How long should a chain and a cassette last?

[peterw_diy]

Ooh, that’s it. It’s my perfect form! All those hours sweating on rollers still playing off, decades later!

[Vicegrip]

@Crickey7 147122 wrote:

I was talking to another mechanic about whether a riding style could toast bottom brackets faster, and he said two things that resonated with me and explained why I quickly destroy a piece of equipment many riders never, ever have to replace. High torque and any unevenness in your stroke will put stresses on the bearings that will cause pitting and eventual failure.

This was at the new location of City Bikes in NW DC. This mechanic really, really seemed to know his stuff, to diagnose my issue with bottom brackets (I run through a new bottom bracket every 12-24 months) without even knowing my riding style.

Not commenting on the Bike Arlington’s Lake Wobegon above average power and mechanics.
Considering the amount of power a human can make and the present state of bearing design and metallurgy this would be a severe case of design failure or some other factor that is causing premature failure. Bearings far smaller in contact area such as wheel bearings are subjected to ball/race contact pressures and thrust loads far in excess of the pittance seen in the far larger bottom bracket bearings. In basic terms I can make 205 watts all day long while on my bike but my track car with 275 HP can make 205,000 watts all day long. The rear wheel bearings in the race car are subjected to large changes in RPM, load and thrust, are not larger by the same factor yet they last in excess of 50,000 miles.

[Crickey7]

Research indicates that 43% of bearing failures are to inadequate lubrication. Since these are largely sealed systems installed by a half dozen different mechanics on several different bikes, that does not seems to be an explanation for me. Beyond that, it becomes something of a detective game. There are a number of factors that explain individual failures, few that explain repeated ones for person that only occasionally rides in rain. I’m not alone in seeing brackets lasting only a year or two, so I’m not quite buying that riding style has nothing to do with it. I have several factors that might explain things, at least according to this mechanic. One, high initial torque. Two, not having a smooth riding style with roughly even stresses. Third, I have a moderate case of spinal stenosis that permanently weakened one leg, so that the right is stronger than the left. Stresses will come from several vectors for me. I’m not cheaping out on these–it was service once at Freshbikes and once at the old Cycle Life in Georgetown.

[Harry Meatmotor]

@Crickey7 147129 wrote:

Research indicates that 43% of bearing failures are to inadequate lubrication. Since these are largely sealed systems installed by a half dozen different mechanics on several different bikes, that does not seems to be an explanation for me. Beyond that, it becomes something of a detective game. There are a number of factors that explain individual failures, few that explain repeated ones for person that only occasionally rides in rain. I’m not alone in seeing brackets lasting only a year or two, so I’m not quite buying that riding style has nothing to do with it. I have several factors that might explain things, at least according to this mechanic. One, high initial torque. Two, not having a smooth riding style with roughly even stresses. Third, I have a moderate case of spinal stenosis that permanently weakened one leg, so that the right is stronger than the left. Stresses will come from several vectors for me. I’m not cheaping out on these–it was service once at Freshbikes and once at the old Cycle Life in Georgetown.

Vicegrip makes a good point. The bearings in a bicycle BB and other mechanical contraptions are not different. I’m not saying you don’t service/clean your bearings properly, but I am saying that in general bearings fail due to neglect, IMHO. Riding a bike with a square taper, adjustable BB out of adjustment for more than a few miles will trash it. As far as sealed cartridge style bearings, crud is crud, and I’ve not yet come across a bearing that’s 100% impervious to crap getting splashed up from the front wheel. pedaling squares won’t prematurely doom a bearing. try looking for angular contact bearings – they’re less susceptible to failure from side loading or misadjusted preload.

[Crickey7]

I appreciate the insight.

Thank you.

[Harry Meatmotor]

@Crickey7 147132 wrote:

I appreciate the insight.

Thank you.

I’ll add, too, that perusing the CX forums a little white ago, it seems like those guys are getting good longevity out of Wheels Manufacturing ZERO ceramics. Pricey, but apparently they aren’t just made to spin better, they actually hold up to mud and grit pretty well. I’ve been thinking about trying them out after I get through this winter. It’s been about a year since I dug around on BB bearings, tho.

Edit – another option, tho hard to find are Enduro -15s.

[huskerdont]

Interesting the problems some seem to have consistently. I’ve never really needed to replace a bottom bracket on a road bike. (I have replaced them–did it once trying to eliminate a noise problem. It didn’t work, and months later it turned out to be the chainstay had been going all along and eventually broke. I’ve broken two bikes at the chainstay, so it might have something to do with riding style.)

Yet I do seem to get fewer miles out of chains than some, and even replacing early, always get the skipping cassette. I do keep my chains clean and lubed. However, I’ve never used an actual plastic chain cleaner before. I just picked up a Park CM-5.2 chain cleaner after watching that GNC video about reduced chain friction. Perhaps that will help them last longer than my old method of merely wiping the gunk off and occasionally using a brush if it looked bad.

