Radius/hairpin sizes

[Tundrajax]

Im trying to make sure I have very thing I need so I can setup as close as possible to a rolling chassis. My question is how do I know which size front and rear radius arms to buy ?? I see sizes from 27 inches to 36 inches. So how do I determine which size to get?? Also not sure if this will help or not but currently the brackets for the front and rear ARE not welded to frame yet. If I'm missing any details

 

[2old2fast]

Generally , longer is better , what type steering , side delivery or cross-steer ?

 

[old round fart]

Do you like the rods long or short? It's your car pick one! There is no wrong answer. The short ones are usually for fendered cars.

 

[Tundrajax]

Generally , longer is better , what type steering , side delivery or cross-steer ?

The plan is to run a reversed corvair box on a 4in bracket so it's right on the cowl. Also I won't be running any fenders

 

[Tundrajax]

Do you like the rods long or short? It's your car pick one! There is no wrong answer. The short ones are usually for fendered cars.

I don't have a preference. As long as it works I don't care.

 

[2old2fast]

If you are gong to run cross-steeer , then the length of the front rods isn't very important , if you run side delivery , then you want the rods to be about the same length as the drag-link , this helps eliminate bump-steer , on the rear , if they're too short , thet lift the back of the car under acceleration & unload the rear tires , longer "plants" the rear tires better . Nowadays w / the 4-link setups out there , they can plant 5the tires w/minimal lifting...

 

[2old2fast]

If you don't want to learn chassis design , CCR [ california custom roadster ] has a sset of well thought out plans , they're inexpensive & you can download them on-line

 

[Spanky]

I am using 27" 'hairpin' style radius rods front and rear with cross-steer, and no problems to date. I like the look.

PS - the steering box in the picture has been relocated forward for cross-steering.

 

[fordsbyjay]

Go long IMO. In theory it will be better but with the limited suspension travel of these cars it doesn't really matter. Longer just looks nicer. I broke a hairpin so I built a 4 bar but you can see the location of the original hair pin bracket.

 

[Tundrajax]

Ok , thanks for all the help so I'm mostly seeing 27in fronts but since I'm running side steering I'm going to go with a 30 just to have a little extra

 

[Swampdog]

Go long IMO. In theory it will be better but with the limited suspension travel of these cars it doesn't really matter. Longer just looks nicer. I broke a hairpin so I built a 4 bar but you can see the location of the original hair pin bracket.

Jay,

Does it ride better with the 4 bar?

 

[choppedtop]

Hairpins seem to do ok on front. I like 4 bar on rear because of more flex and less stress on things. It lets the left to right sides of tires move more independent from each other.

 

[RPM]

What ever you decide, we can make them for you

 

[fordsbyjay]

Jay,

Does it ride better with the 4 bar?

It sure does. Not like a Lincoln or anything but better. I'd like to try some Bilstein shocks next.

 

[fordsbyjay]

What ever you decide, we can make them for you

Ron custom made my 4 bars. Top notch.

 

[ellis8500]

Ron made my bars.

 

[brendonn]

It sure does. Not like a Lincoln or anything but better. I'd like to try some Bilstein shocks next.

Which Bilstein shocks are you planning to use? I want to upgrade mine also and looks like bilstein is the way to go for better ride control.

 

[railroad]

Ron's parts are top quality. He made my gas tank from drawings I sent him. Excellent job.

 

[fordsbyjay]

Which Bilstein shocks are you planning to use? I want to upgrade mine also and looks like bilstein is the way to go for better ride control.

I believe it is this one here. IIRC it was a bit longer than the ones I have now.
Bilstein F4-BOA-0000836 Chrome Front Shock, 10-11 Inch Ride Height

 

[Dan Lockwood]

Go long IMO. In theory it will be better but with the limited suspension travel of these cars it doesn't really matter. Longer just looks nicer. I broke a hairpin so I built a 4 bar but you can see the location of the original hair pin bracket.

Jay, it seems to me that back a couple decades that I read that hairpins were for I-beams and 4-bar were better for tube axles.

The theory is that with the hairpin when the wheel goes up/down that the side going up/down will be caused to twist the axle because of the arc of the hairpin. The I-beam can twist, but the tube axle will not. This over time can break things.

I'm sure there are many more experienced suspension guys here than me, so I would also like to know if there's any truth to this.

4-bar they say will work for either I-beam or tube as they tend to just let the wheel go up/down without any twisting of the axle.

I plan on using a 4" dropped drilled I-beam and I do like the looks of hairpins better than 4-bars. IMO the hairpins have a more classic hot rod look and the 4-bar borders on race hot rod look.

Any thoughts guys?

Dan