet, especially in the hills.

David E. Belcher

Simon Brooke said:

But at the same time we're forever being
told that weight at the rim of the wheel is the worst place to have it,

Only by the terminally clueless. Which, on usenet, is probably a large
majority, but it doesn't make them right.

James
--
If I have seen further than others, it is
by treading on the toes of giants.
http://www.ne.jp/asahi/julesandjames/home/

Deep section rims with low spoke counts do make you go faster. That's a
very vague statement, but about as good as it gets I fear.

http://damonrinard.com/aero/aerodynamics.htm

is interesting on this.

Is it worth the extra weight? Depends. Most of the time, yes. On really hilly rides,
no.

I'm thinking about getting a pair of Zipp 404s for TT'ing. These have a
structual carbon rim not a fairing and just seem nicer. They are also
more expensive though... I'd also not fancy risking a pair of wheels that
expensive in a road race, but that's ok since I have some others for
that 🙂

Arthur

--
Arthur Clune PGP/GPG Key: http://www.clune.org/pubkey.txt
"Technolibertarians make a philosophy out of a personality defect"
- Paulina Borsook

In article <[email hidden]>,
[email hidden] says...

Quoted message said:

Only by the terminally clueless. Which, on usenet, is probably a large
majority, but it doesn't make them right.

So it isn't? Why not?

Jon

"Jon Senior" <jon@restlesslemon_DOT_co_DOT_uk.remove> wrote in message
news:[email hidden]...

Quoted message said:

In article <[email hidden]>,
[email hidden] says...

Quoted message said:

Only by the terminally clueless. Which, on usenet, is probably a large
majority, but it doesn't make them right.

So it isn't? Why not?

For (non-mountainous) TTing, certainly not - since you're pretty much
maintaining a constant speed, weight differences of the orders being
discussed don't matter.

For hill climbing, weight on rims counts exactly the same as weight
elsewhere.

The only time it does matter is when accelerating - it takes more energy to
accelerate mass on the wheel rims than it does to that which is fixed to the
bike/you. But since we're not talking about fitting dumbbells to the rims,
it still isn't that much difference.

cheers,
clive

Clive George said:

The only time it does matter is when accelerating - it takes more energy to
accelerate mass on the wheel rims than it does to that which is fixed to the
bike/you. But since we're not talking about fitting dumbbells to the rims,
it still isn't that much difference.

I'm a bit confused about this. Even when the bike isn't accelerating
the rims must, surely be accelerating all the time - after all they're
stationary at the point of contact with the road and moving at twice
the speed of the bike at the opposite point.

In the absence of friction, air resistance and so forth it wouldn't
matter, but given that we do have these things it's necessary to keep
added a bit of energy to keeps the wheels going round, and doesn't
this acceleration mean that weight is more signiifcant on the rims than
on (e.g.) the frame of the bike - even at constant bike speed?

In article <[email hidden]>, [email hidden]
says...

Quoted message said:

For (non-mountainous) TTing, certainly not - since you're pretty much
maintaining a constant speed, weight differences of the orders being
discussed don't matter.

For hill climbing, weight on rims counts exactly the same as weight
elsewhere.

The only time it does matter is when accelerating - it takes more energy to
accelerate mass on the wheel rims than it does to that which is fixed to the
bike/you. But since we're not talking about fitting dumbbells to the rims,
it still isn't that much difference.

And if your predominant riding style involves rapid sprints from set of
lights to another, or road racing where sprinting may be a significant
part of the competition?

Back to Simon's question. Does the aero advantage of low-spoke count
deep section rims outweigh <sniggers> the disadvantage of the additional
weight? Is it a perceptual thing (I've got aero rims / shiny new bits on
my bike so I must go faster.) or can it actually be quantified?

Jon

In article said:

Clive George said:

The only time it does matter is when accelerating - it takes more energy to
accelerate mass on the wheel rims than it does to that which is fixed to the
bike/you. But since we're not talking about fitting dumbbells to the rims,
it still isn't that much difference.

I'm a bit confused about this. Even when the bike isn't accelerating
the rims must, surely be accelerating all the time - after all they're
stationary at the point of contact with the road and moving at twice
the speed of the bike at the opposite point.

But not in a way which requires work. If you pick up a bike and spin
the wheel, it keeps going round and round, with constant acceleration
towards the centre. Adding a constant linear motion onto that doesn't
change thimgs.

Quoted message said:

In the absence of friction, air resistance and so forth it wouldn't
matter, but given that we do have these things it's necessary to keep
added a bit of energy to keeps the wheels going round

But the friction and air resistance of the wheel aren't affected by
its weight. (At least not directly - if the different weight is because
you have used a different shaped rim, or a disk wheel, then the air
resistance will also be affected.)

