Hey chassis boys... 1.5 degree difference in king pin inclination left to right?

[Lee_in_KC]

Have you tried reducing the toe in to 1/16 or less also have you tried reversing the axle???

I've had the toe set everywhere from 1/2" in to 1/2" out. About 1/4" out seems to work best, but man it chews up the tires!! What do you mean by "reversing the axle?"

 

[Lee_in_KC]

Lee, have you put another set of rims on the front?

Todd, I don't have another set of wheels/tires to try. Maybe someone in the Cowtown Ts has some I can try.

 

[sstock]

Lee, I bumped into a guy last year with a similar problem, turned out to be his Nankang tires, you don't have those do you?

 

[Lee_in_KC]

I've got 125R15 Firestones (Volkswagen tires) on Center Line Auto Drags. Wheels were checked for run-out and out-of-round before tires were mounted. Wheels/tires were spin-balanced on the car... one ended up with 1/2 oz., the other with nothing. I did have occasional wheel-hop until I added the hydraulic shocks.

 

[Duke]

Did I catch that right? Your wheel hop got worse when you went to hydraulic shocks ?

 

[Lee_in_KC]

Shocks cured the wheel hop!!

 

[sstock]

I've got 125R15 Firestones (Volkswagen tires) on Center Line Auto Drags. Wheels were checked for run-out and out-of-round before tires were mounted. Wheels/tires were spin-balanced on the car... one ended up with 1/2 oz., the other with nothing. I did have occasional wheel-hop until I added the hydraulic shocks.

The steering box nice and tight?

 

[Chief-T]

Lee, Is your steering box perfectly centered and wheels straight before the drag link is attached?? I've seen an off centered box cause a wooble.

 

[Lee_in_KC]

Steering box (Flaming River Vega) is tight, abolutely no play. Pittman arm is tight and centered on the output shaft. During set-up, steering wheel was turned lock to lock then set precisely between locks, Pittman arm was then mounted perfectly straight up, then drag link was set to length with the front wheels dead-nuts straight ahead.

Since I have such small front tires with a very small contact patch, I wonder if that has anything to do with. Do the wire wheel guys with the motorcycle tires have more probelms with shimmy than the guys with fatter tires?

 

[EX JUNK]

T-Odd, I know that I'll get some flack for this but I am a firm believer in maintaining proper Ackerman. That pickup does not have proper Ackerman.

Lee. I think that you should check your camber at the king pin not the steering arms. That way you will know exactly what your camber is. Have you checked your Ackerman also?

Jim

 

[T-Odd]

Jim, I said the same thing when the parts started gathering for that pickup. BUT since proper Ackerman shouldn't have any effect on straight line driving (but it'll sure wear out a set of tires quickly) nobody ever changed it. There are a few cars around here that don't have proper Ackerman and people tell me I'm crazy for saying something about it because the cars drive with no issues.

Drove straight, but wore out tires.

 

[lincolnuT]

Lee,

I am sure you have tried Toe Out but if not please do. Start at about 1/16 out and drive about 5 miles if it don't fix it go about 1/2 turn of the tie rod out again drive 5 miles keep doing this until it's gone. Both the Chrome T and the YeloT like toe out and the YeloT is about 1/4 inch out. Try it you might like it......Another car way back in life liked to be about 3/8 out......

Mike

 

[Lee_in_KC]

Mike, I have tried toe out and it does help. Best setting I found was about 1/4" out, but man did it take a toll on the tires! Within just a hundred miles most of the tread at the inside edge of the tire was gone. I went back to toe in just to even out the tread wear!!

 

[lincolnuT]

Well that is interesting because I have never had that happen. I think something else is going on with the tire wear not the toe out.......Because the toe in/out would cause the same thing either way, the tire does not know which way it is rolling. Check to make sure that the wheel bearings are tight again.

Did both tires wear out about the same? Did/does the car feel like it wants to slide the tires when you turn around a corner that is where Ackerman is going to be the most problem....? I think you talked about how you used Toolman's squaring method from the NTBA web site.
Maybe the air pressure in the tires had something to do with the wear in toe out condition.

Mike

 

[Dirt-T]

I changed wheels and tires on my roadster and problem went away. The tires had a wider tread .

 

[2old2fast]

Lee , when my car first went on the road , I fought both wheel hop & wobble, went thru multiple front tires , balancing etc. , finally [in desperation] I changed ALL 4 TIRES , different brand.... solved all my issues , tracks straight , no wobble or bounce , really fun to drive !!!!


dave

 

[RPM]

I had a terrible vibration, shimmy in mine. It was in the rear tires and shacking the whole car.

 

[Lee_in_KC]

Mike, it has always been my understanding (well, since high school auto shop, that is) that tire wear is a good indicator of toe and camber problems. Toe out will wear the inside of the tread more rapidly than the outside and toe in will wear the outside more rapidly than the inside. Tire wear on mine is the same side to side. Right now it is pretty even because I went back to toe in after running about 100 miles with toe out... the wear was very obvious.

The car drives like it's on rails with no strange behavior in the front end other than the wobble/shimmy. I have a panhard bar and proper Ackerman for front steer. I'm very happy with the way the car drives... other than the wobble. I'm pretty sure it is a caster problem... I just need to adjust caster in small increments until I find the sweet spot!!

Dave, I'm going to be needing front tires pretty soon, so we will see what happens. I plan to stay with the 125R15 Firestones, though, so maybe no change. I have been thinking about changing the rear wheels and tires as well, as I have a harmonic vibration in the 55-60 mph range that I'm pretty sure is caused by the wheel/tire combination, since I had it with both the original straight axle set-up as well as the current Jag set-up. The wheels/tires (15x15 Center Line Auto Drags, 31-18.50-15 Hoosiers Pro Streets) were balanced on the car, but they took A LOT of weight to balance. I have heard that people with the bigger Hoosiers frequently have balance problems just because of the massiveness of the tires. I've also heard that the really wide Auto Drag wheels with deep offset can flex around the center disk, causing the same sensation as out-of-balance tires.

Ah the joys of hot-rodding.

 

[sstock]

I' ve been told by Mickey Thompson rep at SEMA this last year that a big tire such as a 18 wide will weigh close to 50lbs can take a 1/2 lb of balance weight and still be "well" within spec. I brought it up to him because one of my big Micky radials took 7 oz the other about 4oz if memory serves me right.

 

[Cool32]

What do you mean by "reversing the axle?"

Swap the axle around side to side.
How long is the drag link and what size rod is it. If it's too thin it could be flexing???