If you don't modify the frame , can you run wider tires with double offset versus regular offset trailing arms .

 

DOUBLE offset?

 

I have been wondering the same thing. Here is where you can get them: VanSteel








www.bigdogvettes.com

 

from vansteels description.
" Double offsets are the exact same as standard offsets except for the spring bolt hole. The spring bolt hole is pushed in 1"(toward the differential) so you must use a shortened spring. "

 

oh ok. seen em' before, just never called em' that. thanks

 

Some of the guys that are running the double offsets are notching their frames at the kick ups to get the extra room for even wider tires. Others just run the to be on the safe side when they run 10" rims. By having the spring bolt hole moved in and a shortened spring they don't have to worry about anything. Regualr offsets would be fine but some just have their superstitions.

 

No use in D/O if your not going to modify your frame
It really depends what your trying to run for wheel offsets.
regular offsets are pretty good also.

 

With the shorter spring I would assume you will raise the rating of the spring (ex. 330lb to 345 lb). With a stiffer and shorter spring does that help the ride.
Also ,since there is not a sway bar for the offset or double offset , does the shorter spring help with handling?

 

I have not figued out what my wheel offsets will be since right now the body has flairs on it and I don't know if I will be keeping them or return it to stock.

 

People who are buying offset trailing arms should know about the situation associated with the rear anti-roll bars.

I bought a "Peformance Plus" suspension kit. This included a very hefty front anti roll bar, a rear anti roll, 500 pounds per inch front springs and a 360 pounds per inch rear composite spring, Bilstein shocks, etc.

I think it can be said that the rear anti-roll bars will only fit cars with pretty much stock tire widths. I have 255/R50-17 tires. The rear anti roll bar slightly rubs the tires. I've called up a few people, but so far the advice is just to run without rear anti-roll bars.

The 255/R50-17 tires will "just about" fit the stock suspension. The trailing arm parking brake bracket was about 1/8 inch away from the tire sidewall. The rear spring was perhaps 1/2" from the tire sidewall. I bought some new parking brake brackets from Volunteer Corvette to have them welded on top of my stock trailing arms. Then I decided this was too much work, so I just bought offset trailing arms from VBP and a composite spring from VBP (the spring shortened 1/2 inch on each side). Now....
When I attached the anti-roll bar, the sides slightly rub the rear tires.
I've talked to Vette Brake Products and also Guldstrand about this. They both have said it won't be a problem to run without the rear anti-roll bar. I guess if I had a torch, I could heat the rear anti-roll bars just a little bit to get them to clear the rear tires.

 

What are you running for wheel offset and are you using a 8 inch rim width?
Also , I was under the impression that have a dual mount spring will eliminate the need for a rear sway bar?
One last question, If you eliminated the sway bar could you go wider and what would you run into (bracket, spring or frame)

Thanks for the input

 

First of all ..as to the anti-roll bar substitution. Yes. VBP suggested that if I needed the effect of an anti-roll bar I should use the dual spring composit mount. Also, I have a bit of a height adjustment problem and VBP said that the dual spring made adjusting ride heights easy.

I have 17X8 wheels with 4 1/2 backspacing. (Wheel Vintiques Billet Rallye). I have 255R50 X17 tires.

Yes, with the offset trailing arms and now that I don't have to fuss with the anti-roll bar I could go with bigger rear wheels. I don't know how much bigger...I'd have to go out and have a look. This is for the rear wheels. The 255R50X17's on the 4 1/2 backspacing are a little bit too big for the front wheels.. on a full left or right turn they just hit the body/frame just a little bit before I come to a maximum turn.

Also, my car car is a 1968. For example the 1970's have a bit of a wheel flare and they may have a little bit more room.

I have the 360# rear composite spring. My car is sitting about 2 inches too high. I curently have 8 inch trailing arm to spring bolts. VBP is sending me 10 inch bolts. This should drop my rear end height and also make the rear half-shafts parallel to the ground. Currently the differential output shafts (yokes) are about two inches higher that the spindle half-axle flanges. The bolts should be sized so that the half-shafts are parallel to the ground. A ten inch bolt should do it for me.

 

The problem is not the swing arms, sure you need offset trialing arms but the problem is right around the swing arm pocket, this is were the wider tires run into the frame, Mine is cut and modified to get a 6 3/4 inch offset 10 inch rim under the fender and an honest 12.5 inch wide tire to fit.
I built my own offset trailing arm and when I ran a buggy spring i also moved the spring bolt in 1 inch of each side and ran a shorter spring.

 

I believe you can “clearance” the sway a bit with a grinder without any strength issues. The diameter of the bar is established by the torsional requirements of the sway bar. The arms are the same diameter because it’s cheap to manufacture them out of round stock. In fact I’m certain that you could grind quite a bit off the side of the arm with no strength issues. Because the cross section of the arm is round and it is seeing bending forces, grinding on the outboard side of the arm will be taking away material from near the neutral axis which is under very little stress

 

Because I am not modifying the frame and relying on bolt on packages, which I will probaly go with the Street and Slalom package.
Will you get any improvments by going to shorter (inch on each side) fiberglass buggy spring?

 

Thanks
That is probaly what I will have to do.

 

So your saying your tires hit the sway bar?Im running 17x9.5 with 4 1/8 bs with 275/50/17's and it clears the sway bar fine.I also have the 360# rear spring and 10 inch bolts.Is there that much difference between the 68 compared to my 73?