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Old 11-10-10, 05:43 PM   #1
chuckb
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Gearing change. Does this sound feasible?

I'm contemplating switching from an Ultegra Triple (53/39/30 and 12/27 on a 2003 Trek 5200) to a compact double (50/34 and 11/28), and trying to do it on a budget.

The objective is to duplicate a friend's very nice SRAM Red setup that has the same gearing (although in a 10-speed configuration). It has basically the same gear range and it looks like there is a lot less double-shifting.

I have a 50/34 Ritchey compact crank and bottom bracket that was once on my bike, so I know it works.

I found a "Shimano compatible" SRAM PG-950 11/28 cassette for $27 and ebay has Shimano Ultegra FD for around $30.

A few questions:

1. Do I need to swap the triple FD for a double?
2. The triple setup has a long cage RD. Can that be swapped for a short cage? Any benefit to that, other than cosmetic.

I'm hoping to take this to the local REI, which has good labor rates on things like this, and get them to do the swap.

Advice, critique, suggestions appreciated!
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Old 11-10-10, 05:49 PM   #2
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For now, you don't have to swap either derailleur, especially since you're on a budget. You'll need to move the FD down a bit, and double check that the chainring spacing (separation) is the same or close on both the new and old cranks, and you'll use the two outer positions on the lever, leaving a phantom granny position, which you'll lock out via the limit screw. It's possible you'll have to use a longer inner limit screw to meet this objective.

You can always use a longer cage RD where a short one works, the only penalties being a very marginal loss of performance, some extra weight (including more chain that you'd otherwise need) and lower ground clearance, none of which matter a great deal. If you have extra cash to blow, an FD better matched to the new crank might be nice, but only if you find one really cheap.
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Old 11-10-10, 05:51 PM   #3
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You want to change from a triple to a compact double in order to reduce double shifting?

What's your favorite flat road gear in gear inches? Where is that gear combination going to fall with your compact double set up? If it falls in the middle of the cassette, you're good. If it happens to fall near the end of the cassette you are going to find yourself doing a lot more double shifting than you are now.
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Old 11-10-10, 05:58 PM   #4
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Retro Grouch raises a good point. Are you matching your friend's double because you think it'll be better for you, or because you've actually ridden and prefer it?

My earlier response was from a purely technical aspect, but you should borrow your friend's bike and decide you prefer the arrangement before you spend dough copying it.
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Old 11-10-10, 07:10 PM   #5
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if i were you, i'd stick with the triple. save cash, enjoy the extra(neous) range, love life. if you were building a new bike, or if your triple was trashed, i'd advocate the double, but there's the ol' adage: if it ain't broke...

but, while we're talking about saving cash, why not invest in some tools and ditch rei/lbs labor rates? it's a bike, which is a fairly simple machine...

-rob
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