deep rims

Other than Velocity, you might consider the Mavic CXP-33, but it's not
quite as deep at only 23.6mm.

It seems radial 28H front would be ok for your weight, but you'll get
responses from much more experienced guys than me shortly...

-Mike

Francesco Devittori wrote:
> Is there any deeper (clincher) rim available in 32 and 28 holes? (Zipp
> 303 would be perfect but are too expensive, other brands seems not to go
> deeper than that --except for pre-built wheels of course)

If that is a 30mm rim, then there are many that are just as deep... but
the only current one I know of that is deeper is the AC420 rim at 34mm.
It isn't available in the US, but I think you can buy just the rims in
Europe.

30mm should be aero enough, unless you are a very competitive TTer
riding in a cross wind...

> I was thinking of DT Aerolite spokes, 32 3x on the rear, 28 front.
> Is radial on the front asking for trouble? (hub is Dura Ace 7800, I
> weight 70 kg/154 lbs if it makes a difference)

Those hubs are ok'ed for radial lacing. You could also go radial on the
left rear. What you are proposing should build up into very strong
wheels... provided that you have a good builder.

> The best rim I found so far is the Ambrosio Fcs 28, it should be very
> similar to the Velocity Deep V (which is not easy to find here).
> Is there any deeper (clincher) rim available in 32 and 28 holes? (Zipp
> 303 would be perfect but are too expensive, other brands seems not to


I switched to Deep V in 2004. I had a lot of problems
when I started biking big-time in comparison to my tooling
around on an old Shimano. My mavic rims just couldn't
keep up.

I rode the Deep V's with one spoke broken for
up to 30 miles without realizing it. It was easily
fixable. The rim is extremely straight in comparison
to my wobblers.

The tension dropped in my rear wheel and all of a sudden
I noticed it was soft and I wasn't getting power transfer
like usual. I was amazed that I noticed it all of a sudden.
I had it retensioned and it seems to be in good shape.
I got them for a good price. You wouldn't go wrong.

Just someone help me with my tendon and my leg problems.

bill



--
---
William O'Hara

Francesco Devittori wrote:
> Hi all,
>
> I just got a very nice pair of hubs for an incredible price and I'd like
> to have them built in a wheelset.
> Priorities would be
>
> 1. aerodynamics
> 2. stiffness
> 3. weight
>
> The best rim I found so far is the Ambrosio Fcs 28, it should be very
> similar to the Velocity Deep V (which is not easy to find here).
> Is there any deeper (clincher) rim available in 32 and 28 holes? (Zipp
> 303 would be perfect but are too expensive, other brands seems not to go
> deeper than that --except for pre-built wheels of course)
>
> I was thinking of DT Aerolite spokes, 32 3x on the rear, 28 front.
> Is radial on the front asking for trouble? (hub is Dura Ace 7800, I
> weight 70 kg/154 lbs if it makes a difference)
>
> Thanks for any advice,
>
> Francesco

If you're limiting your selection to clinchers around 30mm deep, don't
bother, as they won't achieve your stated objectives. Rims that deep
aren't particularly aero, but they are strong as hell, especially in
32/28 drillings.

Having said that, you can find plenty of slightly lighter wheels that
are plenty strong enough, especially in 32/28 drillings.

If you really want aero, you'll need to go deep (at least 60mm), the
deeper the better.

If you want strong, there're loads of choices. Strong and light is a
little more selective, but still plenty to choose from.

Scott

note: my personal training wheels: Mavic CXP 30 clinchers, 28h front
and rear, and Velocity deepV clinchers, 28h front and rear. Not light,
not really very aero, but bulletproof. Especially the Mavics, they're
built on Mavic hubs that are SOOOO sweet and smooth, you wouldn't
believe it. Five years old and they've never needed truing.

Scott wrote:
> If you're limiting your selection to clinchers around 30mm deep, don't
> bother, as they won't achieve your stated objectives. Rims that deep
> aren't particularly aero
> If you really want aero, you'll need to go deep (at least 60mm), the
> deeper the better.

