Okay all you Gasser front axle experts --- I've seen parallel leaf springs mounted with the fixed mount at the rear and shackles up front and also fixed mount up front with the shackles in the rear. Which set up is best? What's the advantages and disadvantages to either for a street/drag gasser?
Pretty sure if you do a search it will come up. If I remember correctly it has to do with where the steering box is located.
I'd put the fixed bushing on the end where the steering box is.... but if it's cross steer, it probably doesn't matter.
Squirrel hit it on the nose. Fixed end goes to the steering box side of the axle. This prevents bump steer.
Thanks for the input guys, that really helps. I've got to move the axle forward two inches on the '39 Olds Coupe gasser project I bought and figured now would be the time question the mounting since I have to cut everything off and start over anyway.
We used the Speedway kit on my '64 Valiant, and they recommend the shackles in the rear. The way I understand it...either way is fine, and guys have had race cars and street cars both ways for years, and never had a problem either way. If you look at old pics of straight axle racecars, there are just as many rear shackled cars as front...it just seems a lot of the more famous and photographed cars had shackles in the front. I also understand that it REALLY doesn't matter much with cross steer, and it comes down to the fact that spring hanger in front, shackles in the rear, cars seem to handle better, and manufacturers have used both ways, and flip-flopped through the years. Mine will be mostly a street car...with cross steer, so we went with the recommended hanger in front, shackle in rear. It also made it much easier to mount them on the frame without too much cutting and fabricating to get the hangers straight on the frame rails like might happen closer to the firewall where a lot of frames tend to curve. Here are a few of the other threads discussing it (lots of opinions both ways): http://www.jalopyjournal.com/forum/showthread.php?t=517125 http://www.jalopyjournal.com/forum/showthread.php?t=371959 http://www.jalopyjournal.com/forum/showthread.php?t=192838
With the steering box mounted with a fore and aft drag link, the steering box and fixed spring mount need to be on the same end (As Squirrel and Dodored said). With a cross steer arrangement, I don't think it much matters. My brother's '39 Willys had a fore and aft drag link with the steering box mounted on the same end as the shackles...it was a bear to drive due to extreme bump steer!
Shackle location is important with side steer, the fixed end should be near the steering box because the spring lengthens slightly when compressed.
On mine I put the shckles to the front, the fixed mounts to the rear... the sterring box (cross steer) is behind the front axle..... Tom
Thanks everyone so far. My car is set up with cross steer with the box behind the axle. dv8 Thanks also for those other links. Just read through them all. No real concensus, but a lot of good info.
Same here on my car in my avatar, the one Im building is the same way. I have driven the yellow car 13,000 miles and zero problems. Drive it on interstate all day long, drives nice and straight and no bump steer.
I’m in the shackles in the rear camp. Solid axle four wheel drive people have been changing there rigs to that for years to get rid of the death wobbles. If you think about it that’s the natural way the spring wants to move going over bumps moving forward.
The 4X4 guys use them different ways for different types of events. Rock crawlers like them in the front because on compression it pushes the axle foward, forcing it over things. That being said there might be some advantage at the strip as to which end they are on, could possibly affect the roll out on starting line, ie chassis lift pulls wheel back as car rolls forward. I know it is a small amount, but some guys build their cars with one front wheel back so the car dosen't redlight.
296 v8 You mention death wobbles, was it directly attributed to the shackles up front or some other front end problems that just made the problem worse with the front shackles? Has anyone actually had trouble with either set up? Still deciding but must make up my mind soon.
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