JScycle wrote: ↑
Sun Oct 14, 2018 12:33 pm
pdlpsher1 wrote: ↑
Sun Oct 14, 2018 12:00 am
JScycle wrote:Thanks everyone. So just to clarify if I buy a mid-cage and run two chains it will work awesome with both 11-28 and 11-34?
To be clear, the cage length determines the chain wrap capacity. If you use a RD and pair it with a cassette that is not recommended by Shimano, you will not have sufficient chain tension for all of the gear combinations regardless whether you use a different chain or not. Using a longer chain will let you run a big-big gear combo but the derailleur won’t be able to take up the extra chain slack on a small-small combination if the RD lacks sufficient chain wrap capacity. There’s a very good reason why Shimano makes two different versions of the RD.
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So can you please clarify for me.
Would a short cage derailleur will suit 11-28. Can I get away with anything bigger
Mid cage will suit 11-32 and 11-34. Will it suit 11-28?
Yes you can "get away" with bigger than 11-28t.
Problem with asking will it work is it will work a little bit less well the more you stray away from the ideal size.
Don't be alarmed though. For most people it works perfect. For some it doesn't feel as good. Depends on how you perceive good shifting to be.
Working well or not assumes you have enough space between upper pulley wheel and the cassette switching from 2nd to 1st gear. If you don't have enough space or if your chain is sized poorly so that you stretch the derailleur in big-big then you risk damaging the derailleur hanger running such a setup.
Another reason why you can't get a clear answer, will it work or not, is because every bike has a bit different length derailleur hanger. It means on some bikes a derailleur can fit a bigger cassette, on some it can't.
Easiest check is to simply borrow a rear wheel from someone that has the size cassette you like and check if it fits (set B-screw and check pulley/big cog clearance). It doesn't even have to be an 11speed cassette. Any cassette with the same size big cog 28/30/32/etc is ok for checking fit.
Wolftooth road link or similar are pretty disappointing when it comes to shifting performance if you stray far from the ideal cassette size (which is the main reason to buy one = more or less always).