Chainline
- Thread starter 139NI
- Start date
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accountantpete
OAP
You can check your existing chainline very easily.
It is the horizontal distance from the centre of the BB shell to a spot in the middle of the two chainrings (or the middle ring for trebles).
Most bikes these days have a 50-51mm chainline so HT II doesn't have differing chainlines - but you do have to measure the BB shell width (68mm or 73mm and buy the appropriate BB)
It is the horizontal distance from the centre of the BB shell to a spot in the middle of the two chainrings (or the middle ring for trebles).
Most bikes these days have a 50-51mm chainline so HT II doesn't have differing chainlines - but you do have to measure the BB shell width (68mm or 73mm and buy the appropriate BB)
Smokin Joe
Squire
- Location
- Bare headed cyclist, Smoker
The chainline will take care of itself with Hollowtech, just fit and forget.
I have a 68mm bb shell.
What are the consequences of getting 'chain line' alignment wrong by a few millimetres anyway?
accountantpete
OAP
Nothing major - the angle of the chain on the outer sprockets will be slightly better/worse.
I assume you have 130mm gap between rear dropouts.
RecordAceFromNew
Swinging Member
- Location
- West London
It does matter for derailleur setups. A potential consequence of getting the wrong chainline by mix and match is the front mech no longer works properly (due to clash with frame or run out of reach). Front mechs are designed to work best with chainsets having the chainline they are designed for, there are exceptions but most road double are 43.5mm, road triple 45mm and mtb/hybrid 47.5mm or 50mm.
For road HT2 chainsets there is not much you can do to adjust the chainline. For mtb ones they come with spacers which allow a little flexibility.
For road HT2 chainsets there is not much you can do to adjust the chainline. For mtb ones they come with spacers which allow a little flexibility.
Smokin Joe
Squire
- Location
- Bare headed cyclist, Smoker
That's the point. The Hollowtech axle is made to automatically give the correct chainline, just as the correct bottom bracket was on square taper chainsets.