Rims: Machined vs. non-machined sidewalls. Any real difference?



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P

Patrick

Guest
Just wondering if it really makes any difference. Some manufacturers don't even advertise whether
the sidewalls are machined; others do. Velocity for example, makes both, but I believe they're the
same price. What gives? Just marketing hype?
 
A

Alex Rodriguez

Guest
In article <[email protected]>, [email protected] says...

>Just wondering if it really makes any difference.

Yes it does. Machined rims will have a shorter life span because they have had material removed from
their sidewalls.

>Some manufacturers don't even advertise whether the sidewalls are machined; others do.

Most do because they think it is a feature and can then charge extra for it.

>Velocity for example, makes both, but I believe they're the same price. What gives? Just
>marketing hype?

Yes, hype.
-----------------
Alex __O _-\<,_ (_)/ (_)
 
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Paul Kopit

Guest
I mistakenly got a set on non annodized Velocity Aerohead rims. They are great. I rode a couple of
thousand miles before they looked like machined rims. I've had similar experience with older
Wolber 59 rims. I wasn't crazy about it on Mavic Open 4s because the sidewall didn't loose the
color evenly.

I vote non machined.

On 23 Jan 2003 09:45:24 -0800, [email protected] (Patrick) wrote:

>Just wondering if it really makes any difference. Some manufacturers don't even advertise whether
>the sidewalls are machined; others do. Velocity for example, makes both, but I believe they're the
>same price. What gives? Just marketing hype?
 
D

Duncan Bourne

Guest
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I'll just put my oar in on the other side of the argument.

I appreciate the merits of non-machined sidewalls (longer life), and maybe it's just bad luck on my
part but I had three successive front wheels with poor joints that no amount of sanding would
improve and it drove me nuts. I know everyone says it's a rare ocurrence but 3 outa 3 is too much
for me. Offroad in particular a grabby spot on the front is a royal PITA when you're doing slow,
steep stuff on loose surfaces.

I've had a few welded and machined rims since and they've all been nice and smoooth. I don't wear
out rims too often nowadays so I'm happy to accept a wheel lasting 5 years instead of 7 or 7 instead
of 10 or whatever and get smooth, controllable braking.

Other folks obviously have better experiences with non-machined rims but that has been mine to date.

Duncan Bourne

Paul Kopit wrote:

>I mistakenly got a set on non annodized Velocity Aerohead rims. They are great. I rode a couple of
>thousand miles before they looked like machined rims. I've had similar experience with older
>Wolber 59 rims. I wasn't crazy about it on Mavic Open 4s because the sidewall didn't loose the
>color evenly.
>
>I vote non machined.
>
>On 23 Jan 2003 09:45:24 -0800, [email protected] (Patrick) wrote:
>
>
>
>>Just wondering if it really makes any difference. Some manufacturers don't even advertise whether
>>the sidewalls are machined; others do. Velocity for example, makes both, but I believe they're the
>>same price. What gives? Just marketing hype?
>>
>>
>
>
>

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Content-Transfer-Encoding: 7bit

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title></title>
</head> <body> I'll just put my oar in on the other side of the argument.<br> <br> I appreciate the
merits of non-machined sidewalls (longer life), and maybe it's just bad luck on my part but I had
three successive front wheels with poor joints that no amount of sanding would improve and it drove
me nuts. I know everyone says it's a rare ocurrence but 3 outa 3 is too much for me. Offroad in
particular a grabby spot on the front is a royal PITA when you're doing slow, steep stuff on loose
surfaces. <br> <br> I've had a few welded and machined rims since and they've all been nice and
smoooth.<br> I don't wear out rims too often nowadays so I'm happy to accept a wheel lasting 5 years
instead of 7 or 7 instead of 10 or whatever and get smooth, controllable braking.<br> <br> Other
folks obviously have better experiences with non-machined rims but that has been mine to date.<br>
<br> Duncan Bourne<br> <br> Paul Kopit wrote:<br> <blockquote type="cite"
cite="[email protected]"> <pre wrap="">I mistakenly got a set on non
annodized Velocity Aerohead rims. They are great. I rode a couple of thousand miles before they
looked like machined rims. I've had similar experience with older Wolber 59 rims. I wasn't crazy
about it on Mavic Open 4s because the sidewall didn't loose the color evenly.

I vote non machined.

