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[QUOTE=MARTINSR;1476036]It's not a bad idea, it's a HORRIBLE idea. The arch of the pivot points simply aren't going to match those same points on the axle. ONE of them is going to change during movement and you will have bump steer.  But the same thing can happen with that Vega box mount, it makes no difference if the rack was mounted to the crossmember or the frame two inches behind or hanging off the frame on that Vega box adapter. The exact same issue exists, are the pivot points on the inner and outer tie rods going to follow the same arch (thus staying the same distance apart) as those same points in the arch of the axle?

The design you are using may be a "rack and pinion" by the design of unit it's self but the way it's mounted it really isn't a "rack and pinion" as we know it, it's simply a cross link "steering box" of a different design.

If it were mounted like that without a tie rod running from left to right spindle and you had the tie rod ends going off the rack to the left and right spindles you would have the exact same issue as if it were mounted to the crossmember.  Just to clear things up your "rack and pinion" in your setup is actually a simply replacing a steering box and drag link.

Brian[/QUOTE]

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Topic Review (Newest First)

10-06-2011 01:20 PM

user151

Quote:

Originally Posted by Irelands child

Steering Terminology 101

Drag link = from steering arm to steering box, whether its cross steering (Vega) or longitudinal (F100, Mustang, Schroeder)

Tie rod = from steering arm to steering arm or spindle to spindle

User 151 - again!! You are in the wrong place/forum for your rinky dink aggressive and condescending comments attempting to "correct" folks like Centerline, Martinsr, or Deuce. Quite frankly, rags like Rod and Custom are often very, very wrong.

I agree with your definitions, Ireland, but when Sam said "if the length of the drag link matches the length of the radius rods.." that could only apply to side steer -- in cross steer (the photo Martinsr showed) the transverse drag link would have nothing to do with the longitudinal radius rods.

If my technical comment is wrong you are welcome to correct me, but ad hominem attacks will not do it.

Sorry you have a problem with Rod and Custom but the reference I gave matches exactly what Sam said -- for side steer.

10-06-2011 11:39 AM

OneMoreTime

If for some reason one is out of money (common hotrod problem), the unisteer looks like it may be an omni or cavelier rack modified for the purpose..So if you just have to have a rack on a cross link steering look into one of those and just attach the link to the right side only. Some thinking on the fabrication of the bracket and one might come up with one that looks good.

Sam

10-06-2011 11:33 AM

OneMoreTime

Pictured is the the drag link style..the other is cross link style. either works if setup correctly..

Sam

Quote:

Originally Posted by Centerline

Correct me if I'm wrong but I believe this is the type steering that's being refereed to as a "drag link" style. In this case the "drag link" needs to be the same length as the "split bones" in order to eliminate bad things happening when the suspension moves around.

Centerline
HotRodsAndHemis.com

"Instructions are just the manufacturers opinion of how it should be put together". - Tim Allen

10-06-2011 09:36 AM

Irelands child

10-06-2011 09:15 AM

MARTINSR

Quote:

Originally Posted by user151

I wish you guys would define your terms because I don't think that's what Sam meant when he said "if the length of the drag link matches the length of the radius rods.." -- that to me describes a side steer drag link. What you show as a cross link can also be called a drag link but that is cross steer.

I'm sorry! The term was wrong as far as cross link or drag link but the geometry is still the same, the arcs of the links have to match.

Brian

10-05-2011 06:42 PM

user151

I agree -- also see page 74 figure 13 in the October 2011 Rod and Custom.

10-05-2011 06:38 PM

Centerline

Centerline
HotRodsAndHemis.com

"Instructions are just the manufacturers opinion of how it should be put together". - Tim Allen

10-05-2011 05:49 PM

user151

Quote:

Originally Posted by MARTINSR

Sam, you can run the Vega or like box up at the crossmember with a cross link.
Edit: I just re-read your post and this is what you meant, sorry.

Brian

10-05-2011 12:50 PM

MARTINSR

Sam, you can run the Vega or like box up at the crossmember with a cross link.
Edit: I just re-read your post and this is what you meant, sorry.

Brian

10-05-2011 12:41 PM

OneMoreTime

I have been following this thread and all I can say is that the uni-steer is about the only practical rack steering box for an early ford that I know of. the vega type box works fine for most guys but if not having the box up front like that requires then one needs to go back to the drag link setup. Drag link setups can work out just fine if and a big if the length of the drag link matches the length of the radius rods..

I have seen this same discussion many times before and while I am not sure just what the guys in the past have wound up doing for me the works good and steers right overrides anything else..

Sam

10-05-2011 09:10 AM

MARTINSR

Quote:

Originally Posted by Deuce

TRUE ,,, I was thinking about my reply ... and came back to change it to BUMP STEER ... and had already been caught with incorrect information.

MARTINSR is correct.

Mounting the rack on the crossmember or the axle is still a bad idea IMHO.

.

It's not a bad idea, it's a HORRIBLE idea. The arch of the pivot points simply aren't going to match those same points on the axle. ONE of them is going to change during movement and you will have bump steer. But the same thing can happen with that Vega box mount, it makes no difference if the rack was mounted to the crossmember or the frame two inches behind or hanging off the frame on that Vega box adapter. The exact same issue exists, are the pivot points on the inner and outer tie rods going to follow the same arch (thus staying the same distance apart) as those same points in the arch of the axle?

The design you are using may be a "rack and pinion" by the design of unit it's self but the way it's mounted it really isn't a "rack and pinion" as we know it, it's simply a cross link "steering box" of a different design.

If it were mounted like that without a tie rod running from left to right spindle and you had the tie rod ends going off the rack to the left and right spindles you would have the exact same issue as if it were mounted to the crossmember. Just to clear things up your "rack and pinion" in your setup is actually a simply replacing a steering box and drag link.

Brian

10-05-2011 08:55 AM

Deuce

Quote:

Originally Posted by MARTINSR

But the caster never changes, or not much at all and it wouldn't effect how it drives.

Brian

TRUE ,,, I was thinking about my reply ... and came back to change it to BUMP STEER ... and had already been caught with incorrect information.

MARTINSR is correct.

Mounting the rack on the crossmember or the axle is still a bad idea IMHO.

.

10-05-2011 08:38 AM

MARTINSR

Quote:

Originally Posted by Deuce

If the rack is NOT mounted to a frame rail, it must be mounted to the front crossmember

Not a good place to mount it ... because of caster changes when the suspension moves up/down. OR ... You can mount the rack to the axle

to eliminate the caster changes ... but then you need a sliding u joint to hook the rack to the steering column. PLUS the added weight on the axle adds to the unsprung weight. ADD ... it is UGLY.

DEUCE ... Moderator

The caster has nothing to do with it as it doesn't change. What goes wrong with the rack is when it is mounted so that when the axle goes up and down the arch of the tie rod ends doesn't match the arch of the axle. The distance between the pivot points of the inner and outer tie rod remans the same while the arch of the axle changes the mounting points. Thus you have bump steer.

But the caster never changes, or not much at all and it wouldn't effect how it drives.

Brian

10-05-2011 08:16 AM

Deuce

If the rack is NOT mounted to a frame rail, it must be mounted to the front crossmember

Not a good place to mount it ... because of caster changes when the suspension moves up/down. OR ... You can mount the rack to the axle

10-05-2011 12:01 AM

65shelby

drop axle

trust me, I understand the vega bracket,I am wondering about another rack design that does NOT use the vega bracket. I am trying to keep that area on the left frame rail clean of obstruction. Thanks again

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