I’m going back to my old method of always replacing the cassette when I change the chain though. It’s worth the little bit of money to me to not have the skipping problem occur. That bike is just sitting in the stable until I change the cassette.

[EasyRider]

@huskerdont 147134 wrote:

Interesting the problems some seem to have consistently. I’ve never really needed to replace a bottom bracket on a road bike.

I’ve never had to replace a bottom bracket because of wear, either, though with a daily 15 mile commute, 3 of which are towing a child trailer — I think I should expect to. What model BB are you using? I’ve only ever used square taper units, either adjustable or sealed. Antiquated sure, but set up right the first time, in my experience, adjustable units are durable.

My daily rider is a old Trek 950 that I bought on CL 5 years ago for $50. It was clearly neglected, but the original adjustable BB and crank are doing just fine after 26 years! I figured let sleeping dogs lie and I’ll replace it when it gets noisy. Not yet. It continues to surprise me. I’ve used the same sealed shimano square taper unit since 2006 on my fixed gear/singlespeed/rain bike. I stopped riding it daily when my commute got longer and I bought the 950, but it’s got plenty of miles on it and was installed 10 years ago. In both cases I’d have thought the grease would’ve turned to gunk by now, and maybe it has. But they feel fine and don’t make noise.

[huskerdont]

@EasyRider 147135 wrote:

I’ve never had to replace a bottom bracket because of wear, either, though with a daily 15 mile commute, 3 of which are towing a child trailer — I think I should expect to. What model BB are you using? I’ve only ever used square taper units, either adjustable or sealed. Antiquated sure, but set up right the first time, in my experience, adjustable units are durable.

My daily rider is a old Trek 950 that I bought on CL 5 years ago for $50. It was clearly neglected, but the original adjustable BB and crank are doing just fine after 26 years! I figured let sleeping dogs lie and I’ll replace it when it gets noisy. Not yet. It continues to surprise me. I’ve used the same sealed shimano square taper unit since 2006 on my fixed gear/singlespeed/rain bike. I stopped riding it daily when my commute got longer and I bought the 950, but it’s got plenty of miles on it and was installed 10 years ago. In both cases I’d have thought the grease would’ve turned to gunk by now, and maybe it has. But they feel fine and don’t make noise.

Threaded BB; I think it was a Shimano BB-RS500 shell.

26 years, sweet. I took apart a one-piece crankset from a 1965 Schwinn Varsity, and the bearings looked like charcoal.

[EasyRider]

I rode a Varsity fixed for a year and repacked the bearings monthly. The grease, it’d just disappear!

[huskerdont]

@EasyRider 147139 wrote:

I rode a Varsity fixed for a year and repacked the bearings monthly. The grease, it’d just disappear!

I converted this one to fixed thinking I’d ride it, but it weighs more than a mountain bike so I only use it on the trainer. The bearings feel smooth, tho I don’t really want to look to see.

I suppose we’re way OT, but here’s the bike:

[ATTACH=CONFIG]12540[/ATTACH]

[hozn]

I get around 6k miles on external threaded bottom brackets, maybe a little more. People talk about bottom brackets lasting forever, but my experience is that an alloy BB in my ti frame needs to at least be pulled out once a year to have anti-seize added or it’ll be stuck in the frame forever. (This was my experience with CK serviceable BB; destroyed the threads removing it after a little over a year.)

I am sure I could also squeeze a lot more life out of my bottom brackets, but as soon as it clicks the first time it gets scheduled for replacement.

Interesting about the Enduro Ceramic Zero bearings being longer-lasting. Maybe I will press those into my BB shell when these bearings are done. I jut ordered a bunch of Enduro ABEC-5 bearings to replace the ones that will come in the Novatec hubs I just ordered; maybe I should have sprung for the pricier ceramic. Though I have yet to wear out cartridge wheel bearings.

[Harry Meatmotor]

@hozn 147144 wrote:

Though I have yet to wear out cartridge wheel bearings.

CX will destroy hub bearings. My GF’s rear hub sounds like a freight train is following her around on course. they’re all getting replaced after this season. I think the idea with the zeros is that they’re hard enough that any gunk that gets inside get pummeled into dust/fine slurry and although the hubs may run dry, they’ll still spin forever.

[hozn]

@Harry Meatmotor 147146 wrote:

CX will destroy hub bearings. My GF’s rear hub sounds like a freight train is following her around on course. they’re all getting replaced after this season. I think the idea with the zeros is that they’re hard enough that any gunk that gets inside get pummeled into dust/fine slurry and although the hubs may run dry, they’ll still spin forever.

Yeah, that makes sense about the cx conditions destroying the bearings. I’m sure BB bearings (and hub bearings) would last much, much longer if they were actually impervious to the elements (and the dirt that gets carried in).

Interesting about the bearings. Looks like it’s ~$90 for a set of the Ceramic Zero bearings, so not entirely sure it’s worth the price of 4 bottom brackets for my usage, but if I were killing a bottom bracket every other race, I’d do it.

