The Stovebolt Site Forums The Parking Lot '60-'66 Trucks Bias Ply to Radial Woes

I recently put a nice new set of radial tires on my 65 Chevy C20 replacing the old worn out bias plys. It now darts left to right when going about 40mph and faster like the steering has become overly sensitive with any slight movements by me of the steering wheel, and taking even slight curves in the road is really scary. Its a white knuckle situation. I did an internet search about going from bias to radials on older vehicles and found plenty of the same cases...these older vehicles were set up to have bias plys not radials and going to radials definitely changes things. So I take the truck to the local shop for them to check the alignment and the mechanic tells me the same thing and says this, "Go put power steering on the truck and then bring it back and I'll set the alignment correctly for the radials". I dont need the expense of installing power steering on my truck and since the 1970s there has to be thousands and thousands of older trucks that have been switched to radials...there has to be a "simple" fix to this type of problem. I would think that many of you have experienced the same thing, how do I fix this?

I've never had that problem switching trucks to radials, radials alone is like adding power steering, the only trouble with going radial is putting way wider tires on, the trucks weren't "designed for bias ply", they were designed for narrow tread.... and I can't imagine why anyone would tell you to add power steering before they can align it .... check over the steering for loose/worn joints, which can cause similar symptoms, make sure the tires are properly inflated, and find another shop that can properly align it, supply the manual if necessary

Bill

I just recently put four new ball joints on it, the two lowers were wore out the uppers were somewhat questionable so I replaced them because I was already there. Everything else checks out. So your saying the factory alignment specs should be correct for either bias or radial?. Ive read where some say when switching to radials to go to a "dead" toe (same measurement front and rear of the front tires).

I don't pay much attention to what 'some say', I prefer what the factory specified, and I haven't found any difference in handling with radials on a truck with steering and suspension in good condition - 0 toe isn't what will work, it will result in toe out when in motion and result in bad tire wear - you need to check camber as well after the suspension work, it can cause 'wandering' .... if you can do it yourself, check and set the toe by the manual, don't know on your year, but toe it in slightly and see if there's a change - also make sure tires aren't under inflated

Bill

I set the toe at dead and took it for a short drive, it drives slightly better than it was, safe enough to get it to a shop for alignment. Thank you for all your help. Im going to get it to a different shop and have them align the front to factory specs.

Ive got a shop manual on order for this truck but I wont receive it until some time this week. If anyone can give me the factory specs so that I make sure the shop does it right it would be greatly appreciated.

I would add a little more caster, set at about plus 1-1 1/2 degrees & set the camber at 1/8 to 1/4 negative. Set the toe-in at 1/16. Make sure the steering gear is good. They were weak on this model.

You beat me to it, especially the part about the 1/16" toe in.

Took the truck in for a front end alignment today, heres the "before and after", print out

The alignment felt pretty good when I first started heading back home, but the further I drove the tighter the steering wheel seemed to get, which started making the truck swerve left to right. Within a mile of home the steering wheel was so tight that I could turn it left, or right, barely, and let go of the wheel and it would stay stuck turning left, or right. Sounds like time for a new steering box to me. Is changing the box gonna screw up the toe adjustment?

It shouldn't. However, looking at your printout, looks like they could have adjusted the camber on the right front in some more. Not to sound like I'm accusing the shop of any foul play, but it almost looks like they "bumped" the alignment head/target (looks to be a Hunter printout, but I can't tell what model aligner they used)to get the camber "in spec", then set the toe. What makes me suspect is that the caster has not changed, had the adjustment been made, the caster should read even on both sides on that particular model truck. Like I said, not meaning to accuse anyone of anything, but 22 years in the alignment business, I know all the dirty tricks some shops use to cut corners/save time.

In doing a search on front end alignments I found this, "If the rear of the vehicle is higher than its designated trim height, the front suspension moves to a less positive caster. With too little positive caster, steering may be touchy at high speed and wheel returnability may be diminished when coming out of a turn."
This is exactly what Im experiencing. When I got the new tires I put taller ones on the back to help "reduce" the gearing. Their taller than the stock tires by a good 2", the fronts are basically stock height. Did I screw myself by putting such a tall tire at the rear and putting the truck on a "rake"?

That should have been compensated for with the alignment. In fact, most newer alignment equipment (hunter for sure) requires the input of the Frame Angle on light trucks so that the program will give accurate readings.

So the print out should reflect the end needed changes in adjustments for the change in frame angle as opposed to the stock specs.

Not necessarily. The specs will have some degree of tolerance based on the frame angle. Some of the older manuals used to have a chart in them showing what the camber/caster should be set at for a given frame angle as well as changes in ride height. With the new equipment, the computer does that for you. Now, if you had a printout of how the truck sat before the tires/frame angle was altered, and compared it to the printout that you have, you would most likely see a difference, mainly in the caster reading.

