My Speed3 seat travel mod

[Demigourd78]

So I finally got it done today! I made seat rail extensions to get anywhere from 2"-4" of rearward travel. I am 6'1" and I have pretty long legs so I do this to all my cars. Fortunately the Speed3 seat brackets are designed in such a way that I could build extenders without altering the seat rails or factory brackets. I usually chop off the brackets and reweld them in different positions which is quite a bit more labor intensive. So, I made this at my work since I am a CNC machinist but it would be easy enough to do at home as well. Also, you don't necessarily need to cut the counterbores where the factory bolts get put back in. I just did it because... well... why not? I wanted to make sure the factory bolts didn't interfere with anything, especially in the rear. I also wanted to use the factory bolts instead of finding new 10x1.25mm longer bolts, which are actually kindof hard to find.

Obviously for the factory bolt locations, I simply drilled a .404 hole using a "Y" drill. Anything bigger than .393 will work though. Then for the holes that the seat gets bolted to I tapped for 3/8-16 and the minor diameter hole size should be a 5/16 drill bit. I drilled three sets off holes for later adjustability incase 4" is too much travel. It is too much travel for me but its also easy enough to just scoot the seat up too. 4" hole spacing makes it easier to tighten everything down as well. Based on interest, I can add some more details on the process, although, this really wasn't that hard. If you can hand drill and tap holes its pretty easy. I used 1/2x2" mild steel flat bar cut into 5" pieces. The two rear plates are pretty much identical to the fronts. Except the one closest to the door, I made the holes about .350 closer to the edge of the plate for interference purposes. It does make the seat sit a bit higher but these cars have so much head room I can barely tell. One could use 1/4" thick flatbar as well and simply through-bolt the seat to the extenders with nuts. There is enough room. However, since the seat belt is bolted to the seat, and I am a 270lb guy, I went with the 1/2" flatbar because I didn't want my extenders to fail in the event of a crash. I was afraid that 1/4" would be too flimsy.

Also, if someone else has done a similar mod I am sorry, I didn't check. Let me know if anybody wants more information.

[kTaLgsTo]

Cool, thanks for sharing. Very helpful to add all the specs on hardware for future people in this endeavor.