I think you are wrong. There is a bigger gain when going from <20mm to
30mm than from 30mm to 60mm. For some data see:
http://forums.roadbikereview.com/showthread.php?p=550582#poststop
Also: http://zipp.com

I agree. In my recent change from Open Pros to Deep Vs, I have a
measurable speed improvement. In an 18.5 mile hilly TT, the 30mm Deep
Vs bought me about a minute.

Ron Ruff wrote:
> Scott wrote:
> > If you're limiting your selection to clinchers around 30mm deep, don't
> > bother, as they won't achieve your stated objectives. Rims that deep
> > aren't particularly aero
> > If you really want aero, you'll need to go deep (at least 60mm), the
> > deeper the better.
>
> I think you are wrong. There is a bigger gain when going from <20mm to
> 30mm than from 30mm to 60mm. For some data see:
> http://forums.roadbikereview.com/showthread.php?p=550582#poststop
> Also: http://zipp.com

Ron,

You can't use your own previously posted message on roadbikereview.com
as evidence in support of your argument. For one thing, anything on
roadbikereview.com is immediately suspect. I'm surprised you would
believe even your own message once posted on that site.

As for anything you may find on zipp.com, keep in mind that A) they
need to sell their 202 and 303 rims, so of course they'll say that
there's an aero benefit to the shallower rims, and 2) they make an 80mm
deep rim that was developed recently in response to market demand for
an especially deep rim, as the HED Deep (90mm) was proving to be a very
fast wheel.

While a 30mm rim is more aero than a 20mm rim, the differences are so
small as to warrant a resounding "so what?" Unless you're talking
about using a very light carbon rim, which I don't think the original
poster is willing to do, the aero benefits do not outweigh the
significant weight of the deeper aluminum rim.

We could argue over the relative perspective of the OP's criteria for
selection, especially as he's ranked them in terms of importance. But,
staying on task and addressing his concerns as he's expressed them, I
still think that he'll be much better off in the long run giving up on
the concept of a significant aero gain using 30mm deep rims, especially
at the 32/28 spoke count he referenced.

Scott

Mike Reed wrote:
> I agree. In my recent change from Open Pros to Deep Vs, I have a
> measurable speed improvement. In an 18.5 mile hilly TT, the 30mm Deep
> Vs bought me about a minute.

Mike,

while it's nice that you improved your TT time, there's no way, based
on a sample size of one (you) in an uncontrolled and unrepeatable
experiment, you can definitively say that you saved a minute over 18.5
miles based on switching from a 21mm rim to a 30mm rim. Just too many
variables involved to say that with any certainty.

Scott

Scott wrote:
> Mike Reed wrote:
> > I agree. In my recent change from Open Pros to Deep Vs, I have a
> > measurable speed improvement. In an 18.5 mile hilly TT, the 30mm Deep
> > Vs bought me about a minute.
>
> Mike,
>
> while it's nice that you improved your TT time, there's no way, based
> on a sample size of one (you) in an uncontrolled and unrepeatable
> experiment, you can definitively say that you saved a minute over 18.5
> miles based on switching from a 21mm rim to a 30mm rim. Just too many
> variables involved to say that with any certainty.

Yeah, I know, and I agree. Statistically, it's not a well founded
argument.

Just the same, I've been riding the same course weekly for 5 years on
open pros. I know how fast I am on it. If I suffer appropriately on it,
I can predict my time -- even though I'm always struggling to improve
it. Then, one week, I throw on the Deep Vs, and there I am. One minute
faster. Same thing the following week.

The course is out and back. I know that it varies, but my times don't
vary by a minute unless there are extreme wind conditions -- and those
always slow my time.

I feel 100% comfortable saying that these rims allow me to ride faster
on this course. Who knows how much of that minute is rims? Dunno, but I
can't think of anything else.

