Bike cassette suggestions and questions

[LibrarIan]

There is something subtle yet dangerously wrong with my bicycle's cassette. I had my chain replaced about 4 months ago due to some odd behavior and when we took the old chain off it was clear it was about to break apart - I had caught it just in time. The replacement chain failed yesterday after I noticed it was behaving the same way as the old one, only this time I wasn't so lucky. I was pedaling at a good clip, the chain broke and I ate serious pavement, re-spraining my wrist and taking a body blow from the ground akin to being hit by a car.

I'm not 100% sure what's wrong with the cassette, but it is the one that came on the bike (Univega Activa Country) when it was built back in the mid-90s. My local bike shop has informed me that my cassette components were manufactured by a company that hasn't existed in quite some time (I think they were called Sunbrite or something like that - I'm not at home to double check the name). So I'll have to replace all that stuff.

For someone who rides about two miles a day, sometimes more on weekends, what would the general MMM community suggest for a gear replacement of this magnitude? And how much do you think this might cost? Could I do it myself? I can replace chains and cables and other basic things, but I've never worked on the cassette and its related parts before.

I'd prefer not to just get an entirely new bike. I'd hate to see the rest of this perfectly good bicycle go to waste. Thanks!

[GuitarStv]

Cassettes wear and need to be replaced, it's no biggie.  Usually you're looking at a 20-30$ part.  Swapping it out is a 10 minute job.  You can do it yourself, but you'll need a few tools: a cassette remover, a chain whip, and a wrench.  If you don't bike great distances and need to regularly remove/clean your cassette it is probably easier to get the guys at the bike shop to do it.

Your chain shouldn't be snapping on a regular basis though.  Are you cross chaining a lot or something?  I'm 200lbs and do about 4-6000 km a year (often hauling groceries or towing my son) and have never had a chain break on me.

[LibrarIan]

You just introduced me to a new term: cross chaining. That might be my problem, as I had never heard of it or knew it was a problem until now. I read some about it at http://www.activesports.co.zw/train_health_nutrition/mtb_cross_chain.htm. This part in particular stuck out to me:

If you need to push hard up a steep section of trail, a stretched or worn chain can cause disaster. It may slip from the gears because of their improper mesh, the pointed teeth could allow the chain to roll off, or the thickness of the teeth could be reduced to the point where they might break off.

When you are putting all of your energy into a down-stroke and a tooth breaks or the chain slips, the likely outcome is a crash.

This is basically what happened to me. I was pushing hard going up an incline and crashed when the chain broke. Prior to the chain breaking, it would occasionally slip or switch gears at random.

When I ride though, I normally have the chain situated on the middle cog in the front. Then I just shift up and down the rear cogs as needed. Do you have an alternative that's better so I can avoid these problems?

[GuitarStv]

Middle cog should probably be OK.  Ideally you want to be using all your gears while cycling . . . I mean, that's what they're for right?  So you should be using the small front and the three biggest in the back, then switch to the middle for the three or four in the middle of your cassette, then use the biggest chainring for the smallest three or four on the cassette.  This does a couple things . . . it lets you spread out the wear to more parts (means stuff tends to last a bit longer).  It also lets you keep a more even cadence to your pedaling - you have more gears to select so can select a more appropriate one for the terrain.  Ideally you don't want to be grinding incredibly hard all the time (it's hard on your drive train and knees).

The key thing that you want to avoid though is the big ring at the front, big at the back and the small ring at the front, small at the back combinations.  They hold the chain at a funny angle and cause excess wear to your parts.  Usually you'll hear clicking/grinding in these configurations as a warning sign.

If you've been riding a bad chain for too long you might have damaged the teeth on your chain rings as well as the cassette (particularly the middle one since you have been spending all your time on it).  It would be a good idea to ask the guys at the bike shop to take a look and replace if necessary  . . . that can get more expensive though.

[BlueMR2]

This is basically what happened to me. I was pushing hard going up an incline and crashed when the chain broke. Prior to the chain breaking, it would occasionally slip or switch gears at random.

