Shock Relocation/Angle Change (sorry for making new threads)

[BENSPEN]

Hello, I am wondering if there is any way to convert the shock from a normal K angle to that of the bike in the attached photo, I like the style an incredible amount, but am wondering what the downfalls are, and what must be done to convert the setup.

Also, Sorry that i have started so many threads, im a newb.

(Also i know the pictured bike has a modified subframe)

Thanks again,
-Ben

[TrueAce]

Ben, that lateral shock mount is a very sophisticated modification which the average biker is not going to replicate...........do you have info on which custom shop produced that bike? You can easily switch the length of the K shock as mounted + or - an inch or so by ordering the different lengths, but to build that lateral rig would cost more than you think. 

[TrueAce]

Ben, that lateral shock mount is a very sophisticated modification which the average biker is not going to replicate...........do you have info on which custom shop produced that bike? You can easily switch the length of the K shock as mounted + or - an inch or so by ordering the different lengths, but to build that lateral rig would cost more than you think. 

[BENSPEN]

Thanks For the quick Response!!

unfortunately i could only find the pic on pintrest so I cannot contact the builder, I dont know how to use pintrest! :yes

[TrueAce]

You can get a 12.5 inch rear shock or a 14 inch ( I think), but you aren't likely to be able to cost-effectively reproduce that lateral shock. You eat what you kill, don't bite off too much.

[Scud]

You eat what you kill, don't bite off too much.

That being said... I just watched an animal show on TV with my daughter. The most amazing thing... a jaguar killed a cayman and dragged it off into the bushes to eat it.

That is a cool-looking shock, but it must have an incredibly small amount of travel - and I think it required significant fabrication to get it mounted.

[TrueAce]

Well put, that just about sums it up.And if you know you ain't no jaguar, don't even try.........

[Dennis de Vries]

Here you go, it's build by an Estonian shop called Renards Speed Shop, they are on Facebook too but couldn't find this bike quickly... If you are serious about this give them a shout maybe?

http://www.pipeburn.com/home/2014/05/08/bmw-k75-by-renard-speed-shop.html

[TrueAce]

 There you go.......beautiful, one-off custom. Now picture doing up an old K like that but with a new Proggressive shock.........wouldn't it look pretty good? That sub frame and lateral shock is just to show their skills. Some folks, like BSK make, sell parts they have designed. Just giggles, contact these folks to inquire about puchasingthat shock unit. Bet it's not a bolt on!

[The Mighty Gryphon]

Cool looking setup on that shock.  That configuration results in very little shock travel.  Something similar to suspensions where the shock is mounted close to the swingarm pivot.   Do the geometry on the rear end to see what the shock travel per unit of wheel travel ratio is versus the original.  That would give you an idea of how much the spring and damping rates need to be increased.  I would guess at something in the three to four times region.

The loading on the shock mounts will increase as well.  Off the top of my head, I would fabricate a bracket that would go over the outer end of the shock mounting stud on the final drive.  It would go forward to be attached to the top bolts holding the final drive to the swing arm.  The goal is to prevent bending the stud by spreading the load to other parts of the swingarm..

At the frame end, a mount could fairly easily be attached to the frame tube, and a gusset to spread the load on the tube to the rest of the frame.  Again, off the top of my head, that gusset could simply be a triangular plate welded into the frame above the transmission mount.  With the transmission being a stressed  member the frame should already be pretty strong in that area.

As I see it, the biggest problem would be dialing in the spring rate, especially if you want a progressive rate spring.  Then there is the damping ratios, although there are shock suppliers like Works Performance that could probably help you with those items. 

All in all, it looks like a pretty doable projec.

[TrueAce]

This configuration is most often used with open wheel racing, which utilize very sophisticated gas/oil shock absorber systems featuring variable rate fluid dampening. While it looks cool on a motorcycle, I doubt the availability of a shock that would be affordable that is also functional in this configuration. Can you see a $3000 shock on a $3000 K?

[The Mighty Gryphon]

Yeah, that's what I was thinkin'.  A $6000 cafe racer...

