jbayes

I'm wearing out cassettes really quickly. Can anybody recommend a more durable cassette?

My first cassette was an HG70-I, which wore out long before I felt it should have. I switched to a PG-850, which lasted around 1000 miles. A second PG-850 lasted a similar span. So I switched to a PG-830 (thinking that perhaps the materials were similar and I'd save some money while getting similar durabilty), but that's starting to skip when I mash now at only around 500 miles. (2 cogs are skipping and I'm using a rolhoff cassette checker to check the wear.) In all cases the chains were less than 0.75% worn; my most recent chain (PC-850) is only 0.25% worn.

This is mostly cleanish road riding, some fire roads. I clean and lube about every 100 miles with Finish Line Dry. I weigh 250, ride mostly in my 16t and 18t cogs, and do tend to mash a little out of stop lights (though I spin at all other times), so I'm aware I'm not being as kind as I should be to my drivetrain, but it seems to me that even so a PG-830 should last longer than 2 months. And in any case, a cassette should last for 2 chains, not the other way around.

So is there another brand or another model of (8-spd mountain) cassette that is perhaps known for its durability? Is my choice of lubricant a problem?

Incidentally, I'm going to try replacing the 2 worn cogs with Miche replacement cogs. If they also last 500 miles, then at least I'll have halved my cassette replacement costs.

mrrabbit 

First off, in the absence of gritty dirt in cogs or chain or your riding/gearing combo style...perhaps the following need to be examined:

1. Ensuring the rear wheel is properly dished - rim centered exactly between the ends of the hub lock nuts or end caps. Dishing tool is typically used to check this.
2. With wheel properly dished, installing that wheel centered between the chain stays.
3. Verifying that the derailleur hanger is aligned in parallel with the properly dished and centered rear wheel. LBS will have this tool and can check the alignment for you.
4. Using a straight edge - verifying that your chain line at the rear lands on or within a few millimeters of the center of the cog set.

The above assumes you do not have an obviously bent rear derailleur...

A poorly dished rear wheel forced to center when installed alone can increase drive train noise, accelerate drive train wear and make index shifting performance sub par - i.e., not as good as it can be under ideal conditions.

=8-)

Kimmo

I'm thinking whatever the cause, maybe it'd be an idea to stick with the worn cogs for a while in order to get into the habit of downshifting more.

250lbs mashing a tall gear is probably a bit outside the design parameters.

Homebrew01

The cassettes are probably fine after such low mileage, and the skipping probably has a different cause. In my experience, skipping is most often caused by a new chain on an old cassette. If your chain & cassette have been paired for a while, then you don't get skipping. Bent or tight link, bad adjustment, bent hanger etc are more likely causes.

Shift the front once in a while so you use different cogs in back.

dnuzzomueller

I have seen people wear out selective cogs on their bikes before like you describe. One guy must have only weighed like 130 lbs but he insisted on only riding in the 11th tooth cog and he went through that cog before he went through the chain. Honestly I just think it is your riding style and you are probably just grinding down those 2 cogs because of overuse. Remember that the estimated mileage of a cassette is based around the idea that the wear has been spread over a number of the cogs.

Bill Kapaun

Maybe your chain checking tool is wrong?
You might verify with an actual ruler.

ThermionicScott 

Are you using a new chain with each new cassette? An old chain will wear the new cassette to match its condition in a hurry.

FastJake

+1 You should be putting a new chain on your new cassettes. A worn chain will tear up a new cassette in a hurry, as I found out.

I think I tried the lube you're using a long time ago. IIRC it was very thin, I don't think you're getting enough lubrication from it. Without starting a chain lube debate... I'd try a thicker oil type lube. Use whatever works for you, but it doesn't seem like what you have is working now.

FBinNY 

Sprocket wear is almost always a function of chain wear. The worn chain's pitch doesn't match the sprocket's anymore and the wear increases on both.

So the key to long lasting cassettes is to increase chain life.

1- if you push big gears climbing short steep climbs, stop, and spin up them with in a lower gear. Also bigger sprockets produce less chain wear, so if you have a choice between the inner with a smaller cassette sprocket, or the outer with a larger one for similar gears, you'll do better with the larger pair.

2- quality chain lube is key, especially at high tensions. Of course I have a bias, so consider that, but if you're wearing out any drive train parts in under 1,000 miles, either you're an animal, or your lube is failing you. If lube isn't preserving the drivetrain's life, it could be the lube, or how you're using it, but nothing will improve until that's corrected.

Also, chain checkers are unreliable for measuring chain wear, and can be used only to measure an indicator. Stretch is only one type of wear. There's also roller wear which can be proportionately greater and more problematic than the pin wear you measure as stretch.

BTW- while chings like derailleur aalignemnt may improve shifting or make a drivetrain quieter, it has zero effect on wear. ALL sprocket wear occurs up between 11 and 12o'clock as the tight upper chord of chain unfurls from the sprocket. No meaningful wear happens near the bottom because there's no load as a chain winds onto the sprocket, nor where it's engaged in the back, because there's no relative movement there.