On 23 Jan 2003 09:45:24 -0800, <a class="moz-txt-link-abbreviated"
href="mailto:[email protected]">[email protected]</a> (Patrick) wrote:

</pre> <blockquote type="cite"> <pre wrap="">Just wondering if it really makes any difference.
Some manufacturers don't even advertise whether the sidewalls are machined; others do. Velocity
for example, makes both, but I believe they're the same price. What gives? Just marketing hype?
</pre> </blockquote> <pre wrap=""><!----> </pre> </blockquote> <br> </body> </html>

--------------080704090501090409080000--
 
T

The Pomeranian

Guest
Alex Rodriguez wrote:
>
> In article <[email protected]>, [email protected] says...
>
> >Just wondering if it really makes any difference.
>
> Yes it does. Machined rims will have a shorter life span because they have had material removed
> from their sidewalls.

That alone doesn't mean much. If they "start" with more material before the machining, they can end
with more or the same as other non-machined rims. Foe example, the Mavic Open Pro weighs about the
same as the older Open 4 CD. One is machined and one isn't and both have eyelets and approximately
the same cross section. So the amount of material depth on the brake track could in the end be about
the same. Of course, I don't really know.

It does probably make a difference in the price. I don't know how much that is either, but I don't
think I would pay for a machined rim, all other things equal.

> >Some manufacturers don't even advertise whether the sidewalls are machined; others do.
>
> Most do because they think it is a feature and can then charge extra for it.
>
> >Velocity for example, makes both, but I believe they're the same price. What gives? Just
> >marketing hype?
>
> Yes, hype.

They are nice and "straight" usually, but I don't know if it is worth
it. A lot of people seem to think it is worth it and do pay Mavic a premium, for example.
 
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Ant

Guest
[email protected] (Patrick) wrote in message
news:<[email protected]>...
> Just wondering if it really makes any difference. Some manufacturers don't even advertise whether
> the sidewalls are machined; others do. Velocity for example, makes both, but I believe they're the
> same price. What gives? Just marketing hype?

Far be it from me to claim any expertise here, but I would venture to guess that in certain cases
the machined rim can make a big positive difference. Take, for example, my bike. With cantilevers up
front, it is a serious squealer. Only with frequent rim cleanings, toe-in, and all the other tricks
does it keep quiet in normal braking. With koolstop bmx pads nothing i did could make it stop, so i
switched back to the stock avid pads. I would guess that if the rim were smooth it would squeal even
more than it does now. i suppose if you are running a canti brake it could possibly make sense to
have a machined sidewall. or perhaps, if you are having uncurable squealing, you could rebuild your
wheel with a machined rim (or you could just sand it, i suppose..)

anthony
 
Q

Qui Si Parla Ca

Guest
mango-<< Just wondering if it really makes any difference.

Mostly marketing. i rode with non-machined sidewall rims for years w/o problem. Some manufacturers
say they increase wall thickness before machining, maybe that's true.

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"
 
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Mark Hickey

Guest
The Pomeranian <[email protected]> wrote:

>Alex Rodriguez wrote:

>> Yes it does. Machined rims will have a shorter life span because they have had material removed
>> from their sidewalls.
>
>That alone doesn't mean much. If they "start" with more material before the machining, they can end
>with more or the same as other non-machined rims. Foe example, the Mavic Open Pro weighs about the
>same as the older Open 4 CD. One is machined and one isn't and both have eyelets and approximately
>the same cross section. So the amount of material depth on the brake track could in the end be
>about the same. Of course, I don't really know.

The way I look at it is you have two choices if you want to machine a sidewall.

One, you want to end up with at least the wall thickness of the non-machined rim. That means the
thinnest portions will be the same, and the thicker portions thicker (which serves no practical
purpose). End result = heavier rim.

Two, you want to end up with the average or maximum wall thickness of the non-machined rim. This
means you end up with sections of the wall that are thinner, meaning the rim will wear out sooner.
We've read reports where a machined wall left the factory in a virtually "worn out state", failing
within weeks due to brake track wear.

Either way, you end up with a non-optimum distribution of material.

Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame
 
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Mark Hickey

Guest
[email protected] (ant) wrote:

>Far be it from me to claim any expertise here, but I would venture to guess that in certain cases
>the machined rim can make a big positive difference. Take, for example, my bike. With cantilevers
>up front, it is a serious squealer. Only with frequent rim cleanings, toe-in, and all the other
>tricks does it keep quiet in normal braking. With koolstop bmx pads nothing i did could make it
>stop, so i switched back to the stock avid pads. I would guess that if the rim were smooth it would
>squeal even more than it does now. i suppose if you are running a canti brake it could possibly
>make sense to have a machined sidewall. or perhaps, if you are having uncurable squealing, you
>could rebuild your wheel with a machined rim (or you could just sand it, i suppose..)