I believe this is similar to what caused my wife's crash (and resulting hospital stay and eventual giving up of her nice road bike for an old cruiser instead).  She was riding fine, and we were just starting to climb a hill together when suddenly she was no longer next to me.  I looked back and she was laying in the middle of the road.  To keep the story short, it involved an ambulance ride, hospital stay due to broken bones and a possible concussion (as she ate pavement face first so the helmet did practically nothing to help, her nose and sunglasses took the bulk of the face impact and the sunglasses ended up embedded into her face).  She doesn't know for sure what happened, but she said it felt like her foot came off the pedals.  Yet they were still firmly clipped in (with her kind of wrapped around the bike) when I found her on the ground.

I repaired the bike, she never rode it again.  We had it up for sale but nobody bought it, so I started using it as an around town beater (since it has platforms on one side of the pedals vs. my SpeedPlay road bike).  On multiple occasions while riding it under power I had the chain suddenly jump gears (up once, down a couple times, and once it jumped in between gears and I lost all power).  I never crashed, but it was a very near miss a couple of times.  I re-adjusted the rear derailleur and the problem is gone...  Cannondale with Shimano 105 components (indexed shifter, I believe hers is the 9 speed rear cassette?).  Probably mis-adjusted right from the factory, but so subtly that it only became an issue when enough power was being put down to flex the (aluminum) frame just enough...

[enigmaT120]

I replaced the cassette on my Fargo when I wore out my first chain, as I rode the worn chain too long.  I think the cassette was about 80 bucks from the local bike shop.  I guess I had about 3 or 4 thousand miles on the bike. 

[FreeWheel]

My condolences go out to those who have crashed due to drive train issues. A couple of thoughts based on many years of riding and working on bikes:

Part of a regular bike check should include getting down low (or better yet use a repair stand) behind the rear cassette. Eyeballing it in every gear, the cassette gear, chain, and derailleur wheels should be in a perfect straight, vertical line. If they are not, the cable needs adjustment, (there are adjusting barrels on one or both ends of the cable for this) or the derailleur has been damaged from a crash or fall.

The only cross chain gears one should avoid are big/big, and small/small. Chains are designed to flex through the range.

There should not be any popping or grinding sounds, or especially ghost shifting while riding. If there is the chain is attempting to jump gears because things are out of adjustment. If this happens under power, there is a greater possibility for a crash. Any bad sounds or ghost shifting should be attended to immediately.

Shifting should only be done while pedaling, under light load. Shifting while pedaling hard is hard on the parts, and also could throw your feet off the pedals. The moment the shift is complete you can safely pour on the power!

If you inspect cassettes and chain rings closely, any wear or damage will be apparent.

With proper care and technique, chains, cassettes and chain rings last a long time.

[TrMama]

Ghost shifting is a key indicator for a worn cassette, stretched (aka worn out) chain or sometimes plain old needing a tune up. Often you end up with all three going on at once. I'd go ahead and bring the bike in to a reputable shop to get any worn parts replaced AND have them do a tune up. IME replacing parts without doing a good tune up is often a waste of money.

When buying cassettes, I've learned that the more "speeds" you get, the more you pay. I've also been told that as the number of speeds increase the thickness of the chain decreases, making it more likely to break. When my current 10 speed cassette wears out, I plan to replace it (and the chain) with an 8 speed. That should still be plenty of gears for me, it will be cheaper and it will hopefully last longer.

[GuitarStv]

The very first thing to do with a poorly shifting derailleur is to put the bike up on a stand, ensure that the H and L screws are set properly (usually they're fine) and then play with the barrel adjuster.  Derailleurs go out of adjustment with use, this is a pretty common thing to need to do.

A chain should be replaced when you put a measuring tape at the center of the pin on one link and then measure out 12 inches.  If the pin at the 12 inch mark is stretched out more than 1/16 of an inch it should be replaced.  You don't want to wait until the chain is stretched 1/8th of an inch, that's when you'll probably need to replace the cassette as well.  This pic should explain what I mean regarding the chain:



A 10 speed cassette can be purchased for 30$ online (http://www.chainreactioncycles.com/ca/en/shimano-105-5700-10-speed-road-cassette/rp-prod50454).  Not exactly free, but not a crippling expense.  There's no need to drop big bucks on them.  I've wondered if the 10 speed cassettes might actually last slightly longer because you are changing gears more often, so should be spending less time on individual cogs.

