new crankset 39/53 or 39/52? help

akcc05

I have decided it's time to upgrade my 6600 compact as it's the only part that is not 6700 on the bike (except 6600 cassette and chain). 50t big ring (12-25 in the rear) is definitely too small in group-ride sprints, but since the pros ride 39/53 with 12-25 in rolling stages, perhaps 39/52 would be more than enough for me?

rickhotrod

A 10 speed 53/39 12-25 combination works well. When you do a front shift you only need to make two rear shifts. ie. 53/21 to 39/17 and vice-versa.

52/39 works just as well, and if you sometimes front shift from 52/23 to 39/19 and vice-versa it works better. This is because shifting from 39/19 to 53/23 is a 12.3% jump (ie. just a tiny bit too big), whereas shifting from 39/19 to 52/23 is a much better 10.1% jump..

moonshine

Either will be fine. You'll notice a difference moving from a compact to a standard chainset, but I don't think you'll notice the difference between them. (between a 53/39 and a 52/39)

paul64

Gear ratios are pretty easy to work out, here's an example including 52 (easy enough for you to change in excel for 53 or anything else). Horizontal toolbar means you can see those hidden. Happy to send you the excel file if you like

ex-pat scot

I've used 39 / 52 for decades, with a 12-21 block.

Perfect for my fitness- allows me to spin along happily in the big ring (52 x 16 or x 17) which is my favourite road bike gear. If I recall, I felt the 53 just made these gears a little too tall, so the 53 ring was relegated to speed duties on the tt beast.