Originally Posted by
Bigbus
For those of you that like to exercise the grey matter in your heads and for the few of you that might know this off the top of your head, is it possible to run a 39/50 front with a 10/50 cassette? Thanks in advance,
When you go from
Large Front Ring & Large Rear Cog to
Small Front Ring and Small Rear Cog there is a considerable difference in the length of chain needed.
This difference is calculated using the teeth difference.
In your case (50 front + 50 rear) - (39 front + 10 rear) = 51
100 - 49 = 51 teeth capacity
The rear derailleur has to be able to take up the slack in the chain for this 51 difference.
Rear Derailleurs are rated in two ways.
Capacity (in your case 51)
Max rear Cog (in your case 50)
You are going to have a really tough time finding a Rear Derailleur to meet both these requirements at the same time.
But now you know what your looking for!
All the best
Barry