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Old 09-21-05, 07:45 AM   #1
Baldanzi
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Lower Gear Options?

My trusty old Giant road bike (1990 vintage) is rapidly becoming my commuting bike. Its a great cromoly frame and very comfortable for me. Here's the thing: on my commute there are some hills...a very steep one on the way home. If it were not for them I'd be building a cool fixed gear/singlespeed with fenders. Right now the bike has a full Suntour Cyclone group (non indexed down tube shifters):

6 speed 12-24 in the back
52/42 chainrings up front

As the lowest cost option to get some lower gears, can I put a 39 up front and not have shifting problems? I want to avoid dumping too much $ into this right now. I want to avoid having to get a long cage in the back or buy a new crankset. Plus the small ring is slightly bent and worn anyway, so can a simply put a 39 there with no big impact? I know the ratio will not be significantly better but I only want a little bit.
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Old 09-21-05, 07:55 AM   #2
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What you can use for a small ring depends on the BCD. 39 for a 135 and 38 for a 130BCD. Sheldon Brown at www.harriscyclery.com has how to measure.Also easy enough to switch to a 28 cog freewheel which the RD should handle.
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Old 09-21-05, 07:56 AM   #3
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If the crank is 130 mm BCD, then 38T is the smallest chainring you can use and you shouldn't have any shifting problems (or any more than you have now), particularly with non-index dt shifters.

38T or 39T chainrings are readilly available and your LBS may be happy to get rid of an old style flat (no pins or shifting ramps) ring at low cost.
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Old 09-21-05, 08:24 AM   #4
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Thanks for the feedback! Another option might be to just ditch the FD and go with one cog up front, but that would probably mean a new crank. I'll stop by the LBS and grab an old 38 or 39 after I confirm 130 or 135mm.
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Old 09-21-05, 10:27 AM   #5
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Quote:
Originally Posted by Baldanzi
My trusty old Giant road bike (1990 vintage) is rapidly becoming my commuting bike. Its a great cromoly frame and very comfortable for me. Here's the thing: on my commute there are some hills...a very steep one on the way home. If it were not for them I'd be building a cool fixed gear/singlespeed with fenders. Right now the bike has a full Suntour Cyclone group (non indexed down tube shifters):

6 speed 12-24 in the back
52/42 chainrings up front

As the lowest cost option to get some lower gears, can I put a 39 up front and not have shifting problems? I want to avoid dumping too much $ into this right now. I want to avoid having to get a long cage in the back or buy a new crankset. Plus the small ring is slightly bent and worn anyway, so can a simply put a 39 there with no big impact? I know the ratio will not be significantly better but I only want a little bit.
As others have mentioned, you could go to 38. Your crank won't be a 135, that's the oddball Campagnolo size. It's going to be 130.

See: http://harriscyclery.com/130

However, the "lowest cost option to get some lower gears" would be to replace the freewheel. I'm guessing you really don't use the 12 all that much. I'd go with a 14-28 or 13-28, most likely a 7-speed, since you don't have any indexing issues to deal with.

See: http://harriscyclery.com/freewheels

Sheldon "Low Gears" Brown

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Old 09-21-05, 10:46 AM   #6
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[QUOTE=Sheldon Brown]As others have mentioned, you could go to 38. Your crank won't be a 135, that's the oddball Campagnolo size. It's going to be 130.

See: http://harriscyclery.com/130

However, the "lowest cost option to get some lower gears" would be to replace the freewheel. I'm guessing you really don't use the 12 all that much. I'd go with a 14-28 or 13-28, most likely a 7-speed, since you don't have any indexing issues to deal with.

See: http://harriscyclery.com/freewheels

Sheldon "Low Gears" Brown

I was just looking at your site - again - (I've been there a lot recently reading stuff). A 13-28 would be fine...as long as I don't need a new RD?

My bike is an old Giant/Schwinn (not too sure as I bought it used after a custom repaint by HH racing - that's a whole other story...I really don't know what this bike is, all I know is I like it and want to keep it). It has a 6 speed freewheel...can I go to 7?

If it wasn't for the killer hill on the way home, I'd do a fixed or single speed. That would make a much more reliable commuter......

Thanks for the input!!
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Old 09-21-05, 11:05 AM   #7
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As others have mentioned, you could go to 38. Your crank won't be a 135, that's the oddball Campagnolo size. It's going to be 130.

See: http://harriscyclery.com/130

However, the "lowest cost option to get some lower gears" would be to replace the freewheel. I'm guessing you really don't use the 12 all that much. I'd go with a 14-28 or 13-28, most likely a 7-speed, since you don't have any indexing issues to deal with.