Chains are certainly thicker on an 8 speed cassette . . . so they might last longer.  I do believe that breaking a chain is likely more a related to poor technique (pedalling in too hard a gear, cross chaining, shifting while pedaling hard) coupled with really bad derailleur adjustment rather than a factor of chain thickness though.

[iknownothing]

Couple of thoughts:

If your bike was built in the mid 90's, it most likely has a 7 or 8 speed cassette. Hopefully it is a cassette, and not a freewheel!

If none of your drivetrain components have ever been replaced before, you may have to replace your chainrings when you replace your chain.

If you are not familiar with any of this stuff, it's best to go to a local bike shop.

Buy the parts from them and ask if they will teach you how to replace them. Some shops will show you how to do this stuff and let you use their tools for a small fee. You will learn something and have a better handle on how your bike works.

Good luck!

[kendallf]

When my current 10 speed cassette wears out, I plan to replace it (and the chain) with an 8 speed. That should still be plenty of gears for me, it will be cheaper and it will hopefully last longer.

If you have indexed shifters (all modern Shimano, SRAM and Campy shifters that integrate the shifters with the brake levers), you won't be able to just swap cassettes and chains to 8 speed.  The shifters won't be indexed to work properly with them.  If you have bar end or down tube friction shifters, you can interchange parts.

[BlueMR2]

Chains are certainly thicker on an 8 speed cassette . . . so they might last longer.

I know for a fact that the 9/10 chains are one particular thickness (I still have the box)  :-) .  The new 11s are even thinner.  Appears that 5 through 8 speed are all the same.  The chain on my 5 speed cassette beater MTB finally gave up the ghost last year after many years of service.  I couldn't find any online (they only list 7 and up), so I walked down to the local bike shop, he flipped me a "8 speed" chain.  Perfect fit.  Same width as my old 5 speed chain.

[MrFrugalChicago]

Pos throw down 1000 watts in 11 speed chains. I do 300 w no problems. 11 speed chains are not fragile, at least a decent one. You clearly can't just use the same chain for 10 years though. They wear out.

[ClutchBeta]

I also have a bike with an old Suntour cassette hub.  I was able to find a replacement cassette on ebay for about $40  --they come up every once in a while if you're patient!  Currently the cheapest option is still over $50: http://www.ebay.com/sch/i.html?_odkw=accushift&_from=R40&_osacat=7294&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xaccushift+cassette.TRS0&_nkw=accushift+cassette&ghostText=&_sacat=7294 I currently have an 8-speed Shimano wheel and the 7-speed Suntour wheel.  I use the Shimano one for everyday use and if I want to restore the bike to original condition I'll put the Suntour one back on. (I'm very vain about my bike.)

Shimano 8-speed has a very similar spacing to Suntour 7-speed and you can get the indexing to work well between the 2 of them. You just won't have access to the lowest gear on the 8-speed cassette.  Source: http://sheldonbrown.com/cribsheet-spacing.html

[minimountainmustache]

I will echo the sentiment that 11 speed chains are in no way "fragile." Pro racers are pushing some thousand watt sprints on those "flimsy" chains and doing just fine. I've personally had an 11 speed chain last me about 4-5000 miles, and I only replaced it because I didn't want to replace expensive 11spd chainrings/cassette...

OP you need to regularly replace your chain. It is the cheapest piece of your drive train to replace, and it will protect the rest of the drivetrain from unnecessary wear. Likely, if you've had an issue with more than one chain, your chainrings and cassette will need to be replaced to get your bike working optimally again. I would also have a mechanic look at the free hub body (what the cassette is mounted on) that you have...different free hub bodies fit different cassettes. Compatibility can definitely be an issue with older, harder to find parts.

