CoachDirty

I took my bike to the LBS for tune up/inspection. The guy said my chain had stretched (apparently this is pretty common) and that it needs to be replaced at some point soon. He also said that when you replace the chain you generally want to replace the rear cassette. (something about the chain being fit to it, I don't really remember the reason)

So my question is: is it generally adviseable to replace the cassette with the chain? And should I just get the same cassette? I have the original 9 speed that came with the Trek 1.2. I've searched the forum, and have found some info on cassettes but alot of it is over my head. I don't know what an 11-28 cassette is or means. Anyway I'm going to take my bike up there sometime this week, so I need to make a decision.

Thanks in advance for the help!

datlas 

How many miles on the chain and cassette? Do you lube the chain every once in awhile?

Generally speaking a 9 speed chain, if maintained properly, should be lasting you something like 3-4 thousand miles. The cassette should be lasting 10K miles or longer. Typically, you do not change a cassette with each chain, but more likely every 3-5 chains, depending.

This assumes you keep your drivetrain reasonably clean and lubed. If you ride in the wet and muck and never lube your chain the numbers will be much lower.

San Rensho 

Don't replace the cassette unless its worn. You will be able to tell if its worn because when you put a NEW chain on it, the chain will skip.

The cassette will last a long, long time if you replace the chain well before the chain reaches its wear limit. I've put at least 7 chains on the same cassette and over 10k miles and the cassette is still fine. Chains is cheap, less than $20. Some cassettes are really expensive, like a Shimano 11-21, which goes for close to $200. I'm not going to get a new $200 cassette every time I change the chain.

CoachDirty

I have around 1800 miles on it (its the original chain and cassette) I didn't lube it for the first 800 or so miles, as I didn't know I was supposed to. I now try to lube it after every couple rides or so. So it sounds like probably just replace the chain this time, and unless it skips, keep the same cassette.

p.s. someone please tell me what 11-21, or 11-28 means when referencing cassettes. I've tried for the life of me to find out and it's driving me crazy.

jwible

range of cogs on the cassette. 11 being the smallest and 21 being the largest. The smaller the low number the faster the theoretical speed. The higher the big number the easier it is to climb.

AngryScientist 

with the numbers representing the number of teeth on the cog.

Mr. Beanz

11-28 means the smalest gear in back is an 11 tooth gear/cog. The 28 is the biggest cog which is the highest gear.

I runa 12/25 with the standard (two rings) in the front.

Riders select their gears based on their preferred style. I like to spin (high rpm's) soa 12 as the small gear (gighest gear) in the rear is good because I wouldn't use an 11. It would be too hard to push for my style, so the 12 is plenty.

THe 28 is the easy climbing gear (low gear). I use a 25 as I can make it up most hills with the 25. A rider that struggles on the climbs would like a 28 as it would give him a few extra gear inches to climb a bit easier.

However, a rider must take into consideration the front gear setup. A standard double is two rings with a 53 big ring and a 39 small ring (other combos exist like a 53/42 etc.) the 53 is the big ring used for high speeds 9high gear) and the 39 for easy spinning (low gear)

SO if you have a triple up front (3 rings) you may not need an 11-28 as the low gear can be obtained by using the front small ring. SO some riders with a triple might prefer a 12/25 in teh rear so that the incremnets between shifts is minute.

A rider with the compact front (50-42?) might like the 11/28 as a rear cassette casue the 11 is a high gear that would compliment the 50 ring up front sine the 50 is smaller than the standard 53 of the standard double.

SO it pretty much depends on the gear you are spinning and what makes you comfortable.

Basic explanation

CoachDirty

Very good explanation....Thank you very much!

dstrong 

You bought your bike in September and just rode your first century (congrats AGAIN!). I'm finding it tough to believe that you'd be ready for a chain replacement at this point. If you're not experiencing shifting problems that adjustments can't fix, then maybe it's time...but until that point, I'd leave it alone.

So, not only did I point out that you've got a triple in FL...but are you implying by your post that it's currently equipped with a 12-28 also????

IF you want to switch out cassettes (which at this point is optional for you) AND you want to stick with the triple, I'd be tempted to look at a 12-21 or 12-23. With your small chainring, you'll have plenty of gearing to climb even the tallest bridge but for all the flat riding, you'll have a nice range on the middle and big ring to find your sweet spot cadence.

The further the two numbers are apart, the bigger the gap between some of the cogs. For instance...a 12-21 cogset typically looks like this:

12,13,14,15,16,17,18,19,21

While a 12-28 looks like this:

12-13-15-17-19-21-23-25-28

Notice after the first two smallest cogs (12 and 13), that the tooth gap on the 12-28 goes to 2 between the next several cogs, then 3 on the last two.

What this means is that, for instance, if you're cruising in your middle chain ring, you'll be able to make smaller adjustments as you shift through the 12-21 and not have such dramatic differences in your cadence as you would with the 12-28. Personally, I'd find this desirable in a predominantly flat area.