-Mike

Scott wrote:
> the aero benefits do not outweigh the
> significant weight of the deeper aluminum rim.

I don't see how that's possible. Deeper rims have a lower Cd due to
their profile, and wind resistance goes up with the square of your
speed. So, at higher speeds, aerodynamics has a huge impact.

Conversely, weight slows you down linearly as steepness goes up.

Going twice as fast up a hill means twice as much work from gravity,
but FOUR TIMES as much work from wind resistance.

So, those 7 ounces of extra weight (Deep V vs. Open Pro) supposedly
hurt you enough to eliminate the aerodynamic benefit of a
rounded-knife-edge rim profile? Surely there are hills for which this
is true, but for the majority of riding (anything over about 17 mph), I
still say you'll come out ahead with aerodynamics.

Another aero benefit of deeper rims is that your spoke nipples are
going slower at the top of rotation. The top of your tire is going
twice your speed, with the hub going exaclty your speed. The further
out the spokes go, the faster the nipples will be travelling at the top
of rotation. The spokes themselves are also ~10mm shorter, reducing
their profile -- and their weight.

Does this make sense? I'm kind of rambling (late in my day)...

-Mike

Mike Reed wrote:
> Scott wrote:
>> the aero benefits do not outweigh the
>> significant weight of the deeper aluminum rim.
>
> I don't see how that's possible. Deeper rims have a lower Cd due to
> their profile, and wind resistance goes up with the square of your
> speed. So, at higher speeds, aerodynamics has a huge impact.
>
> Conversely, weight slows you down linearly as steepness goes up.
>
> Going twice as fast up a hill means twice as much work from gravity,
> but FOUR TIMES as much work from wind resistance.
>
> So, those 7 ounces of extra weight (Deep V vs. Open Pro) supposedly
> hurt you enough to eliminate the aerodynamic benefit of a
> rounded-knife-edge rim profile? Surely there are hills for which this
> is true, but for the majority of riding (anything over about 17 mph), I
> still say you'll come out ahead with aerodynamics.
>
> Another aero benefit of deeper rims is that your spoke nipples are
> going slower at the top of rotation. The top of your tire is going
> twice your speed, with the hub going exaclty your speed. The further
> out the spokes go, the faster the nipples will be travelling at the top
> of rotation. The spokes themselves are also ~10mm shorter, reducing
> their profile -- and their weight.
>
> Does this make sense? I'm kind of rambling (late in my day)...
>
> -Mike
>

It made sense to me, that's why I decided to go with a deep(-ish) rim.

Francesco

Scott wrote:
> still think that he'll be much better off in the long run giving up on
> the concept of a significant aero gain using 30mm deep rims, especially
> at the 32/28 spoke count he referenced.

The difference is ~0.4mph if he also uses aero spokes... and I think
that is significant. The most interesting thing about the Zipp data is
that the Ksyriums did so well... and they are obviously not very aero.
I can easily believe that the 202s (or any 25+mm rim with CX-rays)
would be better than those.

Mike Reed wrote:
> Scott wrote:
> > the aero benefits do not outweigh the
> > significant weight of the deeper aluminum rim.
>
> I don't see how that's possible. Deeper rims have a lower Cd due to
> their profile, and wind resistance goes up with the square of your
> speed. So, at higher speeds, aerodynamics has a huge impact.
>
> Conversely, weight slows you down linearly as steepness goes up.
>
> Going twice as fast up a hill means twice as much work from gravity,
> but FOUR TIMES as much work from wind resistance.
>
> So, those 7 ounces of extra weight (Deep V vs. Open Pro) supposedly
> hurt you enough to eliminate the aerodynamic benefit of a
> rounded-knife-edge rim profile? Surely there are hills for which this
> is true, but for the majority of riding (anything over about 17 mph), I
> still say you'll come out ahead with aerodynamics.
>
> Another aero benefit of deeper rims is that your spoke nipples are
> going slower at the top of rotation. The top of your tire is going
> twice your speed, with the hub going exaclty your speed. The further
> out the spokes go, the faster the nipples will be travelling at the top
> of rotation. The spokes themselves are also ~10mm shorter, reducing
> their profile -- and their weight.
>
> Does this make sense? I'm kind of rambling (late in my day)...
>
> -Mike

Mike,

Your arguments make sense, except that you're giving too high a value
to the aerodynamic gain of a 30mm rim. The real world aero gain isn't
that great. At least, not as a percentage of the overall Cd. The
limited gains of a 30mm profile rim is lost in the noise.

