Triple Chainset replacement

[pfm401]

I have an FSA Vero Triple chainset 50 / 39 / 30 with Shimano Tiagra rear mech. I have a few basic questions about replacement:

- When should you replace? It's done about 9000 miles and some of the teeth look a bit worn. I've had the chain slip off the largest chain ring when changing from second largest - could that be due to wear or tweak needed to front mech?
- Do you have to change whole thing - cranks and all - or just the chainrings?
- Is it easy to do or easy to mess up? Is it a bike shop job?
- I've just replaced the rear cassette and chain. If I see how it goes with the chain rings would this cause issues (how much wear is too much wear!)?

Thanks, Paul.

 

[Yellow Saddle]

With that type of mileage, your chainrings will still be fine but if you are unsure, post a photo with the chain off the ring you want diagnosed. The photo should be side-on, in focus and in good light. I'm sad to have to specify the latter but the number of people who require a diagnosis from photos that could either be a gorilla in a cave on a moonless night taken with a Brownie with a cracked lens or, a chainring, are significant.

Cranks have replaceable chainrings. No need to replace the entire crank.
The mis-shift has nothing to do with wear. Chainring wear does not affect shifting.
It is an easy job but it its best done with the help of a special little cheap tool that works in the slots at the back of the chainring bolts.

 

[raleighnut]

^^^^^^^^ Wot e sed.

 

[Ajax Bay]

I have an FSA Vero Triple chainset 50 / 39 / 30 with Shimano Tiagra rear mech. It's done about 9000 miles and some of the teeth look a bit worn. I've had the chain slip off the largest chain ring when changing from second largest - could that be due to wear or tweak needed to front mech?
- Do you have to change whole thing - cranks and all - or just the chainrings?
- Is it easy to do or easy to mess up? Is it a bike shop job?
- I've just replaced the rear cassette and chain.

At that mileage, unlikely that the chainrings are worn to any significant extent. The change of cassette and chain has no bearing on the issue (except as evidence you have the expertise to change chainrings yourself).
The chain slipping off the large chainring is a front derailleur adjustment (limit screw) issue - easy to solve (and if it happens when you're riding, just pause pedalling, change back down and pedal gently - the chain will normally (8 out of 10) get back on (the middle) chainring. Solution: With the chain on the smallest rear sprocket: screw the limit screw in till it won't change up at the front, and then screw it out (1/4 turn at a time) till it will. Adjust to ensure chain is not rubbing on FD cage (under tension), just. Test it on the road and that it changes up efficiently in middle of the cassette sprockets as well.
It is easy to change one or all of the chainrings provided you can remove the crank from the bottom bracket (BB)(and the ease of this depends on what type of BB). It is not easy to mess up. Worth using lockthread on the chainring bolts.
Your LBS can do this for you, but not while you wait. If you can't (tools/knowledge/confidence) take the crank off the BB yourself, you could just ask them to do that, and then do the rest yourself. Putting the crank back on is intuitive (NB 180 to the other one ) and easy.

 

[the snail]

It is easy to change one or all of the chainrings provided you can remove the crank from the bottom bracket

depending on the design of the crankset/pedals, you may be able to remove the middle/outer rings without taking the crank off, might need to undo the inner ring, then take the chainring bolts off and thread the rings over the crank/pedal.

 

[andrew_s]

Note that the difference in price between a set of replacement chainrings and a full new chainset often isn't very much.
Info: the FSA Vero triple is 130/74 bcd 5-arm square taper.