Does this crankset need to be replaced
06-22-19, 01:04 PM
#1
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Thread Starter
Does this crankset need to be replaced
I bought a Specialized Sirrus off of someone who was moving; knocked $60 off asking price because chain was stretched, and I have already replaced both the chain and cassette (8 speed altus, same as what it had).
On further inspection, I am not thrilled with the crankset, but not sure if it needs replacement right away, or can wait a while. The primary use for this bike is a somewhat hilly 8 mile (each way) commute, particularly on wet/slightly rainy days. I don't need the small ring, and would prefer to be on the middle ring about 75% of the time.
Edit: forgot to add the photos.
On further inspection, I am not thrilled with the crankset, but not sure if it needs replacement right away, or can wait a while. The primary use for this bike is a somewhat hilly 8 mile (each way) commute, particularly on wet/slightly rainy days. I don't need the small ring, and would prefer to be on the middle ring about 75% of the time.
Edit: forgot to add the photos.
06-22-19, 01:06 PM
#2
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06-22-19, 01:25 PM
#3
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$60 off for a stretched chain? Wow, that's some negotiating. Puts me to shame.
I'll answer what I think the real question is: Can I get away with the current chainrings not eating up my nice new chain and cassette?
I'd lean toward no. Chainring wear will eventually translate to your chain, and your cassette by extension, so they will wear faster.
Me personally, I'd replace the chainrings separately if possible, and if you can't, then replace the whole crank. Easy fix and you have a next-to-new drivetrain.
I'll answer what I think the real question is: Can I get away with the current chainrings not eating up my nice new chain and cassette?
I'd lean toward no. Chainring wear will eventually translate to your chain, and your cassette by extension, so they will wear faster.
Me personally, I'd replace the chainrings separately if possible, and if you can't, then replace the whole crank. Easy fix and you have a next-to-new drivetrain.
06-22-19, 01:59 PM
#4
Optically Corrected
It's hard to tell, visually, if a chain will skip on a worn cassette or chain ring - the only way is to ride and see...
From your pictures - the chain rings don't appear to be "hooked" or "shark-finned" which is how they look when worn.
After putting on the new chain and cassette how does it ride/shift? If everything is working OK I'd just ride the bike and not worry about it.
If you look closely you will see that some of the teeth on your crankset are slightly shorter, or have a slightly rounder profile - this is normal. It is called "ramped and pinned" and assists the chain in jumping up and down between the rings.
Under normal situations it takes a long time to wear out chain rings/crankset.
Typically, I get 5,000km to a chain, 5 or 6 chains to a cassette and 5 or 6 cassettes to a chain ring. I keep my drivetrains very clean/lubed and don't ride in a lot of wet/sandy conditions but it gives you an idea of how long rings/cranks can last.
So, if you replaced the chain and cassette and everything is working - pedal on! Wear that sucker out!
From your pictures - the chain rings don't appear to be "hooked" or "shark-finned" which is how they look when worn.
After putting on the new chain and cassette how does it ride/shift? If everything is working OK I'd just ride the bike and not worry about it.
If you look closely you will see that some of the teeth on your crankset are slightly shorter, or have a slightly rounder profile - this is normal. It is called "ramped and pinned" and assists the chain in jumping up and down between the rings.
Under normal situations it takes a long time to wear out chain rings/crankset.
Typically, I get 5,000km to a chain, 5 or 6 chains to a cassette and 5 or 6 cassettes to a chain ring. I keep my drivetrains very clean/lubed and don't ride in a lot of wet/sandy conditions but it gives you an idea of how long rings/cranks can last.
So, if you replaced the chain and cassette and everything is working - pedal on! Wear that sucker out!
06-22-19, 02:31 PM
#5
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Thread Starter
It's hard to tell, visually, if a chain will skip on a worn cassette or chain ring - the only way is to ride and see...
From your pictures - the chain rings don't appear to be "hooked" or "shark-finned" which is how they look when worn.
After putting on the new chain and cassette how does it ride/shift? If everything is working OK I'd just ride the bike and not worry about it.
If you look closely you will see that some of the teeth on your crankset are slightly shorter, or have a slightly rounder profile - this is normal. It is called "ramped and pinned" and assists the chain in jumping up and down between the rings.
Under normal situations it takes a long time to wear out chain rings/crankset.
