Mavic Cosmic maintenance truing

Mike Reed said:

Ok everybody, let's keep this nice 🙂

I have a friend who got a used road bike two months ago, a Klein with
Mavic Cosmic Elite wheels. 20H front and rear. When first showed it to
me, the wheels were perfectly true. I told him to keep a close eye on
them because of the low spoke counts. He weighs 170 lbs, so no huge
scare there.

He came to me yesterday complaining about a wobble in the front, and I
looked at it. It was out of true pretty badly in two spots. I brought
it home to fix it up for him.

First, I went around the wheel and leveled all the tensions at 115 kgf
(w/in spec for these wheels). Of course this brought the wheel further
out of true. I figured it was still a good starting place because the
wheel at that point was as strong as it will ever be.

Then I trued it, but rather than simply tighten one side while
loosening the other, I made sure that any loosened spokes remained w/in
10% of the reference tension and compensating by further tightening the
opposite spokes, even if they went a little higher than 10% above. So
the wheel is now pretty true, but not perfect, and the tensions are all
within 10% of the same value. If I bring it perfectly to true, the
tensions get pretty wild, so I left it. It's probably 0.25mm out of
true in two spots (no tools for runout measurement at this point, so I
used the Mark-V Eyeball Micrometer).

The rear wheel was true, but the tensions were a little crazy and
slightly low. Plus it was 1.5mm out of dish. I went around the
non-drive side to dish it, which slightly tightened the drive side,
bringing it closer to the 105 reference tension. Then I evened up the
drive side tension as close as I could get it and used the non-drive
side to true it. Now the rear is straight as an arrow and really even
tension on the drive side. The non-drive spokes are all pretty tight,
but not super even -- still well w/in 10% though.

So, did I do these wheels the favor I think did?

If you read this far I feel like I owe you a beer, so go to your fridge
and grab one, on me 🙂

Thanks,
Mike

First question I have -were the wheels trued, rounded, tensioned,
dished, stress relieved when new(most come out of the box with none of
thise things)?
If not, riding them with erratic and mostly low tension deforms the
rim. When you then true it you have two choices, even tension or a true
wheel, again using basically a 'bent' rim.

All aluminum rims become deformed when riding. They just aren't that
'hard'. The best bet for a new wheel is to ensure it is perfect when
the rim is the roundest, flattest it's ever going to be, before riding
it.

Qui si parla Campagnolo said:

First question I have -were the wheels trued, rounded, tensioned,
dished, stress relieved when new(most come out of the box with none of
thise things)?

I seriously doubt it. I met the woman who sold the bike, and she wasn't
the tech type who might of done that herself, and It's doubtful that
the shop did it.

So, are bladed spokes stress-relieved the same way as round? (squeezing
adjacent pairs)

-Mike

Mike Reed said:

Ok everybody, let's keep this nice 🙂

I have a friend who got a used road bike two months ago, a Klein with
Mavic Cosmic Elite wheels. 20H front and rear. When first showed it to
me, the wheels were perfectly true. I told him to keep a close eye on
them because of the low spoke counts. He weighs 170 lbs, so no huge
scare there.

He came to me yesterday complaining about a wobble in the front, and I
looked at it. It was out of true pretty badly in two spots. I brought
it home to fix it up for him.

First, I went around the wheel and leveled all the tensions at 115 kgf
(w/in spec for these wheels). Of course this brought the wheel further
out of true. I figured it was still a good starting place because the
wheel at that point was as strong as it will ever be.

Then I trued it, but rather than simply tighten one side while
loosening the other, I made sure that any loosened spokes remained w/in
10% of the reference tension and compensating by further tightening the
opposite spokes, even if they went a little higher than 10% above. So
the wheel is now pretty true, but not perfect, and the tensions are all
within 10% of the same value. If I bring it perfectly to true, the
tensions get pretty wild, so I left it. It's probably 0.25mm out of
true in two spots (no tools for runout measurement at this point, so I
used the Mark-V Eyeball Micrometer).

