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straight axle w/ rack and pinion

Discussion in 'The Hokey Ass Message Board' started by mrconcdid, Mar 6, 2013.

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  1. mrconcdid
    Joined: Aug 31, 2010
    Posts: 1,157

    mrconcdid
    Member
    from Florida

    I have recently seen this combination.

    How well does it work? do you have any pictures of this setup?

    Thanks
    Godspeed
    MrC.
     
  2. Wheres the photos?

    If you are referring to dropped axles with the Unisteer rack & pinion check out Deuce Roadster photo album,,he used one on his 3 window. HRP
     
  3. if you are talking about a "real" rack and Pinion set up, they are a pain in the ass to set up on a street driven car with w straight axle. You have to mount them to the axle or you will have bump steer. Now, since the rack is mounted to the axle you have to accommodate for the fact that the rack is moving in relation to the steering shaft so you have to have a movable shaft that can extend and retract. Yes guy have done it, but there is no advantage in this set up for the amount of work and potential bind in the steering shaft.

    If you are talking about the little Sort of Rack that Unisteer sells, they are pretty much just like using a Vega box
     
  4. dana barlow
    Joined: May 30, 2006
    Posts: 4,429

    dana barlow
    Member
    from Miami Fla.
    1. Y-blocks

    There is kids song,witch of these things go together,well rack and straight axl an't in it:eek:
     

  5. THE FRENCHTOWN FLYER
    Joined: Jun 6, 2007
    Posts: 3,719

    THE FRENCHTOWN FLYER
    Member
    from FRENCHTOWN

    I saw a '34 Ford coupe w/ a straight axle and a rear steer rack welded on the back. The steering column shaft was telescopic to allow for suspension travel. It made me nervous. Telescopic columns aren't designed for millions of cycles.
     
  6. I hope you're not talking about doing this to a Gasser project.

    I have seen it. Stacey David put one on the Roadster he built on GearZ.

    Looked good, but then so did the whole car.

    [​IMG]
     
  7. mrconcdid
    Joined: Aug 31, 2010
    Posts: 1,157

    mrconcdid
    Member
    from Florida

    I am not talking about the rack on the axle, that does sound dangerous. Im refering to a rack on the frame controling a straight axle vs a saginaw or vega box.

    Godspeed
    MrC.
     
  8. metalshapes
    Joined: Nov 18, 2002
    Posts: 10,716

    metalshapes
    Tech Editor

    R&P steering is about the best there is, when it comes to steering feel and feedback.

    Thats why people want to use them.


    On a I-beam that means the Unisteer HRP is talking about.
    But drawback of that one is ( from what I've heard ) limited steering lock, and it sticks out a lot at full RH lock.

    Somebody posted a pic on the HAMB once of a cut and shut hairpin to try and clear a Unisteer.
    I wish I'd saved that pic, it was fuckin hilarious...:D


    There are people that will mount a R&P on the chassis, which will give massive bumpsteer.

    Some of those people will argue that their Hot Rod has a way of defying all laws of geometry and physics, and doesnt have any bumpsteer at all. :rolleyes:


    And then there are people that will mount the R&P on the I-beam itself, eiminating bumpsteer but not rollsteer.

    And the only way to connect it to a column is with a slider of some sort.
    What they usually grab for that is the collapsible part of a double D column, which is not designed for that and will give a lot of bind in the sliding action when there is any load on it ( like steering a car into a corner ...)

    Those people will tell you of the many trouble free miles done with that setup without anything binding up to the point of shearing off.
    I'd still rather pass them, so they can have their accident behind me...:rolleyes:


    The last version is the only good one, IMO, and that is the way it was done in the Uncertain T.

    With the R&P mounted lengthwise in the chassis, hooked to the I-beam like a draglink off a F100 box would be connected.
    ( if you can get the geometry right to eliminate Rollsteer and Bumpsteer.)
     
  9. Dreddybear
    Joined: Mar 31, 2007
    Posts: 6,030

    Dreddybear
    Member

    Terrible idea anyway you configure it, and it will always be ugly.
     
  10. This is the photo of Deuce Roadsters Unisteer rack & pinion when he was building the 3 window chassis. HRP

    [​IMG]
     
  11. Dreddybear
    Joined: Mar 31, 2007
    Posts: 6,030

    Dreddybear
    Member

    I'd like to see that.

    I'll have to go back and look at the Uncertain T's setup. Is it ugly?
     
  12. metalshapes
    Joined: Nov 18, 2002
    Posts: 10,716

    metalshapes
    Tech Editor

    No, but it would still be hard to find the space for while getting the geometry right.

    Also, on anything other than a T it wouldnt look right to have a verical column coming straight up out of the floor...

    ( because it has to be back that far...)
     
  13. old buzz
    Joined: Jan 14, 2013
    Posts: 22

    old buzz
    Member
    from middle tn

    I built My Anglia with one of the r&p from Speeway that replaces a Vega box. It works very well,steers good with little effort.I haven"t had any bump steer out of it to speak of.
     

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  14. [​IMG]

    This looks like the setup Stacey David used.
     
  15. bobw
    Joined: Mar 24, 2006
    Posts: 2,368

    bobw
    Member

    I've done three of them and they worked fine. Total travel in the slip joint on one of them was 3/8". But, of course, I don't know what I'm doing.:D
     
  16. metalshapes
    Joined: Nov 18, 2002
    Posts: 10,716

    metalshapes
    Tech Editor

    Just to be clear, what you have is what I meant in the first option.

    The second option, ( the one that is guaranteed to have bumpsteer ) is where people will use the R&P from a regular IFS setup and connect that to the I-beam with the short draglinks that come with it.