Typically, I get 5,000km to a chain, 5 or 6 chains to a cassette and 5 or 6 cassettes to a chain ring. I keep my drivetrains very clean/lubed and don't ride in a lot of wet/sandy conditions but it gives you an idea of how long rings/cranks can last.
So, if you replaced the chain and cassette and everything is working - pedal on! Wear that sucker out!
From your pictures - the chain rings don't appear to be "hooked" or "shark-finned" which is how they look when worn.
After putting on the new chain and cassette how does it ride/shift? If everything is working OK I'd just ride the bike and not worry about it.
If you look closely you will see that some of the teeth on your crankset are slightly shorter, or have a slightly rounder profile - this is normal. It is called "ramped and pinned" and assists the chain in jumping up and down between the rings.
Under normal situations it takes a long time to wear out chain rings/crankset.
Typically, I get 5,000km to a chain, 5 or 6 chains to a cassette and 5 or 6 cassettes to a chain ring. I keep my drivetrains very clean/lubed and don't ride in a lot of wet/sandy conditions but it gives you an idea of how long rings/cranks can last.
So, if you replaced the chain and cassette and everything is working - pedal on! Wear that sucker out!
Just came back from an 8 mile shakedown cruise, and overall it's not bad. Had to adjust the front L limit screw a bit, as it had trouble getting down to the smallest chain ring, and need a little tweaking on the rear indexing, but I think I can focus on getting fenders first, and then dealing with the front rings.
Yea New Bike Day!
06-22-19, 02:51 PM
#6
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I agree that the chain rings do not look like they will be a problem. I would replace the cassette to be safe it you can afford to do it.
06-22-19, 03:11 PM
#7
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Those chain rings are steel. To me they appear polished by the chain, but don't show any wear. Those Altus cranks are on the low end of quality equipment but do take a lot of abuse. Since you say you don't need a triple, you just may want to upgrade anyway at some point. No need to do it anytime soon though.
How much stretch did the chain show? $60 bucks off for just the drive train on this bike is rich, but then we don't know what the starting price was.
How much stretch did the chain show? $60 bucks off for just the drive train on this bike is rich, but then we don't know what the starting price was.
06-22-19, 05:44 PM
#8
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Thread Starter
Those chain rings are steel. To me they appear polished by the chain, but don't show any wear. Those Altus cranks are on the low end of quality equipment but do take a lot of abuse. Since you say you don't need a triple, you just may want to upgrade anyway at some point. No need to do it anytime soon though.
How much stretch did the chain show? $60 bucks off for just the drive train on this bike is rich, but then we don't know what the starting price was.
How much stretch did the chain show? $60 bucks off for just the drive train on this bike is rich, but then we don't know what the starting price was.
Initially the chain showed about 25% stretch, ie the chain tool was penetrating partially, but as I moved around, at one spot the tool went all the way in on one side (0.75), but not on the other (1.0).
...bent spoke, some scratches on the seat stay, both on the drive side, come to think of it, it sounds like a stick (or something) got caught in the wheel. No damage to the rear derailleur or hanger, though, just as straight as can be...
06-23-19, 10:45 AM
#9
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Look at the pictures, people! Not only are the chainrings not worn, they are practically new. You can still see the machining on the teeth.
To NewATBikeCommute: What you are seeing on the crank...flattened teeth, little protrusions, etc...are features not problems. The teeth with different profiles and protrusions are there to help the chain change from ring to ring easier. They are a good thing.
Additionally, your chainrings aren’t “replaceable”. They are riveted or swaged to the crankarm in a way that is can’t be removed. You have to replace the whole crank. On the good news side, you won’t need to replace it due to wear for about 100,000 miles.
To NewATBikeCommute: What you are seeing on the crank...flattened teeth, little protrusions, etc...are features not problems. The teeth with different profiles and protrusions are there to help the chain change from ring to ring easier. They are a good thing.
Additionally, your chainrings aren’t “replaceable”. They are riveted or swaged to the crankarm in a way that is can’t be removed. You have to replace the whole crank. On the good news side, you won’t need to replace it due to wear for about 100,000 miles.
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Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
06-24-19, 10:38 AM
#10
Senior Member
The rings are good to go. Throw away the chain checker and buy a ruler or a Pedro's https://www.amazon.com/Pedros-Chain-...gateway&sr=8-1
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