Crank problem? or something else?

Infamous

Had my bike about a week (Carrera Virtuoso) done about 170 miles on it. Went out today and there was a strange clicking when pedalling fast, coming from the crank area I think.

Then when I was climbing up a small but slightly steep hill, the chain somehow wedged itself between the front mech and the gears, locking the pedals. It happened again on another steep hill, both times I was on the small front ring and the 3rd lowest/biggest rear ring. As soon as I got off, it had unwedged itself.

Any ideas? thanks

carlstone

That sounds pretty unusual, I have heard of the chain getting stuck between the chain ring and bottom bracket but never the front mech and gears. I am guessing that the front mech could need adjusting so the cage straddles the lowest smallest cog when looking at it from behind when the smallest cog is selected. I am guessing that you are changing down to the smallest cog on the front when you are, say, somewhere in the middle of the rear cassette. This will mean that the chain is at an angle pointing away from the inner plate of the cage. When you go to the larger cogs on the cassette this angle will reduce and throw the chain into the from mech cage so causing the problem.

Adjust the front mech inwards and all should be hunky dory. Check out shaldon brown or park tools as to how to do this.

You are still in the breaking in period of your bike where components are bedding in and cables stretching. You will nedd to adjust things regulary during this phase, but less so later on.

Infamous

Thanks for the help. Strangely though, the chainline seems to be pretty much straight on the gear that it was in when it fell off.

TBH, I didn't get a great look at how it was wedged in, as soon as it happened I got off the bike, which fixed it. Presumably it happens when there is a lot of pressure on the chain.

and any idea about the clicking?

Infamous

Is it possible that the crank arms are loose?

I didn't think it would be that, being quite new, but http://www.bikerepaironline.com/crank%20arm%20loose.htm says:

It is very common for a crank arm to come loose, especially on new bikes. Test often.

:?

keef66

I know it's a new bike but I'd look very carefully at the chain. Last time I had anything like those symptoms it was on a nastily cheap bike and shortly afterwards the chain broke while stomping uphill. Fortunately just a 2 mile walk home.

Infamous

keef you are a star.

One of the pins is barely still in :shock: :shock:

should I just buy a chain tool and fix it (probably handy to own one anyway)? or should I take it back in (halfords :roll: ) and tell them to fix it? I can't see them putting a new chain on or anything.

keef66

I'd insist on them fitting a new chain. The link with the loose pin has been stressed and likely deformed and should be removed, which will leave the chain shorter than originally fitted.

Don't let them just replace the pin.