Rim Failure

[email hidden] wrote:
..

Quoted message said:

Didn't cause a problem with a back wheel, I find the prospect of the
same thing happening with a front wheel rather scary.

Back wheel would be eqaully scary at speed - mine stopped dead as the
peeling rim wound around the brake caliper....

pk

p.k. said:

Quoted message said:

Didn't cause a problem with a back wheel, I find the prospect of the
same thing happening with a front wheel rather scary.

Back wheel would be eqaully scary at speed - mine stopped dead as the
peeling rim wound around the brake caliper....

Mine was at 20+ mph. The wheel kept going round, so not a huge
problem. I'd have thought that at higher speeds the energy might be
too high to stop dead, but I'm not sure, and I'd rather not find out.

Rob

Clive George said:

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

news:[email hidden]...

Quoted message said:

Front wheel should be /more/ worn, because you use your front brake more
(or if you don't you should).

For hardish braking, maybe, but for gentle braking, which is what I do more
of, I tend to use the rear brake - there's no particular reason to use the
front then. So the back wheel ends up more worn.

I tend to use the back brake for gentle braking and controlling speed
on descents (an unfamiliar concept to you, Simon?) and the front brake
when I actually want to stop. Apart from anything else, I like to use
both regularly to be sure they are working properly - someone near
here discovered both brakes weren't working going down a _steep_ hill
- she hit a garden wall at 30 mph, went over the top of it into a bush
and suffered only moderate injuries.

My front and back brake blocks wear out at near enough the same time,
which surprises me slightly - I would expect the fronts to go first.

Rob

Paul Boyd usenet.dont.work@plusnet said:

Rob Morley said the following on 24/07/2007 08:08:

Quoted message said:

As others have said, the
rim thickness is measurable. It has also been widely reported that
Shimano brake blocks cause more rim wear than other good brands - I
don't know if that's still the case.

The last set of Shimano brake blocks I had were so soft that they wore
out in just a couple of months or so of commuting. I kept thinking
"these brake cables seem to be stretching quite a lot" as I twiddled the
adjuster again, because it hadn't occurred to me that any blocks could
wear so fast. I don't think there was much danger of those blocks doing
much damage to the rim - I now have Koolstops and everything is again as
it should be. Other Shimano blocks I've had in the past seem to be made
of carborundum paste or something!

used to ride the hills nr my folks place, which at one area is a old
waste land. opencast mining etc, and the shally mud will wear out brake
blocks in one run given half a chance, also clog all but the best mud
tires.

roger
--
www.rogermerriman.com

in message <[email hidden]>,

(' ') said:

Clive George said:

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

news:[email hidden]...

Quoted message said:

Front wheel should be /more/ worn, because you use your front brake
more (or if you don't you should).

For hardish braking, maybe, but for gentle braking, which is what I do
more of, I tend to use the rear brake - there's no particular reason to
use the front then. So the back wheel ends up more worn.

I tend to use the back brake for gentle braking and controlling speed
on descents (an unfamiliar concept to you, Simon?)

Yeah, yeah...

I'm not really as mad as is sometimes implied, and I no longer really rate
the title 'The Great Descender'... but I don't often brake on a descent -
and I don't tend to use the back brake when I do. Sitting up and using
your body as an airbrake as you go into corners is usually enough, except
on really steep stuff.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
Just as defying the law of gravity through building aircraft requires
careful design and a lot of effort, so too does defying laws of
economics. It seems to be a deeply ingrained aspect of humanity to
forever strive to improve things, so unquestioning acceptance of a
free market system seems to me to be unnatural. ;; Charles Bryant

Noel said:

3. If this is not normal, do you think Mavic would be interested in
hearing about 18 month old rims which do about 60 miles/week doing this?

I'd be happy with that. 4500 miles is more than I usually get out of a
rear rim, although I've never ridden one to destruction.

That said, my current rim (a DT Swiss XR 4.1) has done 7000 (mostly
commuting) miles. The braking surface is bowed to the point where I
would usually replace it, but as yet there's no sign of the rim wear
indicator that it's supposed to have. I'm hoping to get another couple
of months' use out of it (mid September is a convenient time for me to
replace it). I have a replacement DT Swiss XR 4.1 on order - best rim
I've ever had.

--
Danny Colyer <http://www.redpedals.co.uk/danny/>
Reply address is valid, but that on my website is checked more often
"Daddy, put that down. Daddy, put that down. Daddy, put that down.
Daddy, why did you put that down?" - Charlie Colyer, age 2

p.k. said:

The silver lining was that I had an excuse to buy a new bike as new wheels
and all the other stuff needed made the old on uneconomic. In my case too
much wet weather riding to the Towpath - river silt makes a great grinding
paste! I swapped the Specialized rockhopper for a Marin nail trail with
discs!

