Show Your Vintage MTB Drop Bar Conversions
#5476
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Same here, my road bike has a 50 chainring, so I'm not losing much with a 48. Even bikes with 42-32-22 compact gearing, when coupled with an 11 or 12 cog, have a reasonably high gear, considering the terrain and weight of the bike.
#5477
Senior Member
The bike I'm getting has that same 42/32/22 triple currently.
What I was hoping to do is use a double crank and throw something around that 42t on the out outside position with maybe a 32 or something on the inner position and use a single ss cog with a Melvin tensioner in the back.
This would give me the all purpose gearing I've been looking for.
My concern is moving the outer 42 on a triple to the outer of a double. Shifting inboard a couple millimeters, I'm not sure what clearance would look like.
What I was hoping to do is use a double crank and throw something around that 42t on the out outside position with maybe a 32 or something on the inner position and use a single ss cog with a Melvin tensioner in the back.
This would give me the all purpose gearing I've been looking for.
My concern is moving the outer 42 on a triple to the outer of a double. Shifting inboard a couple millimeters, I'm not sure what clearance would look like.
#5478
Senior Member
So 2 x 1 gearing? I have never tried that. Doesn't really sound like most people's idea of all purpose gearing, but maybe it will work for you.
What I have done is a single ring and a 6 speed rear. I don't have hills to speak of so I used 44 x 13-21. That worked out great.
(Edit) aren't most tensioners meant for a straight chainline? Not sure how that's going to work out. Maybe someone has tried it.
What I have done is a single ring and a 6 speed rear. I don't have hills to speak of so I used 44 x 13-21. That worked out great.
(Edit) aren't most tensioners meant for a straight chainline? Not sure how that's going to work out. Maybe someone has tried it.
Last edited by due ruote; 12-18-16 at 09:11 AM.
#5479
Senior Member
Here's part of my inspiration from this very thread:
https://www.bikeforums.net/15547548-post1704.html
The melvin has floating pulleys that can move with your chainline.
https://www.bikeforums.net/15547548-post1704.html
The melvin has floating pulleys that can move with your chainline.
#5480
Senior Member
Here's part of my inspiration from this very thread:
https://www.bikeforums.net/15547548-post1704.html
The melvin has floating pulleys that can move with your chainline.
https://www.bikeforums.net/15547548-post1704.html
The melvin has floating pulleys that can move with your chainline.
#5481
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Here's part of my inspiration from this very thread:
https://www.bikeforums.net/15547548-post1704.html
The melvin has floating pulleys that can move with your chainline.
https://www.bikeforums.net/15547548-post1704.html
The melvin has floating pulleys that can move with your chainline.
A 52X13 on a 26 inch MTB cannot be too much higher than a 48/11 on a 700C, I guess, not bothered to calculate it, suppose I should.
Where can chainrings be (reliably) ordered for older Shimano cranksets?
Last edited by Loose Chain; 12-18-16 at 11:51 AM.
#5482
Senior Member
#5483
Senior Member
See if I could fit up to a 52 that'd make me even happier but it's just too hard to tell. I know the double single system will work, it's come down to how large of an outside ring I can squeeze on with the chainstays.
I had actually intended to run this with a 52/36 mid compact and an 11/34 cassette as that'd be a ton of range. But with some compatibility issues, it was getting too complicated.
So I settled on the double single idea (or even just ss).
I had actually intended to run this with a 52/36 mid compact and an 11/34 cassette as that'd be a ton of range. But with some compatibility issues, it was getting too complicated.
So I settled on the double single idea (or even just ss).
#5484
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Maybe the drops aren't appropriately deep, but here's a GT Tequesta I've recently put together with Origin8 mustache bars. I like it. Those bars offer great leverage for grinding up climbs.
#5485
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It was fun to try, but decided if I'm going to have something hanging off my hanger, it might as well be fully functional.
__________________
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● 1971 Grandis SL ● 1972 Lambert Grand Prix frankenbike ● 1972 Raleigh Super Course fixie ● 1973 Nishiki Semi-Pro ● 1979 Motobecane Grand Jubile ●1980 Apollo "Legnano" ● 1984 Peugeot Vagabond ● 1985 Shogun Prairie Breaker ● 1986 Merckx Super Corsa ● 1987 Schwinn Tempo ● 1988 Schwinn Voyageur ● 1989 Bottechia Team ADR replica ● 1990 Cannondale ST600 ● 1993 Technium RT600 ● 1996 Kona Lava Dome ●
Last edited by Lascauxcaveman; 12-18-16 at 04:34 PM.
