So, saga continues...
Today's ride was uneventful but I have no idea why... !! When I got in today from a decent ride I parked the rig, unloaded, walked away and did a glance back that the rear to notice that the lean out that I had set the cycle to was nonexistent and the car seemed to be lower in the center (toward the right hand side of the tug) giving the car's tire the appearance of leaning in at the top... !!!! ( I should mention here that I used about 100 pounds of ballast to replcate at least part of the normal load I would have with a passenger)
The Velo uses a clamp on the frame at the rear where one of the adjusters is tied to... can this rotate or can the frame just settle...? This is really weird.
If the answer is yes,then let me tell you this...
I bought this rig from a fellow that only put about 400 miles on it, did not dig it (small wonder the way it was set up, but I digress) and I came along. I have put about 1500 struggling miles on it and I'm trying to figure things out. Does the frame just bed in over time and need to be adjusted more ...?
Whatzzuuuup...?
Thanks for all your guidance. I have made this a mission now... 🙂
Rob
It certainly sounds like your clamp is rotating on the frame. Set it up correctly(again) and paint a stripe across the clamp and frame so you can see if it shifts.
This is why I am not fond of clamp mounts. You don't want to overtighten them because you can damage the frame, but any thing less than that and they may rotate in use.
Proper alignment of the clamp and strut may help reduce the leverage on the clamp, which may keep it from slipping.
The Velorex Handbook shows the rear mount attached at a 90 degree angle. Mounting this way increases the torsional leverage on the rear mount and will help it rotate. Another factor is that you are working with a paint to paint connection which will compress in time also helping to allow slippage of the clamp and some rotation.
If the rear strut is mounted in a straight line (you may have to flip the clamp to do this) there is less tendency for slippage. This holds true for all four struts. If you can get a straight push/pull force on the struts there will be no rotation.
Another option would be to align the mounts for the best performance and then spot weld the clamp straps to the frame. A squirt of black Krylon and no more sag. Some manufacturers recommend this as a fix when using clamp type mounts.
Lonnie
You have met up with the notorious Veloreex lower rear frame mount my friend. The poor design of this mount is only surpassed by the poor mounting instructions given for it. Advice by Lonnie and Vernon is right on. If you want another one of these clamps I have quite a collection of them...no wait...I threw them out..lol.
Seriously I usually just replace that clamp with another deal using a welded on bracket and an adjustable eyebolt or clevis.
As Lonnie said you can make the stock clamp work by positioning it so it cannot rotate easily. In line or in a bind, if the setup is good, will be fine. A small pin or spot weld is still a good idea.
Velorex sidecars have used this clamp forever it seems . Always amazed me why. Maybe someone made them a zillion of them back in the stone ages and they still have stock on hand? Heck if you look at it closely that thing is quite complicated and looks to be very labor intensive to manufacture. Great example of an overdesigned component that simple does not work well. Am I putting down Velorex? No, just the famous lower clamp with no feeling of guilt..they basically stink.
Ok, great... well I know what the issue is at least. The clamp does seem to have a pin to help locate it, bolt head going to nowhere right through the top half of the clamp...?? I'll check things out tonight.
So, Hack'n... Is that 90 degrees up that Velo tech manual calls for......? Mine is horizontal. Gotta believe that the paint slippage issue is the problem here. And good idea to match mark the clamp to the frame to check for rotation... 😉
Is there a source for replacement brackets if it comes to that...?
Thanks folks.
Rob
Check with Dauntless Motors or one of the other fine sidecar manufacturers to see if they have a subframe for your bike that you could make work with the Velorex.
This would probably be the easiest and best solution, although, cheap bastard that I am, I would probably see if I could modify the clamp so that it had an additional tab that bolted to the frame to prevent rotation.
If you do something like that, take a hard look at where the mounts attach to your bike frame. If the frame or the mounts are at all weak, or designed in a way that increases leverage in use, they will flex. If there is any flex, you need a subframe. Flex or movement usually results in handling problems, often a bad wobble somewhere in the speed range. Even if it handles ok, flex or movement will eventually damage your frame and/or mounts.
I was amazed at how stout I needed to make the mounts on my Bandits to get ridd of the flex. I had to redesign my mounts several times before I could get rid of the movement.
Can you define what you mean by increasing leverage...? I know the thing is flexing now but, that may be the clamp, I'll know better after tonight. And, not to sound too stupid but... If a subframe is needed, is this in addition to the frame that is under the car now or replacement...?
Also, when aligning the clamp and strut, should the clamp be in-line with the strut, up in a 45 degree angle....? Seems to me the clamp is down at the horizontal position, I'm away from it now... Drove the MGB to work...:)
Thanks,
Rob
On My Bandits I made a piece the top front mount threaded into out of a heavy piece of angle and a threaded boss welded in as a gusset that stuck out from the bike frame at right angles, and bolted to the frame in two places. The eye threaded into it and the top of the strut mounted there. It looked hell for stout and should have worked but actually provided a fulcrum wth the strut acting as a lever and the sideloads of the entire hack working to twist the mount and frame- I had tremendous flex.. I ended up tossing the piece I had made, drilling out one of the boltholes and mounting the eye directly, bolted thru the frame. Problem solved.
Aligning a clamp at right angles to the force applied by the mount can do the same thing. Putting it inline with the force will couse it to push towArds the frame rather than twist around it- a better arrangement providing the frame member is stout enuf for the load.
Originally written by RadGuzziHack on 7/20/2006 6:40 AM
If a subframe is needed, is this in addition to the frame that is under the car now or replacement...?
Rob, the subframe bolts to the bike to spread the loads and re enforce the bike frame and provide good placement for the mounting points. The sidecar mounts to the subframe and the subframe mounts to the bike.
On my Bandits, the subframe carries the bottom two mounts and the top struts are mounted directly to the bike frame. On my Triumph all four mounts were carried by the subframe.
To give you some idea, you can find some photos of the Triumph subframe here:
http://www.triumph-tiger.com/phpBB2/viewtopic.php?t=1378&highlight=sidecar
and the Bandit subframe here:
http://adventuresidecar.com/ASSFLEET/assfleet3.htm
Vernon,
Now THAT is Adventure Riding... ! ! ! ! I have never gotten the Quota that dirty, not without trying mind you. 😉
That sub-frame unit for the Tiger looks to be a piece of work. Does that frame incorporate the engine as a stressed member...?
The Moto Guzzi Tonti frame is a very substantial unit and I do not know of any others that require the sub-frame... not to say there are none.
I'll know more about what is really going on with the mounts, clamps and struts after the weekend's festivities... 🙂
Thanks,
Rob