The rear wheel was true, but the tensions were a little crazy and
slightly low. Plus it was 1.5mm out of dish. I went around the
non-drive side to dish it, which slightly tightened the drive side,
bringing it closer to the 105 reference tension. Then I evened up the
drive side tension as close as I could get it and used the non-drive
side to true it. Now the rear is straight as an arrow and really even
tension on the drive side. The non-drive spokes are all pretty tight,
but not super even -- still well w/in 10% though.

So, did I do these wheels the favor I think did?

If you read this far I feel like I owe you a beer, so go to your fridge
and grab one, on me 🙂

Thanks,
Mike

Weird, I've have a set of these wheels for about five years and have
only had to do minimal maintenance on them. Had the back wheel rebuild
last year because there was garbage build up in the nipples, so it
sounded like a wicker chair when I road it. Maybe you have a dud there?

You could possibly send it off to Mavic if it's that bad and still under
warranty?

Mike Reed said:

Qui si parla Campagnolo said:

First question I have -were the wheels trued, rounded, tensioned,
dished, stress relieved when new(most come out of the box with none of
thise things)?

I seriously doubt it. I met the woman who sold the bike, and she wasn't
the tech type who might of done that herself, and It's doubtful that
the shop did it.

So, are bladed spokes stress-relieved the same way as round? (squeezing
adjacent pairs)

-Mike

Yep, spokes are spokes. need some gloves, but samo-

On 8 Mar 2006 05:55:09 -0800, "Mike Reed" <[email hidden]>

Quoted message said:

So, did I do these wheels the favor I think did?

IMO, it's the owner rather than the wheels for which the favor was
done. I have to say, the front wheel makes me nervous; not just
because it's low-count and giving symptoms of being bent. The bike
has been in service for a relatively short period, and the wheels have
demonstrably not been up to the standards needed for this rider. I
see no good reason to think that they will magically improve in
durability and resistance to further degradation post-fix, but you've
done what you can. I believe a little rider education ("Rule One:
The obstruction that that you do not hit will not damage your
bike."...) may be in order if your favor is to have lasting value.

Be prepared for the bike's owner to claim that he's never gone near a
pothole or curb.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Werehatrack said:

On 8 Mar 2006 05:55:09 -0800, "Mike Reed" <[email hidden]>
wrote:
The bike
has been in service for a relatively short period, and the wheels have
demonstrably not been up to the standards needed for this rider.

The bike was purchased used (see the OP). It's a 2003, I believe. It
was in use by a tallish skinny woman. She may have had the rims trued
prior to sale...

Quoted message said:

I believe a little rider education ("Rule One:
The obstruction that that you do not hit will not damage your
bike."...) may be in order if your favor is to have lasting value.

Yeah, he's gotten this speech 🙂 He was worried that it was from
laying the wheels on their side in the back of his SUV, and I told him
in no uncertain terms that bumps while riding are the cause.

Quoted message said:

Be prepared for the bike's owner to claim that he's never gone near a
pothole or curb.

Yeah, this wheel may have a shady history. It's strange that it's the
front, and the rear is largely fine (though out of dish was odd). Could
have been a rock in the road that the rear missed I guess.

Thanks,
Mike

On 8 Mar 2006 08:28:52 -0800, "Mike Reed" <[email hidden]>

Quoted message said:

... this wheel may have a shady history. It's strange that it's the
front, and the rear is largely fine (though out of dish was odd). Could
have been a rock in the road that the rear missed I guess.

Don't underestimate the "hitting the bump with the brakes hard on"
factor; that transfers a lot of the weight forward, with the result
that the front wheel takes the majority of the impact while the rear
virtually skates across it unscathed.

Come to think of it, I can't recall a pinch flat on any of my *rear*
wheels in many years, but I've had a couple on the front with the
roadie. That may be just luck, though.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Brian S said:

Mike Reed said:

Ok everybody, let's keep this nice 🙂

I have a friend who got a used road bike two months ago, a Klein with
Mavic Cosmic Elite wheels. 20H front and rear. When first showed it to
me, the wheels were perfectly true. I told him to keep a close eye on
them because of the low spoke counts. He weighs 170 lbs, so no huge
scare there.

