convert retro bike to drop-bar gravel
#1
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convert retro bike to drop-bar gravel
I have an itch to scratch: successfully convert an old steel hybrid to a drop bar, singlespeed monstercross bike. I've seen it done with old hybrids and mountain bikes but I only ever see the bikes in isolation, not the rider who supposedly fits on them. it's hard enough to find good bikes on the market right now, but the real challenge to me seems to be finding something that can be made to fit me. most of these bikes have long top tubes, designed with flat bars in mind, so putting a drop bar on them would make the bike incredibly stretched out. I know what size ETT fits me on a drop bar bike, but I might be able to work it out with a shorter stem. how does one find a good candidate so that I don't have to use an irrationally tiny stem, or end up with a yardstick worth of seatpost exposed?
#2
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I accept that things won't look traditional/ideal when a hybrid or mtb drop bar conversion takes place.
Its a bit uncommon to see a conversion thst looks like it was designed thst way. This is due to the bike's geometry and the rider's measurements.
More important than look is if the bike fits. My first gravel bike was an early 90s drop bar conversion. A Univega Via Activa 3x7 hyvrid was what I started with. Some friction suntour bar end shifters, flared drop bar, tektro brake levers, a new saddle, and some pedals got me going. New tires shortly after made it more fun.
The frame was way too small, but the contact points all matched my other drop bar bikes so it effectively fit fine and let me ride for hours on end.
This allowed me to figure out if I liked gravel riding and determine what I would want in a better build..
Info is limited when it comes to early 90s hybrids. the trek 7xx series, bianchi project series, univega, fuji, schwinn cris cross and cross cut, etc- i would suggest you look for these specifically as a starting point and then go from there for what is available.
The Schwinn Crisscross and Univega ViaActiva I've owned both fit like recreational drop bar bikes from the late 80s and early 90s. The early 90s Trek 750 had the same geometry as a drop bar Trek 520 touring bike.
Now may be a tough search due to the seemingly limited online inventory and the relatively high prices.
Its a bit uncommon to see a conversion thst looks like it was designed thst way. This is due to the bike's geometry and the rider's measurements.
More important than look is if the bike fits. My first gravel bike was an early 90s drop bar conversion. A Univega Via Activa 3x7 hyvrid was what I started with. Some friction suntour bar end shifters, flared drop bar, tektro brake levers, a new saddle, and some pedals got me going. New tires shortly after made it more fun.
The frame was way too small, but the contact points all matched my other drop bar bikes so it effectively fit fine and let me ride for hours on end.
This allowed me to figure out if I liked gravel riding and determine what I would want in a better build..
Info is limited when it comes to early 90s hybrids. the trek 7xx series, bianchi project series, univega, fuji, schwinn cris cross and cross cut, etc- i would suggest you look for these specifically as a starting point and then go from there for what is available.
The Schwinn Crisscross and Univega ViaActiva I've owned both fit like recreational drop bar bikes from the late 80s and early 90s. The early 90s Trek 750 had the same geometry as a drop bar Trek 520 touring bike.
Now may be a tough search due to the seemingly limited online inventory and the relatively high prices.
#3
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I don't think there's any substitute for doing your homework. Measure the reach-stack of bikes that fit you. Research the frame geometry of potential bikes..and target bikes that show potential for a good fit.
I ended up with Treks in both of the ones I've done..partly..largely due to the extensive vintage data Trek makes available on the web and Trek sold a lot of bikes..which means they exist on the used market in good quantity. The "ideal" bike for conversion is only theory if you can't actually find one in good condition and in your size.
There's a TON of info available here of BF on this topic if you look for it.
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#5
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There's a whole thread on this; https://www.bikeforums.net/classic-v...nversions.html
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The 970 is a 26" mtb and had like 50mm of bb drop, right? I thought those had a more relaxed head tube angle too.
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#8
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Background: I've tried this with a 17" Bianchi Boardwalk and a 17" Scott Laredo. Both steel framed hybrids with rigid forks and a flat handlebar that fit me just fine in original form. When I put a drop bar on them, they suddenly became waaaay too long no matter how high or short a stem I used. I am trying to avoid a repeat of those. When I did those experiments, I has the keys to a bike co-op, so I could go in any time and tinker. I no longer have that luxury.
#9
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Sorry if I was unclear about my concerns. I don't care what it looks like, I just want it to fit me. Because bikes from that era never had reach and stack published, I can't easily compare older bikes that way unless I can get my hands on the bike first.
Background: I've tried this with a 17" Bianchi Boardwalk and a 17" Scott Laredo. Both steel framed hybrids with rigid forks and a flat handlebar that fit me just fine in original form. When I put a drop bar on them, they suddenly became waaaay too long no matter how high or short a stem I used. I am trying to avoid a repeat of those. When I did those experiments, I has the keys to a bike co-op, so I could go in any time and tinker. I no longer have that luxury.
