vw powered trike

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Marc
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Joined: Thu May 23, 2002 12:01 am

Re: vw powered trike

Post by Marc »

You haven't furnished pictures or described the layout, but from your description of the shifter connection I'm assuming that your trike is rear-engine.
Mine's mid-engine, using a commercially-made sandrail cable-shift setup. That should not be required for rear-engine, and I wouldn't want to introduce the added complexity and potential failure points for no good reason. Not to mention the cost, $500-$600. I also find the "feel" to be very numb, a lot of which is probably due to the long cables needed in the mid-engine layout, but even with shorter cables it'd be unlikely to feel nice & tight compared to a non-cable linkage.

Nor would I want to try and make a linkage with a 90° turn. It could be done with a clever-enough corner coupling, or with a system of links connecting two parallel shafts, but it would be complex with several possible points of failure.
If you have the room to route the "rod" using a conventional U-joint or two with a maximum angle of 45°, it should be fairly simple to come up with something, however.

All of the "action" that the linkage has to accomplish on most other cars takes place inside the front housing (A.K.A. "nosecone") of the VW trans. The only thing the shifter on a VW needs to do is plunge the rod fore & aft and rotate it, and ideally provide some form of Reverse lockout - that's a luxury if the linkage works precisely enough that you can avoid accidentally raking Reverse when downshifting from Third to Second, but if you use a stock VW shifter that incorporates a lockout plate which makes it impossible to hit Reverse without pushing down on the spring-loaded knob (works great).

Another approach to consider would be to change the angular position of the cup at the front of the rod in relation to the transmission's internal shift lever (A.K.A. "hockey stick"). That could be done by altering the coupler, but since you'd be using a shorter shift rod than stock it'd be simpler to just make the change there.
The object would be to leave the rod running straight forward but cant the shifter to the side approximately 45° (to whichever side you want the shift knob). Then extend the shifter shaft if necessary to bring the knob out within reach. The long shifter would make for gigantic throws, but there's an easy/cheap (<$10) fix for that in the form of a readily-available "quick-shift kit" which moves the fulcrum point of the shifter up so you get the same motion at the ball with less travel at the knob:
Image

Or perhaps your seating position would put the knob within easy reach without extending the shifter. Here's one using an aftermarket shifter with trigger-pull Reverse lockout, a little sexier looking: Image

PBS Engineering makes a replacement nosecone which eliminates the stock hockey stick and manipulates the shift rails inside the transmission directly. It's also close to $500 plus the cables. Looks like an elegant solution for a mid-engine, but again IMO overkill for rear-engine.
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Marc
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Re: vw powered trike

Post by Marc »

What control layout are you going for? Mine's basically "automotive" (right foot throttle/rear brakes, left foot clutch, right hand front brake, shifter on right) which works out fine. If you prefer right hand throttle you'll want the shifter on the left; I wouldn't recommend trying to operate the VW clutch with a motorcycle hand lever, by the time you got enough travel at the trans the effort would be extreme - and a hydraulic setup won't change that either.
Eventually I plan to make my right-hand throttle also functional, probably with a bead-chain connection to the primary linkage à la automotive cruise control setups, to let me put my right foot on a highway peg when cruising.
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ALYKAT III
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Joined: Sat Apr 18, 2009 7:42 am

Re: vw powered trike

Post by ALYKAT III »

Uhh...fellas ? Did you notice his post is a year old ? That being said, he may still need help though.
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Marc
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Joined: Thu May 23, 2002 12:01 am

Re: vw powered trike

Post by Marc »

:oops:
Nope, didn't notice that someone had brought it back from the dead. Hope the O.P. still comes around, I'd like to know what he worked out.
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