Here in my country is kind of difficult to get certain types of handlebars, but it is easy to get flat and riser mountain type handlebars and standard types of road drop bars.

So I'm investigating whether it is possible to purposefully bend a straight handlebar to have it in another shape.

Can it be done with common store-bought tools? If not, I can take it to a metal working shop and get it bent there? Will it be safe?

In particular, I'd like to turn straight handlebar into a bullhorn shaped one.

I'd like to have this done on aluminum but i'm not sure whether a finished handlebar can be bent.

A second option is to make the handlebar out of steel pipe that is easily bought locally. However to install it on a bike shims will be needed to make up for the "bulge" that handlebars have in the clamp area.

I have currently configured my bike with a short straight handlebar fit with bar ends and it works pretty well for my purposes, but I'd like to have a rounded curve instead of the sharp angle that the bar and bar ends have.

I currently do not have the means to buy a ready-made bullhorn via internet by myself, but if I had, the hassle of shipping, customs taxes and other annoyances made me wonder if making my own is feasible.

  • 1
    I live in a tricky country too, but, Evans in the UK will ship here and to Honduras. That might be your best bet.
    – alex
    Dec 16 '16 at 5:52
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    Someone downvoted almost all the answers -- curious why.
    – Batman
    Dec 16 '16 at 6:16
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    Better to weld than bend, I think. Bending tube is hard, and sourcing the heat treatable tube to bend will also be hard (even if you find it, the manufacturers often don't like selling it to non-certified buyers because it's so easy to screw it up). The cost of a 6m or 8m length is likely to be more than the cost of a premade set of bars, but you need that much for the stuff-ups you will inevitably make.
    – Móż
    Dec 16 '16 at 9:52
  • @Móż Welding is another not that good idea - one must be skilled in alumunium welding to do such task and the weld must be examined.
    – Crowley
    Dec 16 '16 at 18:01
  • @Crowley I thought that was pretty obvious. We're talking about a significant, safety-critical component after all. And I would suggest steel over aluminium for a DIY handlebar, because it's somewhat more forgiving of mistakes, especially when the OP is talking about using locally available generic tube rather than the usual handlebar material.
    – Móż
    Dec 16 '16 at 20:18

No! Don't do it!

Certainly not with aluminium / alloy bars. Any bending stresses the internal structure of the metal, weakening it. Even in a metalworking shop, I would be doubtful of the safety of the product. I hesitated to say final product because the result could be ... final. For you.

Even with steel bars, I wouldn't do it. With steel bars we used to bend them slightly to have our preferred shape. But the wall thickness of steel bars these days is so low that I would not recommend even slight bending. With such low wall thickness almost no amount annealing or other treatment will restore full strength.

The other thing you mention is using plain pipe. Since it's not high-tensile steel (it'll be plain carbon steel), to be strong enough it will have thick walls and be heavy.

  • 1
    Yah, setting aside the need for tubing benders and needing to learn how to use them to bend thin wall tubing, the OP would need to properly anneal the existing aluminum bars before trying to do work on them. Dec 16 '16 at 1:02
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    Having bent aluminium tube in the past (tent pole) I can only agree with you. Even with liberal application of heat to the bend region, damage to the outside of the bend was apparent. Cold it simply snapped. The risk might be acceptable if it's done by a metalworking shop that's experienced in bending aluminium for structural work, but this would be much more expensive than international shipping.
    – Chris H
    Dec 16 '16 at 6:52

I wouldn't recommend bending handlebar -- if the bar breaks (which is more likely due to the stresses you're putting on it), you're probably going to lose some teeth or worse. I don't know your skills with metal, so I'd also probably not suggest the bent piece of tubing approach.