I tried sending a PM, but apparently can't, but if you're interested in trying something different and seeing if it helps, send me an email via the Chain-L site below, and I'll give you a free sample to try when you replace both the chain and cassette.

fietsbob

buy new chains more often, as said .. chain wear transmits wear pull to the cogs ..

Or lose the Derailleur drive train, an IGH uses a much thicker cog .. 3/32" or 1/8"..

and the older full bushing chains working in a straight line wear longer
than a bushingless chain flexed sideways , constantly shifting gears.

FastJake

OP only has 13 posts. I think you need 50 posts to send and apparently also receive (?) PMs.

ThermionicScott 

I thought people with fewer than 50 posts could receive PMs, they just couldn't send them. Maybe that's changed...

FBinNY 

I think they changed the rule. it used to be newbies couldn't send but could receive. However, the OP doesn't have a "send a PM link (maybe he elected to block PMs?)

OTOH it's possible that that changed the rule because newbies used to get PMs, but couldn't respond.

In any case when looking at someone doing materially worse than average (on anything) we need to look at what's different. So there's not much to look at other than rider weight, riding style and terrain, and chain lube. There's also the unaswered question of whether he's replacing cassettes and quickly killing them with an old chain (a serious no no).

In any case, I've thought about it, and am willing to exrend to offer to anyone who's getting seriously below average chain or cassette life. But they have to inquire via the site.

jbayes

Thanks for all the responses. To answer your questions:
I don't really understand how wheel dish would affect drivetrain wear, but in any case my wheel is dished and true within 1mm, hanger is straight, chainstays are vertical and equidistant from the centerline and the wheel is fully inserted. The bike shifts as if the shifting genie had granted me one wish and I had wished for perfect shifting.

I checked my chainline today. The middle ring is right between cogs 3 and 4, so my most-used middle-4 combination is maybe 2mm out of alignment. Ideally I'd like to move the crank inboard 4mm or so, so that I could use the big ring more, but the crank is almost touching the BB already so a shorter spindle is out.

I understand why y'all are wary of chain checkers, but don't they tend to over-measure chain wear, not under-measure it? I don't use a ruler because I don't feel like I can get an accurate reading that way: I can say with confidence that 24 links are at least 12 inches and less than 12-1/4, so that's basically useless. In any case, my current chain is about 1/8" longer than a brand new chain, which works out to around 0.25%. And yes, I'm using a new chain with each new cassette, so I've got a growing pile of slightly-worn chains.

As for lube -- yeah, the dry lube is thin, but that's because it's teflon in a solvent; the solvent evaporates and leaves the teflon. There would be no point in using a thicker solvent. I used to use finish line wet (back on the HG70), but it gets grimy so quickly. I agree with whoever said that "if your lube isn't working for you, change it", but isn't chain lube primarily to lube up the plate-pin interface, not the chain-cog interface? Should I be lubing my cogs as well as the chain? I may switch back to the wet lube for the winter, when things get a little cleaner, but I doubt that a grimier chain is going to improve things.

Thanks for the IGH recommendation. Heh. I'm not going to do that (unless someone gives me a Rohloff). Nor am I going to move to Idaho and legally coast through all the stop signs (unless someone gives me a Rohloff).

Stoplights aside, I really don't think I'm hammering very hard on the drivetrain. I do 70-80rpm most of the time, geared at 36-16 or 36-18 or so. On hills, I downshift early and keep my butt on the saddle. I don't shift under load. The only time I use my 11t is when I'm trying to figure out why the hell it's on my bike. But my riding style isn't going to change a whole lot (I promise to try to tone it down at the stoplights), so let's just assume I'm deluding myself about my riding style and abusing my drivetrain horribly and I'm looking for a way to cope with the abuse.

So are there any cassette models that are designed to be longer-lasting?

If not, I'll let y'all know how the Miche replacement cogs hold up.

Kimmo

I can see the chain lube affecting the pin wear if it's so poor it doesn't allow the rollers to turn properly...

Try FB's Chain-L, I reckon. With drivetrain durability as its prime criteria in the formulation, it'll at least eliminate the lube as a possibility if it doesn't help.

mrrabbit 

When a rear wheel is not properly dished - typically with the rim off-center to the NDS by about a 1/4 inch in most cases - you are forced when installing the wheel to arbitrarily twist the the forward portion of the wheel about a 1/4 inch to the right in order to center it between the stays. Problem with that is that results in the rear cogs not running parallel to the derailleur and the chain when the chain is on the center line.

This introduces noise and excess wear in certain gears. It also results in index shifting that is sub par.

As others have pointed out - your major concerns are grit, lube, chain and cog wear mismatch and over-dependence on one or two gears.. You can't ignore those.

It doesn't hurt to at least once in a rare while - or after a fall or incident - to ensure that all rear alignment - dropouts, hanger and wheel dish are all up to stuff. Eliminate those at the outset - your eliminate troubleshooting ghosts and can instead focus entirely ON the cogs and chain and their condition and care.

