Sorry I am late to this discussion. I was reading the thread and noticed something Roddguy said that needed correction. Bumpsteer is caused by a problem with geometry. Putting a locator/slider bracket in the middle of the axle will not fix the problem. A solid axle when hitting a bump uses the opposite tire as the pivot point for the arc travel of the axle. The R & P steering uses the pivot point of the end of the box closest to the wheel hitting the bump as its pivot point- So say a typical alxe is 48" and the tie rod on a R & P set up is 12". If you were to draw on a piece of paper a horizontal line with a pivot at the left end then measure to the right out 12" and draw an arc above the line to a height of 6" , then do the same for the 48" axle width. Now measure the change in length between the 2 arcs at 1", 2" and so forth. That difference is what causes bumpsteer. It is the tie rod tugging the steering arm as it changes the distance through the bump. I hope this helps
Rack and pinion
- Thread starter tiny1
- Start date
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PAINLESSTOM
New member
After reading all these posts, it seems I've gotten lucky... I just finished a power rack conversion on my 33' Ford Pickup w/ 5" drop axle... 2000 Toyota Avalon Rack. I've been driving it for the last few days and haven't experienced any bumpsteer... Maybe if I hit a speed bump on only one wheel but the normal bumps and road transitions haven't caused me any issue up to 75 mph.. I did re-use the draglink arm on the spindle to mount a dampner to the frame.. Very stable at highway speeds.. I also have complete articulation of the spindle travel. Only thing I plan to do in the near future is add a steering ratio reducer as the racks ratio is rather fast.. A 1.5:1 ratio reduction will put me at 3.75 turns, lock to lock, from my current 2.25. I think a lot of bumpsteer problems that rack and pinions are blamed for have stemmed from misplacement of the unit... My $.02
Pics of my rod www.painlesstom.com/33.html Click the picture for "Power Steering conversion" for the rest of that prodject...
By the way.. Hi everyone! As you well know I'm new to the forum and look forward to being part of the community...
Tom
www.PAINLESSTOM.com
Pics of my rod www.painlesstom.com/33.html Click the picture for "Power Steering conversion" for the rest of that prodject...
By the way.. Hi everyone! As you well know I'm new to the forum and look forward to being part of the community...
Tom
www.PAINLESSTOM.com
bob w
Still crazy after all these years!
I've build 3 rods with a rack & pinion attached to the axle and they all work well, with no bump steer. I was led to believe that attaching the steering to the frame would be a very wrong way to go. I saw a Model A at a Goodguys event with the R & P attached to the frame and the owner said it worked well. I'm guessing that with the small amount of spring travel that a typical early Ford spring/axle setup provides, the amount of bump steer is kept to a minimum. BTW Painlesstom, nice truck.
donsrods
Well-known member
Getting steering right on a hot rod is really hard to do. The automobile manufacturers have highly paid engineers who know how to figure out what works and what doesn't, but we backyard guys have to rely on what we hear and see on other peoples cars.
My Son and I are wrestling with what to do for steering on his '29 right now. We kicked around the Vega cross steering box route, but he can't run a panhard because of the way his front end is set up. He was going to use a BMW 2002 box in a cowl steering setup, but that puts the box where his feet need to go. I have a '56 Ford pickup box that we tried, and the snout is way too long and the box will hit his Olds engine if we use that.
What we have finally come up with is using the same Flaming River Corvair box I and his Brother are using. It's pretty compact and rugged, plus the arm drops down from the shaft, rather than going up.
Don
My Son and I are wrestling with what to do for steering on his '29 right now. We kicked around the Vega cross steering box route, but he can't run a panhard because of the way his front end is set up. He was going to use a BMW 2002 box in a cowl steering setup, but that puts the box where his feet need to go. I have a '56 Ford pickup box that we tried, and the snout is way too long and the box will hit his Olds engine if we use that.
What we have finally come up with is using the same Flaming River Corvair box I and his Brother are using. It's pretty compact and rugged, plus the arm drops down from the shaft, rather than going up.
Don
Todd
He's just one of them Rusty-Chainers!
One of the things I have been contemplating is a cavalier/grand am rack. Their tie rods mount at the center of the rack and move left or right from there. This would keep the pivot point in the center as is the case with the transverse leaf. This unit can't be mounted to the axle as far as I can see.
Old Gold
Can't leave well enough alone!
Here's a not to expensive unisteer.
http://cgi.ebay.com/ebaymotors/1933...ryZ33589QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/ebaymotors/1933...ryZ33589QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
It is still basically a cross steer setup hust using an offset rack.