Yes having been to the LBS yesterday, a whole new bike is probably the
best bet rather than retro-fitting disc brakes. Also it seems my riding
has rather outgrown my current bike (Claude Butler Cape Wrath) which after
18 months also needs a new large chainset cog. Finances however dictate
that the Trek 6500 with disc brakes in the shop window will have to wait.
A couple of new rims and chainset cog will suffice for another six months.

Cheers

Simon Brooke said:

in message <[email hidden]>,

(' ') said:

Clive George said:

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

news:[email hidden]...

> Front wheel should be /more/ worn, because you use your front brake
> more (or if you don't you should).

For hardish braking, maybe, but for gentle braking, which is what I do
more of, I tend to use the rear brake - there's no particular reason to
use the front then. So the back wheel ends up more worn.

I tend to use the back brake for gentle braking and controlling speed
on descents (an unfamiliar concept to you, Simon?)

Yeah, yeah...

I'm not really as mad as is sometimes implied, and I no longer really rate
the title 'The Great Descender'... but I don't often brake on a descent -
and I don't tend to use the back brake when I do. Sitting up and using
your body as an airbrake as you go into corners is usually enough, except
on really steep stuff.

i think a lot depends on terrain, where i started and do still very
rarely montain bike is nr my folks place which in the clydach gorge
which due to the servity of the hills means you normally are grinding up
in the granny gear or gripping both brakes very firmly.

roger
--
www.rogermerriman.com

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

Quoted message said:

Yes having been to the LBS yesterday, a whole new bike is probably the
best bet rather than retro-fitting disc brakes. Also it seems my riding
has rather outgrown my current bike (Claude Butler Cape Wrath) which after
18 months also needs a new large chainset cog.

What have you been to to wreck a large chainring? They normally last
ages unless they've been bounced off rocks.

Rob Morley said:

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

Quoted message said:

Yes having been to the LBS yesterday, a whole new bike is probably the
best bet rather than retro-fitting disc brakes. Also it seems my riding
has rather outgrown my current bike (Claude Butler Cape Wrath) which after
18 months also needs a new large chainset cog.

What have you been to to wreck a large chainring? They normally last
ages unless they've been bounced off rocks.

yup i'm still on the orginal chain set on my old bike, mind you it's
only now that it's being used on road that that ring gets used. normally
be 2nd or 1st 3rd only for essenatly freewheeling down hills.

roger
--
www.rogermerriman.com

Rob Morley said:

What have you been to to wreck a large chainring? They normally last
ages unless they've been bounced off rocks.

No rock bouncing but as the chain pulls onto the ring it does not link up
tightly so that you can see daylight where the teeth and chain meet almost
until it is halfway wound. My thinking was that the softer metal teeth of
the chain ring had worn against the chain and the LBS chap agreed.
Certainly the teeth were quite ground down. I suggested that perhaps a
new chain would be an idea as well but he said that would mean replacing
the rear derailleur too. What do you reckon?

Cheers
Noel

Noel said:

No rock bouncing but as the chain pulls onto the ring it does not link up
tightly so that you can see daylight where the teeth and chain meet almost
until it is halfway wound. My thinking was that the softer metal teeth of
the chain ring had worn against the chain and the LBS chap agreed.
Certainly the teeth were quite ground down. I suggested that perhaps a
new chain would be an idea as well but he said that would mean replacing
the rear derailleur too. What do you reckon?

I presume he means a rear cassette/freewheel and not a new derailleur.
The latter would make no sense. For the former it depends how worn the
teeth are on that too. If they are worn then a new chain will simply
skip over the teeth but its worth trying it first unless the teeth are
obviously worn. But on the other hand if you run a new chainwheel with
a worn chain it will quickly wear the chainwheel to fit the chain so
back where you started. The secret for next time is to keep an eye on
your chain and change it well before it gets worn. Costs a bit more but
its a lot cheaper than replacing most of the drivetrain each time.

Tony

in message <[email hidden]>, Noel

(') said:

Rob Morley said:

What have you been to to wreck a large chainring? They normally last
ages unless they've been bounced off rocks.

No rock bouncing but as the chain pulls onto the ring it does not link up
tightly so that you can see daylight where the teeth and chain meet
almost
until it is halfway wound. My thinking was that the softer metal teeth
of the chain ring had worn against the chain and the LBS chap agreed.
Certainly the teeth were quite ground down. I suggested that perhaps a
new chain would be an idea as well but he said that would mean replacing
the rear derailleur too. What do you reckon?

