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objective way to tell if cassettes are worn out?(19 posts)

objective way to tell if cassettes are worn out?DougSloan
Dec 29, 2002 5:50 PM
I'm having a hell of a time. I have a huge investment in cassettes, with the Ti Record and DA cassettes from 11-21's to 13-29 and 12-27.

However, I had a big problem with chain skipping in the 508 on the time trial bike (DA), and this last ride on the Record 11-21 the chain skipped nearly any time I put much pressure on the pedals. Both times I had just replaced the chains.

I know you can objectively measure chain wear. Is there any similar objective test for cogs? I read what Sheldon had to say, and it doesn't help much. On the one hand, I don't want to go replacing $100-$250 cassettes prematurely, but on the other hand all the skipping is really annoying, and I fear when it does it could lead to chain damage or breakage.

So, what the heck to do? Any ideas? Thanks.

Doug
hate to say it..str8dum1
Dec 29, 2002 6:05 PM
but the chain and casette get matched in wear. If you change the chain and its skipping, time for a new casette. Thats how i tell. I dont buy DA cassettes either so 35$ isnt that much to spend. the cassette isnt the place i'm worried about saving weight. at 12k miles a year, i need longevity.
Well, you can try this:Spoke Wrench
Dec 29, 2002 6:39 PM
Whenever you change a cassette, take off the chain you had been using and store it together with the cassette you had just taken off.
re: objective way to tell if cassettes are worn out?Leroy
Dec 29, 2002 7:10 PM
I think the objective way you tell if the cassette is worn out is when the chain skips as you described. Sounds to me like yours need replacing. I hate to say it, but if that is what occurred to you, your initial hunch was on the money.
re: objective way to tell if cassettes are worn out?Woof the dog
Dec 29, 2002 10:53 PM
well, isn't there a special tool that looks like a chainwhip basically. You put the chain part around the cog you wanna test and try and lift the last roller off the tooth it is on. If it comes off easy, the cassette is not worn, if it doesn't or does with some energy expenditure on your part, it is time to replace. Its all relative, but I guess you can try and make note of the wear before your chain starts skipping. Keep in mind that some cogs get used more than others, obviously.

Sincerely

Woof the dog.
just an idea, butLeroy
Dec 30, 2002 5:35 AM
if you don't mind the weight, use a campy loose cog cassette. Check the Branford Bikes site. Change the cogs that get the most use and wear fastest. Downside is that the cogs are probably steel and not ti. It's a good way to customize cassettes, too.
re: objective way to tell if cassettes are worn out?Juanmoretime
Dec 30, 2002 8:00 AM
There is a tool for measuring cassette wear. I know it was made by a German company, I'm thinking Rolf but I'm not positive.
Rohloff Cog Wear Indicatorfrankamo
Dec 30, 2002 9:17 AM
Saw one at branford bike. Never used one myself.
found it; thanksDougSloan
Dec 30, 2002 9:26 AM
http://www.branfordbike.com/cassette/cog20.html#item4

That sounds better than potentially destroying new chains to find out. Thanks.

Doug
found it; thanksWoof the dog
Dec 30, 2002 9:29 AM
don't you have leftover pieces of chains when you shorten them? Use those, put 'em together if they are too short. 30 bucks for a piece of chain on a stick sounds like a ripoff. On the other hand, you are rich, so buy whatever you want.

Woof the dog.
is that all it is?DougSloan
Dec 30, 2002 9:37 AM
It looks like the tool as a nub thing attached to the stick that goes in a particular place to measure wear; not sure I could duplicate that right.

I might try using some new chain and see what happens, though.
is that all it is?Woof the dog
Dec 30, 2002 12:37 PM
I thought I replied, but it seems the message didn't get posted. In any case, the nub on the end of where the chain attaches and the handle are both used to put pressure on the chain. Its handy for leverage and shit, but is it worth 30 bucks? Shop price is 10 bucks. All you do after you put the chain on is try and take off the last bushing at the end of the chain off the corresponding tooth it is on. If it comes off fine, your cog isn't worn cause the tool's chain bushings are contacting all the rest of the teeth equally. if its hard to take it off, the cog is hooked which means wear.

I'd make the tool myself.

Woof the dog.
B adjustment screw out of whack?DougSloan
Dec 30, 2002 3:48 PM
I just discovered something. My Record RD had the B adjustment screw (or the equivalent) adjusted for a 29 tooth cog. That put it really far away from the 21, which was in the largest position. I just screwed it all the way in, and now the top pulley sits closer to the cogs and seems to wrap more chain around the cogs. Could that make a difference?
Umm, your chain skips?Kerry
Dec 30, 2002 5:35 PM
Despite all the claims to the contrary, I cannot for the life of me figure out how you can change your chain often enough to prevent cog wear. They've got to be wearing all the time they're in use whether the chain has elongated or not. Yes, it's easy to understand how they will wear FASTER with a worn chain, but I can't understand how they will not wear with a new chain. THEREFORE, they will have to be replaced. The easiest solution, and the cheapest too, is to buy steel cogs (Campy Chorus, Shimano ?) and replace the cogs when you replace the chain running the chain to full 0.5% wear. The $$ is easy to calculate, and your cassettes will have to last a LONG time to justify the super frequent chain replacement that is supposed to prevent cog wear.
Have to agree with you kerry..pa rider
Dec 31, 2002 7:45 AM
I told you earilier this year about replacing chains at 3k to use one cog all year. Your correct because all I saved was $10, by not just buying a new cassette and one chain after the old chain cassette wears out. I may have saved more money by not having to replace my chainring.

For us mtbers you normally have to replace the chainring (middle and granny) when you replace the rear cassette.

Doug never did say if his chainrings were pretty worn either.

Emory
good questionDaveG
Dec 31, 2002 9:55 AM
I have never been able to figure this out either. The last time I left a cassette on too long, it started skipping badly when I replaced the chain. When I took it to that shop the mechanic looked at it and instantly said the cassette was worn out. I compared it to a new cassette and could not tell much of a difference myself - perhaps he had an eye for it. Since then I replace my cassette every 3 chain replacements, which is about 7500 miles for me. Since I use cheap steel cassettes, that doesn't hurt so much.
just had an ideaDougSloan
Dec 31, 2002 10:16 AM
I suppose that when you get a new cassette, you could carefully trace the outline of all the cogs (except the inner of attached cogs) on paper, and then keep that as a reference to compare the worn cogs to later on. It's still a bit subjective, though.

Maybe the teeth can wear in ways other than profile (like the edges) that can cause skipping?

Doug
Doug, your changing chains w/o changing cassettesLeroy
Jan 3, 2003 7:03 AM
is just like using a new piece of sandpaper on the old cassette ;-)
true, it seems, butDougSloan
Jan 3, 2003 7:17 AM
The question is, when is the cassette "old?" Are you saying to change cassettes with every chain change? Do people really do that?

Doug