First MTB conversion. Advice and recommendations needed.
08-11-19, 04:48 PM
#1
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First MTB conversion. Advice and recommendations needed.
I just picked up a 1994 Marin Muirwood mountain bike that I'm hoping to convert to more of a utility rider. The plan is to put some slicker tires on it, bull horns, rack, fenders, and ditch the front derailleur.
The first thing I noticed is that I'll need a new crankset. Looking for just a single ring.
The second thing I noticed is that this bike has a Shimano Alvia system I'm unfamiliar with. The shifters are attached to the brake levers. If I ditch the front derailleur I'd need new levers and shifters.
Open to suggestions on tires that will fit a 1.5 wide rim, and what a decent low cost shifting system would be to make this a 7 speed.
The first thing I noticed is that I'll need a new crankset. Looking for just a single ring.
The second thing I noticed is that this bike has a Shimano Alvia system I'm unfamiliar with. The shifters are attached to the brake levers. If I ditch the front derailleur I'd need new levers and shifters.
Open to suggestions on tires that will fit a 1.5 wide rim, and what a decent low cost shifting system would be to make this a 7 speed.
08-11-19, 04:57 PM
#2
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Haha, I was just at Muir Woods yesterday. Ironic name. They'd never let you ride a MTB there, it's a hiker shrine. This doesn't look anything like the MTB's people were grinding up to nearby Mt Tamalpais.
You usually do not need a new crankset, you can find a single ring that will fit on it. Just before 4-arm cranks there was briefly a weird BCD that was smaller than 110, that one might be difficult. You can just pull the cable out of the left shifter. If it has less than a 32t rear cassette you can get a little more range that way. But 12-32 is still just not very much. If you accepted a 55 inch top gear (bmx equivalent) that would give you a pretty good 21 inch low.
You usually do not need a new crankset, you can find a single ring that will fit on it. Just before 4-arm cranks there was briefly a weird BCD that was smaller than 110, that one might be difficult. You can just pull the cable out of the left shifter. If it has less than a 32t rear cassette you can get a little more range that way. But 12-32 is still just not very much. If you accepted a 55 inch top gear (bmx equivalent) that would give you a pretty good 21 inch low.
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08-11-19, 05:19 PM
#3
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Haha, I was just at Muir Woods yesterday. Ironic name. They'd never let you ride a MTB there, it's a hiker shrine. This doesn't look anything like the MTB's people were grinding up to nearby Mt Tamalpais.
You usually do not need a new crankset, you can find a single ring that will fit on it. Just before 4-arm cranks there was briefly a weird BCD that was smaller than 110, that one might be difficult. You can just pull the cable out of the left shifter. If it has less than a 32t rear cassette you can get a little more range that way. But 12-32 is still just not very much. If you accepted a 55 inch top gear (bmx equivalent) that would give you a pretty good 21 inch low.
You usually do not need a new crankset, you can find a single ring that will fit on it. Just before 4-arm cranks there was briefly a weird BCD that was smaller than 110, that one might be difficult. You can just pull the cable out of the left shifter. If it has less than a 32t rear cassette you can get a little more range that way. But 12-32 is still just not very much. If you accepted a 55 inch top gear (bmx equivalent) that would give you a pretty good 21 inch low.
08-11-19, 05:22 PM
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Some things to keep in mind regarding cost. These are rarely cheap to do right if you are truly planning to use it for utility.
-Bullhorns, like drop bars, greatly extend the reach over flat bars. Mountain bikes are designed with long top tubes to accommodate the short reach of flat bars, so usually when you put dropbars or bullhorns on a flat bar bike you will need a shorter stem. You'll have to figure out whether you have a 1" or 1 1/8" stem.
-Going with a single ring up front means you need a chain retention system if you're throwing out your front derailleur. That means a chain guide or using a narrow-wide chainring and a derailleur with a clutch mechanism.
-Bullhorns, like drop bars, greatly extend the reach over flat bars. Mountain bikes are designed with long top tubes to accommodate the short reach of flat bars, so usually when you put dropbars or bullhorns on a flat bar bike you will need a shorter stem. You'll have to figure out whether you have a 1" or 1 1/8" stem.
-Going with a single ring up front means you need a chain retention system if you're throwing out your front derailleur. That means a chain guide or using a narrow-wide chainring and a derailleur with a clutch mechanism.
08-12-19, 05:07 AM
#5
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Some things to keep in mind regarding cost. These are rarely cheap to do right if you are truly planning to use it for utility.
-Bullhorns, like drop bars, greatly extend the reach over flat bars. Mountain bikes are designed with long top tubes to accommodate the short reach of flat bars, so usually when you put dropbars or bullhorns on a flat bar bike you will need a shorter stem. You'll have to figure out whether you have a 1" or 1 1/8" stem.
-Going with a single ring up front means you need a chain retention system if you're throwing out your front derailleur. That means a chain guide or using a narrow-wide chainring and a derailleur with a clutch mechanism.
-Bullhorns, like drop bars, greatly extend the reach over flat bars. Mountain bikes are designed with long top tubes to accommodate the short reach of flat bars, so usually when you put dropbars or bullhorns on a flat bar bike you will need a shorter stem. You'll have to figure out whether you have a 1" or 1 1/8" stem.
