Old bike - best way to change gearing?
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Old bike - best way to change gearing?
I have an old Ross hybrid that I'm trying to make into a bad-weather road bike. The biggest problem is the gearing. It has a 48-38-28 triple up front, with a 14-28 6-speed freewheel in the back. I can change either the crank or the freewheel. Which is the better option?
3S-CM square-taper BB is good (a durn good thing since no replacement exists). Shimano SIS components (RD-TY20, FD-TY25, shifters). Rear shifter is indexed. Front shifter is friction. The crankset may not be Shimano - it is not marked at all (save for the arm length). It is stamped and riveted so no changing chainrings.
I've been scanning eBay for freewheels and 14-28 is readily available, but there's not much else out there in 6-speed with a wide ratio (13-21 seems a mite narrow). Harris website has some nice 7-speed groups, but I'd have to change the shifter.
I don't see much in the way of new cranksets with 130mm BCD and square-taper fixture. Haven't gone to eBay on these yet. Seems to me that the BB sets the chainline and just about anything with the desired tooth count (and square-taper) should fit, right?
3S-CM square-taper BB is good (a durn good thing since no replacement exists). Shimano SIS components (RD-TY20, FD-TY25, shifters). Rear shifter is indexed. Front shifter is friction. The crankset may not be Shimano - it is not marked at all (save for the arm length). It is stamped and riveted so no changing chainrings.
I've been scanning eBay for freewheels and 14-28 is readily available, but there's not much else out there in 6-speed with a wide ratio (13-21 seems a mite narrow). Harris website has some nice 7-speed groups, but I'd have to change the shifter.
I don't see much in the way of new cranksets with 130mm BCD and square-taper fixture. Haven't gone to eBay on these yet. Seems to me that the BB sets the chainline and just about anything with the desired tooth count (and square-taper) should fit, right?
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Last edited by DMF; 10-29-06 at 06:02 PM.
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Hmmm. Well, you might be thinking too hard or you are a real bicycle fanatic. Both are OK.
Why do you need to change? It would seem that you have enough range for most bicycle needs. What a luxury to have a triple on a road bike.
What are you trying to accomplish?
Why do you need to change? It would seem that you have enough range for most bicycle needs. What a luxury to have a triple on a road bike.
What are you trying to accomplish?
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To get up some speed, and to be closer to what I'm used to. I have a triple (52-42-30?) and 12:27 or 12:25 cassette on my road bike. 48/14 is way too low for a top gear, especially descending.
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Er. You're telling me that 92 gear inches, where 35mph @ 127rpm with that gear is not enough? Well even if you did swap it out for say a 11t low gear, you'll only be getting up to 45mph @ 127rpm
I mean, this is a hybrid right?
I mean, this is a hybrid right?
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How about answering the question?
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To get up some speed, and to be closer to what I'm used to. I have a triple (52-42-30?) and 12:27 or 12:25 cassette on my road bike. 48/14 is way too low for a top gear, especially descending.
Have you actually ridden this bike? An old heavy hyrbrid with wide tires is going to be a lot slower than a road bike.
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Originally Posted by DMF
To get up some speed, and to be closer to what I'm used to. I have a triple (52-42-30?) and 12:27 or 12:25 cassette on my road bike. 48/14 is way too low for a top gear, especially descending.
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Putting a high gear on a heavy bike with heavy wheels and fat tires won't necessarity make it faster without a lot of motor work.
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I guess a 28-38-48 crank is 110 BCD. You can get chainrings up to 54 teeth for that. I don't know where you looked but there are plenty of new and used square taper cranks around in all sizes.
I really don't know why you would want such tall gearing for this bike, but that's your call, not mine. Maybe it would be cheaper and more satisfying to find an old road bike that does what you want.
I really don't know why you would want such tall gearing for this bike, but that's your call, not mine. Maybe it would be cheaper and more satisfying to find an old road bike that does what you want.
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Harris Cyclery lists a 61 tooth chainwheel at 110 BCD... That shouyld give you a high enough gear for those bad weather descents...
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Originally Posted by operator
Phew, almost thought I answered something.
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Originally Posted by BluesDawg
I guess a 28-38-48 crank is 110 BCD.
I've pretty well decided that a new crank is the way to go. The chain needs changing anyway.
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Originally Posted by OLDYELLR
Putting a high gear on a heavy bike with heavy wheels and fat tires won't necessarity make it faster without a lot of motor work.
Tires are definitely due for a change! Once upon a time I had some road tires for it, but they haven't materialized yet. (Did find a set of 700x23c I didn't know I had, so the Lord taketh away with one hand and giveth with the other.)
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