He came to me yesterday complaining about a wobble in the front, and I
looked at it. It was out of true pretty badly in two spots. I brought
it home to fix it up for him.

First, I went around the wheel and leveled all the tensions at 115 kgf
(w/in spec for these wheels). Of course this brought the wheel further
out of true. I figured it was still a good starting place because the
wheel at that point was as strong as it will ever be.

Then I trued it, but rather than simply tighten one side while
loosening the other, I made sure that any loosened spokes remained w/in
10% of the reference tension and compensating by further tightening the
opposite spokes, even if they went a little higher than 10% above. So
the wheel is now pretty true, but not perfect, and the tensions are all
within 10% of the same value. If I bring it perfectly to true, the
tensions get pretty wild, so I left it. It's probably 0.25mm out of
true in two spots (no tools for runout measurement at this point, so I
used the Mark-V Eyeball Micrometer).

The rear wheel was true, but the tensions were a little crazy and
slightly low. Plus it was 1.5mm out of dish. I went around the
non-drive side to dish it, which slightly tightened the drive side,
bringing it closer to the 105 reference tension. Then I evened up the
drive side tension as close as I could get it and used the non-drive
side to true it. Now the rear is straight as an arrow and really even
tension on the drive side. The non-drive spokes are all pretty tight,
but not super even -- still well w/in 10% though.

So, did I do these wheels the favor I think did?

If you read this far I feel like I owe you a beer, so go to your fridge
and grab one, on me 🙂

Thanks,
Mike

Weird, I've have a set of these wheels for about five years and have
only had to do minimal maintenance on them. Had the back wheel rebuild
last year because there was garbage build up in the nipples, so it
sounded like a wicker chair when I road it. Maybe you have a dud there?

You could possibly send it off to Mavic if it's that bad and still under
warranty?

or maybe you have one of the few decent sets that are sold.

Interesting. Makes sense.

The speed at which you hit a bump really plays into it as well. I guess
this would mean that fast riders are harder on wheels, assuming they
hit all the same bumps as everyone else.

Werehatrack said:

Don't underestimate the "hitting the bump with the brakes hard on"

heh-heh. he said...

Bill "and I don't even watch B&B" S.

Quoted message said:

Quoted message said:

Weird, I've have a set of these wheels for about five years and have
only had to do minimal maintenance on them. Had the back wheel rebuild
last year because there was garbage build up in the nipples, so it
sounded like a wicker chair when I road it. Maybe you have a dud there?

You could possibly send it off to Mavic if it's that bad and still under
warranty?

or maybe you have one of the few decent sets that are sold.

I don't know. I remember looking into them a while back after hearing
about them being pretty solid wheels. Found a set on an end of year sale
and haven't had a problem with them at all, except for the one rebuild
due to road grit buildup.

I use them for mostly flat riding (12x21) and push them pretty hard on
weekend fast rides. No problems. Maybe the older rims were better? 3
cross 32's are a better option I think for most people under most
circumstances as they're easily rebuildable, repairable and cheaper.
Even on a 10k timetrail, a disc wheel will net you what, 10 seconds over
normal wheels? How many of us need that advantage anyway?

Mike Reed said:

I have a friend who got a used road bike two months ago, a Klein with
Mavic Cosmic Elite wheels. 20H front and rear.

-snip-

Quoted message said:

He came to me yesterday complaining about a wobble in the front, and I
looked at it. It was out of true pretty badly in two spots.

-snip-

Quoted message said:

First, I went around the wheel and leveled all the tensions at 115 kgf
(w/in spec for these wheels). Of course this brought the wheel further
out of true. I figured it was still a good starting place because the
wheel at that point was as strong as it will ever be.

