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Old 11-05-2014, 12:55 PM   #1
Hookalatch OP
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Location: Cottonwood, CA
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Collet & Ball vs. Clevis & Heim

1978 Ural on a 1984 BMW Airhead. This must have been done many, many times. In searching for the best way to mate the two I am coming up with differing opinions- shock!

I have a DMC subframe for the Airhead and it is setup with clevis mounts for the 2 lower mounts. Apparently they normally also use heim joints instead of just an eye bolt. Must be an angle issue since the clevis is welded in place and can't rotate. If used as-is I would have to modify the lower Ural mounts for clevis instead of the ball and collet.

Alternatively I can weld balls in place of the clevis mounts on the DMC subframe and use the original Ural ball and collet mounts. I am less concerned about permanently altering the Ural frame than I am to use the best approach but have no basis to know which way is the best.

Any suggestions or advice will be much appreciated. Especially if there is an explanation of why one system is superior.

Chuck
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Old 11-05-2014, 02:45 PM   #2
jaydmc
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You will hear lots of opinions both ways. One thing I prefer about the heim joints is ease of installation and fine tuning alignment. The ball clamps I find to be a pain to install as you have to slide the clamps over and then tighten them down while the hiem joints you simply slide a bolt into them. With the ball type you set your alignment by sliding the pinch tubes in or out which may also the case with the heim joints however with the heim joints you can also fine tune the alignment by threading them in or out and as you can count the turns you will know just how much you have changed the alignment for every turn.
Both ways have their supporters.
Jay G
DMC sidecars
www.dmcsidecars.com
866-638-1793
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Old 11-05-2014, 03:19 PM   #3
Hookalatch OP
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Quote:
Originally Posted by jaydmc View Post
You will hear lots of opinions both ways. One thing I prefer about the heim joints is ease of installation and fine tuning alignment. The ball clamps I find to be a pain to install as you have to slide the clamps over and then tighten them down while the hiem joints you simply slide a bolt into them. With the ball type you set your alignment by sliding the pinch tubes in or out which may also the case with the heim joints however with the heim joints you can also fine tune the alignment by threading them in or out and as you can count the turns you will know just how much you have changed the alignment for every turn.
Both ways have their supporters.
Jay G
DMC sidecars
www.dmcsidecars.com
866-638-1793
Thank you for the response Jay. In searching there were references that you might offer something to make this conversion easy. I can't find it now but I remember reading that you no longer offered your balls to weld onto the bike subframe. Do you offer an easy solution to modify the Ural frame? I can visualize capping the collet end and welding on a clevis but wondered if you have a different solution.

Chuck
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Old 11-05-2014, 03:29 PM   #4
jaydmc
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The way we deal with the Ural frame is we provide a new weld in pinch tube clamp to replace the lower front which on the Ural (or Dnepr or CJ) usually are not adjustable which means that the ball would have to be on the bike at exactly the right height for the sidecar to sit level and it would also need to be at the right spacing for wheel lead and sticking out far enough to clear the head. We then also weld on a new pinch tube type clamps for the lower rear as the stock location is so far aft that we end up with lots of flex in the lower rear mount. Once these new pinch tubes are welded in our standard 1.5 inch (or 1.25 in the case of the Dnepr and CJ) angled clamps slide in. To these we slide our angled bosses which have the hiem joints on them. We do provide drawings as to how to do the welding. The parts to do this come to $430
If you email me directly jay@dmcsidecars.com I will send you the drawings.
Jay G
DMC sidecars
www.dmcsidecars.com
866-638-1793
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Old 11-06-2014, 05:38 AM   #5
hdgypsyman
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Modified Dnepr frame

Jay supplied me with the parts and directions to modify my Dnepr frame
Before:


After:


As Jay stated much more and easier adjustment at the front mount. My rear mount got moved from the original position on the Dnepr frame and Jay provided the parts for that transition also:
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Old 11-07-2014, 03:45 AM   #6
iantochips
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This is really useful- having just cut off the front mount from my Dnepr chassis!

Only problem is that the tube is so distorted by the brackets already welded on in this area that Jay's slide in mount certainly wouldn't slide in- is there enough length on Jay's part to cut away the tube some more until approx round stock is reached?

My other fear is that if I order the bits they'll disappear into Portuguese customs and only reappear after I'm dead....

I was making up a subframe long enough to reach the back mount of the Dnepr (mating to 1500LC) but I see this might not be necessary either. I should add I'm drastically lowering the chassis to match the stance of the bike by modifying its trailing arm with a new spindle above the stock location.
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Old 11-07-2014, 08:28 AM   #7
jaydmc
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You can trim off the mount however make sure you have an inch or so of tubing going past the frame clamp, or you can weld it under the frame like on the rear, what ever works best for you. Usually the front of the frame is straight enough for the mount to work.
Jay G
DMC sidecars
866-638-1793
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Old 11-07-2014, 03:59 PM   #8
iantochips
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Quote:
Originally Posted by jaydmc View Post
You can trim off the mount however make sure you have an inch or so of tubing going past the frame clamp, or you can weld it under the frame like on the rear, what ever works best for you. Usually the front of the frame is straight enough for the mount to work.
Jay G
DMC sidecars
866-638-1793
Very helpful Jay, thinking of ordering the bits from you to go to the Uk then I can collect them in a couple of months. The Uk customs aren't quite as trigger happy....
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Old 12-01-2014, 11:52 PM   #9
bmweuro
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Quote:
Originally Posted by jaydmc View Post
You will hear lots of opinions both ways. One thing I prefer about the heim joints is ease of installation and fine tuning alignment. The ball clamps I find to be a pain to install as you have to slide the clamps over and then tighten them down while the hiem joints you simply slide a bolt into them. With the ball type you set your alignment by sliding the pinch tubes in or out which may also the case with the heim joints however with the heim joints you can also fine tune the alignment by threading them in or out and as you can count the turns you will know just how much you have changed the alignment for every turn.
Both ways have their supporters.
Jay G
DMC sidecars
www.dmcsidecars.com
866-638-1793

I disagree. If everything is built correctly to start with there is no need for heims and having two lower ball mounts is is way easier to attach the sidecar and adjust. Talk to any off road or race car guy about heims vs. ball joints.
My rule of thumb is if they are not doing it to sidecars in Europe then it's not good enough
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