Bent Bars...
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Bent Bars...
Ove the years, a few bikes have come my way with handlebars that tend to lean in, like the set on this old Torpado...
I thought, because I had seen a few like this, that the design was original but I am pretty sure that I am wrong. Take a look at how deformed the stem clamp section of the handlebar. The bar slopes away from the center. I might add that it was difficult getting that old TTT stem off of those screwed up bars...
Rarely will I keep a bike off of the road for a missing or incorrect item. With that in mind, and since my stash is long gone, I had to settle for a set of Asian bars...
Seems like that is always one more item to find but at least I will be able to get the bike on the road sooner than later...
I thought, because I had seen a few like this, that the design was original but I am pretty sure that I am wrong. Take a look at how deformed the stem clamp section of the handlebar. The bar slopes away from the center. I might add that it was difficult getting that old TTT stem off of those screwed up bars...
Rarely will I keep a bike off of the road for a missing or incorrect item. With that in mind, and since my stash is long gone, I had to settle for a set of Asian bars...
Seems like that is always one more item to find but at least I will be able to get the bike on the road sooner than later...
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Nothing lost there, IMO. Sakae bars are great, and they hold up well.
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It probably wont straighten that kink near the stem clamp, but i used a 2t car floor jack and some pieces of wood to straighten one of my HVZ drop bars.
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My suspicion is that the AL used on old bars had inferior mechanical properties of more recent ones. That is probably why Cinelli used the sleeve on older bars.
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Bending aluminum seems sketchy to me, but I would worry more about trying to correct a modern bar than a soft vintage bar. I have one nitto bar I might try and correct sometime but the misalignment is minor and I will need to build some sort of jig to even determin what's wronge. The bars came on a nitto stem that was also slightly wraked, which I decomissioned on principle.
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I draw the line at salvaging old bars that have any signs of having been bent or crashed. If it's been bent, it gets tossed.
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Drop bars have multiple radical bends! I don't know if they are annealed after bending or not. I suspect not, so what is wrong with bending them back? Work hardening of AL is an issue but they were bent severely to begin with!
Has anyone seen stress crazing or fractures on new bars from the forming process? Does anyone know what the process yield is for material failure as opposed to dimensional deviations?
Has anyone seen stress crazing or fractures on new bars from the forming process? Does anyone know what the process yield is for material failure as opposed to dimensional deviations?
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Drop bars have multiple radical bends! I don't know if they are annealed after bending or not. I suspect not, so what is wrong with bending them back? Work hardening of AL is an issue but they were bent severely to begin with!
Has anyone seen stress crazing or fractures on new bars from the forming process? Does anyone know what the process yield is for material failure as opposed to dimensional deviations?
Has anyone seen stress crazing or fractures on new bars from the forming process? Does anyone know what the process yield is for material failure as opposed to dimensional deviations?
I have pretty good health insurance, and it covers a lot of facial reconstructive surgery. But I'm on my own for the dentistry that accompanies it. So I toss a lot of olde aluminum bars, even when they look relatively straight. I like the idea of having that reinforcing sleeve right at the stem clamp. But I broke a bar once (half tore it, actually). It got my attention, and maybe until you do that it's hard to understand how frightening it is.
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Drop bars have multiple radical bends! I don't know if they are annealed after bending or not. I suspect not, so what is wrong with bending them back? Work hardening of AL is an issue but they were bent severely to begin with!
Has anyone seen stress crazing or fractures on new bars from the forming process? Does anyone know what the process yield is for material failure as opposed to dimensional deviations?
Has anyone seen stress crazing or fractures on new bars from the forming process? Does anyone know what the process yield is for material failure as opposed to dimensional deviations?
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I worked in the pipe and steel bending trade from 1981 to 2000 in the engineering department. We were able to bend all sorts of structural steel as well as pipe and tubing made from steel, aluminum, stainless steel, Incoloy, Inconel, Hastelloy, etc. Each material had its own idiosyncrasies of what it would tolerate. Aluminum age hardens very quickly. When bending aluminum, we'd have to buy it directly from the mill, because if it spent any time laying on the racks at a supplier, chances are it would crack when bending. These handlebars have had plenty of time to age harden, and any attempt at bending it back into shape it would be an exercise in futility.
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Thanks for the links. Interesting videos. Which AL alloy is not described in either one and doing a quick search did not reveal which is the preferable alloy.
I would be surprised if any were age hardening alloys, which would have to be specified as not all AL age hardens as described. Age hardening is related to temperature (heat) which impacts the crystalline structure to change (as does the work hardening).
I wasn't being critical or expressing a bias, just wondering about the material properties and the production process along with the engineering considerations of both.
@3alarmer - I am sorry you experienced significant injuries as a result of a failed bar. I understand the long term impacts from accidents. If replacing old bars with new ones gives you the confidence to continue to ride, that is great! Enjoy the ride!
