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Discussion Starter · #1 ·
I have a compact crank on my bike and have never really gotten comfortable with the shifting between chainrings. Regardless of where I am in the cassette, I find the difference between rings to be enough that I never make the shift smoothly, thereby messing with my cadence as I move uphill. Recently, I've been thinking about getting a traditional crankset (53/39 chainrings) as my regular cranks and using the compact as the ride and terrain requires.

Have others considered this and the prospects of swapping out cranks? Is there any downside relative to the bottom bracket to taking your cranks off and on on a relatively frequent basis?
 

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How much are you shifting the rear when you shift up front? Sounds like you aren't? I find that the smoothest transitions are brought on by moving two cogs in the rear whenever I make a change up front. This gives a similar feel to a single shift in the rear.

I use 53/39 with a 27t cassette.
 

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Doing the opposite

I currently have a 53/39 - 27t regular setup and am going to a compact. 34/50.
I plan to switch the cranks back and forth, probably not frequently but....
I hope that I do not encounter the shifting issues that you refer to....
Today I have no shifting problems, could just use a lower gear on the hills, that is the reason for my change.
 

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I don't see how a 53/39 would change your shifting issues as far as changing rings is concerned. As the previous poster said, when changing rings you have to change about 2 cogs the opposite way to get an incremental shift (e.g., up one ring, down two cogs).

Also, if you want to swap cranks like that, maybe you should consider a triple. My bike has 53-39-30, so covers both the standard and compact gear ranges.
 

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I went from a 53/39 to a 50/36 compact. The shifting is pretty good, actually. It seems that the 16 tooth jump on most compacts is just too much to shift smoothly.

And I've also noted, it's 2 shifts in the back for 1 shift on the chainrings.
 

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I have both...

When shifting the front on the compact I have to shift the rear at least 3 cogs in the back to keep my cadence relatively close...

With the standard crank I only need to shift one and things are close enough and 2 keeps me bang on...

Personally I prefer the standard. I can sit in the 39 for the majority of my riding and only move up to the 52 when the pace picks up and or the terrain goes down. With the compact I find I need to shift between the 50 and 34 a lot more....

BUT! On hilly rides I am glad to have that 34......
 

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learn how to shift....

Whenever you shift between the chainrings, it most often requires a 3-cog shift to arrive at the next higher or lower gear, with a compact and it can take up to four. A standard 53/39 will require only one less cog to be shifted - usually two. Shimano and Campy shifters can both shift 3-cogs larger with one sweep of the lever (not sure about SRAM). Shimano of course, requires 3 taps of the finger lever to shift 3 cogs smaller, while Campy's thumb button can do any number with a single push.

I made the opposite switch this year and it did take awhile to get used to, but now it's no problem. The other thing you can do to minimize the cog to shifting is to spin up to a higher cadence before making the shift to the big ring and not make the shift into the little ring until the load forces an 8-10 rpm lower cadence on a hill. An 8-10 rpm cadence change is equal to one cog.
 

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you might also be pedaling too hard if you are shifting on a hill. drivetrains dont like to shift under strain, especially the front mech. shift sooner, shift often.

i moved from a standard 53 to a compact and like it. and i usually can get away with only shifting one cog before the change up front. i loose the higher cadance, but you rev up to it anyway.

as far as swapping out the crankset, i wouldnt do it too much. every time you swap a part out and then back in, you risk somehow damaging it. not pulling it correctly, dropping it, not installing it correctly, keeping the bolts a bit loose... plus, you might need two different chain lengths. just a thought.
 

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I've gone from a triple to 50/34 & like the change. I find I stay in 50 for 90% of my riding. Found I shifted between chainrings more on 53/39's I've tried, and the 39 isn't low enough for steepest hills (15%+). Generally use a 12-27 cassette except for long flat rides when I switch to 12-23 (to get the 18 cog). I only use the 34 ring for steeper hills or high-cadence drills.
 

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Discussion Starter · #10 ·
So when people are dropping from the 50 ring to the 34 on their compact cranks, are you simutaniously (sp?) going down two or three gears to get the smooth transition - thats what I think I'm reading? Do I have that right?

With Shimano, that would take two or three clicks to accomplish. That won't be a particularly smooth transition. I'll try it tomorrow on my ride.
 

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I didn't like the huge jump between gears, so I switched out the 34 for a 36. Even so, I switch a cog or two right before shifting my chainring, to make the transition more smooth.

Why not try a cheap fix like swapping chainrings instead?
 

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RoadLoad said:
So when people are dropping from the 50 ring to the 34 on their compact cranks, are you simutaniously (sp?) going down two or three gears to get the smooth transition - thats what I think I'm reading? Do I have that right?

With Shimano, that would take two or three clicks to accomplish. That won't be a particularly smooth transition. I'll try it tomorrow on my ride.
That's how I do it. Three clicks for me. Once you get the hang of it it's not that big of a deal.
 

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tap tap tap...

RoadLoad said:
So when people are dropping from the 50 ring to the 34 on their compact cranks, are you simutaniously (sp?) going down two or three gears to get the smooth transition - thats what I think I'm reading? Do I have that right?

