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Pre-stretched chain?
- Thread starter jaypee
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My patience wears, my incredulity stretches.
Re:
OK, here goes...
1) The chain links do not stretch.
2) The floating bushes and the internal pins wear.
3) The wear makes the effective chain pitch no longer one inch.
Now, if the cassette is already worn - ie. the teeth are skinnier - you can use a worn chain as it will bed in deeper no problem.
A new chain may ride up the teeth and slip since it's bushes can't spread.
Yes, it's not ideal but a worn chain will mate with worn sprokets happily.
When the chainrings are shark finned, then really the whole transmission should be changed.
You can argue it's a false economy, but frankly some bikes are not worth spending a penny on running.
I regularly check chain wear on bikes, the best bikes get the new chain and the low grade bikes get the pass me downs.
OK, here goes...
1) The chain links do not stretch.
2) The floating bushes and the internal pins wear.
3) The wear makes the effective chain pitch no longer one inch.
Now, if the cassette is already worn - ie. the teeth are skinnier - you can use a worn chain as it will bed in deeper no problem.
A new chain may ride up the teeth and slip since it's bushes can't spread.
Yes, it's not ideal but a worn chain will mate with worn sprokets happily.
When the chainrings are shark finned, then really the whole transmission should be changed.
You can argue it's a false economy, but frankly some bikes are not worth spending a penny on running.
I regularly check chain wear on bikes, the best bikes get the new chain and the low grade bikes get the pass me downs.
Re:
Hi. I don't ride a bike but I have experience with a chain relating to stretch.
We have a system design to move a building-on-wheels in 2 directions. The driving system is a sprocket and chain. The chain is size 35 and the total distance of the entire loop is 260 feet long.
The driving sprocket end is a 4" sprocket that is driven by a DC motor at 25 RPM. In other words, it's slow. The idler end is also a 4" sprocket allowing the loop to be tensioned.
For some perspective, manually the building (about 80 feet wide and 25 feet long) can be moved by 2 people with relative ease. The initial startup torque is greater but once it gets moving, then the building is essentially coasting.
Now, when we hooked up the building to the chain, here is what happened. The brand new chain (no wearing of pins, bushings or plate hole elongation), the chain stretched about 10 inches before the loop was pulling. Thus, we stopped, stretched the chain with clever Roman tricks and managed to remove several links of chain and then return to a guitar string type of condition.
Turn the motor on and again the chain is further stretching causing more slack in the slave or non-loaded end. Essentially, the chain is still stretching even after introducing what appeared to be maximum stretch.
I had to bring this up in the discussion because I don't believe that chain doesn't stretch. If you look for pre-stretched chains, you will find a 60 chain being sold as prestretched.
I hope this adds value to the discussion!
Hi. I don't ride a bike but I have experience with a chain relating to stretch.
We have a system design to move a building-on-wheels in 2 directions. The driving system is a sprocket and chain. The chain is size 35 and the total distance of the entire loop is 260 feet long.
The driving sprocket end is a 4" sprocket that is driven by a DC motor at 25 RPM. In other words, it's slow. The idler end is also a 4" sprocket allowing the loop to be tensioned.
For some perspective, manually the building (about 80 feet wide and 25 feet long) can be moved by 2 people with relative ease. The initial startup torque is greater but once it gets moving, then the building is essentially coasting.
Now, when we hooked up the building to the chain, here is what happened. The brand new chain (no wearing of pins, bushings or plate hole elongation), the chain stretched about 10 inches before the loop was pulling. Thus, we stopped, stretched the chain with clever Roman tricks and managed to remove several links of chain and then return to a guitar string type of condition.
Turn the motor on and again the chain is further stretching causing more slack in the slave or non-loaded end. Essentially, the chain is still stretching even after introducing what appeared to be maximum stretch.
I had to bring this up in the discussion because I don't believe that chain doesn't stretch. If you look for pre-stretched chains, you will find a 60 chain being sold as prestretched.
I hope this adds value to the discussion!