[TrueAce]

Cadillac has some interesting shock technology using variables viscosity fluid with magnetic properties, licensed from Ferrari I think. Check your local salvage yard for a totaled Curren model.Caddy, be sure to get the active system controller unit. Send pictures.

[F14CRAZY]

Cadillac has some interesting shock technology using variables viscosity fluid with magnetic properties, licensed from Ferrari I think. Check your local salvage yard for a totaled Curren model.Caddy, be sure to get the active system controller unit. Send pictures.

If I remember right Bose came up with it. Ferrari licenses it from GM though and is used in some Cadillacs and other brands

[Laitch]

Here you go, it's build by an Estonian shop called Renards Speed Shop . . .

Nice example of research persistence, Dennis. Thanks for finding it.

The striking thing about this project to me—which was also observed by one of the Pipeburn article's commenters—is the elegant method used to eliminate the angularity of the joint at the tank and seat—often a focus of these projects' critics. After designing that, they increased the thickness of the padding in the front of the seat to compensate for the slope. The result gives an attractive rake to the whole upper assembly—well done.

[Bill]

Cadillac has some interesting shock technology using variables viscosity fluid with magnetic properties, licensed from Ferrari I think. Check your local salvage yard for a totaled Curren model.Caddy, be sure to get the active system controller unit. Send pictures.

If I remember right Bose came up with it. Ferrari licenses it from GM though and is used in some Cadillacs and other brands

The current GMC pickup features a variety of it.  I believe the Cadillac LMP1 car [lemans racing]  and some of the factory Baja  1000 chevy trucks were proving grounds for the  tech sometimes referred to as 'Magneto restrictive' .... right out of X-Men

[Ardinos]

Sorry I know this is an old thread. I tracked down the guy who did this being very interested in seeing what it would take to do to my K100. Here is his email below. It's not an easy process. He lost me at lengthening the driveshaft.


Hi Chris,[/size]thank you for a good words. We do not sell it as a kit, but I try to help you as much as i can. It was a complicated build, nothing bolts right up and every part needs modifications.Front end (triple trees, fork, front wheels, brake discs, callipers) are from Moto Guzzi Griso. Rear shock plus link are also from Griso, everything else is custom made.


We did new rear shock mounting point on the subframe - new swing arm pins. In original they are aluminium, but now you need steel. Bracket for rear shock is standing in between the rear drive casing and shaft tunnel, it means you need 8mm longer drive shaft. New rear shock (Griso), link for a shock (Griso). - CNC milled needle bearing case for a push rod need to be welded on the gearbox.

Please consider that the bike we made was a single seater and we tested our conversion only with one person.

Kind Regards,



Andres Uibomäe

[Snowman]

Here is a closer shot. This was pulled from the link below. Maybe get on the site and ask who the builder is. Speak French?
http://www.caferacerclub.org/t31293p135-bmw-special-k

[BENSPEN]

I put a lot of thought into this when I originally posted this, I ended up moving on when i started my project and no longer prioritized it, being quite skilled at solving physics equations, I ended up with a desired spring rate. you would have to extend the driveshaft because of the new shock mount plate between the final drive and swingarm (liscense plate mount). personally, if i were to do this, I would not screw with the jig and link. I would try to attach the lower shock directly to the lower jig mount and then find a custom made spring specific for the application. Now, i frankly dont think it looks as super cool as i used to, But, keep in mind that the travel may not be compromised, but the stroke would be very rigid and harsh. Keep in mind, the higher the upper shock mount is on the sub frame, the better the geometry. IDK why you would need custom needle bearings. Also, I feel like you could do the lower shock mount on the swingarm side and not have to lengthen the driveshaft.


"keep in mind" said that too many times

[Ardinos]

So I was thinking of looking at something slightly less complicated. Relocate the shock attachment point to a new angle, just not as parallel as what was done. I'm going to have to do some review and figure out how to do the math for the spring rates and stroke length for the shock. The setup as laid out is too complicated for me. But I hate the naked look with the shock perpendicular to the swing arm. I'm hoping an in between look will be close enough.

[duckytran]

Here's a radical K1100 build from a Swiss shop JV Performances.


http://www.pipeburn.com/home/2016/10/26/turbo-bmw-k1100-jv-performances.html