Bicycle Mechanics - What CrankSet to go with?????

My bike is a Trek 820 (probably 1999) and I ride maybe twice a week. Well I was looking at the original sprockets (Shimano FC-CT92 24/34/42 170) and many where worn. I'm looking to order online and my price range is $20-$80 since I don't ride that much. Well I was looking at Shimano Tourney FC-TX70 and not knowing if it would work or not but the price is right $20.00. I'm thinking it is just as good as the original that lasted 6 plus years, but is there a step better?

Thanks for the feed back!
Shawn

You mean chainrings, not sprockets. You can just buy the chainrings seperately but for the price range of cranks you are looking at, it may be better to just buy the whole crank as you planned. You could find a set of deore or lx cranks for that price range I'm sure.

Well I was looking at the original sprockets (Shimano FC-CT92 24/34/42 170) and many where worn. I'm looking to order online and my price range is $20-$80 since I don't ride that much.

by "many were worn," do you mean one or two on the middle and outer chainring? these are meant to improve shifter and are not a sign of wear. wear should be near uniform. keep in mind a new crankset may require a new bottom bracket. the tourney stuff will do for the occassional recreational rider, and take bottom bracket lengths common on older cranksets. but you should probably inspect the BB as well while you have the chance.

If his crankset really is worn out, he should replace the bottom bracket at the same time. (...and perhaps also the cassette/freewheel, rear derailleur, chain, hubs, rims, etc, etc...)

You can't change the chainrings seperately because they are one piece. If I change brands will I have to change the front derailleur though?
thanks,
Shawn

Hey Dafydd, the one chainring is actually broken in a vally between two teeth. Sorry for being such a newbie but what is a BB (bottom Bracket)? Is that your Crank bearings? Actually I would replace everything if it was a good price!

Hey Dafydd, the one chainring is actually broken in a vally between two teeth. Sorry for being such a newbie but what is a BB (bottom Bracket)? Is that your Crank bearings? Actually I would replace everything if it was a good price!

Don't listen to him - he's messing with you. That or he's insane. Replacing everything is a little overkill.

I'd just replace the whole crank. You might be able to find an abandoned/goodwill bike with one you can use on it, that would be even cheaper. If you don't want to go that route, I'd go into your favorite LBS and ask them if they have any used ones, or spare right cranks that they'd sell you cheap.

donut, how am i messing with him? what he just described is exactly what i described--a ramp in the chainring teeth to promote better shifting under load. on top of that, which i forgot to mention in the first post, if his chainrings were that badly worn he'd probably need a new chain and cassette/freewheel as well. unless he's riding in the granny gear all the time, there's no way the chainrings have worn out before the rest of the drivetrain was symptomatic. and to tell him to use any ole crank off a beater when he doesn't even know what a BB is just doesn't make sense.

shawn m, yes, the bottom bracket is the crank bearings. but i think perhaps someone else should inspect your crank before you go and buy anything. i suspect there's not a whole lot wrong.

donut, how am i messing with him? what he just described is exactly what i described--a ramp in the chainring teeth to promote better shifting under load. on top of that, which i forgot to mention in the first post, if his chainrings were that badly worn he'd probably need a new chain and cassette/freewheel as well. unless he's riding in the granny gear all the time, there's no way the chainrings have worn out before the rest of the drivetrain was symptomatic. and to tell him to use any ole crank off a beater when he doesn't even know what a BB is just doesn't make sense.

shawn m, yes, the bottom bracket is the crank bearings. but i think perhaps someone else should inspect your crank before you go and buy anything. i suspect there's not a whole lot wrong.


Actually, I apologize. I thought he was responding to bkrownd, the one who told him to replace rims, hubs, bottom bracket, etc.

I agree with your post!

Replaced a crank on an 820 Sport with a Shimano Acera scored new on eBay for 25 bucks. Rings and crankarms do not come apart since they are afixed with rivets instead of crabkbolts.

Actually, I apologize. I thought he was responding to bkrownd, the one who told him to replace rims, hubs, bottom bracket, etc.


I didn't "told him to" anything - note the word "perhaps". He said his crankset was "worn", and didn't specify how much. If his crankset was worn out then many of those other things would almost certainly be worn out, or nearly so, as well. There's nothing "insane" about that. On a 7 year old 820, depending on its maintenance, it wouldn't be unusual if those parts were at the end of their lifetime.