Then I trued it, but rather than simply tighten one side while
loosening the other, I made sure that any loosened spokes remained w/in
10% of the reference tension and compensating by further tightening the
opposite spokes, even if they went a little higher than 10% above. So
the wheel is now pretty true, but not perfect, and the tensions are all
within 10% of the same value. If I bring it perfectly to true, the
tensions get pretty wild, so I left it. It's probably 0.25mm out of
true in two spots (no tools for runout measurement at this point, so I
used the Mark-V Eyeball Micrometer).

The rear wheel was true, but the tensions were a little crazy and
slightly low. Plus it was 1.5mm out of dish. I went around the
non-drive side to dish it, which slightly tightened the drive side,
bringing it closer to the 105 reference tension. Then I evened up the
drive side tension as close as I could get it and used the non-drive
side to true it. Now the rear is straight as an arrow and really even
tension on the drive side. The non-drive spokes are all pretty tight,
but not super even -- still well w/in 10% though.

From your rear wheel description and it sounds as if you
did a good job, made some improvement.

But I have never used a tensiometer as you did on the front,
that is, measure every single spoke. We sample 4-5 spokes to
get an idea of the wheel's tension in general.

On a wheel that's been bashed, pulling the thing into one
plane will mean some tight spokes and some loose ones
necessarily. The fact that your reasonably round and flat
wheel has uneven tension merely tells us that if the spokes
were removed the rim would not lie evenly against a true
wheel. Nearly all wheels that have lived a life exhibit that
to some extent.

So my comment is that you should get the tension within
reasonable limits in general and then pay attention to the
roundness and straightness of the wheel ignoring outlying
data points of very tight and very loose spokes.

When the ones you need to tighten won't turn and the spokes
which need loosening are already slack that's the definition
of no brain wave. We replace the rim. Some frugal riders
smack it back the other way and true again.

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

It sounds like I ended up with the standard state for a bent rim on a
front wheel, but got there a different way. It's not bad enough that
some spokes would go slack. I figured that with a tension range of
110-140 kgf that I could keep the loosest spokes at least close to the
110 number while not exceeding even 120 anywhere else. Next time I see
the wheel, I figure I may not be so lucky 🙂

Thanks for the advice.

-Mike

In article
<[email hidden]>,

Mike Reed said:

It sounds like I ended up with the standard state for a bent rim on a
front wheel, but got there a different way. It's not bad enough that
some spokes would go slack. I figured that with a tension range of
110-140 kgf that I could keep the loosest spokes at least close to the
110 number while not exceeding even 120 anywhere else. Next time I see
the wheel, I figure I may not be so lucky 🙂

One more thing to try on an out of true, unbalanced
tension wheel is to reduce the tension on the spokes to a
balanced tension and manually bend the rim to straight.
Then bring the spoke tension back up and true.

--
Michael Press

Qui si parla Campagnolo said:

riding them with erratic and mostly low tension deforms the rim. When you then true it you have two choices, even tension or a true wheel, again using basically a 'bent' rim.

This raises a good question. If a rim is slightly deformed, is it
better to accept a slightly out of true/round wheel to get even
tension, or true the wheel and accept some tension variation?

Art Harris

In article
<[email hidden]>,

Art Harris said:

Qui si parla Campagnolo said:

riding them with erratic and mostly low tension deforms the rim. When you then true it you have two choices, even tension or a true wheel, again using basically a 'bent' rim.

This raises a good question. If a rim is slightly deformed, is it
better to accept a slightly out of true/round wheel to get even
tension, or true the wheel and accept some tension variation?

It is best to reform the rim; it is simple to do.

--
Michael Press

Michael Press said:

Quoted message said:

This raises a good question. If a rim is slightly deformed, is it
better to accept a slightly out of true/round wheel to get even
tension, or true the wheel and accept some tension variation?

Quoted message said:

It is best to reform the rim; it is simple to do.

It may be "simple" to improve a deformed rim's shape, but you rarely
get it back to like-new condition.

The question remains: Is it better to have a wheel perfectly true and
round but with slightly uneven tension, or slightly out of true/round
with perfectly even tension.

Art Harris