Switching between compact and standard cranks

[DCWD]

I'm wondering how much work it'll be to switch back and forth between compact and standard cranks.

Good news! My wife wants to take a month-long trip to France next year. Why is this good news? ...because I get to buy a new road bike to ride while I'm there. My big plans include Mt Ventoux (riding distance from the house we'll be renting) and Alp d'Huez (because I have to do it!).

Here's the rub. I live in DC and everything is (for the most part) flat-flat-flat. Occasionally, I travel to PA where I find some respectable hills. ...nothing like Alp d'Huez. In preparation for my France trip, I'm planning on doing the Courage Classic in Colorado (the land of my inheritance) with a buddy.

So I'm thinking that my new bike ought to have compact cranks to get me up all these hills I intend to ride for "fun". But it's not like I need a compact crank for the other 99,000 miles I'll put on these new wheels.

 

[rudycyclist]

I'd say a 39 should be fine. I am no pro by any means and have never climbed Alp d'Huez, but I'd put a 39-27 on. You should be fine. No sense in putting a compact crank on because when you get home you will be in the 50 wondering why you didnt put on the standard set

 

[LeDomestique]

I'd say a 39 should be fine. I am no pro by any means and have never climbed Alp d'Huez, but I'd put a 39-27 on. You should be fine. No sense in putting a compact crank on because when you get home you will be in the 50 wondering why you didnt put on the standard set

I haven't climbed D'huez or any other high mountain for that case, but I disagree. Although you haven't mentioned how fit / trained you are, the fact that you're not used to hills is enough to justify the compact or triple.

Think of it this way: half up Alpe D'huez, do you think you'll be complaining because you've got a few low gears which you're not using?. Not a chance.

As far as switching cranks, I don’t think it's relevant. Just take it to the shop a couple of weeks before travelling to test it thoroughly.

Cheers

 

[Walrus]

I'm wondering how much work it'll be to switch back and forth between compact and standard cranks.

Good news! My wife wants to take a month-long trip to France next year. Why is this good news? ...because I get to buy a new road bike to ride while I'm there. My big plans include Mt Ventoux (riding distance from the house we'll be renting) and Alp d'Huez (because I have to do it!).

Here's the rub. I live in DC and everything is (for the most part) flat-flat-flat. Occasionally, I travel to PA where I find some respectable hills. ...nothing like Alp d'Huez. In preparation for my France trip, I'm planning on doing the Courage Classic in Colorado (the land of my inheritance) with a buddy.

So I'm thinking that my new bike ought to have compact cranks to get me up all these hills I intend to ride for "fun". But it's not like I need a compact crank for the other 99,000 miles I'll put on these new wheels.

You don't lose that much top end speed with a compact. It's only really a problem if you race and are sprinting regularly.

For example, if you install a compact crank and are riding on the flat @ 90rpm, in 50/11...you'll be going 32mph. If you ride 50/12...you'll be going 29.3mph.

If you had a standard chainring (53) under the same conditions, you'd be doing 33.9mph and 31.1mph respectively. A drop of 6%. How often are you cranking these speeds?

That being said, if you are not planning any other major climbing trips...I'd get get a 27 and stick with a standard chainring for the new bike.

 

[sideshow_bob]

I'd say a 39 should be fine. I am no pro by any means and have never climbed Alp d'Huez, but I'd put a 39-27 on. You should be fine. No sense in putting a compact crank on because when you get home you will be in the 50 wondering why you didnt put on the standard set

huh? alp d'huez is give or take 10km at 10%. a lot of very good cyclists won't get very far in 39/27.

if you want a lasting memory of a spectacular ride and not a suffer fest that you cursed the whole way up stick on a set of compacts.

there is virtually zero difference in gear inches in a cog for cog comparison between a 50 with an 11-23 and a 52 with a 12-25. So by all means if you race now and Boonen like give the highest gear 52/12 a workout, then maybe you'll feel like you're missing something, otherwise it'll be just fine. I race around 70 events a year, and while I'm not a sprinter per se, I do okay in bunch finishes. The number of times I'm sprinting to the line in 52/12 is umm ... virtually never.