[Ocelot]

Chains are certainly thicker on an 8 speed cassette . . . so they might last longer.

I know for a fact that the 9/10 chains are one particular thickness (I still have the box)  :-) .  The new 11s are even thinner.  Appears that 5 through 8 speed are all the same.  The chain on my 5 speed cassette beater MTB finally gave up the ghost last year after many years of service.  I couldn't find any online (they only list 7 and up), so I walked down to the local bike shop, he flipped me a "8 speed" chain.  Perfect fit.  Same width as my old 5 speed chain.

Hi, I'm a bike mechanic (all day, most days - sadly...) I can confirm the following:

5/6/7 speed are all the same dimensions
Early 8-speed are the same as 5/6/7, but modern 8-speed are narrower. This doesn't matter in terms of compatibility with cogs/cassettes, but does matter in terms of joining pins, quicklinks etc.
9- speed are narrower,
10- speed externally narrower again, internal similar to 9sp
11-sp narrower again.

Basically as the number of cogs went up, the chain had to get thinner to physically fit. Here's the cool part though - basically any way you want to test it, effectively each newer chain has been stronger and more durable than the chain it replaced. This is due to new technology being used to new chains while old chains just kept being made the same way they always have, in conjunction with modern cog/chainring shift ramps being way easier on the chain than previous generations. Modern 11-sp chains are extremely tough and durable compared to anything from before (although obviously there is some difference between brands/models).

[dragoncar]

Anyone have a suggestion on a tune-up tutorial?

I recently broke a chain and replaced it.  But then I noticed a bunch of other problems.  Worn/broken gear teeth, clicking noise every revolution, freewheel hub problems (recently I have to shock/oil it to get forward power).  Basically I'm looking at replacing the freewheel hub and chainrings.  Sorry if my terminology is off, still learning.

Is it worth doing all this for a really old bike?  I want to learn either way, but part of me just wants to get a new one.

[GuitarStv]

http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur  -  Probably get rid of your clicking noise

If you need to replace the chainrings it can get more expensive, often on cheaper bikes the chainrings are permanently attached to the cranks.  Take it to a bike shop and ask for an estimate.  They'll be able to give you an idea of how much it would cost.  If the bike doesn't fit you really well, it's probably not worth replacing stuff regardless of the cost.

[spokey doke]

Shifting should only be done while pedaling, under light load. Shifting while pedaling hard is hard on the parts, and also could throw your feet off the pedals. The moment the shift is complete you can safely pour on the power!

This...I ride with a guy who eats up chains and derailleurs and always rants about bike parts not being built tough.  We ride the same trails at the same speeds and I never break those same parts. He doesn't know how to shift properly.

I also see tons of newer cyclists struggling with their shifting because they get caught on an incline trying to shift while pedaling hard.

Learn to anticipate when you need a lower gear and only make it when you can get full rotation of your cranks with a light load (either be shifting before the grade increases, or by a burst of power into pedaling in your current gear to provide momentum to pedal lightly while shifting to a lower gear on the current grade).  If you are coming up to a steep hill, don't bother trying to pedal hard in a big gear hoping momentum will carry you farther up the hill--grab a low gear that you can clearly make it up the hill in the whole way, saving yourself a bad shift mid-climb.

[ClutchBeta]

Is it worth doing all this for a really old bike?  I want to learn either way, but part of me just wants to get a new one.

That depends.  Old stuff can sometimes be more reliable than new, since it had to be pretty nice to survive that long. In my opinion a good rule of thumb is that if your frame is "butted" the bike is almost certainly worth saving.  Often it will say on a sticker on the seat tube.  If not, you can flick the tubes with your fingernail -- if the tube sounds much thinner in the middle than at the ends, it's butted.

[BrooklineBiker]

As as a general recommendation, I encourage you to invest in some bike tools. Long term you will save money and time waiting for repairs. Also I recommend getting the Park Tools' Big Blue Book of Bicycle Repair – 3rd Edition and Anybody's Bike Book: A Comprehensive Manual of Bike Repairs. With those books, You Tube videos, and some tools, you will be able to fix a lot of stuff.