Bicycle Mechanics - Converted MTN bike into commuter, needs taller gears...
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05-04-06, 10:08 PM
I recently converted my old school hardtail Cannondale mountain bike over to a road only commuter bike. I need some higher gears as 44-12 is the highest combination I now have. Does anyone have any recommendations for swapping out either front, rear or both drive train components for something that will give me more top end gears while still maintaining enough low end for the occasional hill I encounter on the way into work. My current set up is as follows:
LX 9 speed shifters
XT front derailleur 44/32/22 chain rings
XT rear derailleur 12/32 cassette
Can I put a road crankset up front? Will I have to swap out the front derailleur too? Will it work with my shifter? Then there is the whole 26Ē versus 700c wheel diameter issue. Plus my frame was made back in the days of the 7 speed cassette and I donít think I can go as small as 11. The 12 barely allows the chain to clear the stay and there is evidence of rubbing, so I try to stay out of that gear now as it is. I have been building bikes for years (30+) and can handle the mechanical part fine. I just need some advice on mixing/matching road and mountain components to achieve my desired results. Any help would be greatly appreciated. Thanks!!
05-04-06, 11:10 PM
I had the same problem.
I assume your bike has a square taper bottom bracket since it is so old. If so, you might consider getting a 110 bcd crankset, in particular, the Sugino XD. They are quite cheap and come with a 46 tooth ring for the large chainring. You may already have a 110 bcd crankset due to the age of your bike, in which case you could just replace the chainrings with larger ones. Usually front derailleurs have a maximum capacity specification ( the difference in the number of teeth between the largest ring and the smallest ). Also there may be a specified minimum for the difference between the large and middle chainring for the front derailleur to work properly. For commuting I like 48-36-26.
A road crankset might not work on a mountain bike due to the wider spacing of the chainstays. This can cause the rings or the crank arms to strike the chainstays.
I feel your pain of being too slow on the road. I changed my chainrings up a bit before I eventually turned my mtb into a single speed. I found a 46T chainring for my shimano compact (94 bcd?) cranks. Then again, that was a big jump for me since I was going from 42/11 to 46/11. I'm thinking that if you can find a 48T ring it might be worthwhile, otherwise only going up 2 teeth probably won't be enough of a change. If you can find a way to fit an 11T cog on, I think that would be the best solution. Wouldn't the 11 give the chain more room compared to the 12? If not, would it be possible to put something like a 1mm space on the axle and spread the frame a touch for more room? I'm assuming it's a steel bike, so that shouldn't be a problem. Someone please let me know if that's a stupid idea, and if so, why.
As for the wheel idea, can you even fit 700 wheels? MTBs wheels that large are called 29" instead of 26", so you'd probably have trouble with frame clearance and brake mounting.
oh, if the spread between gears bothers you, I had also swapped out my cassette from an 11-28 to an 11-23. with the granny gear, 22/23 or 22/25 should be low enough unless you are super loaded down or have gigantic hills. 22/32 is just ridiculous on the road! ;)
05-05-06, 12:20 AM
Honestly you guy's must be a bunch of grinders because 44-12 x 26" =95 gear inches and honestly that's high enough for commuting.
OK I've just read your post again and if your not actualy using 44-12 and your using 44-14 well then it makes a little more sense. 44-14 is only 81 gear inches and that's not high. Good gear to learn to spin on though.
Yes you can fit a road triple crankset. I've done it before and had no issues despite all the warnings. I would look at sorting out the cassette first though. See if you can fit a thin spacer on the axle to stop any chain rub so that the smallest sprocket is usable. With a 22 t chainring I would be fitting a close ratio road cassette at the back for a better selection of gears but you will still have say 22-23 for hill climbing which is honestly small enough on the road.
05-05-06, 12:39 PM
I feel your pain! I commute on my old MTB and have a top gear of 46/12 with a 26x1.4 slick. I often spin out on the downhills but since I'm not racing, I don't feel a need for a taller gear.
1) If your freehub is Hyperglide, 11T will work and that's what I recommend. If its a Uniglide freehub or a freewheel, 12T is the smallest you can go. It is, however, possible to swap a Uniglide freehub to a Hyperglide freehub.
2) I'd insert a 1mm axle spacer in the drive side and see if that gave enough clearance to use the smallest cog.
3) You can also look for bigger chainrings for your current crank. I found a 46T for my 94mm/58mm BCD 5-arm crank (which was 42x32x22 originally). You could also put on a 110mm/74mm BCD triple but that will cost more.
4) If you're running a narrow slick, you could also get a wider one. A 26x2.1 slick will give you a gear about 7% bigger than a 26x1.25.
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