A new rim will always fix a squealing brake problem. Until it's dirty like the old rim it replaces -
whether you're changing to or from machined sidewalls. Either way, the braking surface of either
type of wheel will "devolve" to the identical surface.

About the only advantage in regards to squealing brakes is that any anodizing has been removed from
the brake track. Of course, I'd never purposely buy an anodized rim anyway... ;-)

Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame
 
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Matt O'Toole

Guest
"Mark Hickey" <[email protected]> wrote in message
news:[email protected]...

> About the only advantage in regards to squealing brakes is that any anodizing has been removed
> from the brake track. Of course, I'd never purposely buy an anodized rim anyway... ;-)

Unfortunately, about ten years ago, you couldn't buy anything else. At least the sidewalls
are machined these days. I'm no fan of machined rims, but I'll take them over anodized
sidewalls any day.

Matt O.
 
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The Pomeranian

Guest
Mark Hickey wrote:
>
> The Pomeranian <[email protected]> wrote:
>
> >Alex Rodriguez wrote:
>
> >> Yes it does. Machined rims will have a shorter life span because they have had material removed
> >> from their sidewalls.
> >
> >That alone doesn't mean much. If they "start" with more material before the machining, they can
> >end with more or the same as other non-machined rims. Foe example, the Mavic Open Pro weighs
> >about the same as the older Open 4 CD. One is machined and one isn't and both have eyelets and
> >approximately the same cross section. So the amount of material depth on the brake track could in
> >the end be about the same. Of course, I don't really know.
>
> The way I look at it is you have two choices if you want to machine a sidewall.
>
> One, you want to end up with at least the wall thickness of the non-machined rim. That means the
> thinnest portions will be the same, and the thicker portions thicker (which serves no practical
> purpose). End result = heavier rim.
>
> Two, you want to end up with the average or maximum wall thickness of the non-machined rim. This
> means you end up with sections of the wall that are thinner, meaning the rim will wear out sooner.
> We've read reports where a machined wall left the factory in a virtually "worn out state", failing
> within weeks due to brake track wear.
>
> Either way, you end up with a non-optimum distribution of material.

That makes sense, thanks. I only buy machined rims anymore when other factors come into play and
overide the machining aspect. I've never had much trouble with non-machined rims and it seems like
it is probably unnecessary and would mainly add cost. Welded non-machined rims do sometimes have an
uneven section near the weld that is "grabby." I don't know how much it matters in practice, but
because of this I question the weld technique of joining too.

I wrecked a racing rim in a crash awhile back and think I will try the Torelli Master as a
replacement. I'm not sure about all the construction details. What I'd really like is an old
non-anodized Open 4 CD, but that isn't in the cards.
 
M

Matt O'Toole

Guest
"Mark Hickey" <[email protected]> wrote in message
news:[email protected]...

> The way I look at it is you have two choices if you want to machine a sidewall.
>
> One, you want to end up with at least the wall thickness of the non-machined rim. That means the
> thinnest portions will be the same, and the thicker portions thicker (which serves no practical
> purpose). End result = heavier rim.
>
> Two, you want to end up with the average or maximum wall thickness of the non-machined rim. This
> means you end up with sections of the wall that are thinner, meaning the rim will wear out sooner.
> We've read reports where a machined wall left the factory in a virtually "worn out state", failing
> within weeks due to brake track wear.
>
> Either way, you end up with a non-optimum distribution of material.

This is in fact the main problem. Rim extrusions are not perfectly straight, varying by a thou or
two here and there. So when the sidewalls are machined flat, it leaves them with thick and thin
spots. If left alone the thickness would have remained uniform. As the rim wears, this variance in
thickness becomes greater, in relation to total thickness. This results in a rim that won't stay
straight because it's stiffer in some places than others. It requires uneven spoke tension to keep
straight, so its overall strength is compromised too. It's likely to fail sooner, and without
warning. An unmachined rim will stay straight until the sidewalls are so thin there are detectable
bulges around the spoke holes. Not only will it last longer, it gives plenty of indication of its
state of wear.

I have worn out several sets of rims of each type, and observed the behaviour of one type vs.
the other.

Most people's rims last longer than their biking careers, so there's little incentive for bike
companies to consider this issue -- especially if they think customers may be attracted to pretty
colors and machined sidewalls.

Keith Bontrager, who built the first-ever lightweight mountain bike rims and is now a bigshot
engineer at Trek, has posted here on this issue. He says it's actually easier and cheaper to build
rims with consistently good joints by welding and machining, vs. just cutting and pinning. Not
having run his production line I'm not in a position to second-guess, but I don't think he'd lie.

