Chainline, BBs and chainsets
A little help...
Rebuilding a 70s Raleigh Clubman 531 and the old Tange BB is shot. Obviously i'll 'just' bang in a cartridge type.
At the same time i'm cold setting the rear dropouts to accept an 8 speed setup. (from 120 to 130mm)
This gives me a chainline at the rear of...47. (By my calculations)
The original BB had an axle length of 119 (excluding the old style studs on the end. It was a single chainwheel setup, 5 speed on the rear.
The downtube is 28.6 .
Now the question....id i buy a BB-ES30E for instance, it quotes..
Chainline.......47.5 / 50
BB Shell Width..68 / 73
Spindle Length..113 / 118
I ASSUME these are two different BBs, one for 68mm, one for 73mm.
I want 68mm, that should give me a 47.5 chainline...which is good for me.
AM I RIGHT....?
The thing that confuses me is the axle length is shorter..113 on the new BB....119 on my old one ??...and i want to put on a double...it doesnt seem very reassuring.
Any thoughts guys..
Chill out, fer Christsakes....
Rebuilding a 70s Raleigh Clubman 531 and the old Tange BB is shot. Obviously i'll 'just' bang in a cartridge type.
At the same time i'm cold setting the rear dropouts to accept an 8 speed setup. (from 120 to 130mm)
This gives me a chainline at the rear of...47. (By my calculations)
The original BB had an axle length of 119 (excluding the old style studs on the end. It was a single chainwheel setup, 5 speed on the rear.
The downtube is 28.6 .
Now the question....id i buy a BB-ES30E for instance, it quotes..
Chainline.......47.5 / 50
BB Shell Width..68 / 73
Spindle Length..113 / 118
I ASSUME these are two different BBs, one for 68mm, one for 73mm.
I want 68mm, that should give me a 47.5 chainline...which is good for me.
AM I RIGHT....?
The thing that confuses me is the axle length is shorter..113 on the new BB....119 on my old one ??...and i want to put on a double...it doesnt seem very reassuring.
Any thoughts guys..
Chill out, fer Christsakes....
Chill out, fer Christsakes....
0
Comments
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Required axle length depends on the model of chainset. Some chainsets place the chainrings further out than others even when used on the same bottom bracket.
If using a chainset designed with 130mm hubs in mind, the default axle length the chainset manufacturer recommends will be suitable for your bike. So in this case you don't need to know the chainline figures.
<i>~Pete</i><i>~Pete</i>0 -
The BB specs show there are 2 BB shell sizes and 2 BB lengths available - therefore you should look at the 68x118.0
