Girl friends just got a road bike with Shimano 105 compact, 50/34 - 28/12 10 speed I think.

She asked me what rear sprockets she can use on the big front sprocket and what rears she can use on the small front. Thinking about it I don't really have a difinitive answer, does anybody??

Please help in explaining to her.

Cheers

G

You can use whatever you can push....

It is generally considered bad form to use the big chainring with the biggest two sprockets because this causes an excessively offset chainline and premature wear to the chain and sprockets.

The same is true of small chainring to smallest sprockets, although you will probably find that the chain rubs annoyingly on the inside of the large chainring anyway when doing this.

Otherwise, try to choose whatever gearing keeps pedalling speed or cadence nice and high ie. 80-100rpm.

When I got home from my commute yesterday evening one of my neighbours (who's a very knowledgeable roadie) told me I shouldn't be on the big ring/big sprocket. Also I've been wondering what my chain was rubbing on when in the small/small. I'd been too embarrassed to ask him why on both counts.

 So RH, many thanks to you for the excellent public service posting above!  I've learned something today

Simple rules of thumb.

1. Try to keep the chain line as straight as possible.

2. Big ring middle to outside cogs

3. Small ring middle to inboard cogs.

It reduces the sideways bending on the chain.

Glenn, Wishfull thinking Campag Super Record 11 spd is only on pre order at the moment.