--brett

 

[alienator]

If you're going to switch cranksets, you won't lose anything with a compact. I mean, there is no penalty, since, iffin' you want, you can always put a 53/39 on the compact, later, if you want.

On a big, long climb--one you've never done--you're better off erring on the low gearing side. I ride a 50/36 with a 12-25 in back, most of the time, and it doesn't cost me anything.....I like spinning over grinding anyway.

 

[Insaneclimber]

If you're going to switch cranksets, you won't lose anything with a compact. I mean, there is no penalty, since, iffin' you want, you can always put a 53/39 on the compact, later, if you want.

On a big, long climb--one you've never done--you're better off erring on the low gearing side. I ride a 50/36 with a 12-25 in back, most of the time, and it doesn't cost me anything.....I like spinning over grinding anyway.

This guy is right on the money. dont switch back and forth between cranks , you will only wear and damage them. get some compacts and change chainrings back and forth.

 

[bobbyOCR]

If you're going to switch cranksets, you won't lose anything with a compact. I mean, there is no penalty, since, iffin' you want, you can always put a 53/39 on the compact, later, if you want.

On a big, long climb--one you've never done--you're better off erring on the low gearing side

Exactly.

If you keep switching crankarms (I presume it is with the same BB. If its not, stick a compact on and leave it, way too much hassle) you could ris wearing out the interfaces and it would be frustrating having to readjust your derailleur every time you switch. Another reason to keep the same set of cranks is the fact that you may need to run a shorter chain with the few less teeth.
And yeah, put a 27 on the back to be sure you have enough low gears. alpe'd huez gradients would be nasty.

(I'm a ginder more than a spinner)

 

[Bob Ross]

It's not so much that switching cranks is "too difficult" but that -- in addition to all the good advice already proffered about how switching cranks too often can prematurely wear or damage the bottom bracket -- this the best justification for getting a second bike!

 

[Retro Grouch]

I replaced the standard crankset on my Klein with a compact in roughly an hour. That included relocating and readjusting the front derailleur, resizing the chain, removing and reinstalling the (cartridge) bottom bracket, and reprogramming my Flight Deck computer.

 

[youhaditcoming]

Maybe you could rent a suitable bike, at Grenoble for example, for your Alpe d'huez ride ? I've done that climb, if you are not fit enough you will suffer on either cranksets, on your cassette everyone seems to agree with a 26 or 27 or even 28.

Good luck !

 

[DCWD]

I replaced the standard crankset on my Klein with a compact in roughly an hour. That included relocating and readjusting the front derailleur, resizing the chain, removing and reinstalling the (cartridge) bottom bracket, and reprogramming my Flight Deck computer.

Wow! These have been some excellent responses. My fitness? I'm solidly a cat5 rider (like, 27th of 38 in the '06 state TT champs). I do hit 48kph on occasion (one of my goals for 2007 is to hold 54kph on the flats for at least 15 seconds; 50 kph for 60 seconds). But I have figured out that climbing is very different, indeed.

Ya'll have really hi-lited my concerns and squared up the answers nicely. Thanks. Really, since I'd like to do a few *significant* climbing events each year but always weeks or months apart, some kind of mechanical advantage is probably warranted to keep it fun. It also sounds like I could probably tune in a crank change in an hour or two, once I've done it a time or two; even have my LBS do it if it'll really only be a couple times each year. It's not out of the question.

Since this is for a new bike (I'm talking of dropping, like $3k or more), another bike for climbing is out of the question unless I hit the lottery. An extra $300 on a crank and a bit of elbow grease will have to do me. But it sounds like I can probably swing it that way.

 

[sideshow_bob]

It's not so much that switching cranks is "too difficult" but that -- in addition to all the good advice already proffered about how switching cranks too often can prematurely wear or damage the bottom bracket -- this the best justification for getting a second bike!

This doesn't apply to cranks using the external BB design. You can pop them out in less than a minute and there's no friction parts on the spindle so the off side crank slips off and on without needing a crank puller for example.

--brett