Rear suspension travel?

[PeterAllen]

I have opened up the rear arches to fit extended tubs which fill the gap between the original Nissan S30 guards and the new GTO fibreglass rear section. I'm trying to establish a ride height based on the clearance between the tyre and the tub.

Would anyone like to comment on whether there is an NSW legal requirement and/or what is a sensible gap to leave considering this will be a road/touring car and not a track car. Thanks.

The weight distribution should be around 550kg front and rear.

Photo attachment note: The first photo would not load despite several attempts. I sprayed a bit of dark colour on it (MS Paint) and it loaded up fine. It appears this system can't tell the difference between primer and flesh tones!

[RICK LAKE]

Peter Allen Peter in simple terms tuff answer. We at this point don't have real weight in the car. We need your weight, full tank of gas, spare tire if added. From there it depends on the rear suspension design and angle of struts or shock and springs. If you are staying with the N30, can you find another car and measure the top of the tire to the body edge at the closest point. With out seeing it, a 2"-4" clearance. It depends on spring rate, size of rear swap bar, strut adjustments, ratio of rebound to compression. We also need to take into account road surface and if you can find one smooth in the US. I would go with 4". you can always cut the springs to get a look or better wheel to body clearance. It's alot harder to not have enough clearance and can't go the other way. The couple of pictures I have seen of GTO car show about 3-4" on the rear but we don't know how much gas, weight of driver, and "g"s the car is or will pull. I have seen more car dropped and the outter side of the tires cut from bottoming out and loosing tires for this reason. It's easy to drop the car, it takes a suspension kit to do the same and give you the solid handling ride. Rick L. Ps there are suspension CD on the market for seting up your car with weights and everything. They are about $40.00.

[PeterAllen]

Rick - Thanks for that. I was trying to eliminate those calculations/estimates and get feedback on someone else's experience, i.e. someone who has experienced tyres rubbing on the tubs or arches.

However, I now think I have come at this from the wrong direction - a trait not unknown to me!

With the exhaust tucked up close to the floor and the tyre-well removed and replaced with a fuel cell there was a huge amount of clearance underneath, in fact I was able to lower the rear 90mm and sill have 110mm ground clearance. However with 16" rims and high aspect ratio tyres (225/70/16) I was left with only 55mm tyre/tub clearance as well as requiring repositioning of the struts of the IRS to eliminate the negative camber.

Last night I raised the rear 50mm (i.e. still down 40mm from standard) which created over 100mm tyre/tub clearance and leaves minimal negative camber. The car clearly looks higher at the rear but cars of the 60s did have good ground clearance so it actually enhances the character of the car - win, win.

[Rob. Smith]

G'Day Peter, as far as I can remember since I played with my old 210 import the only requirement was the 4"-100mm ground clearance rule and the fact that the cars ride was acceptable. The total travel of the suspension component should determine what you can do with your body mods. Set the car on stands at the correct ride height and remove the springs and shocks. Move the wheels through their travel range and see what happens at both stops. There are rules regarding suspension mods though. That applies to modified suspension components ( cutting and welding etc. ) You must be working with a signatory engineer though....ask him. Good luck.