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Thread: 1973 R75/5 bent rim returning from Rally

  1. #1
    Registered User kwb210's Avatar
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    1973 R75/5 bent rim returning from Rally

    Those darn Rallies!
    My son and I rode my 1971 and 1973 Slash 5's to the Rally. Bikes ran about as good as it gets. On the return route heading northbound on WA State Route 25 I struck a rock. I didn't bother to record it's size in my brain, it was enough mass to bend the rim and pop the headlight out. Duct tape fixed the hanging headlight and since the tire was holding air I rode on home. My question is how do I bend this rim back into or near its original shape? I like character but this is not what I had in mind!
    Regards,
    Kurt

    PS: rally was great! Thx to all the workers!
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    1977 R100/7 1971.1972.1972.1973 R75/5
    1974 R90/6 multiple boxes
    Airhead Revival
    "Objects in the mirror appear to be losing" unk

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    On my /5 90, I had almost exact thing happen to me - with my front spoked alloy wheel.

    I had my young son on the back and I hit a manhole they had sticking up about 2" above the road surface which they were about to repave.

    I was just lucky to have been able to keep control of the bike.

    My wheel wasn't quite as bent as yours, but I was able to get it straightened out.

    I took rather large "C" clamps and put some extra support on the opposite side of the bent side, so that squeezing the rim with the "C" clamps would not bend the opposite side in.

    I carefully with a lot of time and patience, kept working the clamp tighter and tighter checking often. I personally did not use any thing else like heat. I just kept working it and it eventually went back into shape. It was almost invisible when I got done. Only if one were actually looking for it could one see it.

    I am sure, that there may be others with more technical and more reliable information.

    One thing I would keep an eye out for is any cracking - as that would really affect safety.

  3. #3
    Registered User lmo1131's Avatar
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    That must have been a surprise ... I don't think I'd be bending that rim into anything other than a shape able to fit into a recycle bin. Aluminum doesn't do well with being bent and rebent; it work hardens the metal and it gets brittle. There are plenty of wheel shops that could handle it, if you had time to send it out. I imagine the tire's a goner too; I'd want it off for an inspection, at least.

    If you have an Anonymous Book you might be able to locate a "loner" to get you home.
    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  4. #4
    Outlander Omega Man's Avatar
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    There is a great deal of information at Woody's Wheel Works that may help you in a decision.....and nice job staying up-right
    http://www.woodyswheelworks.com/home.htm
    OM
    "Well they say.. time loves a hero but only time will tell.. If he's real, he's a legend from heaven If he ain't he was sent here from hell" Lowell George
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  5. #5
    '92 R100GS '81 R100/t brittrunyon's Avatar
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    After bending a rim on a pothole the size of a small pony in Honduras, this is how we (they) fixed it.
    It's still rolling today.

     photo Wheel_3828_zpse1acfc84.jpg
     photo WheelRepair_3822_zps87056032.jpg
     photo WheelRepair_3827_zpsedfb2bef.jpg

    Good luck with the repair!
    1992 R100 GS, 1981 R100/t, 2007 F 650 GS

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  6. #6
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    Here's another answer. My brother made this nice little video of a similar problem he had with a bent rim.
    http://www.youtube.com/watch?v=5wYWvuneFvE
    Only a Biker knows why a dog sticks his head out of a car window.

  7. #7
    Benchwrenching PGlaves's Avatar
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    I would send it to Woody's Wheel Works, or one of the other experienced reputable wheel shops. Done correctly the wheel can be as good as new. Done incorrectly the wheel can be a hazard.

