Hot Rods bias ply open fender last resort (drivers please)

ok, so I'm totally out of patience now. I'm running coker classic 600 16's up front and firestone drags out back. I have a shake wobble or whatever you want to call it but I litterally cannot get it to go away! I've dropped pressure as low as 15lbs, I paid $60 for the so called "balance beads" with no luck. Went to local shop today and spun balanced all four and allthough a little weight was involved, low and behold the same shake. it comes on at about 60 and I cannot drive through it. it just gets worse. With 24lbs up front i was getting bout 5-6 inches of b-ball bounce at 70! Friggen scary! So I'm leaning on radials........dammit! anyone with advice would be great but I'm tired of chasing loose ends. Has anyone run the coker 16 radials with the bias out back? Heres a pic of the car. Speedway 6" drop axle sprung behind, cross steer with panhard front and rear. Any pics of the radial 16's would be great as well, thanks in advance

I'll post some better geometry pics soon
<input id="gwProxy" type="hidden"><!--Session data--><input onclick="if(typeof(jsCall)=='function'){jsCall();}else{setTimeout('jsCall()',500);}" id="jsProxy" type="hidden">

 

search death wobbel.

 

looking at that motor, just go radials

 

Lots of threads on this topic, but don't mix radials and bias plys.

 

Death wobble is at super slow speeds...not 60. It's a violent side to side shake, not up and down bounce.

 

Hands down, DiamondBacks

 

Ive searched this sight up and down. I get a side to side and a bounce....
<input id="gwProxy" type="hidden"><!--Session data--><input onclick="if(typeof(jsCall)=='function'){jsCall();}else{setTimeout('jsCall()',500);}" id="jsProxy" type="hidden">

 

caster or toe are probable out

 

would the shocks being parallel be adding to the side to side play? just spitballing here. but i would think you need a little outboard action on at least on part of the suspension.

 

Holy crap, look at the front shock angle.....


I'm not a pro builder, but that's not right.

 

Alright it was a joke. Thanks though.

 

If alignment is in spec try going up on the air pressure, 30-35# is not unusual. Shocks OK?

 

I have a 1926 t lakes modified style. I had been given the front wheels and tires,on the front. Had a terrible shake above 50 mph. Figured the old tires were the issue. Bought new tires and had them balanced. The shake was still there. At this point, scratching my head. In desperation, I rotated the wheel one (1) lug nut. Some people call it clocking. Amazingly eliminated the shake. good luck

 

Front wheels are bouncing. Just sitting here and thinking. Are the shocks doing anything for you? What is it like without the shocks on? After doing all that you have, I would look at stiffening up the shocks.

Neal

 

I notice that the front shocks are leaning to the rear at about 45 degree angle,, not good. The shocks should be attached at the bottom as close to the kingpin as possible,, then lean toward the spring center not more than 65 degrees. The shock should also be rated 50/50,, I know this will be difficult for you to do with your car,, but study it and it can be done.

 

I've been down this road before a few times.

First off, are the tires round? Many bias plies are not and require truing. You can balance a cube but that doesn't mean it's gonna roll! Check your rims to make sure they're straight as well. Looks like you're running F1 brakes... Check your drums to make sure you haven't lost a weight on one of them. You can try clocking the wheels on the drum in a different spot, sometimes if there's a drum imbalance this will lessen the symptom.

Throw some "whatever you have laying around" radials on there and see if it still does it. That way you can quickly figure out if it's a tire or mechanical/alignment problem.

While your front shock installation isn't the most conventional setup, it won't cause this problem.

 

Are you sure the front tires are round? No joke. Look at Sept. " Ole Skool Rodz " page 56 for an article on truing bias ply tires. I'm rebuilding a vintage Kemsway Tire Conditioner for this purpose now and hope to offer the service soon in my shop. Shock angle? Luck.

 

Those shocks can't be doing anything at all. At that angle, there will be almost no movement of the shock piston with a typical transverse spring. An angle like that might work on a soft rear parallel leaf or coil that had "lots" of travel. I just can see it working in this case.

So, if you are chasing more of a "bounce", then I'd be trying to find a way to mount them better.

You may have other issues all at once, but when something is dead wrong, it should be fixed regardless.

