Bike chain
- Thread starter SGC
- Start date
Problem with running worn on new is that actually neither then fits either.
If you think that a new chain and cassette fit together at all points around it, when one is worn you actually are pulling on less surface area as less is now in contact.
This can be seen on a front chainring quite clearly......on a new assembly, if you were to try to pull the chain towards the front wheel at 3 o'clock, there's little movement.....as they wear that movement increases. When you apply drive force, your therefore only engaging part of the chain / cog if the components are worn.....this speeds the wear as the force is being spread over maybe (for arguments sake) 60% of the seemingly engaged chain / cog rather than 100%.
So a new chain on an old cassette will were faster than a whole new assembly.
As for slipping gears with a new chain, its the same issue, the chain is shorter mesh than the worn gear, so the chains not engaging with the teeth full depth at the derailleur...it wobbles, ramps catch etc, poor shifting / slipping.
But its a question of economics and how good you need your shifting too!
Btw...that cassette looks shot to me too! I wouldn't be afraid of doing the cassette, buy the tool for £5 and have a go.....im sure there's a video.....
If you think that a new chain and cassette fit together at all points around it, when one is worn you actually are pulling on less surface area as less is now in contact.
This can be seen on a front chainring quite clearly......on a new assembly, if you were to try to pull the chain towards the front wheel at 3 o'clock, there's little movement.....as they wear that movement increases. When you apply drive force, your therefore only engaging part of the chain / cog if the components are worn.....this speeds the wear as the force is being spread over maybe (for arguments sake) 60% of the seemingly engaged chain / cog rather than 100%.
So a new chain on an old cassette will were faster than a whole new assembly.
As for slipping gears with a new chain, its the same issue, the chain is shorter mesh than the worn gear, so the chains not engaging with the teeth full depth at the derailleur...it wobbles, ramps catch etc, poor shifting / slipping.
But its a question of economics and how good you need your shifting too!
Btw...that cassette looks shot to me too! I wouldn't be afraid of doing the cassette, buy the tool for £5 and have a go.....im sure there's a video.....