I spoke with the shop that did the alignment and told them it still wasnt quite right and they told me again what they told me right after the alignment, theyve aligned it as far as they could align it and that its as close to spec as it could be and shouldnt be still acting up, there must be something else going on they said. I did put a new steering box on today and took it for a drive. Definitely better and no more sticking steering wheel, but I still had to use both hands on the wheel because of what I quoted before,("touchy at high speed and wheel returnability diminished when coming out of a turn.") For a test I removed the new 2+" taller than stock tires off the rear and put on a pair of stock height tires. Took it for a test drive, this time I could go with one hand on the wheel all the way down the road and back, drove about 5 miles this way, even through the curves in the road, I sure coudnt do that before with the tall tires on the back. I think this test proves that having those new tall tires on the back was the main problem all along. Looks like Ive got two nice new 235/85R16 E rated tires that will be going on CL and having another pair of stock height tires on the rear. Opinions??

do what works .... you might have found putting matching larger tires on front improved things as well, I much prefer keeping tire size close to stock and the same size front and back

Bill

I'm still skeptical about the alignment. Especially since they're claiming that it was "adjusted as close to spec as it could be". You might check the upper control arm on the right front, see how many, if any, shims are present. If there's any shims in there, especially at the front of the control arm, then they should have been able to adjust the camber in. Also, for stability with the larger rear tires (I do agree with Bill about having same size all around, unless OEM uses mismatched, in most cases), they should have laid the caster back, say about 3-3.5 degrees.

The first 3 photos are the passenger side, the other 2 are the drivers side, which they did not touch. It looks like there is one thick shim and one thin shim on the front setting of the passenger side and no shims at the rear. Photos

From what I can see, they never touched the right side, I notice that there are no wrench marks on the nuts and the threads of the studs are not clean where the nut would have been backed off. They could have taken out the 1/32 shim, perhaps maybe taken out the 1/8 shim and installed a 1/16, to bring the camber in to spec, which would also bring the caster at least to match side to side. That really supports my theory that they did a "head bump" to make the camber read "in". Essentially, what you got was a "toe and go", not uncommon in the alignment business. The bad part is that your truck is one of the easiest to get set right.

When it comes to front end alignments Im mostly in the dark. Is this something I can do myself, and get it right, with some knowledgeable guidance? Your help with this so far has been much appreciated. The wet oil on the pass. side is from them. Is this penetrating oil so they could adjust that side or is the oil a "smoke screen"?

edit: looking at the photos again I do see what you mean about wrench marks and uncleaned threads.hmmm Looks like I might have gotten an $85 "shaft job"

They might have sprayed with the intent to make an adjustment if it was way off, the mechanic might have decided to "cheat" when he saw how close it was. Most shops do pay on a commission rate, so the faster a job gets done, the faster the next one can come in. Unfortunately, that can cause some mechanics to take shortcuts.
As far taking the shim out, you can do that yourself fairly easily. You'll need to jack the truck up, supporting it by the frame preferable for better access to the nuts. Then take both nuts loose, but not off, the front one a bit more than the rear, to allow for the shim to be able to slide out. Then simply tighten them back up. You will toe the right front wheel out a bit, but that can be easily compensated for as well. That procedure is covered in depth in several threads on the site.

So I need to remove the thinnest shim first and then pull the right front wheel in a touch at the tie rod end, and then take it for a test drive.?

Yes.

I'll give it a try tomorrow. Thanks for all your help. I'll post the results.

I removed the 1/32 shim and kicked the toe in a hair on the passenger side and took it for a drive. Definitely better but not 100% yet. I was able to, for most of the drive, one hand the steering wheel, even through the curves, but I still had to be diligent. So do I remove the 1/8 shim and replace it with a 1/16 and the 1/32 shim, and then kick the toe in a hair more or do I call it good and put the same size tires on the back that I have on the front? Im thinking I might have to take those tall tires off the back irregardless.

I'd probably leave for now, and either put the one size or the other all around, just as long as they match. Not sure what the tires are on the front that you have, but putting another pair of the larger size tires on the front will not hurt anything, and will give you the same overall results as putting the smaller size back on the rear.

I cant put the same size tires on the front as the back, they would rub hard on turns. 245/75R16's on the front and 235/85R16's on the rear.

As a point of comparison: On my '65 C10 I am running 29" diameter tires front and 33" diameter tires rear, yet I do not have any steering issues?

As previously stated, if they aligned the truck with the larger rear tires it is accounted for in the alignment.

In any event good luck to you!

John

Years ago I had a 63 Chevrolet C10 that I put new 3/4 ton rear springs on, which did raise the back of the truck up a good amount, it had radials on it and drove fine. I dont know what it is about this truck, its just particular.

Well, Ive got new all matching tires now on the truck, 245/75R16's all the way around. The drive to the tire shop was a little touch and go. After the changed rear tires, big difference, a better difference. It still has some slight touchiness at highway speeds though but its so much better. I checked the toe when I got home and its at a 1/16 toe in, should I bump it to an 1/8? I would like to eliminate all of the touchiness if I could.

1/16 in. is fine. Make sure the steering gear is operating on center when the wheels are straight ahead.

Finally an update. Thanks out to Wrenchbender Ret.

I didnt think about the steering box being "centered". Checked it today and sure enough the steering wheel was maxed 2-1/2 turns to the right but to the left it came up shy, like 2-5/16 turns. With some judicious back and forth with both tie rod ends I finally got the box "centered" and the toe in at 1/16. Took it for spin and its like whole new truck. Thanks for the reminder "bender". And thanks to all the posters that helped.

I haven't been on here in a while; glad to hear you got it worked out.

I have the 235/85 rear and 245/75 front combo on my truck; it would handle better with the shorter rear tires (less squirm), but the reason I went with the shorter front tires was better handling/braking (I also had 235/85's on the front for a while).