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Hot Rods Any ridged rear ends?

Discussion in 'The Hokey Ass Message Board' started by JimSibley, Apr 30, 2015.

  1. JimSibley
    Joined: Jan 21, 2004
    Posts: 3,372


    A guy that works for
    Wants to build a budget drag car. I'm wondering, since it will be a purpose built car, can he solid mount the rear end. The thought is a
    Simple square tube frame, 325 horse small block. Power glide,Model a front end and a butchered up 1927 t coupe body.he will be running 8.5 inch slicks and a 9 inch.
  2. cretin
    Joined: Oct 10, 2006
    Posts: 2,954


    Last edited: May 1, 2015
  3. MANY drag cars have been built that way.
  4. blowby
    Joined: Dec 27, 2012
    Posts: 7,752

    from Nicasio Ca

    Hmm, I'm thinking there must be advantages to having suspension (other than a smooth ride down the track). Sure is a lot of engineering that goes into those 4 links and such. Weight transfer?

  5. check the rule book.
    most full bodied classes require rear suspension.
    solid mounted rear ends make the car a dragster which means mucho more requirements.

    if your local track is sanctioned, the tech has discretion and will always defer to the rulebook regardless of his understanding of it.

    we went through a whole rigamarole getting the HA/GR cars on the track at famoso with ANRA even though they run in the 15's.

    a car like that should be able to get away with a transverse leaf and some ladder bars or hairpins, or a set of coil overs.
  6. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 2,761

    Alliance Vendor

    Funny this came up right above "I'm going to build an Altered" this morning. Don went through the same thing. He wound up going to a 4 link.
  7. oldolds
    Joined: Oct 18, 2010
    Posts: 3,169


    Suspension is more forgiving on parts, especially on a low budget car. Easier to a adjust to the track as well. Which is important if you race different tracks. Just in case you get involved in division points racing which means a different track 2 or 3 times a week
  8. I haven't run a solid mount in ages. Someone mentioned that suspension is more forgiving and that is exactly correct. When you solid mount everything becomes extra critical, staring with the mounting of the housing, and ending with tire pressures. Springs absorb a lot of our minor mistakes. :D

    One thing to keep in mind is that when you run no suspension you have more unsprung weight. OK someone told me that I don't know the actual physics of it. ;)

    But it can be done and is one way to build one.
  9. dreracecar
    Joined: Aug 27, 2009
    Posts: 3,176

    from so-cal

    Suspension is only really nessasary if the driver is offset in the frame, It will allow to tune the chassie for side to side weight difference so that the car launches straight. Center steer cars get away with ridgid because the side weights are close to the same, so in effect the whole car becomes a ladder bar, with the front pivot being the front wheels and the shocks/springs the rear tires. I guess one could have the driver offset and a solid suspension, but would have to add enough weight to the oposite side to match the driver weight. People have put suspension on center steer cars before, but its $3000 that I could put to better use in other areas since the solid mount just plain works.
    AHotRod and prewarcars4me like this.
  10. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695

    Member Emeritus

    I don't remember exactly who it was, but a few years back, one of the chassis manufacturerers was offering a solid rear mounting setup for drag cars, and not just for the open wheel type of car. Maybe someone else will remember who it was. I am Butch/56sedandelivery.
  11. The37Kid
    Joined: Apr 30, 2004
    Posts: 28,173


    That was how Lyndwood built their rails, tabs welded to the narrowed bandjo Ford rear. Bob
  12. Lots of digger chassis and early drag chassis had them mounted solid. I have even seen a few early coupes with solid mounts. if you get one setup right it is a good deal and if you don't and you throw much meat at it then it is a nightmare. It is not hard to make one right but one needs to take care with the build, keep everything square and centered as much as possible. You can't half ass at the track either, it is easier to get tire steer with a rigid mount. You can get away sometimes with a pound or two difference on a sprung chassis but a rigid doesn't like that at all. At least that's been my experience.

    None of this is to scare anyone away from that type of chassis, just to exhort you to do your due diligence. :D
  13. rooman
    Joined: Sep 20, 2006
    Posts: 4,052


    I think that everyone is over thinking this. Suspension in altered style cars is a reasonably recent development if you look at the big picture. Look at the cars from the 60's. Gassers had suspension because the class rules required it but just about every altered was rigid.
    As Bruce notes, if the car is center steer there is no real reason to add a bunch of complexity to a simple build. Even with the driver offset the car can still be balanced with battery placement etc. It sounds like Jim's mate is not going to be putting a lot of power to the ground with relatively small tires so torque reaction should not be a major problem.
    Porknbeaner, "tire steer" is usually a function of different rollout and is generally independent of suspension or lack thereof. Modern day nitro funnycars chassis are tuned by adjusting the front spindle height to put a little preload on the right rear tire to counteract the torque and a bit of tire pressure variation can be used on a low power car like we are discussing if it does have a problem. I have found through experience that a huge number of hobby level racers with suspended cars have no idea of how to set them up correctly. A car with non adjustable ladder bars has no provision for adjusting the rear tire preload and a four link car is a can of worms for anyone who does not understand the dynamics (instant center, squat or rise geometry etc).
    I think that Jim's buddy is on the right track, just keep it simple (and cheap).


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