Compact Cranks

[stanngg]

OK...stupid question. As far as cranks, I run the standard 53/42. Used a loaner over the weekend with a compact 50/34. I really liked the smaller crank for climbing but found the big ring didn't have enough speed on the flats, rolling and down hills. So...can you mate a 34 with a 53? The best of both world...or do you have to have either a standard or compact? No mixing...

 

[rosborn]

OK...stupid question. As far as cranks, I run the standard 53/42. Used a loaner over the weekend with a compact 50/34. I really liked the smaller crank for climbing but found the big ring didn't have enough speed on the flats, rolling and down hills. So...can you mate a 34 with a 53? The best of both world...or do you have to have either a standard or compact? No mixing...

They don't come standard that way from any of the component manufacturers but you could probably get one "customized" by purchasing a 50/34, removing the 42T ring from your current crank and having the 34 put on your current crank. Of course, you could just purchase a 53/39 crank and be close.

 

[graf zeppelin]

Extralite makes a 53-39 chain ring set for 110 BCD cranks, so I suppose in theory you could set up a 53-34 on a compact crank. I dont think that can be done on a standard crank. 53-34 would set up some huge leaps, though I never have checked how that would pan out. Problem is, in practice, my hunch is you'd be chain dropping a lot trying to shift down to a 34 from a 53, provided you could adjust a front derailleur to make the shift.

The better option might be to get 50-36 front rings and an 11-23 cassette in back, as that's very close to a 53-39 12-25, and the 50-11 is bigger than the 53-12. Should give you enough speed on flats unless you are a huge sprinter. When you head into the mountains, you could then simply change out the cassette to a wider ratio and partake of better climbing gears without ever having to touch the front rings, although nothing would be stopping you from changing the 36 to a 34 too. Through all that you'd never have to change the cranks, and would even have the option of running 53-39 on the compact cranks via Extralite.

 

[PeterF]

OK...stupid question. As far as cranks, I run the standard 53/42. Used a loaner over the weekend with a compact 50/34. I really liked the smaller crank for climbing but found the big ring didn't have enough speed on the flats, rolling and down hills. So...can you mate a 34 with a 53? The best of both world...or do you have to have either a standard or compact? No mixing...

Shimano (130mm BCD) or Campy (135mm BCD)? The smallest rings you can use wih a standad 130 bcd is 38t and 39t with a 135mm bcd. A 42 doesnt give you much of a climbing gear. Have you considered a more common 39t small ring? Jumping from a 53t big ring to a 34t small ring may be troublesome with a standard short cage rear derailleur. Also, you will need a compact specific front derailleur.

 

[kdelong]

Your biggest worry is if your FD has the lift required to make the jump. Its times like these that make you wonder if a triple might be worth the extra weight.

 

[oldbobcat]

I really liked the smaller crank for climbing but found the big ring didn't have enough speed on the flats, rolling and down hills.

Unless you're used to rolling with a 53/11, a 50/11 gives you a slightly taller ratio than the commonly used 53/12. So, as graf z. says, look at your cassette. If you're concerned about the top end, I don't see where the 36-tooth small ring fits in, though.

Personally, I find 50/11 useful only for sustained efforts above 31 mph so 53/11 must be a total leg-breaker.

 

[Peter@vecchios]

OK...stupid question. As far as cranks, I run the standard 53/42. Used a loaner over the weekend with a compact 50/34. I really liked the smaller crank for climbing but found the big ring didn't have enough speed on the flats, rolling and down hills. So...can you mate a 34 with a 53? The best of both world...or do you have to have either a standard or compact? No mixing...

Depends on whether it's Campagnolo ro shimano/sram. If you shift deliberately, and slowly, with little pedal pressure, you can shift from the 34 to a 53 with Campagnolo. shimano/sram, beng much ore positional, if difficult at best.

The 'best' of both worlds is really a compact 50/34 with a 11-25. Higher high gear and lower low gear than a 53/39 with a 12-27.

 

[Bob Ross]

Its times like these that make you wonder if a triple might be worth the extra weight.

You mean the ~100g extra weight?

Yeah, I used to think the weight penalty was one of the reasons to avoid a triple...until, on an internet forum (much like this very one) some ******** (much like me) called me out, just like I'm doing here.

Check the specs: The difference between Campy's lightest Super Record crankset & their Comp Triple is ~ 76g. The difference between Shimano's lightest DuraAce 7900 crankset & their Ultegra Triple is even less than that.

Yeah, I know there's also the long-cage RD, the wider FD, a longer chain, and (I think) a different bottom bracket to factor in. But the weight difference still winds up being less than what you'd save by taking the two spare tubes out of your saddle bag. (And putting them in your jersey pocket, of course. I'm not advocating riding w/o emergency spares, but everyone knows weight on your body doesn't count, right?)

Now, if you'd said "Its times like these that make you wonder if a triple might be worth the performance sacrifice" I wouldn't have a snappy answer to that. But as soon as I learn one, I might just have to buy me a triple!

 

[bikecoach]

Unless you're used to rolling with a 53/11, a 50/11 gives you a slightly taller ratio than the commonly used 53/12. So, as graf z. says, look at your cassette. If you're concerned about the top end, I don't see where the 36-tooth small ring fits in, though.

Personally, I find 50/11 useful only for sustained efforts above 31 mph so 53/11 must be a total leg-breaker.

Spot on with this call. My new bike I built up with compact cranks for the first time ever. I was pleasantly suprised when my top gear had a larger roll-out than my previous bike. (50/11 vs 53/12). And up the hills is just awesome.

 

[Meek One]

OK...stupid question. As far as cranks, I run the standard 53/42. Used a loaner over the weekend with a compact 50/34. I really liked the smaller crank for climbing but found the big ring didn't have enough speed on the flats, rolling and down hills. So...can you mate a 34 with a 53? The best of both world...or do you have to have either a standard or compact? No mixing...

I guess the first question is what range the cassette has on your bike and the one you rode? If you just rode a 50x12, a 50x11 would help. Are you sure you have a 42 and not a 39? If your current cassette is only 11(or 12)x21 or even 23 swapping to 11(or 12) x 25, 26, or 27 would help flatten some hills for you...