How often do Cranksets typically last?



Uawadall

Well-Known Member
Jun 14, 2015
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A reliable bike shop, do it yourself guides and another reliable shop later and the chain keeps falling off... What I noticed is, it will hover around the big ring for a while and not catch on. The chain is new, less than 150 miles, the crankset is old, probably between 3000-4000 miles(bought it used). Will a old crankset cause a chain to keep falling off. How long do cranksets typically last before going dull?
 
My experience has been that chainrings last 15K miles or more, but that's based on my specific riding and maintenance conditions. Basically, they last until they are worn. If the tooth profile looks "shark-finned" in appearance, it's worn out. Well before that point, you'll find that wear causes a new chain to "ride up" from the ring when pressure is applied.

To test your chainring for wear, put slight pressure on the crankarm to take up the slack in the chain (watch the top). Then, press down harder on the pedal while watching for chainring and chain movement. If the chainring is badly worn, you'll find that it moves under pressure while the chain "rides up" off of the bottom. Slight movement is acceptable. If the movement is significant, or you can see daylight between the chain and the chainring (with the pressure applied), it's time for a new chainring.

Since you got yours used, there is no telling how much wear is on the chainring. Using them with a dirty or dry chain, or a chain that's worn (stretched) could wear them out quickly.
 
Being used, it's hard to know how well it was maintained before you got it.

I'm just learning, but with several failed attempts to fix it, the crank is a good place to start.
4,000 miles is a lot if the original chain was on it.

I measured a chain with 1400 miles on it, it was worn, measured 48-5/8 " at 96 lilnks
My bike new, so all my wear. Showed me I need to do better with chain cleaning & lube.

If a worn chain is ran many miles, it's putting excessive wear on all the gears.
If you replace gears, I'd replace both the cassette & chain ring gears . If one is worn, the other is too.

The other thing to check is both the derailleur alignments or a bent crank or bent RDr.

Can you post some "Close up" pictures ?
 
A reliable bike shop, do it yourself guides and another reliable shop later and the chain keeps falling off... What I noticed is, it will hover around the big ring for a while and not catch on. The chain is new, less than 150 miles, the crankset is old, probably between 3000-4000 miles(bought it used). Will a old crankset cause a chain to keep falling off. How long do cranksets typically last before going dull?

FYI ...

If your chain keeps falling off, then more-than-likely the front derailleur is NOT adjusted properly UNLESS you are talking about the chain coming off a Granny when the chain is also on your bike's largest Cogs OR you are a CX racer who is mounting-and-dismounting several times over a comparatively rough terrain vs. not-too-rough pavement ...

In the former instance, the best solution is to simply add a chain keeper/minder ...

In the latter instance, the preferred solution is to go to a single Chainring.
While Wrenches like oldbobcat have the patience to properly tune a Shimano-or-SRAM front derailleur to its respective shifter, apparently most Wrenches do not ...

For the rest of us who are riding on pavement with a comparatively mundane Double, short of making a pilgrimage to Boulder (Colorado) and have oldbobcat adjust your front derailleur's stops ...

Then, despite the expected protestations of others who love THEIR bikes & their choice of the me-too-because-look-at-all-the-Tour-winners-who-use-them components, trust me when I say that the EASY solution is to simply switch to a set of Campagnolo shifters ...

If you can change an incandescent light bulb, then you can set up a pair of Campagnolo shifters + almost ANY (there may be exceptions) derailleur ...

Not only are Campagnolo shifters exceptionally easy to set up, they have the added benefit of working better under (subjectively) adverse conditions.​
 
FYI ...

If your chain keeps falling off, then more-than-likely the front derailleur is NOT adjusted properly UNLESS you are talking about the chain coming off a Granny when the chain is also on your bike's largest Cogs OR you are a CX racer who is mounting-and-dismounting several times over a comparatively rough terrain vs. not-too-rough pavement ...
I took it to the shop again.....This time the owner was there, he's a cool guy. I told him the situation and he played with the front derailleur and barrel adjuster for 10 minutes or so. I rode yesterday and today,purposely shifting at weird times to see the difference. Finally, the chain will not come off. I
 

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