[Vicegrip]

@hozn 147148 wrote:

Yeah, that makes sense about the cx conditions destroying the bearings. I’m sure BB bearings (and hub bearings) would last much, much longer if they were actually impervious to the elements (and the dirt that gets carried in).

Interesting about the bearings. Looks like it’s ~$90 for a set of the Ceramic Zero bearings, so not entirely sure it’s worth the price of 4 bottom brackets for my usage, but if I were killing a bottom bracket every other race, I’d do it.

ding! I suspect we have a winner. Cartridge bearings even within a single size, format, hardness and finish spec can be furnished open, simple dust shielded, sealed and environmentally sealed form to list but a few formats. The higher the environmental resistance the the bearing seal system the higher the internal resistance they often exhibit. Resistance is not a positive aspect for us low power producing meat motors. If you are on set # 3 or more of a brand and seal type of bearing you might want to look at increasing the environmental protection factor of the bearing. Bike makers don’t make bearings. Bearing makers make bearings and for the most part bike and bike component makers select the bearing they want to use from what is available. I suspect that bike based bearings rarely fail due to load and fail after being contaminated. I had a single front wheel bearing go bad. On disassembly and inspection I found that it had a little tiny ding/grit scrape in the wiper ring of the seal, the lubricant had been contaminated and had dried up. The other bearing, which saw the same service and exposure, was in great shape internally. if your wheel or BB bearing spins forever I bet it uses shielded bearings. I would not want a non sealed bottom bracket bearing on anything less than a fair weather race day bike. The watt loss from the seals is hard to measure and bottom brackets are exposed to dirty road water spray at the least.

Below is a cut-n-paste description of the most common formats for shields and seals on ball and roller bearings.

“Ball and roller bearings are available with different types of shields and seals. These are commonly referred to as closures. Closures can extend bearing life by preventing contaminants from reaching the critical surfaces inside the bearing, and they help retain the lubricant in the bearing. Different types of closures may be supplied on the same bearing. Special designs are also available. The following are descriptions of the most common types AST can supply.

Type ZZS – Removable non-contact metal shield retained in the outer ring with a snap wire. This type of shield is manufactured from 300 series stainless steel and is available only on miniature and instrument series bearings. Max operating temperature is 600° F. Since there is no contact made with the inner ring there is no appreciable impact on torque or speed and operation can be compared to that of an open bearing. The removable closure allows for cleaning and re-lubrication. The code for a single shield is ZS.
Type ZZ – Non-removable, non-contact metal shield retained in the outer ring via crimping, or pressing. This type of shield cannot be removed once installed. This type of shield can also be manufactured from 300 series stainless steel. On larger bearings, this type of shield is manufactured from 1008 or 1010 strip steel. Max operating temperature is 450° F. Since there is no contact made with the inner ring there is no appreciable impact on torque or speed and operation can be compared to that of an open bearing. The code for a single shield is Z.
Type 2RS – Molded rubber seal. This type of seal is Buna-N bonded to a steel insert. The seal is fixed into a groove in the outer ring. This type of seal can be removed but care must be used not to bend or cut the seal lip. Max operating temperature is 240° F. This type of seal makes contact with the inner ring providing better protection in contaminated environments than a metal shield. However, this results in an increase in torque and reduces the max speed capability of the bearing. Certain lubricants and chemicals react with rubber. The code for a single seal is RS.
Type 2RU – Molded rubber seal, non- contact. This type of seal is Buna-N bonded to a steel insert. The seal is fixed into a groove in the outer ring. This type of seal can be removed but care must be used not to bend or cut the seal lip. Max operating temperature is 240° F. This type of seal has a very thin lip adjacent to the inner ring but does not make contact. It provides better protection than type ZZ or ZZS, but without the increase in torque exhibited by type 2RS. Certain lubricants and chemicals react with rubber. The code for a single seal is RU.
Type 2VS – Molded Viton seal. This type of seal is made of Viton bonded to a steel insert. The seal is fixed into a groove in the outer ring. This type of seal can be removed but care must be used not to bend or cut the seal lip. Max operating temperature is 400° F. This type of seal makes contact with the inner ring providing better protection in contaminated environments than a metal shield. However, this results in an increase in torque and reduces the max speed capability of the bearing. This seal has excellent chemical resistance. The code for a single seal is VS.
Type TTS – Glass reinforced PTFE seal is retained in the outer ring with a snap wire. This type of seal can be removed but care must be used not to bend or cut the seal lip. Max operating temperature is 400° F. This type of seal makes contact with the inner ring providing better protection in contaminated environments than a metal shield. However, this results in an increase in torque and reduces the max speed capability of the bearing. This type of seal exhibits less torque than type 2RS, but is more delicate. This seal has excellent chemical resistance. The code for a single seal is TS. Teflon seals are only available on certain series of bearings.”

[Author]

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