Failing Chain set on a Marin

Gweilo_uk said:

Hopefully I can get some advice on a Failing Chain Rings on a Marin. I have had a 2006 Rock Springs for a VERY short period of time, the bike hase done about 100 miles so far, and to date the front crank has F***ed up twice. The middle chain ring seems to bend in use leading to the chain jamming between the middle and top chain rings. This has happened after 40 miles the first time and then less than 30 on the replacement. I believe that the chain set is maufactured by deore

My question's are:

1) Is this a common fault that people have experienced before

Common experience?

Well, perhaps, it is all too common experience for people who choose to buy their bike from a bike shop rather than a USED bike or a bike from a non-specialized outlet because you rightly believe that part of the reason for the premium is that you will receive a bike that is properly set up.

There is an unfortunate legacy from who knows how many decades ago that you would bring the bike in after the first month and the shop would make adjustments based on what may have gone wrong. Can you imagine how tedious that might be if you didn't live close to the shop?

I think a lot of shops still adhere to the come-back-in-a-month philosophy and/or they think that their charming personalities are worth the price difference you are paying. THAT IS A CYNICAL VIEWPOINT, BUT AT LEAST IT'S AN EXCUSE ... WELL, AN EXPLANATION FOR A POORLY SET UP NEW BIKE.

No, the chainrings on the Deore (Shimano) crank should not seem to bend when the chain is on the middle ring. DAMAGED GOODS.

Having said all of that, chains do come off cranks ... even on properly adjusted bikes; but, if you are noticing a perceived bending ... well, there is something wrong ... EITHER with the chainring(s)/wheelring(s) OR the crank-itself.

When you say "replacement" ... does that mean the middle ring was actually changed one-time by the shop?

If so, ask them to replace the crank with an equivalent-OR-better off a floor model the next time you go in. Perhaps, the chain, too ...

FWIW. The fact that the chain actually jammed between the rings suggests to me that the wrong WIDTH chain was installed ... or, the wrong thickness chainrings.

I don't know what the consumer laws are where you are ... they should have to make good under warranty for a new chainring OR crankset.

Try to be nice ... at least, at first.

alfeng said:

Common experience?
because you rightly believe that part of the reason for the premium is that you will receive a bike that is properly set up.

I think a lot of shops still adhere to the come-back-in-a-month philosophy

No, the chainrings on the Deore (Shimano) crank should not seem to bend when the chain is on the middle ring. DAMAGED GOODS.

When you say "replacement" ... does that mean the middle ring was actually changed one-time by the shop?

If so, ask them to replace the crank with an equivalent-OR-better off a floor model the next time you go in. Perhaps, the chain, too ...

FWIW. The fact that the chain actually jammed between the rings suggests to me that the wrong WIDTH chain was installed ... or, the wrong thickness chainrings.

I don't know what the consumer laws are where you are ... they should have to make good under warranty for a new chainring OR crankset.

Hi AlfEng and thanks or your comments.

The points you make are worryingly accurate, thier idea of setting the bike up was at best guess work, the rear air shock needs to be set up according to weight, which it wasnt so it went back first time to have that done. I'm fairly certain the front shocks are not set up properly either.

The second time it went back the crank was literaly moving about on the bottom bracket and the chain was jamming between the chain rings as a consequence. They did on that occasion have to replace the chainring/crankset though as to what the problem was they did not enlighten my wife. (I was polite that time :cool🙂

This time around the gears began to show problems after 13 miles only ten of which were off road! Not exactly what I'd expect of a mountain Bike that costs £1345. When I took it back to the shop its became apparent that the middle chain ring was bent! I was edging towards the opinion that the chain was the wrong width or simply that the crank is substandard rubbish.

I have written to the shop, and the vendors UK sales agent suggesting that the bike is not fit for purpose and as such that they are in breach of the sale of goods act, I'll let you know what they have to say.

Paul