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Riding when I find time
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I have a 2000 Lemond Zurich (I've had it for 3 years) with original Ultegra drivetrain. Standard 52-39 Crankset and 12-25 (9-speed) cassette. I'm still new to riding and would like to change out some of these parts to get a better climbing ratio for the mountains in CO. What are my options? Today a shop told me there is only one cassette possible with a 12-27 and I would have to get a now chain and for a compact crankset there is only one that would fit an Ultegra 9-speed (why is that important for a crank?). Can't I just swap out to a 105 compact crank or is my stuff too old to be upgraded easily? I'm going to see another shop tomorrow to see what they say. Thanks for any advice.
 

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Cranky Old Bastard
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I don't know everything but can't see why you couldn't go with a 105 compact crank.
As long as the BB shell is 68mm the external bearings would work. That would give you a 50/34 combo that would really help your climbing.

If you then added an 11-28 cassette your low gear would be 34-28 instead of 39-25; much better.

Amazon.com: SRAM PG950 9-Speed Cassette: Sports & Outdoors


 

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Burnum Upus Quadricepus
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Anything can be done if you throw enough money at it.

The 6500 crankset uses a different bottom bracket than the contemporary cranksets, like the 5700 series. Thus, it's not the "speeds" per se, but rather, the other stuff Shimano changed at the same time. So in addition to the crankset, you'll need to replace the bottom bracket.

The FD will need to be lowered since the smaller diameter chainrings will be further away from the FD's current position.

The chain will need to be shortened because the smaller diameter chainrings use less of it, leaving too much slack to be taken up by the RD. Depending on how worn your chain is now, then perhaps it should be replaced. Worn chains skip on new gears, especially when climbing.

The standard cage 6500 RD is more limited than contemporary stuff WRT how much chain it can take up. This is what limits the size of the biggest cog in back. If you can find one, you could switch to a long cage 6500 originally designed for use with a triple, (or switch to an MTB RD) and use one of the contemporary 9-speed 11-32 MTB cassettes back there.

This would yield a 34-32 lowest gears, something you could probably climb trees with.
 

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Cycling induced anoesis
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The standard cage 6500 RD is more limited than contemporary stuff WRT how much chain it can take up. This is what limits the size of the biggest cog in back. If you can find one, you could switch to a long cage 6500 originally designed for use with a triple... and use one of the contemporary 9-speed 11-32 MTB cassettes back there.

This would yield a 34-32 lowest gears, something you could probably climb trees with.
This won't work. The difference between a RD-6500 GS and SS isn't so much the max cog capacity (28 versus 27T, respectively) as it is total tooth capacity/ chainwheel difference.

I think the better option for the OP would be to to go with a 5700 compact (Hollowtech ll) crankset/ BB and a new RD-5700-A SS (or similar) derailleur. He could then run a 30T (but probably 32) max cog.

A GS would only be needed if he opted for a triple.

Sources:
http://techdocs.shimano.com/media/t.../RD6500/SI-53Z0C_En_v1_m56577569830611842.pdf

http://techdocs.shimano.com/media/t...0A/SI-5XN0A-001-Eng_v1_m56577569830746860.pdf
 

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Cycling induced anoesis
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Tell that to the guy in my club who runs exactly that setup, and has been running it for years.
I've not seen 'the guys' bike or drivetrain set up, so can't comment other than to say there are a number of reasons why certain combinations work on certain bikes and won't on others (something like chain stay length can factor in).

That said, the sources I cited - Shimano's specs, although conservative, back what I've posted, so I'll stay with my recommendations to the OP.
 

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Registered
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I'm with PJ352. The difference between the two RDs is not the maximum tooth sprocket they can accommodate, but the chain take up. Both can accommodate, essentially (slight difference) the same large sprocket.

This isn't to deny brucew's friend's experience. There's a lot of variability in what will actually work in spite of the stated specs. But both the ss and gs RD's are made for conventional road cassettes, not mountain bike cassettes.

If a larger cassette is needed, the most fool-proof, and very cost-effective way to accomplish it is not to buy a longer cage road RD that might or might not work (you won't know until you try it), is to buy a Deore or better mountain bike RD of the 8 or 9 speed variety. They aren't very expensive, especially in comparison with replacing with a upper-end road RD. They work flawlessly with 9 speed shifters.
 
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