 

From my troubles with my last tires that were definatly out of round, I would seriously check that! The more miles I drove on them over the year + the speed before the bounce kept slightly dropping. I bought new Firestone bia and everything is much better. I myself am not a big fan of the coker brand tires. And yes check the alignment!

 

Being that you are from Nevada,, I'll bet you that the problem is shock position and angle.

 

i would try moving the shock angle move it to the radias arm you can actually get a stiff shock if you do that make a tab the ties the upper and lower bars to mount lower shock then the other on frame rail having an over all rake of no more than 30% you loose shock the more you lay it over i got a truck in my shop and it hops real bad so were gonna change angle of rear shocks to fix problem. and the should go more engine to tire then rear to front if that makes since(shock angle)

 

I am with the majority here. Who told you that shock angle would do anything? Bad engineering right there. Get some help relocating those shocks and you will be on your way.

 

shocks are doing nothing to dampen suspension movement.

 

I agree with moving the shock mounts.

Also, I saw some of the coker radials that look like bias ply tires on the rolling bones 32 s at speed week and they look real good and I hear the ride much better than the bias ply. I was going with the firestones until I saw these.

 

+ 37 or so on the shocks. Those might as well not be on the car for all the good they are doing. mounting studs/bolts should be parallel with the frame,15-20* off vertical.

 

Lots of good sugestions. I would look at all of them.. Have you spin balanced the tires on the car? Gives you a good chance to see what the tires & wheels are doing at speed. Look for both up & down & side to side. I have sold alot of Cooker tires and most have been ok. But on one car I have i had to true the tires. Yes they come square and alot of these cars sit for long periods of time and go square that way.
Good luck and Get the shocks changed.

 

lots of variables here... i agree with the fact that those shocks are not helping anything at that bizarre angle..

is there any way you can borrow a set known good mounted and balanced radial tires to throw on there for a test run? that will give you a good idea...

 

I am, and F&J is right.

Relocate the shocks before doing anything else. They will provide no useful dampening whatsoever in that position.

 

First off, a shock only dampens oscillations [ it doesn't prevent them.]
So changing the shock angle will not "cure" a vibration unless the shock is so weak that driving over gravel sends oscillations through the car.
Admittedly, a shock is more efficient when it is mounted 90 degrees to the force it's trying to dampen.
Laying the shocks over alters the "motion ratio" so they need to be stiffer to compensate [ or this is an easy way to soften them ] early motocross bikes laid the shocks over so they could increase wheel travel in relation to shock travel .[ this is more efficient when using monotube shocks eg:bilsteins ]

Back to your vibration problem!!!!!
You never mentioned if it was "in the seat of your pants" or in the steering only!
Do you know which it is?? because there is a big difference.

Most "Out-of-Balance" issues occur within a limited range [35-45mph etc] then disappear, except driveshaft balance because it tries to bend like a skipping rope.

Because the vibration gets worse as it gets faster, my money is on something being bent or out-of -round , or something is loose!

I would reccomend setting the car on axle stands [as in level and solid ] and go around and check everything is running true, including the rear wheels.
Check to see if the tires are running true at the contact area [as well as being egg shaped ]

Run the steering through it's whole range of movement to check if the balljoints are worn funny [ I have come across oval shaped ones before that were OK in a straight ahead position ]

Try over inflating the tires ,and check them again. I once had a tire de-laminate internally but it looked ok on the outside [ when I over inflated it ,a huge bulge appeared ]

Also check the scrub radius [ kingpin inclination ] of the front wheels, too much positlve offset causes them to wobble [usually over lowspeed bumps] but once this wobble starts, you cannot "drive it out"

I recently was at the track ,when a friend had similar symptoms on a Capri, all his wheels were balance and true, the problem was the rear axles were slightly bent from some "bush mechanic" replacing the rear axle bearings [ he thought it was in the steering ]

Just be patient and get back to the basics

 

All very true, but these are not stiff shocks, or is this a long travel suspension setup.

That setup, at most, has 4" of suspension travel. Combine that with the shock angle, and shock travel is likely too short to be accomplishing anything.

Try this: Put a zip-tie on each shock rod and cut off the excess. Slide it down to the shock body and go out for a spin.

When you get back, see where the zip tie is. That is how much shock travel you are really using.