My worst accident left me with a permanent vision impairment causing me to see double, depending on the range of focus. It is a challenge to wake up every morning and get my brain to switch dominate eyes! The nerves in my left forearm are still growing back after 11 years with new sensations occurring over long periods of time. Leaning the wrong way on my left arm is painful when the skin is pinched between the plate on the bone and whatever I am leaning on. Accidents and age change your perspective and sometimes makes you more aware of a given situation.
I would be surprised if any were age hardening alloys, which would have to be specified as not all AL age hardens as described. Age hardening is related to temperature (heat) which impacts the crystalline structure to change (as does the work hardening).
I wasn't being critical or expressing a bias, just wondering about the material properties and the production process along with the engineering considerations of both.
@3alarmer - I am sorry you experienced significant injuries as a result of a failed bar. I understand the long term impacts from accidents. If replacing old bars with new ones gives you the confidence to continue to ride, that is great! Enjoy the ride!
My worst accident left me with a permanent vision impairment causing me to see double, depending on the range of focus. It is a challenge to wake up every morning and get my brain to switch dominate eyes! The nerves in my left forearm are still growing back after 11 years with new sensations occurring over long periods of time. Leaning the wrong way on my left arm is painful when the skin is pinched between the plate on the bone and whatever I am leaning on. Accidents and age change your perspective and sometimes makes you more aware of a given situation.
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Last edited by SJX426; 01-27-21 at 07:04 AM.
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The above cautions are valid and believe me cutting a gorgeous Cinelli or a beautifully painted fork matching a complicated frame pattern that was dropped on the fork end, bending it, are truly painful .
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As far as aluminum bending, who here hasn't reefed their alloy brake arms for toe-in? Especially those squealing Mafacs. Perhaps solid alloy is more tolerant of bending than something hollow, like a bar.
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As for Mafac, as I recall, they have a toe-in adjustment built into the design, do they not?
Anyway, just a thought or two on the subject. The handle bar is now a matched set of handlebar (I cut it up but hated doing so - that said, I had to cut up a Pinarello years ago for the same reason, I still have nightmares).
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Yep, the Universal levers cracked just looking at them. Mafacs had no toe-in, you just bent them.
Fine looking Torpado Randy.
Fine looking Torpado Randy.
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Unless for a wall hanger, straightening bent alloy handlebars and then riding to any significant degree is foolhardy at best. Bars get bent generally for two reasons, a significant crash or long term metal fatigue (the dreaded droop) both of which should relegate the bars to the recycling bin. Compare the price of a pair of new bars to new teeth if you think I'm wrong (and that's if you only face plant...ever seen what happens when bars break while riding? I have, not pretty) and if you still want to straighten and use such damaged goods, I'll show you natural selection in action.
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Universal lever bodies and brake calipers are cast and not forged. Castings do not have an noticeable elasticity and don't deform, they fail catastrophically. That doesn't make them a bad caliper or lever base.
Designing with castings is a poor choice of saving money over durability, however.
P1000593, on Flickr
Impact with a car at 21mph
P1000602, on Flickr
Oh and look at the bend of the AL lever! Rolled sheet AL that is formed. It is all AL but the process to make the part can have dramatic difference. Not all AL is alike not only in the process but by the alloy of choice. AL alloys are a receipt of ingredients to get a desired result of mechanical properties based on the application and choices of the engineer. That receipt also determines the manufacturing process, both in the "cooking" of the receipt and the final process to make the end product.
Designing with castings is a poor choice of saving money over durability, however.
P1000593, on Flickr
Impact with a car at 21mph
P1000602, on Flickr
Oh and look at the bend of the AL lever! Rolled sheet AL that is formed. It is all AL but the process to make the part can have dramatic difference. Not all AL is alike not only in the process but by the alloy of choice. AL alloys are a receipt of ingredients to get a desired result of mechanical properties based on the application and choices of the engineer. That receipt also determines the manufacturing process, both in the "cooking" of the receipt and the final process to make the end product.
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Unless for a wall hanger, straightening bent alloy handlebars and then riding to any significant degree is foolhardy at best. Bars get bent generally for two reasons, a significant crash or long term metal fatigue (the dreaded droop) both of which should relegate the bars to the recycling bin. Compare the price of a pair of new bars to new teeth if you think I'm wrong (and that's if you only face plant...ever seen what happens when bars break while riding? I have, not pretty) and if you still want to straighten and use such damaged goods, I'll show you natural selection in action.
But yeah not recommended.
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Universal lever bodies and brake calipers are cast and not forged. Castings do not have an noticeable elasticity and don't deform, they fail catastrophically. That doesn't make them a bad caliper or lever base.
Designing with castings is a poor choice of saving money over durability, however.
P1000593, on Flickr
Impact with a car at 21mph
P1000602, on Flickr
Designing with castings is a poor choice of saving money over durability, however.
P1000593, on Flickr
Impact with a car at 21mph
P1000602, on Flickr
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They bent at different locations because the previous locations were work hardened with the last bend action. Typical behavior and an indicator.
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