rlekun,
This is one of the first safety modifications I made to my ITA RX7. I am 6'3" and this modification makes it alot easier to enter and exit the car. It also may be critical if you have a dangerous situation that demands you "abandon ship" rather than testing various features of your safety equipment.
The version (RPW-177) you are considering on p64 of the RWP catalog is the same one I have installed. I would stay away from anything with a button. (too hard to find) I am currently at work, but I am 75% sure it is the 5/8 version that I used. Maybe someone else can confirm or correct me.
Installation presented some unique challenges. The first problem I encountered was the tapered end of the shaft and threaded part after you remove the steering wheel. When you slide the inner hex shaped part onto the shaft it will not fit securely. You will need to fashion a "sleeve" or piece to fit inside the inner steel part. Here is how I did it:
1- I went to local surplus/Lowes and found a long and large partially threaded bolt that would fit inside the inner steel part. I also selected the lowest grade bolt. The softer metal makes it easier to drill.
2- Next, I placed the inner steel part on the shaft and I measured how far the sleeve would have to go in. Once I was had that measurement, I used my recipercating saw to cut the end of the bolt.
3-I then used the locking nut to find a bolt simlilar to the threaded end of the shaft. I took the cut bolt and the threaded bolt to my local machine shop. I had them drill into the large bolt and tap it so that the other bolt would thread into it. (My local machinist does not want to "know" if he is doing any work for a racecar or aircraft- something to do with liability- you may want not want to mention the purpose)
4-Prep the shaft and the inner steel part for welding. Place it on the shaft and turn the large modified bolt into the inner part.
Weld it on. Then take your recipercating saw and cut the head of the bolt off. I was then able to spot weld at the top of the shaft and grind down excess so that the outer aluminum part would fit on and lock.
I hope this helps.
Bill Emery
ITA#23
Glen Region