Leading Link(s) - whose?

[lmo1131]

Way too much loose information on all of the "other" hack sites to be able for me to boil it down...

What, or whose, leading link front end would be compatible (with the least amount of surgical intervention) on a LWB R75/5?

A genuine BMW Earles (if you can find one), or... ?

[angysdad]

I always wondered if a URAL leading link would fit on a /5. Here is one on ebay...

http://cgi.ebay.ca/Military-Bike-Lea...item45e9d875f4

There is also a bmw earles fork listed on ebay...

http://cgi.ebay.ca/BMW-Earles-Fork-L...item563d11690a

I do not know if either of these would work, but someone in the know could certainly take some measurements and point you in the right direction.

[lmo1131]

Thanks for the heads-up on that Earles. He's selling the swing-arm separately. The last one I saw went for $35o I think it was. It had had the lower cross-member cut off at some point, and it was chrome plated (or what was left of chrome).

I've seen an Earles on a /5 so I know it will fit without the application of too much fowl language (everything being equal).

[angysdad]

you probably already found it, but here is the swing arm...

http://cgi.ebay.ca/BMW-Earles-Fork-S...item335dccc85b

[hhshort]

The old Slash 2 earls fork can be adapted to a slash 5. It does take some surgury and welding to adapt brembos to the leading link. The first problem is finding one.

[pmdave]

I've seen the Earles forks from a /2 adapted to fit the R100. The word from the owner was that the Earles fork downtubes are relatively thin wall. So, they aren't as sturdy as they appear. And, a bit of rust on the inside over the years really eats away the steel.

The Earles Forks have two pivot bosses on the bottom of the legs, where the leading link pivots. The rear hole is for "solo" operation (without a sidecar) The front holes are the "sidecar" position. However, if you look at the bottom of the legs, you'll notice that the pivot positions are not that far apart. Translation: sidecar trail isn't as short as might be desirable for easy steering.

For many years Keith Wash at Hedingham Sidecars in England produced the "Unit" fork, which is considerably stronger (and heavier) than the BMW Earles Fork. The Unit fork tubes are double wall. I know Keith was trying to retire a few years ago, so I don't know if he is still manufacturing the Unit forks. But if so, he can build them to order for different machines, different brakes, etc. I have a Unit fork on my R100/Ural rig.

I seem to recall that Dauntless Motors in Enumclaw WA was working on their own leading link. For anyone looking for a leading link front end, I would suggest contacting Jay Giese at Dauntless.

I would advise against trying to adapt a Ural front end to a BMW. The BMW aluminum triple clamps are a bit on the skinny side--appropriate for the slim R-bike downtubes. There really isn't enough meat to carve away the clamp to fit the Ural forks, and it would be unwise to turn the Ural fork tubes down to fit the BMW clamps. I've seen this done, and I didn't think the (mediocre) performance of the Ural front end was worth the risk.

Side Effects (Kamploops BC, Canada) does modify triple clamps by cutting and welding. I haven't heard of any failures, but personally I would prefer to not cut/weld critical parts made of aluminum.

I haven't looked into what would be involved, but I wonder if it would be possible to convert an airhead to an oilhead telelever. The critical part would be creating pivot points for the rear of the A arm. But if that would be possible, the Telelever can be converted to sidecar trail by replacing the lower ball joint bridge.

There are machine shops who produce triple clamps to specified dimensions--primarily for racers. I suspect it would be possible to have custom triple clamps made that would push the axle slightly forward. That would allow using the stock front end, wheel, fender, etc.

Another way of reducing trail is to reduce wheel diameter. Of course, that reduces ground clearance, but since an outfit isn't leaning into corners, leanover clearance can be compromised--if you watch those bumps in the road.

pmdave