Rim wear

Probably an old question but,

My rear wheel is Mavic D521. The rim is not flat, it appears to have been
worn by the brake. Both bikes seem to have the same shape which is odd as
one gets far more wear.

An image here shows what I mean:

http://www.brian.drury.dsl.pipex.com/images/wheel01.jpg

Maybe the explanation is that these wheels have dished rims. The front Mavic
X618 rims are flat.

The remaining material is 2mm thick. Tyres 80 psi.

Any ideas?

Thanks

Brian

"Brian Drury" briandotdruryatdsldotpipexdotcom wrote in message
...
Probably an old question but,

My rear wheel is Mavic D521. The rim is not flat, it appears to have been
worn by the brake. Both bikes seem to have the same shape which is odd as
one gets far more wear.

It is worn. IME mtb rears wear quicker than fronts, possibly as a result of
crap getting thrown onto the rear wheel from the front.
Unless it's a modernish rim with a wear indicator milled into the inside
(which wears through first creating a window in the rim) then it's
difficult to know what safety margin is left.
But be assured there is a point when the rim will fail, catastrophically but
outside his house in a friends case and in my case cracks were spotted when
washing the bike :-(

Pete

Brian Drury wrote:
Probably an old question but,

My rear wheel is Mavic D521. The rim is not flat, it appears to have been
worn by the brake. Both bikes seem to have the same shape which is odd as
one gets far more wear.

An image here shows what I mean:

http://www.brian.drury.dsl.pipex.com/images/wheel01.jpg

Maybe the explanation is that these wheels have dished rims. The front Mavic
X618 rims are flat.

The remaining material is 2mm thick. Tyres 80 psi.

It's wear. I have a pair and they have also worn. Not particularly long
lasting IMHO

...d

But be assured there is a point when the rim will fail,
catastrophically but

I have always been frightened of this.Fortunately some other major
problem has happened first to cause me to scrap the rims.

10days ago I met a man in Buxton on a Harry Hall frame 531+/_ 20yrs old
with the rear rim completely worn through so that the inner tube and
edge of tyre were clearly visible for a 4cm by 2mm strip with a trench
out to the rim edge which had gone for 3mm.

He said he was thinking of getting a new wheel.

When I last saw him he was planning to cycle back to warrington via
the cat and fiddle to macclesfield, which would test anyone's brakes.

Anyone here know if he made it?

TerryJ

On Sun, 27 Feb 2005 08:16:27 +0100, "Peter B"
wrote:

My Mavic D521 wore out after 10,000 plus miles, I noticed some minor
hairline cracks in them and discovered the rims were that thin I could
put my fingernails through them. They had still kept their integrity
though and were straight and true.

Previous wheel a Mavic X or D 313 I think the side bellied out

I was that pleased with the D521 I've just purchased another pair

Merlin Cycles Mavic D521, Deore hubs, DT spokes, freehub body and QR
skewers £56 the pair including delivery


"Brian Drury" briandotdruryatdsldotpipexdotcom wrote in message
...
Probably an old question but,

My rear wheel is Mavic D521. The rim is not flat, it appears to have been
worn by the brake. Both bikes seem to have the same shape which is odd as
one gets far more wear.



Pete

Brian Drury wrote:
Probably an old question but,

My rear wheel is Mavic D521. The rim is not flat, it appears to have been
worn by the brake. Both bikes seem to have the same shape which is odd as
one gets far more wear.

An image here shows what I mean:

http://www.brian.drury.dsl.pipex.com/images/wheel01.jpg

Maybe the explanation is that these wheels have dished rims. The front Mavic
X618 rims are flat.

The remaining material is 2mm thick. Tyres 80 psi.

Any ideas?

Thanks

Brian


As a follow-up to your question. How long should a rim last?

I bought a pair of Mavic crosslanders, for my mountain bike, at the
beginning of the year and there is already a noticable concavity (?) to
the rim. I fitted good quality new brake blocks with the new wheels,
have probably covered about 1000 miles on them, clean the rims once a
week, and inflate to around 80 - 100 psi.

Is this reasonable wear?

This is my commuting bike so I don't want to have to clean the rims
every day but replacing the wheels each year would also seem excessive.

Many thanks,

Gordon

"Gordon Taylor" wrote in message
...

As a follow-up to your question. How long should a rim last?

I bought a pair of Mavic crosslanders, for my mountain bike, at the
beginning of the year and there is already a noticable concavity (?) to
the rim. I fitted good quality new brake blocks with the new wheels,

What sort of brake blocks? Some are definitely much nastier to rims than
others. I find the grey aztec ones are nice to rims, as are the pink/salmon
kool stop ones. Shimano ones eat rims IME.

cheers,
clive

Gordon Taylor wondered:
As a follow-up to your question. How long should a rim last?

I bought a pair of Mavic crosslanders, for my mountain bike, at the
beginning of the year and there is already a noticable concavity (?) to
the rim. I fitted good quality new brake blocks with the new wheels,
have probably covered about 1000 miles on them, clean the rims once a
week, and inflate to around 80 - 100 psi.

Is this reasonable wear?

What sort of brake blocks? Some will cause more rim wear than others.

Front or rear rim? The front rim is likely to be subject to more
braking, so will probably wear more quickly. Is it mostly ridden on or
off road?

For comparison, I use Aztec blocks and ride almost exclusively on paved
surfaces. I replaced my last rear rim (a 26" Mavic F519) after 2500
miles, due to marked concavity of the rim. I replaced the previous rear
rim (also a Mavic F519) after 3200 miles, and I probably would have done
at least another 500 miles on that rim if I hadn't needed a new hub,
meaning that I just built a complete new wheel.

My front rims are smaller (20") and subject to more braking, so should
wear faster. But I think they may also have thicker walls. I use
Schurmann DoubleMaster rims. The current rim has done 3200 miles and
there is no noticeable concavity yet. The previous rim did 4800 miles.

This is my commuting bike so I don't want to have to clean the rims
every day but replacing the wheels each year would also seem excessive.

Ditto. I commute all year round on the same bike and probably clean the
rims once or twice a month. I run my tyres at 100psi.

--
Danny Colyer (the UK company has been laughed out of my reply address)
URL:http://www.speedy5.freeserve.co.uk/danny/
"He who dares not offend cannot be honest." - Thomas Paine