Having said that, I'll admit that the weight difference between the
Open Pro and the Deep V isn't that great, either, relative to the total
weight of bike and rider. Frankly, I've tried climbing on MA3's, Open
Pro's, Deep V's, CXP30's, Reynolds DV carbon tubulars, and Zipp 440's.
The only rims I even THOUGHT I could feel a difference with were the
440's. The Reynolds gave a really nice expectation of riding well,
considering that when you picked the bike up you could notice the
weight difference. Couldn't feel it when riding.

My favorite wheels are the CXP30's built up on Mavic hubs. Very smooth
rolling hubs, bulletproof rims, NEVER put a spoke wrench to them in 5
years, to include training (often on dirt roads) cyclocross racing for
a season, and on & off use as my race wheels. They're heavy to pick
up, but ride soooo sweet.

Scott

Scott wrote:
> Ron Ruff wrote:
>> Scott wrote:
>>> If you're limiting your selection to clinchers around 30mm deep, don't
>>> bother, as they won't achieve your stated objectives. Rims that deep
>>> aren't particularly aero
>>> If you really want aero, you'll need to go deep (at least 60mm), the
>>> deeper the better.

>> I think you are wrong. There is a bigger gain when going from <20mm to
>> 30mm than from 30mm to 60mm. For some data see:
>> http://forums.roadbikereview.com/showthread.php?p=550582#poststop
>> Also: http://zipp.com

> While a 30mm rim is more aero than a 20mm rim, the differences are so
> small as to warrant a resounding "so what?"

Do you have a reference to back that up? I'd like to know the answer, too.

Here's a reference from this group a few years back...

> The differences in drag would be very small at 17 mph and at
> 30 mph the box section wheel would have about .5-.6 lb of drag, the
> 35mm would be in the .35 to .45 lb drag range and the
> 60mm would be in the .25 to .35 lb drag range (these are all
> ballpark values, mind you).
>
> =============================
> Kraig Willett
> K-dub Enterprises
>
> Product Evaluation/Testing
> Technical Writing
> Market Surveys
> =============================

So there is a continuum; the 35 mm deep rim is more aero than the box
section rim, and I'd call that difference significant. Going deeper to
60 mm, you get another reduction that I'd consider significant.

Kraig also opined:

>>What is the minimum rim depth required for a rim to be considered aero?
>
> For me, it is somewhere between 40 and 50mm.

Is there a magic depth at which aero benefits become "significant?"
There are three opinions represented in this message (Ron, Scott, and
Kraig), and I'd like to see independent data to confirm any of these. I
haven't seen it yet... maybe it's in Kraig's wind tunnel report (see
biketechreview.com), but I haven't forked over the cash since it's
merely a matter of curiosity for me.

--
Dave
dvt at psu dot edu

dvt wrote:
> > Ron Ruff wrote:
> >> There is a bigger gain when going from <20mm to
> >> 30mm than from 30mm to 60mm. For some data see:
> >> http://forums.roadbikereview.com/showthread.php?p=550582#poststop
> >> Also: http://zipp.com

> Is there a magic depth at which aero benefits become "significant?"
> There are three opinions represented in this message (Ron, Scott, and
> Kraig), and I'd like to see independent data to confirm any of these.

You must have missed the links...? There is enough test data there to
keep you busy for awhile. Aerodynamics of bicycles is a murky subject,
but if you distill all that and reach a different conclusion than I
did, then I'd like to know.