Bending chainrings

[[email protected]]

Look, this is probably going to seem like a weird one.

Running FSA cranks with 53/39 FSA chainrings. After 250k of riding,
the bloody chainrings have bent. They're out 2-3mm with no load on the
crank, which is enough to hit the cage when I'm riding and putting some
load on. That's read: A LOT of load - at 215+ and reasonably strong.

Can I bend them back to shape? - I've checked that the spider is
straight, BB tight etc.
Or if I can't, is there something stronger that I can use? Not too
fussed about weight - I'm too tall and heavy to climb anyway.

Regards,

Alister

 

[Lou Holtman]

[email protected] wrote:
> Look, this is probably going to seem like a weird one.
>
> Running FSA cranks with 53/39 FSA chainrings. After 250k of riding,
> the bloody chainrings have bent. They're out 2-3mm with no load on the
> crank, which is enough to hit the cage when I'm riding and putting some
> load on. That's read: A LOT of load - at 215+ and reasonably strong.
>
> Can I bend them back to shape? - I've checked that the spider is
> straight, BB tight etc.
> Or if I can't, is there something stronger that I can use? Not too
> fussed about weight - I'm too tall and heavy to climb anyway.
>
> Regards,
>
> Alister
>


250k of what?

Lou
--
Posted by news://news.nb.nu

 

[Chalo]

[email protected] wrote:
>
> Running FSA cranks with 53/39 FSA chainrings. After 250k of riding,
> the bloody chainrings have bent. They're out 2-3mm with no load on the
> crank, which is enough to hit the cage when I'm riding and putting some
> load on.

If they are "bent" parallel to each other, then it's not your
chainrings, but some issue with the crankarm or spindle.

Chalo

 

[Kenny]

Lou Holtman wrote:
> [email protected] wrote:
> > Look, this is probably going to seem like a weird one.
> >
> > Running FSA cranks with 53/39 FSA chainrings. After 250k of riding,
> > the bloody chainrings have bent. They're out 2-3mm with no load on the
> > crank, which is enough to hit the cage when I'm riding and putting some
> > load on. That's read: A LOT of load - at 215+ and reasonably strong.
> >
> > Can I bend them back to shape? - I've checked that the spider is
> > straight, BB tight etc.
> > Or if I can't, is there something stronger that I can use? Not too
> > fussed about weight - I'm too tall and heavy to climb anyway.
> >
> > Regards,
> >
> > Alister
> >
>
>
> 250k of what?
>
> Lou
> --
> Posted by news://news.nb.nu

If he meant "k" as in thousand then I can only presume he's been riding
those chain rings for 250,000 miles. I'd say he got his money's worth.
To top it off, he wants to repair them and continue using them. Killer!

 

[Lou Holtman]

Kenny wrote:
> Lou Holtman wrote:
>
>>[email protected] wrote:
>>
>>>Look, this is probably going to seem like a weird one.
>>>
>>>Running FSA cranks with 53/39 FSA chainrings. After 250k of riding,
>>>the bloody chainrings have bent. They're out 2-3mm with no load on the
>>>crank, which is enough to hit the cage when I'm riding and putting some
>>>load on. That's read: A LOT of load - at 215+ and reasonably strong.
>>>
>>>Can I bend them back to shape? - I've checked that the spider is
>>>straight, BB tight etc.
>>>Or if I can't, is there something stronger that I can use? Not too
>>>fussed about weight - I'm too tall and heavy to climb anyway.
>>>
>>>Regards,
>>>
>>>Alister
>>>
>>
>>
>>250k of what?
>>
>>Lou
>>--
>>Posted by news://news.nb.nu
>
>
> If he meant "k" as in thousand then I can only presume he's been riding
> those chain rings for 250,000 miles. I'd say he got his money's worth.
> To top it off, he wants to repair them and continue using them. Killer!
>


That's what I thought.