    Because they are so short, the outside balljoint will travel on an arc and the steering arms on the I-beam do not ( or if it has a Panhard, it will be a much wider arc )
    Which is what gives the massive bumpsteer.
     
  17. metalshapes
    Joined: Nov 18, 2002
    Posts: 10,716

    metalshapes
    Tech Editor

    If you are argueing that those sollutions are fine, I may have to agree with you...
     
  18. pitman
    Joined: May 14, 2006
    Posts: 5,092

    pitman

    Metalshapes, you raise the important considerations in the design issues.
    I have done 2 installs on the Ford I-beam dropped axle and one on a '32 Chevy.
    I've not had any bumpsteer as yet. The telescoping joint selection is a valid concern.
    I'd rather err on the side of an over-built selection here. The rack from a GTI rabbit was free, the column worked out well and has the std lock, turn signal and high/low stalk for headlights.
    I love the road feel it gives. The column shaft is level/horizontal at the tele-joint, and my guess is there are about 12-14 k miles on the systems. No issues, low weight, no clearance problems. It's one solution I would use again, carefully.
     

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  19. metalshapes
    Joined: Nov 18, 2002
    Posts: 10,716

    metalshapes
    Tech Editor

    The bind on telescoping problem is something that designers ran into with the rear halfshafts on powerfull IRS cars.
    ( different scale and torque, but the same problem )

    One way around it was a complicated slider that had the splines cut in such a way that it could trap several bearing balls.

    And the problem was solved when the Rzeppa Joint became affordable ( AKA the Constant Velocity Joint )


    If you could do it with one of those, there shouldnt be a problem.
     
  20. willymakeit
    Joined: Apr 13, 2009
    Posts: 1,326

    willymakeit
    Member

    Has anyone tried it on a Jeep Cherokee axle? Im talking about the 2 wheel drive tube,straight axle.
    I have one and have neen mulling it over. The steering arms are in a good position.
    From what I can tell it looks like a M2 will work.
    Only issue is they are ugly in front of the axle and I would have to build a cover for it. My other alt. is to cowl steer and build the mount at the axle.
     
  21. metalshapes
    Joined: Nov 18, 2002
    Posts: 10,716

    metalshapes
    Tech Editor

    And my appologies to Bobw for possibly offending him.

    But my experiences with catastrophic loss of steering makes me have strong opinions about it.

    Once as a spectator, when a buddy lost all steering in his racecar.

    Once as a driver in a racecar built and owned by buddy.

    Both times the results weren't pretty.


    Steering is just not something to clown around with...
     
    Last edited: Mar 6, 2013
  22. need louvers ?
    Joined: Nov 20, 2008
    Posts: 12,906

    need louvers ?
    Member


    Hate to sound as snarky as I am about to, but in considering this option I'll take it you don't care about going straight or tracking around corners due to bumpsteer? See, when you mount the rack to the frame meant to control a suspended axle, as the axle goes up and down the tie rods travel in an arc. The high spot in that arc, and the low spot in that arc are both shorter than mid point. In other words the couple of times I have seen this mess done, you can bounce on the frame and watch the front tires toe in on both compression and drop. That means that basically any steering input you have will be pretty much null and void. PLEASE do not even consider this!!!

    What in hell is wrong with a simple geometrically correct steering box on solid axle cars? If it's not this question, it's "how do I make a rack fit my___ with an independant front end".... Nine times out of ten it's "not correctly"!
     
  23. MATACONCEPTS
    Joined: Aug 7, 2009
    Posts: 2,069

    MATACONCEPTS
    BANNED

    After, I.M. me & I'll hook you up with some real "DOPE" shit for your ride!!!
     

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  24. bobw
    Joined: Mar 24, 2006
    Posts: 2,368

    bobw
    Member

    [​IMG]
    Here's one of my cars with a Magnum tube axle with a rack & pinion mounted to the axle.
    It's been on long road trips as well as going pretty fast on the drag strip.

    Built my first hot rod (1931 Model A pickup with flathead) in 1958. Still building and racing at age 72.
     
  25. metalshapes
    Joined: Nov 18, 2002
    Posts: 10,716

    metalshapes
    Tech Editor

    With all due respect, Bob.

    Just because you have gotten away with it sofar, doesnt make it right.
     
  26. amen! ;)
     
  27. bobw
    Joined: Mar 24, 2006
    Posts: 2,368

    bobw
    Member

    With all due respect, Metalshapes just because I know of a dozen cars set up this way with possibly an accumulation of over 200,000 miles, doesn't make it wrong.

    You've had two steering failures, I've had none.

    Man, there's so many "wrongs" on accepted traditional hot rods as compared to truly safe designs and execution that we should all pack it in and buy new cars.
     
  28. metalshapes
    Joined: Nov 18, 2002
    Posts: 10,716

    metalshapes
    Tech Editor

    Yes.

    It very wrong.

    And the fact that you cant even accept that there might be a problem is why you make the same mistake on 3 cars.
     
  29. need louvers ?
    Joined: Nov 20, 2008
    Posts: 12,906

    need louvers ?
    Member

    Double Amen!! When some one tells me about how well this works mounted either way, it always seems later in the same conversation I hear "well, ya it's a little floaty, but that just how hot rods are...". No, done correctly they aren't!
     
  30. metalshapes
    Joined: Nov 18, 2002
    Posts: 10,716

    metalshapes
    Tech Editor

    Had one and seen another one happen, yes.

    I dont see how this can count against me.

    Thanks to the work of others, I've gained knowledge and experience.
     
    Last edited: Mar 6, 2013
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