If you really want a bullhorn and want to make it yourself, your best bet is probably to buy a set of drop bars and cut the drops to get a bullhorn shape. This is likely safer. You might need a different stem (road bars and straight bars generally don't have the same clamp diameter. You can do this cutting it with a hacksaw with an appropriate blade , some sandpaper and a bastard or finer file; I guess a pipe cutter would work too, but you're less likely to have access to one that you can use (the little ones most people have at home, which are like 10 bucks at home depot are too small). I would not do this on carbon fiber bars, but I've seen it done on Aluminum and Steel bars a lot (especially among hipsters on a budget; Most of them are still alive, the rest had beard, flannel and glasses accidents..). It is likely the safest option for a home made bar (by far), but of course, this is completely at your own risk (I think its pretty minimal on a sturdier handlebar, but again, you're going well beyond what the thing was engineered for, so no guarantees.).

from wikipedia at https://en.wikipedia.org/wiki/Bicycle_handlebar Photo of converted drop bars from Wikipedia

You'll likely need to grab a few new brake levers and shifters too though (I'd be okay with shimming the shifters on; brake levers not so much; the grip diameters also generally don't match).

Personally, if I wanted bullhorns, I'd buy bullhorns. There are places to cheap out on a bicycle, but something that takes a significant amount of stress like a handlebar (e.g. when accelerating hard, you pull on it), I wouldn't mess around with it.

  • 1
    What is the actual difference between a bullhorn and a chop-n-flip drop bar? Older drop bars had much longer hoods, so are a good candidate for trimming.
    – Criggie
    Dec 16 '16 at 2:53
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    @Criggie - Not all that much I suppose -- the bend angle is a bit sharper on a real bullhorn versus an arc on a drop bar. A bullhorn bar sold as a bullhorn is probably tested a lot better as a bullhorn. A chop and flip bar, not so much (I doubt any manufacturer tests their bars when cut, except for some of them who sell lock on grips which require the bar to be cut carefully). Depending on what drop bar you cut, you might get some weirdness at the point where you'd cut it to be bullhorn like.
    – Batman
    Dec 16 '16 at 3:03
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    Compare a typical bullhorn to a typical drop bar and look from the side.
    – Batman
    Dec 16 '16 at 3:04
  • The drop bars I have access to here have a very short flat, so, when cut and flipped would have a very short length on the section going straight forward, leaving little room for support + controls. I have tried a flip+cut bar on a friend's fixie. For him i'ts fine since his bike doesn't have shifters nor brakes. Bullhorns I have seen personnally on other rider's bikes have a rather long pipe strech in the part going straight towards the front.
    – Jahaziel
    Jan 31 '17 at 13:24

Doing it safely with aluminum is not simple or equipment-minimal, either modifying it or making it from scratch. But, if you want to make a hobby of it for a while, you can do it safely in steel in very equipment-minimal fashion.

Here's a link to the public domain book usually referred to as "Bicycle Repairing 1896." It's a US bicycle shop repair book from 120 years ago, when the distinction between manufacturer and consumer-level service shop was nothing like we know it now. There's theory and instructions for how to fabricate many parts of a bike using the technology of the time. Page 115 shows a way to bend bars with a simple, carefully made hardwood form. Note that the type of wood they're talking about isn't so easily obtained these days, but it's around.

Make sure you choose steel tubing that will accommodate the type of controls you want. If you want it to be like a conventional bullhorn, they use road bar OD for (23.8mm or 15/16") for things like track grips and cross levers. But if you want to run tri levers, you'll need to make sure the tubing ID is right for the ones you want, which may involve jumping through some hoops because they're all made for an aluminum or carbon bar with greater wall thickness than you'll probably be working with in steel. 15/16" tubing does exist but it's not one of the super common sizes. Especially if you're brakeless, you may just decide to use 22.2mm (7/8") tubing because it's much more common, the smaller OD will make it easier to work with, and it will also be easy to make a stem clamp shim using a piece of 25.4mm tubing in the common .065" wall thickness. (The "telescoping" wall thickness for common steel tubes used in bike-land.)

