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Discussion Starter · #1 · (Edited)
I just bought a Trek 5.2 Madone with the compact crankset (50/34 with 12-25). I'm coming from a triple (50/39/30 with 12-27). I want my lowest gears back. LBS has suggested an 11-28 cassette. What do you think?
 

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I can't advise you what cassette would best match your prior gearing, since you didn't say what it was. But here's a link to a gearing chart. Find what your low gear was, and look for what size cassette sprocket would be the nearest match using your new inner chainring.
 

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Lowest as in everything that was working with the 30 chainring?

With your compact crankset, and Sheldon Brown's calculator, I'll point this out:
-In the photo below, I compared gear inches between the 30 and 34 rings, when paired with 32,30,29,27,26,25,23,21,29,18 cogs. This is to see how things stack up whether you pick an 11-32 cassette, or 11-28 cassette.
-I crossed out 30x32, 30x30, and 30x28 since you never had those combinations (using an 12-27 as you say)
-Those green lines are there to somewhat "match" gears. In terms of gear inches, the smallest the 11-28 cassette would offer when paired with your compact (34x28) is only as small as your previous 30x25 combo.
-If you get an 11-32 cassette, you will be able to go just as/lower than your 30x28.

You really have to decide if you need such gears, because sometimes, an 11-32 cassette installation typically demands a longer cage RD. I don't know how your legs are, but I bet you can muscle to an 11-28 no problem. :thumbsup:
 

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Discussion Starter · #5 ·
35.9 - 29.3 = 6.6
6.6/35.9 = 18% loss

Can that be correct? I'm math challenged so I don't trust my conclusions.

32.0 - 29.3 = 2.7
2.7/32 = 8% loss

Other than to be "cool," why would I give up my triple? BTW, I'm not 50 anymore.
 

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Trek2.3 said:
35.9 - 29.3 = 6.6
6.6/35.9 = 18% loss

Can that be correct? I'm math challenged so I don't trust my conclusions.

32.0 - 29.3 = 2.7
2.7/32 = 8% loss

Other than to be "cool," why would I give up my triple? BTW, I'm not 50 anymore.
Not sure about your math, but how often did you rely on the 30x23 to 27 range?
 

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Larry Lackapants
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Trek2.3 said:
35.9 - 29.3 = 6.6
6.6/35.9 = 18% loss

Can that be correct? I'm math challenged so I don't trust my conclusions.

32.0 - 29.3 = 2.7
2.7/32 = 8% loss

Other than to be "cool," why would I give up my triple? BTW, I'm not 50 anymore.
So why would you give up your triple? :)
Normally people would do that if the 30 ring was overkill. Or if the 53 and 52 rings would rarely be used..
If you can't move your triple over, or replace the current crank with a triple for free / little cash, the cassette change might be the cheapest option though.

A shimano RD might work up to a 30T cog
 

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Trek2.3 said:
Other than to be "cool," why would I give up my triple? BTW, I'm not 50 anymore.
You should have thought about that before you bought the new bike.


You can get a long cage rear derailleur (use a 9sp mtb one if you're on shimano, or an Apex if you have Sram) and a wide range cassette. There are plenty in the {11,12}-{30,32,34} range.
 

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Discussion Starter · #11 ·
ericm979 said:
You should have thought about that before you bought the new bike.
Not at the price I paid. Besides, "everyone" said "get a compact, you'll love it."

Now, I just have to find someone with a lightly used Ultegra triple who wants to be "cool" and upgrade. Them we swap parts at no cost. That person is out there.
 

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I made almost the same switch on my new bike- I had a 50/34 with 12-32. I used an Ultegra long cage, but even with that the clearance between the pulley and my 'pie plate' was very tight. There was a lot of bounce/chain slap against the stay when in the smaller cogs and getting the trim right was tricky. My new Gary Fisher has a compact w/ an 11-28 in back. Some days I wish I had my old 'bail-out' gear, but I'm still getting up the hills and getting stronger. Get the 11-28 if that's what you want. And read the 'compact crankset' threads about double-shifting. BTW I'm way over 50.
 

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Trek2.3 said:
I just bought a Trek 5.2 Madone with the compact crankset (50/34 with 12-25). I'm coming from a triple (50/39/30 with 12-27). I want my lowest gears back. LBS has suggested an 11-28 cassette. What do you think?
If you're not strong enough to climb with a 34x28, you're not strong enough to need a 50x11 or even 50x12.

For less money through something like a 13-29 on there.

For more money switch to a triple, perhaps exchanging derailleurs between old and new bikes.
 

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Drew Eckhardt said:
If you're not strong enough to climb with a 34x28, you're not strong enough to need a 50x11 or even 50x12.

For less money through something like a 13-29 on there.

For more money switch to a triple, perhaps exchanging derailleurs between old and new bikes.
13-29 is a Campy cassette, isn't it? Is that going to be at all compatible with his Shimano brifters? :idea:

SRAM now has a 12-28 out (or will shortly) and their stuff is shimano-compatible. That could also be an option, and a superior one to the 11-28 IMO, as the huge jump from 15-17 is removed, and there's no wasted 11t.

And 34x28 is a pretty farkin' low gear... if I were the OP, I'd at least try it and see.

The 11-32 cassette idea mentioned elsewhere isn't that appealing, IMO. First off, SRAM chose some odd ratios on that one ("let's preserve the 11-12-13, but then give you a big fat jump from 19 to 22"... wha?). The new Shimano 10-spd MTB cassettes are actually more logical in their progressions.

Secondly... if your cassette has got 2-tooth jumps through most all of your go-to flatland gears, that slightly blows, unless you're running some sort of 6- or 7-spd retro rig intentionally. But for modern road-riding purposes, with 10 or 11 cogs potentially on tap, it sort of becomes like... why? Isn't this the reason we went to 10 or 11 cogs in the first place, to avoid having these kind of jumps? :nonod:
.
 

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Discussion Starter · #16 ·
I just bought a Mitche 29 and I'm going to pull the 12 and substutute it (at the opposite end of the cassette, of course). That will give me 13-29 and an uphill range near my 12-27 triple.
 

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You will probably run into the problem of locking down the cassette properly. Unless the lock ring is specific for a 13 tooth gear, it might not be secure. The lockrings are small gear specific. One for an 11 tooth, one for a 12 tooth.
 

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frdfandc said:
You will probably run into the problem of locking down the cassette properly. Unless the lock ring is specific for a 13 tooth gear, it might not be secure. The lockrings are small gear specific. One for an 11 tooth, one for a 12 tooth.
I don't know of any 13t specific lockrings. There are special ones for 11t, and standard ones for 12t and bigger.
 

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FBinNY said:
I don't know of any 13t specific lockrings. There are special ones for 11t, and standard ones for 12t and bigger.

I have never seen a 13t lock ring either. Hence what I posted. But also did not know if the 12 lock ring will work with a 13 tooth.
 
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