help w /5 sidecar mnts

[irv1231]

I'm looking for help (or pics) in setting up '73 75/5 to Velorex hack. I have to basic tube mounts, but I think I need at least a plate at the bottom of the rear. Looking for pics, measurements, about anything will help. Thanks.

[r60us]

Perhaps the best place to post your request for help is the chat room/forum on sidecar.com.

First, remember that BMW states the post 1969 airhead BMWs are *not* suitable for sidecar attachment.

That said, IMO the easiest solution and at the same time preventing butchering an original /5 or possibly damaging the frame by overtightening those horrible Velorex mounts is to purchase a complete sidecar mount from Dauntless Motors or build a similar one. Also, the /5 frames aren't very strong (called Gummikuh - rubber cow, in the fatherland) and IIRC some /5 frames on sidecar outfits cracked/broke under the gas tank, probably at the rear of the backbone where the down tube loops are welded on, unless it was reinforced. If you don't mind attacking the /5 frame with a MIG/TIG welder, the alternative is to gusset the frame in the appropriate places, weld on the two upper mounts, and build a sub frame for the two lower mounts that straddles the engine inside the frame and is held in place by the engine bolts (it takes place of the spacers between the engine and the frame). The subframe looks like a lower case H:

http://img398.imageshack.us/img398/6070/smountrf3.jpg

BTW the 1977 - 1980 /7 frames are probably the best for sidecar use without a Dauntless style mounting system - they have the double backbone and also thickest down tubes - almost twice as thick as any other year including the /2's.

Hope this helps.

[irv1231]

Thanks a ton,

I will probably build a subframe. I hate to weld on the frame if I can help it, and I don't care for the clamps that came with it. A dif bike would be nice but I don't see it in the near future.

I was looking at the frame to see if I could run a mount to both tube in the top front.

[HankPfister]

Irv,
I have a Dnepr sidecar mounted to my R75/5. R60 is correct in his recomendations. Throw those Velorex mounts away. They are notorious for failing. My rig utilizes a lower subframe that accepts the sidecar lower mounts. It is a heavy steel pipe that mounts to the two engine bolts, and then at the rear at the passenger foot peg. Then for the front upper mount it has a thick steel plate that joins the two down tubes together and the front angle mounts bolts here. I'll post some pictures later when I get home to my 'puter there.
Used sub frames do come up for sale once in a while. I've seen them on the IBMWR.org marketplace, and on Ebay. The Dauntless sub frame is a good one.
There is an active sidecar group on Yahoo Groups, Sidecar Talk. Lots of knowledge shared there, as well as some nonsense.
Good luck.

[aerohead9]

Go to Lowell Neff website. He builds an excellent subframe for the R bike. I've had one mounted to my R75/6 for 14 years. He also sell unit forks which will improve your steering. Below is his website.

http://neffdesign.angelcities.com/aboutus.htm

[grasslander]

You might also check out Dauntless motors. I use Jay's R-bike mounts on my R90/Jupiter rig.
http://www.dauntlessmotors.com/Mountinghardware/bmw_mounts.htm
Please check out these sites for lots of good info:
http://www.sidecar.com
http://autos.groups.yahoo.com/group/SCT

[HankPfister]

Here is a photo of the mounts that hold my Dnepr to my R75/5. I don't know the manufacturer, but apparently they were made in Germany for BMW Airheads.

http://pfestus1.smugmug.com/photos/279659385_AnvmX-S.jpg

Upper left is a clamp that fits over the battery and ties the main frame tubes together. Upper right is the piece that mounts on the front main frame just below the steering head and ties both down tubes together and accepts the sidecar front upper diagonal mount. Then below them is the main lower sub frame that bolts to the engine mounts, and accepts the front and rear sidecar frame mounts. The next two are the diagonal struts, then the steering dampner.

Here is a shot of the mounting:
http://pfestus1.smugmug.com/photos/279659393_hXrxR-S.jpg

This is a custom steering triple tree system from Perry Bushong Sidecars in Fort Worth Texas. It changes the trail to a more sidecar friendly geometry, makes the rig steer a LOT easier. Cheaper than Leading Link Forks, which are stronger and do the same thing.
http://pfestus1.smugmug.com/photos/159105958_tAAVP-S-1.jpg

Here is the rig:
http://pfestus1.smugmug.com/photos/43760268_4nV9a-S.jpg