Forum menu
Chainline help plea...
 

[Closed] Chainline help please

Posts: 1308
Free Member
Topic starter
 
[#11872679]

Doing my head in question .....Would going from 30t Middleburn chainring up to 32t Middleburn chainring affect my chain line??? 12 speed and chain keeps dropping of front chain ring when shifting into easiest gear ....did not on the 30t... new chain and new cassette and new rear mech all set up by me and all checked by lbs. ??????????


 
Posted : 07/05/2021 5:17 pm
Posts: 756
Full Member
 

Don't reckon so. Could be that you need narrow/wide to help keep it on, or just get a chain device - that'd keep it on.


 
Posted : 07/05/2021 5:24 pm
Posts: 1308
Free Member
Topic starter
 

Both old and new chain rings narrow wide 🙁


 
Posted : 07/05/2021 5:46 pm
Posts: 3783
Free Member
 

Both old and new chain rings narrow wide 🙁

Are they identical apart from no of teeth? No off set or boost to change the chain line?

Is the rear cassette on properly? Tightened? No spacers etc?

That's sounds an odd one. Is the chain ring damaged or bent?


 
Posted : 07/05/2021 5:53 pm
Posts: 1308
Free Member
Topic starter
 

30t was Wolftooth .... 32t is Middleburn ..., both direct mount for Middleburn RS8.
All my 12 speed GX came off and new SRAM shifter mech and new cassette gone on.
Will take it all of and refit.
Seems to be quite a “bend” in the chain when on the top gear 48t cog.


 
Posted : 07/05/2021 8:12 pm
Posts: 13865
Free Member
 

Direct ring could be boost (wider chainline) so would be 3mm wider than a "normal" ring.

Also wondering if your chain was tight to begin with and a larger ring had made it too short?


 
Posted : 08/05/2021 7:33 pm
Posts: 1308
Free Member
Topic starter
 

Thank you for all the replies so far. New chain, apologies I didn’t mention also a new chain previously. I am sure Middleburn do not make a boost version at the moment?????
Started to remove everything again and go through the rebuild process


 
Posted : 08/05/2021 8:13 pm
Posts: 13865
Free Member
 

Just lie both rings flat on a table, you'll be able to see if one has more offset than the other


 
Posted : 08/05/2021 8:34 pm
Posts: 66111
Full Member
 

honourablegeorge
Free Member

Just lie both rings flat on a table, you’ll be able to see if one has more offset than the other

Yup, this. If there's a difference enough to make a difference, it'll be very visible.

Having said that, chainline'd have to be miles off to really affect chain retention that much.


 
Posted : 09/05/2021 5:08 pm