#5486
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See if I could fit up to a 52 that'd make me even happier but it's just too hard to tell. I know the double single system will work, it's come down to how large of an outside ring I can squeeze on with the chainstays.
I had actually intended to run this with a 52/36 mid compact and an 11/34 cassette as that'd be a ton of range. But with some compatibility issues, it was getting too complicated.
I had actually intended to run this with a 52/36 mid compact and an 11/34 cassette as that'd be a ton of range. But with some compatibility issues, it was getting too complicated.
Diameter = s* N/pi
Radius = Diameter/2
s=12.75mm
N=Number of Teeth
pi=3.14
So a 52t chainring will have a diameter of about 105.5mm
52 => 105.5mm
48 => 97.4mm
With your current setup, measure the clearance between the chainring and chainstay.
Calculate the Radius of the current chainring
Since the bicycle flexes when it is pedaled you'll want some clearance between the new chainring and the chainstay.
Typically the middle chainring is aligned to the middle of the cassette/freewheel, so in theory this would be a better location for a single chainring. But the clearance between the middle ring and the chainstay is much less so you won't be able to fit as large of a chainring in the middle position.
As for calculating your maximum gear...
Determine your maximum cadence (say 115 rpm)
Determine (measure or calculate) the circumference of your wheel in inches
- Example for 26" wheel: pi*Diameter = 3.14*26 = 81.64"
Convert inches to miles: 12 inches in a foot, 5280 feet in a mile
81.64/12 = 6.8 feet
6.8ft/5280 = 0.001289 miles
So every revolution of the wheel is 0.001289 miles
With a 52/11 top gear, every revolution of the cranks results in 4.727 revolutions of the wheel.
A cadence of 115 revolutions per minute, or 60*115= 6900 revolutions per hour
6900*4.727 = 32,616 revolutions of the rear wheel
32616*0.001289 = 42 miles per hour
So with a 52/11 top gear, if your maximum cadence is 115 RPM then you'll spin out at 42 mph.
All of this math is linear, so if you can spin at 120 RPM, that is 4.35% faster so you'll spin out at a 4.35% higher speed (43.8 mph). Similarly if the chainring is only a 48 (7.7% smaller), then you'll spin out at about 38.8 mph.
Hope this helps,
Greg
#5487
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I'm not fully understanding your goals but as for the calculating the diameter of a chainring use this equation. It's an approximation but will be very close:
Diameter = s* N/pi
Radius = Diameter/2
s=12.75mm
N=Number of Teeth
pi=3.14
So a 52t chainring will have a diameter of about 105.5mm
52 => 105.5mm
48 => 97.4mm
With your current setup, measure the clearance between the chainring and chainstay.
Calculate the Radius of the current chainring
Since the bicycle flexes when it is pedaled you'll want some clearance between the new chainring and the chainstay.
Typically the middle chainring is aligned to the middle of the cassette/freewheel, so in theory this would be a better location for a single chainring. But the clearance between the middle ring and the chainstay is much less so you won't be able to fit as large of a chainring in the middle position.
As for calculating your maximum gear...
Determine your maximum cadence (say 115 rpm)
Determine (measure or calculate) the circumference of your wheel in inches
- Example for 26" wheel: pi*Diameter = 3.14*26 = 81.64"
Convert inches to miles: 12 inches in a foot, 5280 feet in a mile
81.64/12 = 6.8 feet
6.8ft/5280 = 0.001289 miles
So every revolution of the wheel is 0.001289 miles
With a 52/11 top gear, every revolution of the cranks results in 4.727 revolutions of the wheel.
A cadence of 115 revolutions per minute, or 60*115= 6900 revolutions per hour
6900*4.727 = 32,616 revolutions of the rear wheel
32616*0.001289 = 42 miles per hour
So with a 52/11 top gear, if your maximum cadence is 115 RPM then you'll spin out at 42 mph.
All of this math is linear, so if you can spin at 120 RPM, that is 4.35% faster so you'll spin out at a 4.35% higher speed (43.8 mph). Similarly if the chainring is only a 48 (7.7% smaller), then you'll spin out at about 38.8 mph.
Hope this helps,
Greg
Diameter = s* N/pi
Radius = Diameter/2
s=12.75mm
N=Number of Teeth
pi=3.14
So a 52t chainring will have a diameter of about 105.5mm
52 => 105.5mm
48 => 97.4mm
With your current setup, measure the clearance between the chainring and chainstay.
Calculate the Radius of the current chainring
Since the bicycle flexes when it is pedaled you'll want some clearance between the new chainring and the chainstay.
