Bill Sukhbir in London thinks he is getting stronger and wants to change his compact chain set for a normal 53/39 chain set and he needs to know if there will be any problems with the swap.
Question: Dear Sam,
Firstly, can I say a BIG thank you for all of your hard work publishing this e-mag. I’ve learned so much from it in the past months although this is my first question to you:
I use my daily ride to work as a training run and have an Ultegra 50/34 compact chainset running a 12-27 cassette at the back. My legs have got a lot stronger in the last year and I want to change the crank set to 53/39 (especially because my ‘good’ weekend bike runs 53/39 and I would benefit from having the same configuration on both bikes). Can I simply replace the compact set and leave everything else the same or will I have to change the whole drive train? i.e. change the cassette, re-position the front derailleur to accommodate the new larger ring, use shorter or longer cranks, etc?
Thanks for the kind words and we are all glad you enjoy the site.
No, there is no problem (or not many) with changing to a 53/39 from a compact 50/34 chainset.
You will need to move the front derailleur up slightly and check that it works well with the bigger chainring. There is a triple chainset specific front derailleur, but the derailleur you have should be OK.
You won’t have to change the shifters, cassette or rear derailleur, but you may need a longer chain to accommodate the larger chainring. If you stay with the same crank manufacturer then you shouldn’t have to change the bottom bracket either.
If you are happy with your present crank length then there is no reason why you shouldn’t stay with that length, you may push a bigger gear, you will probably use a similar size gear as before, but you will have the option of a larger gear.
As you get stronger you do find that bigger gear is very useful. However, if you are not racing and live in a hilly area then the compact chainset is a wonderful invention. There are fewer and fewer riders using triple chainsets because you can have the same spread of gears with a compact chainset with less duplication of gears.
The 53/39 chain ring combination is the combination of choice for most Pro riders for competition riding. The jump between the two rings is quite big, but then it’s not as bad as between the 50 and the 34.
So go for it Bill, but don’t forget to test the new set up before you go for a big ride.