Background: I've tried this with a 17" Bianchi Boardwalk and a 17" Scott Laredo. Both steel framed hybrids with rigid forks and a flat handlebar that fit me just fine in original form. When I put a drop bar on them, they suddenly became waaaay too long no matter how high or short a stem I used. I am trying to avoid a repeat of those. When I did those experiments, I has the keys to a bike co-op, so I could go in any time and tinker. I no longer have that luxury.
For example, the old Trek Antelope. Bringing up Google Image pics and straightaway it seems the smaller sizes look too low at the front. However go up a few sizes and you can see a decent-height head tube start showing up. e.g. currently on ***red-it***there's one of the larger Antelope built up as a drop bar 650b conversion. Even though the pic shows a stem that's a little shorter than normal, the reach and stack is pretty good (I asked the owner to measure those numbers and it came up very similar to my short-reach gravel frame). Its the blue frame bike with tan walls.
https://velozout.blogspot.com/2015/05...elope-820.html In this smaller frame Antelope dropbar you can see how the frame is longer proportionally.
Last edited by tangerineowl; 08-26-20 at 01:56 AM. Reason: txt
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#10
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With time looking at side-on pics of a frame triangle you can spot shorter-reach/taller-stack potentials.
For example, the old Trek Antelope. Bringing up Google Image pics and straightaway it seems the smaller sizes look too low at the front. However go up a few sizes and you can see a decent-height head tube start showing up.
For example, the old Trek Antelope. Bringing up Google Image pics and straightaway it seems the smaller sizes look too low at the front. However go up a few sizes and you can see a decent-height head tube start showing up.
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...that fit me just fine in original form. When I put a drop bar on them, they suddenly became waaaay too long no matter how high or short a stem I used. I am trying to avoid a repeat of those. When I did those experiments, I has the keys to a bike co-op, so I could go in any time and tinker. I no longer have that luxury.
Stem Comparison Tool | yojimg.net
give you a specific idea of the impact a stem will have on stack and reach.
Stack and reach isn't published on vintage frames, but seat tube and top tube length usually is, as well as the frame angles. If you have a stack-reach range that you know fits you well, then the potential for a drop-bar conversion fit can be ballparked reasonably well. If no specs are available and you at least have a side photo of the bike, then you can use parts on the bike to make scale measurements of the tob tube and seat tube (example..the crank is most often 170mm..measure the crank arm and then use that to make scale measurements of anything else). The shorter headtubes on some bikes usually means some stem extension is needed. Longer exposed stem results in shorter (handlebar) reach..this can be estimated with the stem calculator above.
There are always some unknowns with how a converted bike will all feel in the end, but most of the mystery can be taken out before you start.
edit: I should have mentioned...in making estimates on how a conversion will go, you'll need to work with both the frame stack and reach as well as the handlebar/flat-bar stack and reach AND the potential drop bar stack and reach...the key is to put the new bars in the "space" that's comfortable for you to ride. That "space" can be calculated-estimated before you start.
Last edited by fishboat; 08-26-20 at 06:51 AM. Reason: forgot..
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#12
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There's nothing sudden about it. Nearly everything is known before you start a conversion. Drop bar specs (reach) are published on most bars. Sites like:
Stem Comparison Tool | yojimg.net
give you a specific idea of the impact a stem will have on stack and reach.
Stem Comparison Tool | yojimg.net
give you a specific idea of the impact a stem will have on stack and reach.
whatbars.com
bikegeo.net
bikegeo.muha.cc
I think that second link can help you estimate the reach and stack on a vintage bike with some degree of accuracy. useful for conversions, but I didn't know how to use it at the time of those builds mentioned above.
I've seen that thread about vintage conversions and I probably need to spend more time reading it carefully. most of it is photos of conversions but I would need to know the frame size and the rider's height as a starting point. that information is not always given. the rider just says in effect "I slapped a some drop bars [sic] on this bike and it rides like a dream!" I have pretty average proportions with perhaps longer legs for my height.
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...I've seen that thread about vintage conversions and I probably need to spend more time reading it carefully. most of it is photos of conversions but I would need to know the frame size and the rider's height as a starting point. that information is not always given. the rider just says in effect "I slapped a some drop bars [sic] on this bike and it rides like a dream!" I have pretty average proportions with perhaps longer legs for my height.
I don't understand why "frame size and rider's height" in that thread is necessary. You create lots of roadblocks..do the research and numbers from the knowledge of what frame & handlebar stack and reach fit's you. If you're not sure what fits you..then you need to start there, as any conversion without that knowledge is a random walk..
#14
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I've reviewed/read/searched that thread for hours..there's lot's of discussion about all aspects of a conversion. The problem is, the thread is so big that searching it is cumbersome. I tried to get the entire thread into one document to allow broad searching of all of it at one time..no success in that, so I searched it by page, by topic..as needed.
I don't understand why "frame size and rider's height" in that thread is necessary. You create lots of roadblocks..do the research and numbers from the knowledge of what frame & handlebar stack and reach fit's you. If you're not sure what fits you..then you need to start there, as any conversion without that knowledge is a random walk..