    I bent one on my F650 Dakar so badly that I could see the inner tube - still holding air - when I looked at the rim from the side. It had stretched the metal to the point it wouldn't go back where it belonged. Woody's laced up a new rim with new spokes at a very reasonable price. I got it back balanced and true, with my tire put on the new rim.
    Paul Glaves - "Big Bend", Texas U.S.A
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  8. #8
    Registered User kwb210's Avatar
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    Excellent idea and certainly on the safe side

    I have been mulling over the idea of a home shop repair. If I were on the road i would certainly consider it, but I'm not! I think the idea of a professional shop doing the repair is the way to go. Regardless of how much I ride the slash 5 in the coming years, a poorly repaired wheel could still fail near home. My luck is breakdowns just don't seem to occur in my shop! I'll contact them and report back with their options. I also have another slash 5 I bought without wheels, well the wheels on it were borrowed from a rusty donor just to get her home. I have the rims and hubs but have not finished the project. Maybe send all three wheels out.
    Thank you,
    Kurt

    Quote Originally Posted by PGlaves View Post
    I would send it to Woody's Wheel Works, or one of the other experienced reputable wheel shops. Done correctly the wheel can be as good as new. Done incorrectly the wheel can be a hazard.

    I bent one on my F650 Dakar so badly that I could see the inner tube - still holding air - when I looked at the rim from the side. It had stretched the metal to the point it wouldn't go back where it belonged. Woody's laced up a new rim with new spokes at a very reasonable price. I got it back balanced and true, with my tire put on the new rim.
    1977 R100/7 1971.1972.1972.1973 R75/5
    1974 R90/6 multiple boxes
    Airhead Revival
    "Objects in the mirror appear to be losing" unk

  9. #9
    Registered User lkchris's Avatar
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    Quote Originally Posted by kwb210 View Post
    ... and since the tire was holding air I rode on home.
    Hate to mention this, but if you were running tubeless this would not have been the case.

    Our club has had fun with this, as I've related here previously. In 1984 a member riding a '77 R100S hit a pothole in Yellowstone on the way to the National in Missoula and flat-spotted his front (wire) wheel. He humpty-bumped the rest of the way to the rally, where he found a new wheel, IIRC.

    In 1998 another member flat-spotted a rear wheel on her R850R in Yellowstone on the way to the 2nd MOA National held in Missoula. She waited right there for a new wheel to arrive.
    Kent Christensen
    21482
    '12 R1200RT, '02 R1100S, '84 R80G/S

  10. #10
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    Never been under the impression that the way a dented aluminum rim was fixed was beating on it with whatever. always thought that pressure was put on the dimple, preferably over night, the next day a little more pressure over the next night and so on until the aluminum remembers the memory of its shape?

  11. #11
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    As a metallurgical engineer, I do not advocate straightening of rims or any other critical safety parts. One is advised to proceed at one's own risk in this matter. For what it is worth, the wire spoke wheels came with two different alloy rim types. The later rims were heat treated and my BMW parts book shows p/n 3631 1233 325 & 3631 1236 543 rears and 3631233 323 & 321 fronts as the heat treated items.
    A heat treat rim would be problamatic for straightening;the non heat treated rims less so.

  12. #12
    Registered User lkchris's Avatar
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    Quote Originally Posted by swall View Post
    As a metallurgical engineer, I do not advocate straightening of rims or any other critical safety parts.
    Thanks for your valuable post.

    Indeed motorcycle maintenance and repair should be science-based rather than word-of-mouth legend based.
    Kent Christensen
    21482
    '12 R1200RT, '02 R1100S, '84 R80G/S

  13. #13
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    Quote Originally Posted by swall View Post
    As a metallurgical engineer, I do not advocate straightening of rims or any other critical safety parts. One is advised to proceed at one's own risk in this matter. For what it is worth, the wire spoke wheels came with two different alloy rim types. The later rims were heat treated and my BMW parts book shows p/n 3631 1233 325 & 3631 1236 543 rears and 3631233 323 & 321 fronts as the heat treated items.
    A heat treat rim would be problamatic for straightening;the non heat treated rims less so.
    Your thoughts on the use of a torch on a cast rim as shown in the Honduras pics above? To my knowledge the "rim shops" commonly straighten them w/o heat using hydraulic pressure only.Thanks
    "If I had my life to live over, I'd dare to make more mistakes next time...I'd relax,I'd limber up... I would take fewer things seriously...take more chances... take more trips...climb more mountains...swim more rivers...eat more ice cream." Jorge Luis Borges at age 85.

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