=8-)

jbayes

Oh. Right, yeah, if the wheel is THAT bad, I can see how that would screw up the drivetrain. No, I'm not doing that.

I do rely on just 2-3 gears, yeah. I can't help it: it's mostly flattish around here. If this is just normal wear on those few cogs, then I kind of have to live with that. In order to get the same 36:16 ratio on my big ring, I'd have to cross-chain to the 46:21 combo, which would be (calculating...) about 16mm of cross-chain. Maybe I'll install a shorter spindle and see if I can get away with it, but I think it's gonna rub. If replacing a worn cog or two works out, then it's eight bucks every few months; I can live with that.

I keep the drivetrain clean, so I very much doubt grit is the trouble. Maybe it's the lube; I doubt it, but I'm willing to experiment. They make drill-bits with superhard coatings; I'd be a little surprised if they didn't make cogs the same way. But it doesn't sound like anybody's found anything like that...

Agreed about periodically checking everything. I had a bad crash in February, after which I re-centered and re-aligned and re-trued.

Kimmo

Sounds like you need a really close-range setup so you can spread the wear over more cogs.

Bigger chainrings allow for closer spacing in the same range... maybe you could use a road crankset and get a fairly close but low 10s cassette made of individual cogs and respace to 8s, ditching the smallest cogs.

mrrabbit 

Ditto...in the old days - "Mr. Masi" who I used to ride with would growl at us babies:

"Get a friggin 13-19 freewheel you wussies! Toss the damn 26's!!!"

And if I remember correctly, he ran a 46/53 front...

=8-)

ThermionicScott 

If you're using a new chain with each new cassette like a good boy , I think we can safely say that your chain lube (and perhaps cleaning protocol) ain't doing the job. A thick oil like summer-weight chainsaw oil, Chain-L, or Phil's Tenacious is good because once it penetrates to the inside of the chain (give it a couple minutes after application), it stays put for a long time. The key to avoiding grit build-up is to wipe it really good after letting it soak in, like dry to the touch. And then wipe it off after the next ride or two.

I agree with the other guys that a closer-ratio cassette may help, too. A flatland cassette would let you spread the wear over more sprockets. (The Shimano 12-21 or 12-23 can be found pretty cheap, too -- pity no one sells a 13-23.)

jbayes

I get the feeling that y'all just don't believe me when I say that my chain is barely stretched. So please just assume that it's stretched all to hell, that I coat my chain on a daily basis with powdered aluminum oxide, and that I'm looking for a more durable cassette to deal with that.

I'm not going to switch to a 12-23 -- how would I go up steep hills?

Look, guys, I appreciate that you're trying to help with all the recommendations for an IGH, a 10-speed cassette, a road crankset, and that I ditch the bike and ride a burro. But I like my bike, I ride the way I ride, and changing all that stuff in order to avoid buying a $25 cassette or an $8 cog three or four times a year is swatting a mosquito with a sledgehammer. Thanks for the advice, but I think my original question got lost in the chaos.

Does anybody know anything about extra-durable 8-spd mountain cassettes?

FastJake

Here's the thing. No one wears out a cassette in 1000 miles unless something is seriously wrong. So:

- You're using a worn chain on a new cassette (can't remember if you responded to this one or not?)
- Your cleaning/lube technique is failing you.
- You're hammering the hell out of your cassette (which you indicated is not the case.)
- Something else weird is going on. Doesn't sound like this is the case, as you have checked other obvious things.

shelbyfv

Your choices are pretty much limited to low and mid range SRAM and Shimano. Not much high end 8 speed available. You found the 830 to be less satisfactory than the 850, so go the other way and try an 870 if one can be had. There are only a few more options so why not try them all?

FBinNY 

There's only a very narrow band in wear resistance among cassettes. The older freewheel sprockets used to be stamped out of harder materials, but these materials aren't suitable for the amount of coining and forming that modern sprockets have. Also the wear process of sprockets isn't abrasive as much as the result of highly concentrated roling action by the chain. This flows the material to the side, where the passing inner plates burnish it off.

I don't have a problem accepting that you can prematurely wear out a freewheel with a chain that isn't stretched. However, not stretched, doesn't mean not worn. Roller wear can have a huge impact on how the chain engages and acts on sprocket teeth.

No matter how you slice it, you're getting seriously sub par wear. Thinking that you can continue doing the same thing, and somehow getting different results is one definition of insanity.

If you want better cassette life, change something (anything), your chain, your lube, your riding style or whatever. Try one, and if things don't improve change something else next time, until you start seeing reasonable life.

BTW- nobody here has an agenda, or an axe to grind. You came asking for help, and folks are trying to offer you options. Of course you have no obligation to listen, after all it's your bike and problem, not ours. But don't get mad because nobody is telling you what you want to hear.

mrrabbit 

OP, unless you are using garbage dump box-store components for 99.00 bikes, do you understand what you are asking?

=8-)