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Discussion Starter #1
I'm building up my girlfriend's Gunnar roadie and need a crank and cassette. Since previously she has used a triple I need something that will give her the lower range like a triple and if it sacrifices top-end that okay she never uses the big ring - 12t combo anyhow. We've looked into compacts, I wanted to go with a 50-36 to keep the jump between rings the same as 53-39 but options are limited. So I got to scribbling a little math out and realized that with a 53-39 crankset and a 13-29 rear derrailer it would give her a lower gear than a compact with a 12-25 and not give up much in top-end. Also the jumps between gears would be slightly less than with the 50-36x12-25 setup. Sounds good to me. Here's the rub...#1 Am I missing something, and this would actually be inadvisable? #2 Where to buy a 13-29 cassette for shimano? I've seen Campy ones but that's no good for me. Thanks a lot! I'll post a pic when it's done, maybe even with her on it! :D
 

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Doesn't exist as a "standard item.......
Just get a compact crank.
 

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Discussion Starter #5
Just get a compact crank....Thanks, pretty sure I'd outlined why that way would not be preferable both in cost and performance..

I had heard Sheldon Brown did some special cassettes, I'll look into it. I noticed that 10speed Ultegra has come out with some wider range cassettes now and thought maybe something had exsisted for 9spd that had slipped past me. Off to harriscyclery! :)
 

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In recent years, Shimano has never offerred a road cog larger than 27 teeth. You need to specify 9 speed or 10 speed? If 10 speed, one option is to use the Campy cassette with one of those Campy/Shimano cable converters. Another 10 speed option is the IRD 12-28 if you can downsize 1 tooth.
 

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Put a mountain bike cassette on with an XT rear derailleur. Simple to do, and bolts on without a hitch. you can get a huge range out of it as well.

What about having a triple up front?

The Flash
 

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Discussion Starter #8
It's Shimano 9spd. Pretty much all 105 kit. Looking at qbp online catalog it appears you can buy individual cogs. I already had her a 105 12-25 cassette, I need to look at it and if I can take it apart, I could swap in a couple larger cogs. I could put a 27 and a 30 on, or a 28 from a mtn cassette. I think something like that can work. The 13 isn't really the issue, so the 12 could stay. I'm just looking for a "bailout" gear for her.

No triple. She's got a bike with a triple and she thinks it makes her a wuss. She wants a double on this one for purely aesthetic reasons really. Sometimes a pretty bike is important! I'm just glad she rides, so whatever makes her like her bike more is good in my opinion.

I don't know we might still do the TruVativ Rouleur Compact because it comes in 50-36. No big hurry, I've still got to build the wheels but I figured I'd start looking for the drivetrain now.
 

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So she needs a bailout gear, but won't use a triple because she thinks she'll be a "wuss"????? If she can't handle the gearing, she shouldn't be riding...get a new girl, or tell her to go to the gyms some more....

Flash Out!
 

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TACSTS said:
I already had her a 105 12-25 cassette, I need to look at it and if I can take it apart, I could swap in a couple larger cogs. I could put a 27 and a 30 on, or a 28 from a mtn cassette. I think something like that can work. The 13 isn't really the issue, so the 12 could stay. I'm just looking for a "bailout" gear for her.
You'll probably end up doing whatever you want to do, but what she really needs is 13-30 in order to have something that works well. You would keep the 14-21 cogs and you'd need a new 13 (with spacer), 24, 27 and 30 which would set you back $50 at Harris.
 

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TACSTS said:
It's Shimano 9spd. Pretty much all 105 kit. Looking at qbp online catalog it appears you can buy individual cogs. I already had her a 105 12-25 cassette, I need to look at it and if I can take it apart, I could swap in a couple larger cogs. I could put a 27 and a 30 on, or a 28 from a mtn cassette. I think something like that can work. The 13 isn't really the issue, so the 12 could stay. I'm just looking for a "bailout" gear for her.

No triple. She's got a bike with a triple and she thinks it makes her a wuss. She wants a double on this one for purely aesthetic reasons really. Sometimes a pretty bike is important! I'm just glad she rides, so whatever makes her like her bike more is good in my opinion.

I don't know we might still do the TruVativ Rouleur Compact because it comes in 50-36. No big hurry, I've still got to build the wheels but I figured I'd start looking for the drivetrain now.
I think the best bet is indeed a compact crank. cobbling your own cassette together is a pain, and it won't shift as well as stock. you might have big gaps in between cogs. and lastly, when it comes time to change the cassette, you'll have to go through the whole process again. you can always get a 50-34 compact and change the chainring. oh, and you can get a 12-27 cassette to go with that, which will give her a pretty low gear. a 9s 12-27 is basically the same as a 12-25, except that the last 3 cogs are 21, 24, 27 as opposed to 21, 23, 25. a 10s 12-25 and 12-27 are the same as 9s, except that 10s also has a 16t cog.
 

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I combined an 11x28 with a 12x25 to make a 12x28.
Shifts just fine and with the unending hills around here, it helps.
 
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