Chainline

boyabouttown

Pedelecer
Oct 3, 2016
132
92
59
sheffield
Not strictly ebike related but if i bought an ebike with a double chainring, would it be possible to use just one ring and be able to use all of the 8 speed cassette. Can the double ring be moved, leaving one of the rings in line with centre of cassette. Or remove a ring and shim the other to the centre position. Would this allow me to use all the cassette on one ring, keeping the front derailleur but not using it.
 

TobyAnscombe

Pedelecer
Jun 7, 2012
124
24
Epping Forest, Essex
Depending on the attachment then yes; I've just swapped my ring out for a larger one and in doing so moved it from inside the spider to outside https://www.pedelecs.co.uk/forum/attachments/45df6fdf-6311-4014-9f90-cf7c7bd20526-jpeg.30763/

This has done exactly as you describe - it puts low stress on the bottom of the cassette because its further over but on the inside (big cog) of the cassette the chain is at quite an angle, but it still shifts ok.

The move to X11, X10 etc setups is exactly as you describe - a single sprocket with no front mech for lightness and simplicity. Take some photos of the chain at the top and bottom of the cassette in each of the front rings and see how acute the angle of the chain is - its unlikely that you will be in 1st for a long time and far more likely that you will be in 6-9th so choose how you want to optimise your setup for your riding.
 

thirteen

Pedelecer
Jul 16, 2014
115
55
West Sussex
Yes, I've done exactly that with a 24 speed MTB, converting it to one ring at the front.

If it won't set up without a bit of rubbing at either the largest or smallest cog, don't worry as long as it engages without slipping.

As TobyAnscombe says, optimise it for your riding. Mine was set up for hills so clean engagement on the larger cog was more important.

I took my front derailleur and shifter off, but you can leave it on. Just make sure the shifter is disengaged as you don't want to be moving your chain onto a non existent chainring inadvertently. :)
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
It's best to keep the front derailleur if you change to a single chainwheel because it stops the chain jumping off, otherwise get a chain-guide for that purpose.