Creating shift linkage

[RussMcB]

Soon I will start thinking about how to create shift linkage for my conversion.

I've heard that some cars, perhaps Stohrs, have a mechanical paddle shifter. I can't afford a high dollar paddle shifter, but I am interested to hear about a mechanical paddle shifter if they aren't too expensive. However, I can't really see how they would work with a steering wheel that can turn more than a full revolution. Can someone describe the set up for me?

Another idea I've been pondering is to use part of the shift linkage left over from the Pinto/LD200, and attach one or two cables to the shift rod in the neighborhood of my right elbow. I'm considering not just one push-pull cable, but two. As the shifter is pulled back to upshift, it will "push" a cable and at the same time "pull" on another cable so the shift arm at the transmission will feel both the pull and push forces from the two cables (one pushing from behind while the other pulls from ahead). Hope that makes sense.

Looking forward to suggestions. I haven't searched the DSR forum yet but will when I get a chance.

[preform resources]

Russ,I believe that is how the Stohr paddle shift works,two cables attached to the paddles run back to the gearbox.
Dave Craddock

[Wren]

I'll try to go take some pictures of a paddle shifter that I developed for our FSAE car. I integrated the clutch into it as well, but the principle is the same.

I used an aluminum paddle and a push-pull cable. It was pretty effective.

[RussMcB]

Thanks for the quick responses.

IIRC, my steering wheel has something like 1.5 turns lock to lock. Seems to me that would be asking a lot from two shift cables. Am I full of it? :-).

[Wren]

Thanks for the quick responses.

IIRC, my steering wheel has something like 1.5 turns lock to lock. Seems to me that would be asking a lot from two shift cables. Am I full of it? :-).

ours was mounted to the frame, but was big enough to let you get a hand on it from any position(~1 turn lock to lock for us).

We were also autocrossing, so it was a slightly different problem.

Since then, an air shifter has been developed for dyno work that does a decent job too.

[High Desert Racing]

Russ,

By what I understand the Stohr Paddle is actually mounted to the dash behind the steering wheel (similar to what Wren says) to resolve the cable turning issue, but I could be wrong.
I am also very interested in how to do this.

Cheers,

Ed

[RussMcB]

Oh, I think I'm getting it. The paddles do not turn with the wheel. Rather, they are mounted to the chassis and they are usually within reach of fingers? I guess you're rarely shifting when the wheel is turned more than a little bit.

[Wren]

Oh, I think I'm getting it. The paddles do not turn with the wheel. Rather, they are mounted to the chassis and they are usually within reach of fingers? I guess you're rarely shifting when the wheel is turned more than a little bit.

I have also seen more complicated assemblies that have the paddles turn with the wheel. Normally there is some mount for the morse cable on the back of the wheel, and the wheel is usually tethered to the car by this assembly.

[carnut169]

The Stohr definately does not turn with the wheel.

My suggestion: KISS.

I had a terrible time with the shifter- 1st a Pingle that was fantastic 90% of the time, which is great for people who are happy with not knowing if a shift happened or not. Then a system that utilized most of the stock stuff- all I can say there is that I remember how horrible an LD feels when an Apex joint is a little loose... same with any system, I imagine. There was several joints and each had a tiny amount of slop- on the bench the car shifted great but once underway there was very little feel and it was awful.
Lasting solution is the single, stout push-pull cable mounted into the stock shifter (slides front to back). It is not as good as Scott's car for feel- best I've experienced is the system in the Radicals- but it does shift everytime as long as nothing comes loose. It allows for the placement of the shifter on the right side of the car and cost next to nothing.
... and it is simple.

[RobLav]

I'm on board with Sean here. Keep it simple. It seems I just made mine last week. I cut off the bottom of my old RF96 shift handle and welded it to a piece of 1/2 by 1" rect tubing. That tubing contains the pivot bushing (around an AN 6 close tolerance bolt threaded into steel rod in a shift bracket on the chassis) as well as 1/4" holes at the bottom for the rod end that connects to a high quality push / pull cable.

What I wrote seems confusing as h***. I'll take a picture over the weekend.

[Wren]

Here is what I did last year on the UA FSAE car. We wanted the frame small enough for two pedals, so I integrated the clutch into the shifter. You automatically get a certain amount of clutch(that you dial in) with each downshift. Upshifts have a limit switch to stutter the ignition for a few milliseconds, but no clutch. Shifter is permanently mounted to the frame.

This is the mounting assembly behind the shifter. Clutch is the cable on the left. There is a bolt there to stop the shifter from retracting too far and keep everything tight. That is part of the adjustment for how much clutch you want. On the right you can see the end of the push-pull cable that is for shifting.



This is the tab that the push-pull cable mounts to. Nothing complicated there, very simple and very little slop.



A look down the right side of the shifter to see how everything mounted. No, I had nothing to do with the decision to make the steering run like that.



The assembly we used at the shift linkage on the transmission. It just a very simple piece of aluminum with a hole that can be tightened down around the rotating shift thing(what do you call that piece?). It is slotted on the other end to let a 10-32 rod end attach. There is another tab welded to the frame for this as well to pick up the mount for the push-pull cable. Don't laugh, it's the best we could do with a manual mill and a bandsaw.




The shifter itself, the clutch is the seperate part on the left hand side, you could use it individually, or there was a tab on the back that automatically pulled it with the downshift. Not pictured, there are simple tabs welded on the back to pick up the clutch cable and the push-pull cable.



In all, I would say this was a fairly successful design. It didn't really have slop in it, was very simple, very cheap, and worked the first time(very important when you have to design and build a car in 9 months). The feedback from the drivers was very positive.

If I was to put it on an F1000 car, I would lose the clutch mounting system entirely(can you imagine trying to grab that in a spin?) and just use the shifter as a shifter.

[Whoomah]

Here is a pic of the Stohr paddle in the f1000 car

Curt