New crankset ahead......compact or mid?

Triathlon Forum
1

I’m updating my crankset based on a fit and going shorter. I’m on a compact now and am with a 50/34 and 11-26 setup (172.5). I am NOT a spinner by any means, usually feeling most comfortable mid to low 80’s cadence. It seems the shorter crank gets me able to ride more comfortably lower, but I would like some input as to gearing. I’m in Madison, so some pretty good hills and am older so not the leg strength of many of you. Any thoughts if I should stay with the compact and if so, which cassettes would be a good fit? I’m possibly changing out the entire drive train, so want to do it right. Opinions?

Thanks.

2

Are you currently on a 50/39 or 50/36?

3

oooppps. Sorry, my mistake. The standard 50/34 compact.

4

50/11 is plenty of top end for most of us AGers.
If 34/26 is low enough for your area and cadence preferences, I wouldn’t change anything.

A 52/36 with a 12-28, for example, would be give you a slightly lower high gear and slightly lower low gear.

Based upon your comments, I’d would stick with a 50/34 and stick with the 11-26 or consider a 11-28.

You can use this calculator.

5

Thanks. I appreciate the help. I wasn’t sure if going from a 172.5 to a 167.5 was going to make any differences as far as power output or comfort that I would have to account for with a gearing change.

6

Are you considering going 1X? I went from 53/39 12-25 10 speed to a single 50 with 11-36, 11 speed, used all SRAM it is pretty cool, only downside is the bigger jumps in the larger rear gears.

7

I would think that a mid 36/52 with an 11-28 would be close on the back with a higher gear front end, but you could go long cage derailleur and go 11-32 and get the best of both worlds. If you are totally fine with the 34x26 the 32 would be granny-esque! But you wouldn’t run out of gears.

When I switched from 172.5 to 165 I really didn’t notice much other than comfort in aero. I don’t train with power so can’t help there, but I climb well and I am much more of a masher for sure - and I moved from a compact to a 53/39 with 11-28 and never change it…strong enough rider but I LOVE having a bigger chainring for flats and slight downhills.

My 2 cents anyways! Hope it helps.

Brent

8

Thanks. I appreciate the help. I wasn’t sure if going from a 172.5 to a 167.5 was going to make any differences as far as power output or comfort that I would have to account for with a gearing change.

A 5mm change won’t be too big a deal. We’re talking ~1/5 of and inch or about 2.9% change. I see no change in power output going from 177.5 down to 165mm cranks or actually a small increase what I can hold in aero position with the shorter cranks.

YMMV,

Hugh

9

Thanks. I appreciate the help. I wasn’t sure if going from a 172.5 to a 167.5 was going to make any differences as far as power output or comfort that I would have to account for with a gearing change.

A 5mm change won’t be too big a deal. We’re talking ~1/5 of and inch or about 2.9% change. I see no change in power output going from 177.5 down to 165mm cranks or actually a small increase what I can hold in aero position with the shorter cranks.

YMMV,

Hugh

Thanks Hugh. I think the aero advantage may be what I need, but when I think of the science and torque that can be applied with a longer lever I get skittish about going shorter.

10

Are you considering going 1X? I went from 53/39 12-25 10 speed to a single 50 with 11-36, 11 speed, used all SRAM it is pretty cool, only downside is the bigger jumps in the larger rear gears.

I think my age and where I live the 1x may not be the best. I was looking at Shimano Di2 from my SRAM 10 speed Red.

11

My experience.

With a 11-28, I like my 50-36 (powertap C1 chainring).
With a 12-25 for flatter courses, wish I had a 52/36 chainring set up.

The 11-28 is great for group training rides. The 12-25 is good for flatter courses and crits.

3 teeth in front is worth 1 in the back. Hence a 53-12 = 50-11.

Crank length. Shorter crank is more comfortable in aero AND responds faster to jumps from other riders in a group AND has more road clearance while cornering or turning. I think it may negatively/positively impact running though. Yet, from a cycling perspective I was happy going from 175 to 172.5 to 170 on a 56cm bike while 6’0 tall.

12

Thanks. I appreciate the help. I wasn’t sure if going from a 172.5 to a 167.5 was going to make any differences as far as power output or comfort that I would have to account for with a gearing change.

A 5mm change won’t be too big a deal. We’re talking ~1/5 of and inch or about 2.9% change. I see no change in power output going from 177.5 down to 165mm cranks or actually a small increase what I can hold in aero position with the shorter cranks.

YMMV,

Hugh

Thanks Hugh. I think the aero advantage may be what I need, but when I think of the science and torque that can be applied with a longer lever I get skittish about going shorter.

Put another way, it’s less of a change in leverage than a single tooth increase on the cassette would give you back if needed. I’m 63, ride in a hilly area and really enjoy 165 cranks but ride a 50X34 crankset and appropriate cassette.

13

Unless you’re doing low cadence, high power workouts, I think you’ll be fine with compacts. This question isn’t as important as it once was since Shimano (and others, I think) has one BCD for all three. Granted the rings are expensive.

14

Unless you’re doing low cadence, high power workouts, I think you’ll be fine with compacts. This question isn’t as important as it once was since Shimano (and others, I think) has one BCD for all three. Granted the rings are expensive.

Thanks for the post. I was surprised (pleasantly) that Shimano made the bolt pattern the same. I’m looking forward to a new setup, but wanted to make sure I did the appropriate research. With cranks a mistake is $$.