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Old 03-09-2011, 10:36 AM   #36
The Road Scholar
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Joined: May 2003
Location: CheeseHead Land...
Oddometer: 1,115
Originally Posted by brockoli View Post
BMWzenrider, agreed, each have our wish lists and what works for what we want to do. The R1200 is a great machine and powerplant, no doubt. The old military hacks with minimal hp, did the job and did it well.
One thing that the boxer powerplant arrangement has over most of the inlines is that nice wide torque curve that starts at pretty low RPM's and just lets it pull strong off the bottom, even if you are lugging it a bit.

Of course, the new BMW K1600 inline-6 blows that concept right out of the water with 75% of its' max torque available from 1,500rpm all the way up to redline.
Now THAT is a powerplant that sounds like it was made for pulling a sidecar!
Compact, powerful, and with loads of torque right from idle...

Originally Posted by brockoli View Post
I like to have more hp than needed. ( is it wrong to want a super charger for my truck and to turbo my GS1000?)
Not at all, my old R75/HitchHiker rig was just fine, but I lusted after more power which drew me to find a R100RT to mount that lightweight sidecar to. And then I eventually felt the "need" to upgrade to the R1200 rig that I currently have.
I think that some people just begin to crave more speed/power....
{Not that there is anything wrong with that...}

Originally Posted by brockoli View Post
Great ideas on on the suspension setups. A lot of designs differ with the chosen power transfer (driveshaft, chain, hydraulic, flux capacitors). A-arms don't like chains if the arms are pivoting off the sidecar frame, shafts don't overly care for linked setups unless the driveshaft has a slip yoke or runs perfectly parallel up and down, and that poses problems to.
I agree, every suspension solution has its' own challenges as well as strengths. The trick is to decide which one works best for the purposes that the vehicle is being designed for.

Any shaft driven IRS is going to want some kind of slip coupling at one end to work properly. Either a plunging type CV joint as is common on the inboard end of front-wheel-drive cars or a slip spline CV as used on the 930 CVs which are common in the sandrails and 4x4 community.

Although I have seen one novel sandrail IRS setup which used a rigid shaft drive going through a pair of phased univerals. It uses the rigid shaft as the upper suspension links. No idea how well it worked in practice, but a novel approach!

I am leaning towards using the 930 CV's in my design because of the relatively high working angle that they are capable of, and how commonly available they are.
Also, they are a flange mount model, which means easy removal/replacement in the field if required. You could carry a spare joint & boot pre-greased in a sealed zip-lock and replace a failed joint relatively easily out in the boonies if you were on an adventure trip and find a replacement spare in the next big town. (or at least get one ordered in without much drama...)

Also, because the sandrail and 4x4 community is starting to standarize on this size joint there are sources for wheel hubs with this flange/spline readily available in the aftermarket as well as lists compiled of what production hubs work with it. (Easier sourcing of parts...)
Karl Kugler
2005 BMW R1200RT w/Hannigan-LT sidecar
2002 BMW R1150RA
In Memoriam: Harley, 1993-2010 You will be missed.
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