offset trailing arms

[tscott9330]

If I go with offset trailing arms do I have to get a shorter rear spring?

Right now I have some sort of after market mono spring back there that the previous owner installed.

 

[76okievette]

Tom, sorry I can't answer you question but I do know that mono spring is a pretty popular replacement spring for lots of folks. The sping alone should not be driving you to offset trailing arms. I am sure you will get some good info soon.

 

[tscott9330]

I dont mind the monospring, in fact I like it because I think it will last longer than the origional metal leaf spring. I want bigger tires on the back to help plant some of my torque, and to do that I need the offset arms for clearence.

 

[70 LS1]

The trailing arms themselves do not need a shorter spring. The mounting points are the same. The only thing that is offset is forward of the axle assembly to allow more tire clearance. However depending on how wide of tires and what diameter wheels, might. I have 275/40/18 tires on 18x9.5" rims with 4 7/8" backspacing (stock trailing arms). The ends of the spring sit just inside the rim. As long as you keep the diameter of the wheels to 17 or larger, you should not need a shorter spring. You can get shortened springs from vansteel, vette brakes and guldstrand.

 

[Robin7TFour]

Tom, is your spring worn out? or you just upgrading to a mono spring. if it's in good shape i might be interested in the old unit.

Robin

 

[tscott9330]

sorry Robin the origional spring is long since gone, the previous owner must have replaced it with a composite mono unit. The only reason I asked about a new spring was just in case I needed a shorter one for my offset trailing arms.

Tom

 

[Robin7TFour]

Tom thanks for the response.i am looking around for a spring to try. i have on made by JRS . JohnZ pointed out that they tend to ride high,and he's absolutly correct. maybe i can find one not too worn to try out .

thanks again...

another orlandoan

 

[vindro]

The trailing arms themselves do not need a shorter spring. The mounting points are the same. The only thing that is offset is forward of the axle assembly to allow more tire clearance. However depending on how wide of tires and what diameter wheels, might. I have 275/40/18 tires on 18x9.5" rims with 4 7/8" backspacing (stock trailing arms). The ends of the spring sit just inside the rim. As long as you keep the diameter of the wheels to 17 or larger, you should not need a shorter spring. You can get shortened springs from vansteel, vette brakes and guldstrand.

Your 18x9.5 rims and 275/40/18 rubber is almost exactly what I'm getting ready to order for my 1971. I've been spending a lot of time under the back of my car measuring for backspacing and I'm curious about how much clearance you have and if any of the tire extends out past the fender well.

I have the Vette Brakes offset trailing arms and according to them, I should be able to get another 1" to 1 1/2" of clearance on the inside of the tire. That would put the backspace at 5" to 5 1/2".

Would your '70 have that much clearance if your trailing arms weren't in the way? I'm mostly worried about the frame rails above the trailing arms at this point. Is it even necessary to go any farther in? Do those big meats stick out from under the top of the fender wells?

BTW, saw your site. Two very cool projects there. You should post more pics of you Vette, post C5 brake conversion.

 

[norvalwilhelm]

You do not need a shorter spring for offset trailing arms since the actual track width doesn't change but the reason you put on offset arms is so you can either run more offset rims or wider tires. This causes a spring interference problem.
A normal steel spring is easy to shorten but not a fiberglass spring.
I remove about 1 1/2 inches from a steel spring on one end only and run 5 inch offset rims with 12 1/2 inch section width tires.

Norval

If I go with offset trailing arms do I have to get a shorter rear spring?

Right now I have some sort of after market mono spring back there that the previous owner installed.

 

[70 LS1]

vindro,

There is still at least 1" to the frame rails. And the tires stick out about 1/8". If you have offset trailing arms, I would go with 5.25" backspacing.

 

[vindro]

There is still at least 1" to the frame rails. And the tires stick out about 1/8". If you have offset trailing arms, I would go with 5.25" backspacing.

Thanks for the advice. I'd been waffling back and forth between 5" and 5 1/4" backspacing (and about everthing in between). I'll be putting in an order later today for a set of these. Wish me luck!

 

[70 LS1]

Those are cool. I looked at those when I picked out my wheels. I couldn't decide between those and the Boyd Coddington Nemesis. I ended up going with the Nemesis and don't regret it at all.