Ask yourself why you want to use a rack versus box, is it to save room near or around the engine, or to save room in the cab area? Either way you would be saving room where ever because the steering mechanism would be out front. I tried to hide mine so it didnt show so much.
I did it for ease of installation. It seemed easier than using a box. I found that it was about the same. I used a Dodge Omni rack. Bought it used, paid $30 shipped. It works great.
As for center mounting a rack that would be a bugger because then you would need to run the steering rod basically under the motor and would probably have too many U-joints for my taste.
Either way, I don't like the idea of mounting the rack on the axle (although I was originally going to) because of the need of the sliding steering shaft.
Well here is mine.
Please ignore my way gayee brake lines... I think I was drunk when I did that...
Tacked on here I just used some scrap 1/4" I had laying around. I don't have recent pic this is really old.
It goes straight down the road even at high speeds and hitting MASSIVE bumps, I took it down an old farm road. Other than the truck rattles a lot and the exhaust is loud it steers well and stops well, that comes in handy.
I will be honest thouh, I think I didn't have the rack at it's center point when I hooked it up because it turns sharper one way than the other. Oops... When it is warm out again I will fix that. I am pretty sure I know what I did.
Ask yourself why you want to use a rack versus box, is it to save room near or around the engine, or to save room in the cab area? Either way you would be saving room where ever because the steering mechanism would be out front. I tried to hide mine so it didnt show so much.
I did it for ease of installation. It seemed easier than using a box. I found that it was about the same. I used a Dodge Omni rack. Bought it used, paid $30 shipped. It works great.
As for center mounting a rack that would be a bugger because then you would need to run the steering rod basically under the motor and would probably have too many U-joints for my taste.
Either way, I don't like the idea of mounting the rack on the axle (although I was originally going to) because of the need of the sliding steering shaft.
Well here is mine.
Please ignore my way gayee brake lines... I think I was drunk when I did that...Tacked on here I just used some scrap 1/4" I had laying around. I don't have recent pic this is really old.
It goes straight down the road even at high speeds and hitting MASSIVE bumps, I took it down an old farm road. Other than the truck rattles a lot and the exhaust is loud it steers well and stops well, that comes in handy.
I will be honest thouh, I think I didn't have the rack at it's center point when I hooked it up because it turns sharper one way than the other. Oops... When it is warm out again I will fix that. I am pretty sure I know what I did.
Last edited:
35Mastr
Mastr Blastr
It is still basically a cross steer setup hust using an offset rack.
Ask yourself why you want to use a rack versus box, is it to save room near or around the engine, or to save room in the cab area? Either way you would be saving room where ever because the steering mechanism would be out front. I tried to hide mine so it didnt show so much.
I did it for ease of installation. It seemed easier than using a box. I found that it was about the same. I used a Dodge Omni rack. Bought it used, paid $30 shipped. It works great.
As for center mounting a rack that would be a bugger because then you would need to run the steering rod basically under the motor and would probably have too many U-joints for my taste.
Either way, I don't like the idea of mounting the rack on the axle (although I was originally going to) because of the need of the sliding steering shaft.
Well here is mine.
Tacked on here I just used some scrap 1/4" I had laying around. I don't have recent pic this is really old.
It goes straight down the road even at high speeds and hitting MASSIVE bumps, I took it down an old farm road. Other than the truck rattles a lot and the exhaust is loud it steers well and stops well, that comes in handy.
I will be honest thouh, I think I didn't have the rack at it's center point when I hooked it up because it turns sharper one way than the other. Oops... When it is warm out again I will fix that. I am pretty sure I know what I did.
You can fix the lock to lock problem.Just pull the steering shaft off the rack.Then turn it lock to lock counting the turns.Then just turn it back until you have the equal amount of turns either way.Attach the steering shaft back to the rack and adjust tie rods to get you toe back to 1/8 in.
Viola its fixed.
IAM-LDS-2
Well-known member
That looks pretty neat,may I ask why you did it that way? Was there a need or were you just wanting to be different. Looks like a lot of engine clearance problems could be solved with this set up, Also the speedway hoop thing looks good too.Did you do a pan hard bar to stop the side to side movement of your wheels.Sorry for all the ? but I'm still in my learning curve , and just when I think I have something understood somebody comes up with something I have never seen before.
I want to thank you guys for the good information. I am new to hot rod building. I plan to start on a '23 Tbucket within the next year and I am spending most of my time now garnering as much information as I can before I start. I am also new to the forum. Bill is the name Arkybill the handle. Look forward to many enjoyable sessions. Again thanks and will talk to ya'll on the next go round.
Bonehead
Skull Master
Glad you posted up. Welcome to the site.