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

Quoted message said:

Clive George said:

The only time it does matter is when accelerating - it takes more energy

to

Quoted message said:

Quoted message said:

accelerate mass on the wheel rims than it does to that which is fixed to

the

Quoted message said:

Quoted message said:

bike/you. But since we're not talking about fitting dumbbells to the

rims,

Quoted message said:

Quoted message said:

it still isn't that much difference.

I'm a bit confused about this. Even when the bike isn't accelerating
the rims must, surely be accelerating all the time - after all they're
stationary at the point of contact with the road and moving at twice
the speed of the bike at the opposite point.

(did you enjoy the 'more on fat people going downhill' thread?)

But equivalently other bits of the rim are also decelerating all the time -
and amazingly, these cancel each other out.
(Alternatively look at it from the cyclist's point of view - the wheel rim
is moving at constant speed from what he can see. Then consider it from the
sun's point of view. The wheel rim is going at <large speed> +- the
cyclist's speed. The important thing is relative, not absolute speeds.)

Quoted message said:

In the absence of friction, air resistance and so forth it wouldn't
matter, but given that we do have these things it's necessary to keep
added a bit of energy to keeps the wheels going round, and doesn't
this acceleration mean that weight is more signiifcant on the rims than
on (e.g.) the frame of the bike - even at constant bike speed?

Adding energy to overcome friction isn't the same as acceleration - if you
add energy at the same rate as it is lost, which is what happens if you keep
a constant speed, there is no acceleration. (which is pretty obvious,
constant speed being the state of no acceleration).

(Even if you pedal a bit lumpily it doesn't matter - heavier wheels/bike
will mean more inertia, hence you slow down less between power inputs, which
offsets the slower acceleration under power.)

cheers,
clive

Jon Senior said:

In article <[email hidden]>, [email hidden]
says...

Quoted message said:

For (non-mountainous) TTing, certainly not - since you're pretty much
maintaining a constant speed, weight differences of the orders being
discussed don't matter.

For hill climbing, weight on rims counts exactly the same as weight
elsewhere.

The only time it does matter is when accelerating - it takes more
energy to accelerate mass on the wheel rims than it does to that
which is fixed to the bike/you. But since we're not talking about
fitting dumbbells to the rims, it still isn't that much difference.

And if your predominant riding style involves rapid sprints from set
of lights to another, or road racing where sprinting may be a
significant part of the competition?

Then you get a light bike/light wheels. But you still need to
consider the aero advantages - if these outweigh your acceleration
advantage, then it's worth getting the heavier wheelset. Eg in road
racing, if you want to make a break, having aero wheels would be
useful while trying to keep in front. Having light wheels would help
in the intial burst of speed, but not by that much (eg try spinning a wheel
up to 40mph in the stand pedalling with your hands - it isn't very hard at
all. Then consider how much stronger your legs are.)

And remember it isn't that much of a difference - the wheels Simon was
talking about had an 8% weight difference - 160g in 2kg. Equivalent
to 320g on the frame during acceleration if all the difference is at
the rim, or about 0.5% total weight (includes rider).

cheers,
clive

Jon Senior <jon@restlesslemon_dot_co_dot_uk.remove> wrote:

: Back to Simon's question. Does the aero advantage of low-spoke count
: deep section rims outweigh <sniggers> the disadvantage of the additional
: weight?

See my other post. The aero advantage v weight thing trade off depends on
the terrain and the type of riding. There's no universal rule.

Of course, it's possible to get very light all carbon aero wheels to
get the best of all worlds. The problems with these are a) expense and
b) carbon braking surfaces are far harder to brake with than Al ones.

--
Arthur Clune PGP/GPG Key: http://www.clune.org/pubkey.txt
"Technolibertarians make a philosophy out of a personality defect"
- Paulina Borsook

Jon Senior <jon@restlesslemon_dot_co_dot_uk.remove> wrote:

: Back to Simon's question. Does the aero advantage of low-spoke count
: deep section rims outweigh <sniggers> the disadvantage of the additional
: weight?

More helpful reply that has just occured to me: a good rule of thumb would
be the amount of time you spend above 25mph while pedaling (downhill counts
but only if you are putting effort in). Above that speed you're getting
noticable benifts from the aero affect. Below that and it drops off.

--
Arthur Clune PGP/GPG Key: http://www.clune.org/pubkey.txt
"Technolibertarians make a philosophy out of a personality defect"
- Paulina Borsook

"Simon Brooke" <[email hidden]> wrote in message
news:[email hidden]...
--snip--

Quoted message said:

That's really what I'm asking, I suppose. Clearly there is some benefit
from a more aerodynamic wheel. But at the same time we're forever being
told that weight at the rim of the wheel is the worst place to have it,
and, clearly, a non-structural aero fairing (which is what the Cosmic
Carbon appears to have) is just that - weight in exactly the wrong
place.

So is there a realistic trade off here, and does it make sense?

--snip--

(Don't know where the rest of this thread is, but) check out

http://www.diablocyclists.com/pauldec00.htm

--Art