PDA

View Full Version : Help! Low Gearing Advice Needed!



kfergos
07-01-2008, 01:02 PM
I need some additional opinions on my bike gearing situation.

I have a new (2007) cross bike with a compact double on the front (38/46T) and a 10-speed cassette (12-27) (additional specs here (http://www.lemondbikes.com/bikes/cross/poprad_disc.php)). I'd really like to have some much lower gearing for those climbing big, steep hills that I'm inexplicably attracted to. I seem to have a couple options:

1. Convert to a triple and get a nice low granny gear.
2. Convert the rear derailleur to a mtb one and put a mtb-geared cassette on there.
3. Get a smaller small chainring.

When I talked to my LBS, they said:
1. Converting to a triple will cost like $500 -- about 1/3 the total cost of the bike. Ick. They said I didn't have a compact on my bike right now, which confused me, because I really thought I did.
2. Converting to mtb stuff on the rear will also be expensive, because there aren't any 10-speed mtb cassettes. I'd have to get a new shifter, etc. to accommodate a 9-speed cassette.
3. There aren't smaller small chainrings that would fit on my bike.

I very recently replaced my cassette and chainrings, so I'm kind of reluctant to make any major changes this go-round, but for the next time everything wears out, what are other options I might have?

ilima
07-01-2008, 01:36 PM
Bontrager's website doesn't say, but it looks to me like the GXP crank on your Poprad is a standard, not compact, crankset. 38 teeth is the smallest you can go with those. Pretty dumb move on Bontrager's part, IMO.

One issue you have with a mountain cassette is that mtn cassettes and derailleurs are 9 speed. IRD does make a 10-speed mountain cassettes http://www.interlocracing.com/cassettes_steel.html and I believe that you can make a 9sp derailleur go to 10. For example, Terry's Isis sport is a 10-speed but uses as IRD mountain cassette and Deore LX derailleur.

Functionally (in terms of gear inches), switching to a triple (30 tooth smallest ring) with your current cassette OR switching to a 34-tooth mountain cassette with your current cranks are going to be the same.

While I think $500 seems high for a new crankset, getting a mountain cassette and derailleur is going to be considerably cheaper. I recently bought a Deore LX SGS (super long cage-you might not need with a double up front) for like $30. The cassette is going to run you considerably more, though, probably over $100. And you'll probably need a new chain.

7rider
07-01-2008, 02:08 PM
I think converting to a triple would require a new front derailleur and shifter....that may be where some of the expense is (and that may make a $500 pretty cheap, actually).
Still, can't you put a road compact crankset on it (a 50/34)? I don't think that would require anything other than the cranks. You could get a compact crankset - for instance the FSA Gossamer with a MegaExo BB (http://road.fullspeedahead.com/fly.aspx?layout=product&taxid=53&pid=146)for pretty cheaply I would think...
ETA: http://www.performancebike.com/shop/profile.cfm?SKU=21957&subcategory_ID=5122

ilima
07-01-2008, 02:16 PM
Oh, you're right. My Ultegra 9-speed shifters can be double or triple, but I think the 10-speeds are specific.


I think converting to a triple would require a new front derailleur and shifter....that may be where some of the expense is (and that may make a $500 pretty cheap, actually).
Still, can't you put a road compact crankset on it (a 50/34)? I don't think that would require anything other than the cranks. You could get a compact crankset - for instance the FSA Gossamer with a MegaExo BB (http://road.fullspeedahead.com/fly.aspx?layout=product&taxid=53&pid=146)for pretty cheaply I would think...
ETA: http://www.performancebike.com/shop/profile.cfm?SKU=21957&subcategory_ID=5122

tulip
07-01-2008, 02:43 PM
For a cheap solution, I'd go with a 34 cog, but you might not like that big jump to the easy gear.

I had a similar situation with my Luna. I originally had a double--don't remember the up front gearing, I guess standard 42-52 or something like that--but 11-23 cassette (for some reason, don't ask me why). Well, that certainly wasn't going to do me much good, and I became acutely award of that while visiting my brother in Asheville and riding with him. Yikes.

I got a new cassette, 12x27. Not good enough.

I called around about compact double vs. triple, and the triple would cost alot more because it involved the derailleurs. I paid $300 to have a bike shop install a compact double, and it's been great. I kept the 12x27 in the rear, but the up front change is fine for the riding I do. Got me up Skyline Drive on the Blue Ridge Parkway, and that's as much as I expect to do with my bike. No Alps or Rockies for me.

Good luck and let us know what you decide on.

redrhodie
07-01-2008, 03:14 PM
I have an 11-32 10 speed IRD cassette that's Shimano compatible. Since I have a compact double with a triple front derailleur, I didn't need a MTB rear derailleur.

http://www.interlocracing.com/cassettes_steel.html

I have this on my road bike. Sorry I don't know if it will work on your cross bike or not, but worth checking out as an option.