With Shimano, that would take two or three clicks to accomplish. That won't be a particularly smooth transition. I'll try it tomorrow on my ride.
Most Shimano users brag that they can tap out three shifts as quick as I can push a Campy thumb button down, but I doubt that. If you haven't been shifting 2-3 cogs smaller either immeidately before or after shifting to the little ring, no wonder you're having problems. All cranks require some cog shifting - a compact just requires one more.

The suggestion to change the little ring to a 36 will reduce the cog shifting to the same amount as a 53/39, but then you're not gaining any gearing range, just moving the whole gearing range lower. That's OK, if you really don't ever need your lowest gear ratio, but if you need it, you lose it with the 36.
 

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RoadLoad said:
I have a compact crank on my bike and have never really gotten comfortable with the shifting between chainrings. Regardless of where I am in the cassette, I find the difference between rings to be enough that I never make the shift smoothly, thereby messing with my cadence as I move uphill. Recently, I've been thinking about getting a traditional crankset (53/39 chainrings) as my regular cranks and using the compact as the ride and terrain requires.

Have others considered this and the prospects of swapping out cranks? Is there any downside relative to the bottom bracket to taking your cranks off and on on a relatively frequent basis?
You shift the front when your going up hill?
 

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I personally have a 53/39, but changed the 53 for a 50. Perfect match. In the older days, the common setup was 52/42, but I forget what was in the back. I use my 50/39 with a 12-27 in the back. Probably the best overall setup, and you don't have to double-shift all the time.

Johnnydrz
 

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I personally have a 53/39, but changed the 53 for a 50. Perfect match. In the older days, the common setup was 52/42, but I forget what was in the back. I use my 50/39 with a 12-27 in the back. Probably the best overall setup, and you don't have to double-shift all the time.
I'm certainly not a shifting guru, but that's what I use too. Not recommending it, just stating it works great for me.
 

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I've been out of the game for a little while, but compact cranks seem to have it all over the traditional 53/39 setup for most ppl, so I'd think the cost of switching is the main barrier, not the shifting.

For example, a lot of fit rec riders/wannabe racers seem to love 53/39 cranks with a 12-23 cassette. But with a 50/34 compact crank, they could run an 11-21 cassette, and wind up with a higher high gear, a lower low, and would have one more 1-tooth jump besides. You've saved a little weight as well, and rotating weight at that. What's not to love? :thumbsup:

Some ppl seem to feel the shift between chainrings is a bit slower, but so what? You're going to be in your big ring 90% of the time anyway, and unless you have a certain kind of hill topography where you live ('really big rollers'), you shouldn't be going back and forth between rings constantly I'd think.

So, for most ppl most of the time, seems like a small price to pay for what you get in return. I got out of cycling in '97 (bad move on my part), and am only now coming back, but right before I left I was considering using a MTB crank as a road double with small rings to simulate what are now compact cranks. It's gratifying to see that they've caught on, they make sense.

.
 

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C-40 said:
Most Shimano users brag that they can tap out three shifts as quick as I can push a Campy thumb button down, but I doubt that.
Bragging of swift fingers isn't the point there. You can undoubtedly get the movement done faster - but the mechanicals can't, which is the important bit. With either method, it still takes the chain a certain amount of time to step itself down the cogs, and a practiced Shimano user (or Centaur user, for that matter) can easily outpace it. Even though your fingers are done faster, the shift takes the same time to complete.

Earlier, you mentioned needing up to four rear shifts in the rear for a compact. Mathematically that's true, but in practice it's relatively rare. Depends on the gearing chosen, but for most I've charted, those four-hops only occur in parts of the cassette where the upshift would be relatively infrequent, though I suppose that depends on which 'school' of shifting one adheres to. Also, for most that I've seen, that 'fourth' cog gets you to a gear that was within a few gi's / percent of the original gear, and so probably wouldn't be the target anyway. Just saying that I agree with you on the facts, but I don't think it's enough of a concern to change thinking on compacts or lever choices. It seems to be of most concern (in terms of losing time) on the big upshift/rear downshift, and there, all levers are essentially equally limited to three.


OP: Yep, that's the story - a correct shift of the chainrings requires a shift of the rear, too. If you construct a gear chart (or refer to the gearing section of Sheldon Brown's site), you'll see about half the time, the 'next' gear is a double shift away. But doing both simultaneously is an invitation for a dropped chain, especially if done under load. I usually trip off one from the rear, then make the front change, then the last one or two on the rear as needed. It sounds complicated and unsmooth, but becomes second nature in a short time. The first shift drops tension in the drivetrain, making the rest go more smoothly and reliably.

The other direction is easier - just swing both levers at the same time.
 

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RoadLoad said:
I have a compact crank on my bike and have never really gotten comfortable with the shifting between chainrings. Regardless of where I am in the cassette, I find the difference between rings to be enough that I never make the shift smoothly, thereby messing with my cadence as I move uphill. Recently, I've been thinking about getting a traditional crankset (53/39 chainrings) as my regular cranks and using the compact as the ride and terrain requires.

Have others considered this and the prospects of swapping out cranks? Is there any downside relative to the bottom bracket to taking your cranks off and on on a relatively frequent basis?
You-all sure go through a whole lot of crap just to avoid a triple. Vanity, vanity. - TF
 
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