I'll leave it to you to figure out what you need from the steel tubing in terms of safety, workability, and availability, but needless to say you need to get all three points right.

  • 1
    I'm not convinced you can bend up decent bars without an internal mandrel. I've tried, and even a 30 degree bend was impossible without wrinkling the tube. You'd need to heat and bend mild steel, I think, the heat and quench to harden.
    – Móż
    Dec 16 '16 at 9:49
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    @Moz - Yes, you need an internal mandrel, but this is pretty easy to do. The next page includes the line "The tubing bent on this machine is first filed with rosin". Nowadays, we use typically use cerrobend, sand, frozen water, springs, or the internal ball or disk mandrels you mention. Or the original hardened pitch or rosin still work too! Anything to make the hollow tube behave like a solid bar when bending.
    – johannes
    Dec 16 '16 at 14:01
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    @johannes my experience with fluid fillers was bulges and wrinkles - and I think most people would struggle to make a proper solid mandrel bender. The book is all very well, but remember that it was written when the world hour record was under 30 kilometres and the average height of an adult European male was under 170cm.
    – Móż
    Dec 16 '16 at 20:20
  • If you could get an internal bending spring of the right diameter you might get away with it (which isn't exactly a recommendation).
    – Chris H
    Dec 19 '16 at 16:46

Could you bend one yourself? Probably.. but it would lose structural integrity if done incorrectly. It may seem okay but could fail catastrophically under load. Without using a pipe bender the material would likely crease which could potentially lead to stress cracks and end up bad.

To do it correctly, or have a shop do it, you would need steel tubing and a suitable pipe bender. You may be able to use a pre-existing bar but i worry it would weaken the structure. I'm by no means an expert, this is just my 2 cents.

Lots of motorcycle and chopper people have bars custom made or make their own, it needs to be done correctly to be safe, but it can be done.

I don't know enough about aluminum to answer that portion but i would be scared that the material would not take well to a second shaping.

  • Customized motorcycle world was indeed my inspiration, however, they don't usually struggle much with weight as whe cyclists do.
    – Jahaziel
    Jan 31 '17 at 13:30

Steel and aluminum conduit are routinely bent using nothing more than a tubing hickey. A piece of conduit is uniform in diameter whereas most handlebars I've seen are larger in diameter at the point where it clamps to the stem so you may have to make up for the difference with a shim made to fit over the tubing but with a little space (1/8" or so) so that when you tighten the stem the shim has room to clamp down. You could use a piece of tubing for the shim.

  • 3
    Hi Alan, and welcome to the site! We recommend all new users take the tour to get the most from the site, and since you volunteered an answer, it couldn't hurt to also read how to answer. Regarding your answer, electrical conduit is meant to be bent when installed, but I'm skeptical about bending handlebars the same way; handlebars have different metallurgy, because they're meant to be light, stiff, and strong. Of course someone might try using handlebars made from conduit ;) Again, welcome.
    – rclocher3
    Dec 19 '16 at 18:47
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    Good idea, but I can bend modern conduit with my hands, so its not up to the job. Plus its heavy, and a metric diameter whereas handlebar clamps and grips and brake/shift levers expect to mount on 1" bars.
    – Criggie
    Dec 19 '16 at 19:25
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    @Criggie I suspect the empire have conduit in imperial sizes.
    – Móż
    Dec 20 '16 at 0:39
  • I should clarify - handlars would be 1" external diameter, whereas pipes are measured on their internal diameter with wall thickness as a separate measurement. So 1 inch might not equal 1 inch. Also, 25.0 mm is not close enough to 1 inch to fit properly without shimming.
    – Criggie
    Dec 20 '16 at 1:24
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    Conduit may be fine for prototyping stages, but not remotely for real use. I have built racks out of conduit that resulted surprisingly resistant, but indeed, the material doesn't have thestrengt for structural applications.
    – Jahaziel
    Jan 31 '17 at 13:34

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