If you've got a worn chainwheel, I think you would be MUCH better off
replacing - or at least very carefully checking - the whole transmission.
Typically the chainwheel is the last component to wear in a transmission.
If you don't change the chain, the new chainwheel will simply wear out
quickly. If you change the chain but don't change the cassette, the new
chain will wear out quickly and cause damage to the new chainwheel.

This is expensive. The lesson for the future is, change your chain early,
before it starts doing damage to the rest of the transmission.

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

;; An enamorata is for life, not just for weekends.

Tony Raven said:

I presume he means a rear cassette/freewheel and not a new derailleur.

Yes sorry I was going to use the word 'cog' which might have been better.

Quoted message said:

obviously worn. But on the other hand if you run a new chainwheel with
a worn chain it will quickly wear the chainwheel to fit the chain so
back where you started. The secret for next time is to keep an eye on
your chain and change it well before it gets worn. Costs a bit more but
its a lot cheaper than replacing most of the drivetrain each time.

Yes I see your point. I'll have to keep a much closer eye on the wear and
tear of my components with the new bike when I can afford to get it. I am
quite surprised how quickly this one has worn.

Cheers
Noel

Quoted message said:

Yes I see your point. I'll have to keep a much closer eye on the wear
and tear of my components with the new bike when I can afford to get
it. I am quite surprised how quickly this one has worn.

A couple of chain checkers here:

<www.edinburghbicycle.com/ebwPNLqrymode.a4p?f%5FProductID=4493&f%5F>
<www.edinburghbicycle.com/ebwPNLqrymode.a4p?f%5FProductID=2249&f%5F>

To help your chain last longer, NEVER lube without cleaning first (from
experience, this REALLY speeds up the wear).

Noel said:

Rob Morley said:

What have you been to to wreck a large chainring? They normally last
ages unless they've been bounced off rocks.

No rock bouncing but as the chain pulls onto the ring it does not link up
tightly so that you can see daylight where the teeth and chain meet almost
until it is halfway wound. My thinking was that the softer metal teeth of
the chain ring had worn against the chain and the LBS chap agreed.
Certainly the teeth were quite ground down. I suggested that perhaps a
new chain would be an idea as well but he said that would mean replacing
the rear derailleur too. What do you reckon?

If you can see daylight around the chainring like that it usually means
the chain is "stretched" (i.e. worn). Measure 12 links and see how much
longer than 12 inches they are.

According to Sheldon Brown (I think but check the website yourself) less
than 1/16" too long over 12", keep the chain, between 1/16" and 1/8"
replace it, greater than 1/8", replace it and the sprockets as well.

Ben C said:

If you can see daylight around the chainring like that it usually means
the chain is "stretched" (i.e. worn). Measure 12 links and see how much
longer than 12 inches they are.

According to Sheldon Brown (I think but check the website yourself) less
than 1/16" too long over 12", keep the chain, between 1/16" and 1/8"
replace it, greater than 1/8", replace it and the sprockets as well.

For the avoidance of doubt that is with the chain under tension, not
loose. Measure it along the top chain run with a little bit of
pressure on the pedal.

Tony

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

Quoted message said:

Rob Morley said:

What have you been to to wreck a large chainring? They normally last
ages unless they've been bounced off rocks.

No rock bouncing but as the chain pulls onto the ring it does not link up
tightly so that you can see daylight where the teeth and chain meet almost
until it is halfway wound. My thinking was that the softer metal teeth of
the chain ring had worn against the chain and the LBS chap agreed.
Certainly the teeth were quite ground down. I suggested that perhaps a
new chain would be an idea as well but he said that would mean replacing
the rear derailleur too. What do you reckon?

I reckon he's a cowboy. In normal use with proper maintenance a
chainring should outlast several cassettes (rear clusters), and a
cassette should outlast several chains, so if the chainring is knackered
the whole drive train almost certainly needs replacemement. Proper
cleaning and lubrication of the chain, and replacement before it becomes
too 'stretched' (actually worn) is essential to reduce wear on the
cassette sprockets and chainring. If any part of the drive train is
worn significantly more than any other part it won't mesh properly and
everything will wear at an accelerated rate. See
http://www.sheldonbrown.com/chains.html for a full discussion of chain
wear issues.

Rob Morley said:

I reckon he's a cowboy. In normal use with proper maintenance a

Probably more my fault as I requested it and pushed for it without
thinking it through 🙁 Got the old chain ring so I'll probably swap the
old back on again.

Did the chain measuring thing and my chain is about 1/2" stretched which
is pretty bad I think? No easy answer I know, but after 18 months of
climbing hills and off-road riding I guess it has to be expected to go the
same way as the rims...

Read somewhere that Lance Armstrong wore out a chain each week during the
Tour which I assume means he stretched it rather than broke it?

Cheers