I’m currently running a 53-39, 11-23 on my Cervelo…however, I’m looking to change to a 12-25 to negotiate the hills of IM Moo next month.
Is this change as easy as swapping out the cassettes, or will I need to resize my chain, etc.?
Thanks all!
a bike wrench once told me to never, ever change cassettes without changing chains. he said something about an old chain will wear out the new cassette. you can, however, do it the other way around- change a chain without changing the cassette. i don’t know if this is true or not. maybe people here will know more about it…
yes please help! all you smart mechanics, help a brotha out and tell us what to do…
If you put on a new cassette, put on a new chain. An old chain on a new cassette is very likely to be noisey and may even skip under load.
To prevent premature cassette wear, you should frequently check your chain and/or keep track of the milage on the chain. Most chains start to stretch beyond proper tolerances after 2000 to 3000 miles. A simple check to determine if the chain is worn is to measure 24 links. A new chain should measure 12". One worn beyond 12-1/16" should be replaced.
If you’re careful with chain maintenance, you might get 15,000 miles out of a cassette before the most used cogs wear beyond practical use. Otherwise you might be replacing cassettes at the same rate you replace chains.
No need to swap the chain, just don’t ride in the 53-25 (though I seriously doubt that would be a problem).
WRT the “you need a new chain when you get a new cassette” thing, well, that applies to people that don’t frequently swap cassettes. I swap cassettes all the time, and there is no way I’m installing a new chain each time.
I swap between 3 cassettes (11/21,11/23,and 12/25) and never have a problem with shifting or chain tension. I just sized the chain for the 11/23 so I don’t have a problem going to a larger or smaller cassette. As far as chain wear and shifting goes, the more frequently you swap out your chain, the more mileage you will get out of cassettes. If you have a lot of miles on your current chain, you might want to start with a new chain and size it for the larger cassette. Then you will not have any problems when you go to the smaller one.
Jeff
I don’t think you’ll need to resize your chain. I swap between a 25 & 27 without any issues there. I also don’t think you need to change your chain with every cassette change but if it is an important race coming up and you’ve got some miles on your exisiting chain it might be a good time to replace it just to ensure your equipment is in top notch shape for the race.
You should be fine, unless your chain is already on the short side.
As far as all of these suggestions that a new cassette needs a new chain–not necessarily true. If your old cassette/chain have a lot of miles then maybe that is true–it also depends alot on the nature of those miles (climate, rain, dust, amount of shifting, cleanliness/lube of drivetrain, etc…).
You can use the same chain on the same cassette and if you don’t change either, both will be worn out at about 4000 to 5000 miles. You can use the same chain on three different cassettes, and if you don’t chage the chain, all three cassettes will be worn out at about 4000 to 5000 miles. OTOH, if you keep relatively new chains in the rotation, your cassettes will last about three to four times longer. A nice chain is $30. Street price on a DA cassette is about $150. Do the math.
As others have advised, it’s best to change chains when changing cassettes. I keep my spare cassettes and their chains in Ziplock bags so I don’t mix them up.
That said, you might get away with it and you might not. Depends on how the chain was sized in the first place and whether you ever try to use the 53-25 combo (you shouldn’t but it can happen by accident). If the chain was sized to be tight on the 53-23, you could be in for a rude surprise.
David