I don't understand why "frame size and rider's height" in that thread is necessary. You create lots of roadblocks..do the research and numbers from the knowledge of what frame & handlebar stack and reach fit's you. If you're not sure what fits you..then you need to start there, as any conversion without that knowledge is a random walk..
so I have a for range stack, reach, and ETT, but it might be possible to fit a bike with different measurements by changing the stem length and height. a frame that has a longer ETT sounds too big at first, but when you raise the stem quite a bit, the reach becomes shorter. at a certain point, that could compromise handling, though. I'll keep an eye out for something that can fit like the above within reason.
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This is a good thread with useful info on bike fitting. I'm working on a drop bar conversion on a '92 Specialized Stumpjumper and I'll use some of the websites linked to in this thread to run some numbers.
It sounds like the OP has made up his mind to go with a drop bar conversion but the right flat bar can make for a good gravel bike as well. I like trekking bars and installed a set on a 1992 Trek 950. They're comfortable and cheap. And the set up issues disappear.
One thing I was going to suggest is that maybe it is possible to overthink this? I dunno. I set up my first drop bar conversion with a 1987 Specialized stumpjumper. I measured the seat and top tube and then guesstimated the set up. It worked out fine. I think bike set up tends to based on rules of thumb that in turn are based on lots of data points from experienced riders, racers, etc.
It sounds like the OP has made up his mind to go with a drop bar conversion but the right flat bar can make for a good gravel bike as well. I like trekking bars and installed a set on a 1992 Trek 950. They're comfortable and cheap. And the set up issues disappear.
One thing I was going to suggest is that maybe it is possible to overthink this? I dunno. I set up my first drop bar conversion with a 1987 Specialized stumpjumper. I measured the seat and top tube and then guesstimated the set up. It worked out fine. I think bike set up tends to based on rules of thumb that in turn are based on lots of data points from experienced riders, racers, etc.
Last edited by bikemig; 08-26-20 at 08:35 AM.
#16
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I did a couple 90s steel bikes last year (Schwinn CrissCross 700c hybrid and Specialized Rockhopper 26" MTB). They both had kinda wonky geometry with the long top tubes, and short head tubes that I could never quite get right. They were fun projects, but I just couldn't see myself riding thousands of miles on them due to the fit, weight and crummy brakes, so I got a modern steel bike. The only conversion I would consider doing now would be a really, really nice Trek 750 with a lugged, made in USA frame, and no expense spared on the parts to keep the weight down, the fit as good as possible, and the brakes as good as you can get from rim.
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he went opposite you though and kept the conversion cheap so it isnt a featherweight.
here it is mid-conversion.
Last edited by mstateglfr; 08-26-20 at 11:58 AM.
#18
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my brother in law converted a lugged 750 frame to drop bar- they were really cool frames. I was shocked when he said he was going to sell it because its just a solid neat frame.
he went opposite you though and kept the conversion cheap so it isnt a featherweight.
here it is mid-conversion.
he went opposite you though and kept the conversion cheap so it isnt a featherweight.
here it is mid-conversion.
#19
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My main goal is to get something with a drop bar and room for tires wider than 35mm. my focus on converting and old bike comes from just being cheap. new bikes are expensive and the used market is all over the place. I thought that if I could make it work with an old bike, I could spend a lot less and be happy. it still might work, but scouring the local used marketplace is exhausting. I constantly see crapped-out old bikes that have good bones that should probably sell for $150, but because they are "vintage" people are willing to pay 2x or more than that.
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One way to avoid the fit issues you may have with a drop bar conversion of a bike designed for flat bars is to start with a road bike and go with a 650b conversion. That need not be uber expensive. Quality, lightweight road bikes can be had for reasonable prices if you shop hard and can live with some patina. Spreading an old frame to 130 is not hard and then you can run modern gearing.
Here is a long thread with some ideas:
https://www.bikeforums.net/classic-v...nversions.html
Here is a long thread with some ideas:
https://www.bikeforums.net/classic-v...nversions.html
#21
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I tried that too. my bike has "room" for 700C 35mm tires with a sliver of clearance on the sides. I put a borrowed 650B wheel on it and the clearance is oddly the same because of the way the dimples in the chainstays taper off in toward the back.
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There is no point, IMO, of doing a 650b conversion unless you can fit at least a 38c tire. Otherwise you may run into issues with the bottom bracket dropping down (650b x 38c is roughly the diameter of 700c by 23c if memory serves me). Plus finding a 700c bike that can take a 35c tire is no big deal (just find a touring bike or a bike that uses a "long" reach brake). So I don't think a 650b conversion is worth your time unless you can fit a 38c to 42c tire. And there are plenty of people who have done that with 650b conversions.
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This is her all-rounder bike for occasional day rides, gravel, and touring. We've toured with it..she rides with about 30# of gear in a 4 pannier setup and says it handles great...it appears to as she keeps a healthy pace on it. We're setting up another week-long tour now.
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#24
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Lower BB also requires hunting around for.
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