Lou
--
Posted by news://news.nb.nu

 

[Marz]

[email protected] wrote:
> Look, this is probably going to seem like a weird one.
>
> Running FSA cranks with 53/39 FSA chainrings. After 250k of riding,
> the bloody chainrings have bent. They're out 2-3mm with no load on the
> crank, which is enough to hit the cage when I'm riding and putting some
> load on. That's read: A LOT of load - at 215+ and reasonably strong.
>
> Can I bend them back to shape? - I've checked that the spider is
> straight, BB tight etc.
> Or if I can't, is there something stronger that I can use? Not too
> fussed about weight - I'm too tall and heavy to climb anyway.
>
> Regards,
>
> Alister

250000 km of riding or 250 km of riding? If it's the first then I'm
amazed the chainrings lastest that long, if it's the second then they
sound like **** cranks. If you need mega strong cranks you could try a
set of Truvativ Rouleur Cyclocross.

At 225 pounds I've never bent a set of cranks (snaped a few cranks
arms), but if I give it enough power I can flex the chainring to touch
both sides of the cage. You don't mention which FSA crank set you are
using, but if you need the performance from a reasonable to good set of
cranks you're going to have to spend around $200.

laters,

marz

 

[Michael Warner]

On 21 Sep 2006 02:54:15 -0700, Kenny wrote:

> If he meant "k" as in thousand then I can only presume he's been riding
> those chain rings for 250,000 miles. I'd say he got his money's worth.
> To top it off, he wants to repair them and continue using them. Killer!

It's possible that he's only human, and uses 'k' to refer to kilometres

--
Home page: http://members.westnet.com.au/mvw

 

[R Brickston]

On Thu, 21 Sep 2006 09:21:56 +0200, Lou Holtman
<[email protected]> wrote:

>[email protected] wrote:
>> Look, this is probably going to seem like a weird one.
>>
>> Running FSA cranks with 53/39 FSA chainrings. After 250k of riding,
>> the bloody chainrings have bent. They're out 2-3mm with no load on the
>> crank, which is enough to hit the cage when I'm riding and putting some
>> load on. That's read: A LOT of load - at 215+ and reasonably strong.
>>
>> Can I bend them back to shape? - I've checked that the spider is
>> straight, BB tight etc.
>> Or if I can't, is there something stronger that I can use? Not too
>> fussed about weight - I'm too tall and heavy to climb anyway.
>>
>> Regards,
>>
>> Alister
>>
>
>
>250k of what?
>
>Lou

250 KM?

 

[Lou Holtman]

R Brickston wrote:
> On Thu, 21 Sep 2006 09:21:56 +0200, Lou Holtman
> <[email protected]> wrote:
>
>
>>[email protected] wrote:
>>
>>>Look, this is probably going to seem like a weird one.
>>>
>>>Running FSA cranks with 53/39 FSA chainrings. After 250k of riding,
>>>the bloody chainrings have bent. They're out 2-3mm with no load on the
>>>crank, which is enough to hit the cage when I'm riding and putting some
>>>load on. That's read: A LOT of load - at 215+ and reasonably strong.
>>>
>>>Can I bend them back to shape? - I've checked that the spider is
>>>straight, BB tight etc.
>>>Or if I can't, is there something stronger that I can use? Not too
>>>fussed about weight - I'm too tall and heavy to climb anyway.
>>>
>>>Regards,
>>>
>>>Alister
>>>
>>
>>
>>250k of what?
>>
>>Lou
>
>
> 250 KM?


Maybe. In that case bring them back to the store.

Lou
--
Posted by news://news.nb.nu

 

[Mike Jacoubowsky]

>> Running FSA cranks with 53/39 FSA chainrings. After 250k of riding,
>> the bloody chainrings have bent. They're out 2-3mm with no load on the
>> crank, which is enough to hit the cage when I'm riding and putting some
>> load on. That's read: A LOT of load - at 215+ and reasonably strong.

Have FSA cranks existed more than 4 years? Let's say he's had them for 5.
That would be 50,000 miles (or 31,000 miles if it were 50k kilometers)/year.

