Proper Chain Line

[tyler_derden]

What is the proper set-up for the chain line on a bike with 3 chain rings in front and an 8-speed cog on the rear? Is the smallest chainring supposed to line up with the largest cog, or is the largest chainring supposed to line up with the smallest cog, or is there some other arrangement based on the middle chain ring?

TIA

TD

 

[boudreaux]

Originally posted by tyler_derden
What is the proper set-up for the chain line on a bike with 3 chain rings in front and an 8-speed cog on the rear? Is the smallest chainring supposed to line up with the largest cog, or is the largest chainring supposed to line up with the smallest cog, or is there some other arrangement based on the middle chain ring?

TIA

TD

For a triple, the middle chainring should be in line with the middle of the casette. If you use the proper BB/spindle for the crank,it should be correct.

 

[allmountain]

Originally posted by tyler_derden
What is the proper set-up for the chain line on a bike with 3 chain rings in front and an 8-speed cog on the rear? Is the smallest chainring supposed to line up with the largest cog, or is the largest chainring supposed to line up with the smallest cog, or is there some other arrangement based on the middle chain ring?

To measure chain line its actually pretty easy. The perfect chainline for a mountain bike is 50mm (45 for a road) .. currently 2 chain lines exist for a MTB - 47.5 & 50. This measurement is derived as follows:

measure from Center of the BB shell to the Center of the Middle ring. This measurement should be as close to 50 as possible. If it is too short, you may need a new BB to adjust this.

This is what chainline is. the standard mountain bike rear OLD (Over Locknut Dimension) is 135mm and this is what this measurement of 50mm is based on.

cheers!

 

[tyler_derden]

Originally posted by allmountain
To measure chain line its actually pretty easy. The perfect chainline for a mountain bike is 50mm (45 for a road) .. currently 2 chain lines exist for a MTB - 47.5 & 50. This measurement is derived as follows:

measure from Center of the BB shell to the Center of the Middle ring. This measurement should be as close to 50 as possible. If it is too short, you may need a new BB to adjust this.

This is what chainline is. the standard mountain bike rear OLD (Over Locknut Dimension) is 135mm and this is what this measurement of 50mm is based on.

cheers!

Thank you. Where does one find this sort of information?

TD

 

[boudreaux]

Originally posted by tyler_derden
Thank you. Where does one find this sort of information?

TD

www.parktool.com or Sheldon Browns stuff at www.harriscyclery.com also Barnnettes manual.