-Going with a single ring up front means you need a chain retention system if you're throwing out your front derailleur. That means a chain guide or using a narrow-wide chainring and a derailleur with a clutch mechanism.
In the mean time I need to figure out where I'd out shifters if I wind up with narrower bars. Not sure the current set up would fit.
By chain retention system you mean one of those rings mtbs have outside the chain ring? Mountain bikes are foreign to me.
08-12-19, 07:21 AM
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Thanks for the help. Pretty sure it's a 1" stem. Ideally I'll keep the stock stem since it has the guides and pulleys for the brake cable. It also matches the fork. I have a long torso and generally ride with a 110 stem so I think bullhorns might be ok for me. I'll have to find time to try things out.
In the mean time I need to figure out where I'd out shifters if I wind up with narrower bars. Not sure the current set up would fit.
By chain retention system you mean one of those rings mtbs have outside the chain ring? Mountain bikes are foreign to me.
In the mean time I need to figure out where I'd out shifters if I wind up with narrower bars. Not sure the current set up would fit.
By chain retention system you mean one of those rings mtbs have outside the chain ring? Mountain bikes are foreign to me.
The best way to determine if the bike will be too stretched out is to actually measure the effective top tube using a tape measure and then compare it to your other bike that fits you. The stem on your Muirwoods is at least 110, probably closer to 130 or 150, so unless your road bike that fits you has a much longer top tube than this bike, you are going to waste a bunch of time building this bike with this stem that won't be comfortable for you.
A problem with bullhorn bars is that they are generally designed for track bikes that don't need shifters, so it's difficult to find a place to mount the shifters on the bars. Most non-track builds with bullhorn bars are on road bikes with downtube shifters for this reason. You could look into stem shifters perhaps.
I don't mean to say all of this to rain on your parade. I'm just trying to save you the cost of buying a bunch of parts and spending a bunch of time on a plan with many elements that don't work. Fit and parts compatibility are things that need to be addressed before doing something like this.
A chain guide is something that keeps the chain from falling off the front chainring when a front derailleur cage isn't used. They are becoming obsolete now that narrow-wide chainrings with clutch derailleurs are prominent.
Last edited by TenGrainBread; 08-12-19 at 07:50 AM.
08-12-19, 07:26 AM
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The easiest and cheapest thing to do is to swap out the tires, overhaul the bike, and ride it. After you've ridden it for a while, you can figure out what you want to swap out. We're all tinkerers but it doesn't hurt to ride a bike for a while first.
Tires: best prices tend to be the British mail order places for Schwalbe and Conti tires. I'd run a 1.75-2.0 tire on these.
Tires: best prices tend to be the British mail order places for Schwalbe and Conti tires. I'd run a 1.75-2.0 tire on these.
08-12-19, 08:02 AM
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If you are game for no tread at all....., I've been very happy with Schwalbe Kojacs on a MTB I converted to drop bars.
Dean
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08-12-19, 10:02 AM
#9
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Well, from looking at your picture, and knowing that era of mtbs, I'm pretty sure it's a 1 1/8" headset and stem. Use some calipers or a steel rule to measure the diameter of the stem insertion.
The best way to determine if the bike will be too stretched out is to actually measure the effective top tube using a tape measure and then compare it to your other bike that fits you. The stem on your Muirwoods is at least 110, probably closer to 130 or 150, so unless your road bike that fits you has a much longer top tube than this bike, you are going to waste a bunch of time building this bike with this stem that won't be comfortable for you.
A problem with bullhorn bars is that they are generally designed for track bikes that don't need shifters, so it's difficult to find a place to mount the shifters on the bars. Most non-track builds with bullhorn bars are on road bikes with downtube shifters for this reason. You could look into stem shifters perhaps.
I don't mean to say all of this to rain on your parade. I'm just trying to save you the cost of buying a bunch of parts and spending a bunch of time on a plan with many elements that don't work. Fit and parts compatibility are things that need to be addressed before doing something like this.
A chain guide is something that keeps the chain from falling off the front chainring when a front derailleur cage isn't used. They are becoming obsolete now that narrow-wide chainrings with clutch derailleurs are prominent.
The best way to determine if the bike will be too stretched out is to actually measure the effective top tube using a tape measure and then compare it to your other bike that fits you. The stem on your Muirwoods is at least 110, probably closer to 130 or 150, so unless your road bike that fits you has a much longer top tube than this bike, you are going to waste a bunch of time building this bike with this stem that won't be comfortable for you.
A problem with bullhorn bars is that they are generally designed for track bikes that don't need shifters, so it's difficult to find a place to mount the shifters on the bars. Most non-track builds with bullhorn bars are on road bikes with downtube shifters for this reason. You could look into stem shifters perhaps.
I don't mean to say all of this to rain on your parade. I'm just trying to save you the cost of buying a bunch of parts and spending a bunch of time on a plan with many elements that don't work. Fit and parts compatibility are things that need to be addressed before doing something like this.
A chain guide is something that keeps the chain from falling off the front chainring when a front derailleur cage isn't used. They are becoming obsolete now that narrow-wide chainrings with clutch derailleurs are prominent.
After sleeping on it I'm thinking there may be very little I change about this bike right away. It functions just fine. The thing is, I really hate the look and feel of super wide mountain bike bars. I might just keep them and chop a few inches off for now. I don't need the width for control since I won't be doing much "mountain biking" with it.
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