CoachDirty

I just used 11-28 as an example. I have no idea what I actually have (other than a 9 speed). I do know that I never use the small front gear. I like your explanation of not having a dramatic difference in your cadence with 12-21. I'd definitely like that. When I do replace the cassette I'll probably go more towards that/those sizes.

P.S. now that I know what those numbers mean, I'm looking forward to finding out what I do have when I get home this evening.

Mr. Beanz

1.2 Trek, I see it in the pic now....50/39/ 30 crank with a 11/26 cassette

https://www.trekbikes.com/us/en/bikes/road/1_series/12/

prathmann

Another thing to do when you get home is to measure your chain yourself to see if it really needs to be replaced. Bike chains are exactly 1/2" long per link, so if you hold a ruler up to one the pins should all line up nicely on the 1" and 1/2" marks. The way to tell if a chain has become too worn is to line up one pin with the end of a ruler and check to see that another pin about 12" away also lines up right at the inch mark. If it's off by 1/16" or more then it's time to replace the chain.

By the time the chain wears enough so that the measurement over 12" is off by over 1/8" then there may well have been enough wear on the cassette so that will need to be replaced too. But I would always first try just replacing the chain and seeing if there's any skipping before changing the cassette.

idoru2005

Bike mechanics, like auto mechanics and doctors, are prone to telling customers that something needs to be "replaced soon". It's how their employers make money.

coasting 

no way! shock horror.

every year when i have my car inspected i get a fail for windscreen wipers and then they charge me a king's ransom just to replace those. this year i thought i would test my suspiscions by changing them before i took the car in. guess what? they failed again!

Hunt-man

Replace the chain. Not much money and a badly worn chain can wear out your gears. It had a good long life.

CoachDirty

Thanks, now I know!



Ok I'll try that tonight. Thanks.



Yeah I kind of assumed this. I'm all right with a salesmen trying to sell me the ideal as opposed to the necessary. (I mean they have to make a living) Just don't try to sell me the unnecessary.

banerjek

Since you have the 30T ring, I agree with dstrong's advice to go with a 12/21 or 12/23.

With 3 rings, there is no point in having a wide cassette since you don't have big climbs, there is already plenty of overlap, and the jumps between gears will be much smaller.

CoachDirty

I was thinking about just changing the chain, but I'm starting to lean towards getting the more compact cassette. There have been several times (especially when I'm tired) where I felt like the change in gears was too big. Meaning I couldn't comfortably cadance at either one. So the 12/21 sounds like it may be ideal.

Looking at the link that Mr. Beanz provided, it appears that my rear cassette is a SRAM. Would it be smart/easy to just use that brand again, or does that really matter (hope I'm not opening up a bag of worms with that question) Or maybe it would just be easier to use the brand my LBS prefers?

Hunt-man

Sram, 105 or Ultegra will be fine. Don't spend too much, more money usually means lighter and how much is a few grams worth?

Just get a new chain at the same time.

dstrong 

And as long as we're edumacating on chains...many prefer the SRAM (or non-shimano) chains that have "quick links" or some other type of link that allows you to more easily remove the chain, either for switching out cassettes or thorough cleaning. The Shimano chains require that you have a "chain breaker" tool, to push out the pin to take it apart. then you have to buy a pin to push back in. Some use quick links with shimano chains but to mixed reviews and opinions (what else is new on BF!).

banerjek

SRAM and Shimano cassettes are compatible. There are a number of other companies that sell cassettes that you also could use. For your purposes, you'll be fine if you get whatever costs less.

You can keep the old cassette in a plastic bag since there could be some circumstance in the future when you'd want it again.

Daytrip

I use a Wippermann on my 105 10 sp chains and it works great.

banerjek

Just to weigh in on the quick links. The OP has a 9 speed cassette, so the quick links he'd be using are all pretty good. I really don't like the master links for the SRAM 10 speed systems. The Wippermans are my favorite. A 9 speed SRAM or Wipperman link can last through several chains and both are good. Even if he goes with a Shimano chain, I'd recommend buying the link separately.

I've heard people complain about the Wippermans before. But many people don't seem to be aware that they can be installed upside down. If they are installed upside down, you can get issues when on your smallest cog.

CoachDirty

All right hold on, you guys lost me on the "link" thing. Is that a tool that comes with the chain? Is it a part of the chain? I was with you up until that part.

Hunt-man

SRAM has a link that you can push together, remove it, and take the chain off. Only really matters if you want to remove the chain to clean it. I don't think you will ever be removing your chain to "clean" it, since you went 800 miles with no lube. Good to clean the chain every few months or so. Spray it with wd40 and wipe it off. Or buy a chain cleaning tool. Or have the LBS do it.

9spd chains will last a long time, usually.