Either he meant-

250 miles
250 kilometers

Otherwise, he's putting in 85 miles/day, average based on metric, on a bike.
Impressive!

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
"Marz" <[email protected]> wrote in message
news:[email protected]...
>
> [email protected] wrote:
>> Look, this is probably going to seem like a weird one.
>>
>> Running FSA cranks with 53/39 FSA chainrings. After 250k of riding,
>> the bloody chainrings have bent. They're out 2-3mm with no load on the
>> crank, which is enough to hit the cage when I'm riding and putting some
>> load on. That's read: A LOT of load - at 215+ and reasonably strong.
>>
>> Can I bend them back to shape? - I've checked that the spider is
>> straight, BB tight etc.
>> Or if I can't, is there something stronger that I can use? Not too
>> fussed about weight - I'm too tall and heavy to climb anyway.
>>
>> Regards,
>>
>> Alister
>
> 250000 km of riding or 250 km of riding? If it's the first then I'm
> amazed the chainrings lastest that long, if it's the second then they
> sound like **** cranks. If you need mega strong cranks you could try a
> set of Truvativ Rouleur Cyclocross.
>
> At 225 pounds I've never bent a set of cranks (snaped a few cranks
> arms), but if I give it enough power I can flex the chainring to touch
> both sides of the cage. You don't mention which FSA crank set you are
> using, but if you need the performance from a reasonable to good set of
> cranks you're going to have to spend around $200.
>
> laters,
>
> marz
>

 

[[email protected]]

On Thu, 21 Sep 2006 19:43:15 GMT, "Mike Jacoubowsky"
<[email protected]> wrote:

>>> Running FSA cranks with 53/39 FSA chainrings. After 250k of riding,
>>> the bloody chainrings have bent. They're out 2-3mm with no load on the
>>> crank, which is enough to hit the cage when I'm riding and putting some
>>> load on. That's read: A LOT of load - at 215+ and reasonably strong.
>
>Have FSA cranks existed more than 4 years? Let's say he's had them for 5.
>That would be 50,000 miles (or 31,000 miles if it were 50k kilometers)/year.
>
>Either he meant-
>
>250 miles
>250 kilometers
>
>Otherwise, he's putting in 85 miles/day, average based on metric, on a bike.
>Impressive!
>
>--Mike Jacoubowsky
>Chain Reaction Bicycles
>www.ChainReaction.com
>Redwood City & Los Altos, CA USA

Dear Mike,

I assumed $250k, a reasonable amount to spend on one's hobby.

Cheers,

Carl Fogel

 

[* * Chas]

<[email protected]> wrote in message
news:[email protected]...
> Look, this is probably going to seem like a weird one.
>
> Running FSA cranks with 53/39 FSA chainrings. After 250k of riding,
> the bloody chainrings have bent. They're out 2-3mm with no load on the
> crank, which is enough to hit the cage when I'm riding and putting
some
> load on. That's read: A LOT of load - at 215+ and reasonably strong.
>
> Can I bend them back to shape? - I've checked that the spider is
> straight, BB tight etc.
> Or if I can't, is there something stronger that I can use? Not too
> fussed about weight - I'm too tall and heavy to climb anyway.
>
> Regards,
>
> Alister
>


Yes, they can be straightened. Park and others make special slotted
tools just for that purpose.

Some brands of chainrings are very prone to bending especially larger
sizes with small bolt hole diameters (BCD): TA cranks were/are a classic
example. A 2-3mm bend is an awful lot. It sounds like they may have been
damaged by something other than normal riding.

In the early days of mountain biking (1975) I bent 2 classic forged
steel cottered crank arms, one Stronglite and the other one Zeus. I
figured that steel would be more durable than aluminum for off road and
with alloy chainrings they were actually lighter. I'd like to think that
I was strong enough to bend them but it was hitting rocks that did them
in. I switched to TA cranks and never had a problem with the crank arms
again. Chainrings were a different situation.

Like someone else said, I would take them back to where you got them and
have them checked.

Chas.