Matt O.
 
A

Alex Rodriguez

Guest
In article <[email protected]>, [email protected] says...

>I wrecked a racing rim in a crash awhile back and think I will try the Torelli Master as a
>replacement. I'm not sure about all the construction details. What I'd really like is an old
>non-anodized Open 4 CD, but that isn't in the cards.

The non-anodized rim wasn't called Open 4 CD. The CD in the name implies hard anodized. It was Open
something or another, I forget.
-----------------
Alex __O _-\<,_ (_)/ (_)
 
J

John Albergo

Guest
Duncan Bourne wrote:

> I'll just put my oar in on the other side of the argument.
>
> I appreciate the merits of non-machined sidewalls (longer life), and maybe it's just bad luck on
> my part but I had three successive front wheels with poor joints that no amount of sanding would
> improve and it drove me nuts. I know everyone says it's a rare ocurrence but 3 outa 3 is too much
> for me. Offroad in particular a grabby spot on the front is a royal PITA when you're doing slow,
> steep stuff on loose surfaces.
>
> I've had a few welded and machined rims since and they've all been nice and smoooth. I don't wear
> out rims too often nowadays so I'm happy to accept a wheel lasting 5 years instead of 7 or 7
> instead of 10 or whatever and get smooth, controllable braking.
>
> Other folks obviously have better experiences with non-machined rims but that has been mine
> to date.
>
>
Having lived with front rims that go "bip-bip-bip-bip..." I can agree with your sentiment. A
perfectly even surface is a nice thing. I agree with a previous post - there's no reason the
resulting wall thickness has to be insufficient; just start with thicker material. I don't know if
that's done but there's nothing about machining per se that mandates too-thin sidewalls. Whether the
added expense is justified is a judgement call. But seeing how I only buy about 1 rim per year, it
doesn't make too much difference to me. I currently have a machined rim on the back and a
non-machined on the front (with a good smooth joint). The selection was made on other factors.
 
P

Pete Biggs

Guest
Mark Hickey wrote:
> A new rim will always fix a squealing brake problem. Until it's dirty like the old rim it replaces
> - whether you're changing to or from machined sidewalls. Either way, the braking surface of either
> type of wheel will "devolve" to the identical surface.

That can take a long time to happen though. Some Open Pro rims have a deeply grooved effect which
can last a few thousand miles before they become totally smooth (albeit when used mostly in dry
conditions). These machined rims improve braking, ime. The depth of the grooves vary according to
the batch. The last OP I bought was nearly smooth to begin with.

~PB
 
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Jobst Brandt

Guest
Patrick Mangos? writes:

> Just wondering if it really makes any difference. Some manufacturers don't even advertise whether
> the sidewalls are machined; others do. Velocity for example, makes both, but I believe they're the
> same price. What gives? Just marketing hype?

What you hear and read is marketing hyperbole, but there is a reason for machining rims, and it
isn't for your benefit. If you inspect a machined rim closely, you'll find a surface that looks as
though a stupid machinist used a thread cutting tool to get a flat braking surface, a series of fine
grooves that are noticeable when running a fingernail across the width of the brake surface.

Rims are not machined to make them flat. Machining a series of LP vinyl record grooves prevents
brake squeal on new bicycles for test rides and sales. The grooves wear off on the first descent in
wet weather which is the cause of rim wear in the first place. Even anodizing, a hard ceramic layer,
whether thick or thin, is far more durable than the bare machined rim. Besides, the thicker the
anodized coating the poorer brakes will work, because anodizing is also an insulator, something that
overheats brake pad surfaces.

The claim that machining is for other purposes than suppressing brake squeal is far fetched. For
instance, rim joints have been made with no perceptible discontinuity almost as long as there have
been aluminum rims. Unfortunately, some marketing people thought rims would come apart if they were
not riveted. Riveting nearly always distorts rim joints. Fortunately rims of a few years ago were
made without rivets and had flawless joints.

For practical purposes, machining only serves to make an irregular and unknown thick rim wall and
adds a bit of sparkle to the new product, giving elegant reflections in showrooms. Mavic, for
instance has rims listed as having "CERAMC2", "SUP, "CD", "UB", MAXTAL", all features that add
expense on top of a plain aluminum rims that were offered at about 1/4 the price not long ago. The
web site explains that "CERAMC2" is an insulator that improves braking. This is a tipoff to hype,
because without special brake pads, this feature rapidly wears pads from heating that also degrades
performance.

Jobst Brandt [email protected] Palo Alto CA
 
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