stapfam

Enough has been said about the number of teeth that Dérailleurs can handle but when I set up the bike with an 11/28 and 52/40/26 for the mountains I had a problem. Set it up for Big/Big and with the shortest chain possible and when I went 26/28 I had a problem. The top RD cog was rubbing on the cassette. Tried to set the screw to tension the chain away but had to go 28 on the granny to get it acceptable. This was with a Sora RD and there is a limit to how many teeth the RD can handle. It was still too close for comfort though

Finally set the Chain length too short for big/big but I reckoned that for mountains I would not be using the 52 in any case so it would not have been a problem. It wasn't till I got back to the UK and loaned the bike out and I then had to give a lesson to the "NEW" rider on how to utilise the gears

And also had a problem on the Pinnie that had 50/34-11/25 fitted when I put on the 12/30 cassette. Chain length was perfect but I had to adjust the Tiagra RD away from the cassette to stop the grinding noise of the cogs touching.