Typically the middle chainring is aligned to the middle of the cassette/freewheel, so in theory this would be a better location for a single chainring. But the clearance between the middle ring and the chainstay is much less so you won't be able to fit as large of a chainring in the middle position.
As for calculating your maximum gear...
Determine your maximum cadence (say 115 rpm)
Determine (measure or calculate) the circumference of your wheel in inches
- Example for 26" wheel: pi*Diameter = 3.14*26 = 81.64"
Convert inches to miles: 12 inches in a foot, 5280 feet in a mile
81.64/12 = 6.8 feet
6.8ft/5280 = 0.001289 miles
So every revolution of the wheel is 0.001289 miles
With a 52/11 top gear, every revolution of the cranks results in 4.727 revolutions of the wheel.
A cadence of 115 revolutions per minute, or 60*115= 6900 revolutions per hour
6900*4.727 = 32,616 revolutions of the rear wheel
32616*0.001289 = 42 miles per hour
So with a 52/11 top gear, if your maximum cadence is 115 RPM then you'll spin out at 42 mph.
All of this math is linear, so if you can spin at 120 RPM, that is 4.35% faster so you'll spin out at a 4.35% higher speed (43.8 mph). Similarly if the chainring is only a 48 (7.7% smaller), then you'll spin out at about 38.8 mph.
Hope this helps,
Greg
#5488
Senior Member
Ha! Alternatively you could take a 52 ring of any bcd and lay it on top of your current ring, and then with a China marker or piece of tape mark where it landed on the stay. Sight down your current ring and see how it looks. Maybe you could add a BB spacer.
Edit-easier still, and more accurate, forget the overlay thing; just measure the diameter of a 52 ring and go half the distance from the crank bolt; mark the same way.
Fwiw I have roughly 1/4" clearance from the large ring (46t) to the stay on my Stumpjumper. I bet it would be close, but it's going to depend on your frame.
Edit-easier still, and more accurate, forget the overlay thing; just measure the diameter of a 52 ring and go half the distance from the crank bolt; mark the same way.
Fwiw I have roughly 1/4" clearance from the large ring (46t) to the stay on my Stumpjumper. I bet it would be close, but it's going to depend on your frame.
Last edited by due ruote; 12-19-16 at 07:37 AM.
#5489
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#5491
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#5493
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#5494
Senior Member
I'm seeing a lot of Moustache bars in this thread aand am seriously considering them for my build.
What types are you guys running? Nittos primarily I'd assume?
What types are you guys running? Nittos primarily I'd assume?
#5495
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1993 Kona Fire Mountain
Took this for its first ride today. Rides amazingly well. This was designed to be a mountain bike touring rig. Awesome for paved roads, dirt roads, gravel, and single track.
https://goo.gl/photos/wy7fzKmBedhe1DB87
https://goo.gl/photos/wy7fzKmBedhe1DB87
#5496
High Plains Luddite
I happened to see this on craigslist today. I do not know the seller and am certainly not shilling for him by posting this here.
What caught my eye, other than seeing a drop bar MTB conversion on craigslist in the first place, and beyond the delightfully mis-matched handlebar tape, are downtube shifters. I've seen someone's orange Stumpjumper posted here with DT shifters, but this is the only other MTB I remember seeing with them.
Is this some kind of aftermarket clamp-on DT shifter mount that I've never heard of or seen before? I'm not looking to buy them, but just thought it might make for good discussion.
Or were those original equipment from the manufacturer? I'm guessing not.
Classic 90's Steel MTB Turned Gravel Grinder
What caught my eye, other than seeing a drop bar MTB conversion on craigslist in the first place, and beyond the delightfully mis-matched handlebar tape, are downtube shifters. I've seen someone's orange Stumpjumper posted here with DT shifters, but this is the only other MTB I remember seeing with them.
Is this some kind of aftermarket clamp-on DT shifter mount that I've never heard of or seen before? I'm not looking to buy them, but just thought it might make for good discussion.
Or were those original equipment from the manufacturer? I'm guessing not.
Classic 90's Steel MTB Turned Gravel Grinder
#5499
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@Squeeze, it's likely an aftermarket add on as I'm certain Miyata didn't offer MTBs with DT bosses. Origin 8 makes such a clamp.
#5500
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WTB Dirt Drops
Soma Portola
Nitto Noodle
Nitto Randonneur
Trekking bars
I eventually "settled on" the two Nitto bars on two of my bikes and a set of Trekking bars on a third.
Despite their legendary awesomeness, I didn't care for WTB Dirt Drops, but that's just because of the kind of riding I do. I did feel like I had the most control with those, though.