See: http://harriscyclery.com/freewheels

Sheldon "Low Gears" Brown
Quote:
Originally Posted by Baldanzi
I was just looking at your site - again - (I've been there a lot recently reading stuff). A 13-28 would be fine...as long as I don't need a new RD?
Your present derailer should handle a 28. If you want something bigger, a new derailer would be the way to go. Derailers are dirt cheap these days, and you can buy a much better one brand new for $30 or so.

You will need a new chain...should always replace the chain when you replace the cluster.

Quote:
Originally Posted by Baldanzi
My bike is an old Giant/Schwinn (not too sure as I bought it used after a custom repaint by HH racing - that's a whole other story...I really don't know what this bike is, all I know is I like it and want to keep it). It has a 6 speed freewheel...can I go to 7?
Yes, that's why I suggested it.

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Old 09-21-05, 12:05 PM   #8
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Just to offer another perspective... If it really is a killer hill (very long, very steep), then even a 38/28 may not be low enough for you especially if you're packing a heavy commuter load. But if it's just "inconvenient", then you could simply approach it differently. I have a reasonably steep hill in my commute that I think of as "good exercise." I purposely stay withinin one or two gears and stand up to take the hill. Since it's on the way home you don't have to worry about getting sweaty. Maybe think of it as your workout.
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Old 09-21-05, 12:19 PM   #9
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Quote:
Originally Posted by dbg
Just to offer another perspective... If it really is a killer hill (very long, very steep), then even a 38/28 may not be low enough for you especially if you're packing a heavy commuter load. But if it's just "inconvenient", then you could simply approach it differently. I have a reasonably steep hill in my commute that I think of as "good exercise." I purposely stay withinin one or two gears and stand up to take the hill. Since it's on the way home you don't have to worry about getting sweaty. Maybe think of it as your workout.
I agree completely...in fact I love hammering up that hill on the way home. I was overseas for work for the summer living off an expense account. I came home to sky-high gas prices and a bigger waist (due to said expense account and lots of Italian food!!). I started commuting by bike to save $ and get back in shape. 4 weeks later I can actually go up the hill without killing myself, but I still have to mash the pedals a bit. That's why I thought about changing the small chainring only (since it's bent anyway). It'll change my lowest from a 94 inch gear to a 83 inch gear (about). That should be enough of an improvement to help a little. I really love the bike commuting thing...the other day I got up one of the hills on the way in to work, I felt tired, thought that it was a bit tougher than usual (lack of sleep?)...looked down to see that I was in the middle cog in the back! There is no way I could have done that just 3 weeks ago. Hills are good for you! I just want to make this one a little easier (there is a short 11% grade section).

-Thanks
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Old 09-21-05, 12:32 PM   #10
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"Do not go gentle into that steep hill."
Sneer at it. Make it insignificant. Chew it up and spit it out.
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Old 09-21-05, 02:15 PM   #11
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Quote:
Originally Posted by Sheldon Brown
As others have mentioned, you could go to 38. Your crank won't be a 135, that's the oddball Campagnolo size. It's going to be 130.
I have a suntour cyclone that is 144 BCD.IIRC I had some other japanese stuff, some possibly suntour Cyclone, that was 135.That's why I got rid of it.Never hurts to measure.
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Old 09-21-05, 07:33 PM   #12
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Quote:
Originally Posted by sydney
I have a suntour cyclone that is 144 BCD.IIRC I had some other japanese stuff, some possibly suntour Cyclone, that was 135.That's why I got rid of it.Never hurts to measure.

I'd be very surprised if Sun Tour was making 144 or 135 BCD cranks by 1990. But, as you said, measuring is good.

BTW, to the OP: the lowest gear now on the bike (42x24) is 47 gear inches. Going to a 38x24 will give 43 gear inches, a 42x28 would be 40.5 gear inches and a 38x28 would be 36.6 gear-inches.

Your current high gear at 52x12 is 117 gear-inches and a 52x13 would give 108 gear-inches.
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Old 09-21-05, 08:02 PM   #13
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Quote:
Originally Posted by HillRider
I'd be very surprised if Sun Tour was making 144 or 135 BCD cranks by 1990. But, as you said, measuring is good.

.
I'd question the originalty of the stuff on it even if it really were 1990.
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Old 09-22-05, 08:34 AM   #14
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Quote:
Originally Posted by HillRider
I'd be very surprised if Sun Tour was making 144 or 135 BCD cranks by 1990. But, as you said, measuring is good.

BTW, to the OP: the lowest gear now on the bike (42x24) is 47 gear inches. Going to a 38x24 will give 43 gear inches, a 42x28 would be 40.5 gear inches and a 38x28 would be 36.6 gear-inches.

Your current high gear at 52x12 is 117 gear-inches and a 52x13 would give 108 gear-inches.
Your right about the gear inches I goofed...I copy-pasted the wrong stuff over and never checked...I grabbed the 42-12 vs 38-12 number - doh! Those are combos you'd never use!
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