Problems with new radial tires

[Guest Dave May]

I've got a 1960 Buick Invicta and have beed riding on polyester Bias ply tires. Other than the typical bias tire issues, I had no problem. Since they were old, I thought I'd get new radials. I bought a set of wide WW radials from Diamondback tires, had them mounted and balanced on my original steel rims. Thinking I was going to get a great ride with the radials, I was disappointed when I got up to about 45 mph and the front end started shaking. I had the tires/wheels rebalanced and switched the fronts to back, but it didn't make a difference. The shocks, ball joints and upper control arms have all been recently replaced. I did not replace the springs because the car sits fine.

I didn't have this problem with the old tires, but I'm wondering if the softer and larger (8.20), side walls on the bias tires may have "masked" the problem ??? When the new tires were being balanced, I did notice a bit of wheel run out when they were on the machine, but I'm wondering if some run out was normal with the old stamped steel wheels???

Anyone ever have this problem going from bias ply tires to radials???? Any thoughts on what I should be looking for??

Thanks

[Thriller]

I can't speak specifically to the issue you are encountering, but some cars really seem to like bias ply tires, while others do better with radials. My '41 and '54 are quite happy with bias ply tires, and I have a set of each for the Wildcat (can't really speak to a comparison as it has been on the bias ply tires for a while now).

I understand that some of the front end geometry / alignment may need to be modified for the different style of tire.

Good luck.

[old-tank]

Radials are much more sensitive to run-out than bias ply, whether it is in the rim or the tire. The way the Diamondback radials are made would suggest that tires with excessive run out would be rejected. I have my tires static balanced with all of the weights on the inside; this was done initially for cosmetic purposes, but I discovered that the ride was better than the so-called dynamic balance that had weight scattered all over the tire. Many current radials have higher recommended pressure than before: I get a better ride and handling at 42psi vs my long term usual 32psi with bias or radial tires. If you used anything other than 75 series radials, then all bets are off. It could even be the balancing equipment at the shop you use. It is probably the rims; I inspected and tested 20 to get 4 that were acceptable. In the past when equipment was available I had tires trued by cutting/buffing followed by spin balancing on the car (I hate tire vibration).

Willie

[Ben Bruce aka First Born]

My vote is for defective tires.

Dave, for a test, go to any good tire shop and beg, borrow, buy or steal a pair of [ or a set of 4] used 235/75R tires and have them balanced and mounted. I find it hard to believe radials,as such, will not work on any car. I have seen new tires with crooked treads cause some shaking and shimming.

Ben

[RivNut]

When I first bought my '63 Riviera it had bias ply tires on it. I took if for a test drive and the only problem I could find was front end wander. I figured that I'd probably need to replace tie rods ends, etc. I took it to the local Goodyear store where I'd done business over the years and the mgr. suggested that I first try a set of radial tires. I knew that I needed tires anyway so I put on a good set. 60+K miles later and the car still has the same tie rods, etc. and I'm on another set of radials. The only thing I noticed when I switched to radials was improvement in everything. No modifications to the steering parts or geometry were done.

Ed

[NTX5467]

I concur with the "bad tire" orientation, BUT it could well be that what you're experiencing is a "flat spot" condition due to how the tires were stored prior to shipment . . . even if they were wrapped. I'm not so sure that radials will drastically change much of what you might be used to, other than to make the good stuff better.

ALL steel wheels have a certain "run-out" spec, laterally and also "up and down", but these are NOT huge tolerances. Modern steel wheels still have similar tolerances to the wheels on your car (from new). I would expect that the additional flex of a radial tire's sidewall to further mask any lateral run-out, compared to the more rigid bias-ply tire's sidewall. I have cars that came with bias ply tires that later got bias-belted tires, and then radials. Each upgrade felt better to drive, even on the steel wheels they came with, than it did before each upgrade.

BACK when radial tires were new to the USA market, there were some articles about how to make your car better-able to benefit from the radial's attributes. It was also mentioned that a radial tire was more critical of toe-in settings than a bias ply or bias-belted tire, but that camber was not nearly as critical. You can't change the front-end geometry, as that's a "designed-in" situation, but what you CAN change is the alignment spec adjustments. Generally, as evidenced by 1980s+ GM alignment settings for radial all-season tires, set toe-in as near to "0" as the specs might allow (think, "minimum spec" for your vehicle), set camber to "as close to 0 as you can" (but also allowing for changes to better tolerate the "road crown" for the roads you usually drive on), I like to set caster more toward the "max spec" as this helps the outside wheel (when turning) to go more into negative camber to better brace the sidewall against the turn, also letting the tire be more perpendicular to the road surface as the vehicle might lean in the corner . . . but that's just my orientation).

I've seen some people who are adamant that the alignment be set to EXACT factory specs, but the reality is that with the amount of "compliance" in earlier suspensions, as soon as the vehicle starts to roll, things change slightly, which is why you set the toe as "toe-in" so that as the vehicle rolls, the "rolling toe" will be almost "0". If the alignment is set without any passenger load, as soon as somebody sits in the car, or some weight is placed in the trunk, the prior alignment settings will vary slightly. You get the idea.

So, I've used my guidelines (as mentioned) with good results over the years. I sometimes feel that front-end alignments CAN be somewhat over-sold by service establishments, but I also recognize that not everybody drives on the same roads as I might, BUT alignment which might be a little "out" (enough to wear a tire!) can be costly in the long run, due to more frequent tire replacements. Be that as it may.

Back to the tire storage situation . . . IF the tires were stored vertically in a two-rail rack, the two rails will indent the tire's tread area with time. These indentions might not be really visible AND should pretty much go away when the tire is mounted and inflated, IF they stayed on that rack very long, it might take a 60 mile run on a very warm summer day for everything to become "round" again. In the vintage tire warehousing situation, this might well be what you're experiencing . . . like an old nylon tire after it sat overnight, so to speak. Usually, this type of storage is not that much of an issue, with the more flexible sidewalls of modern radials and the fact that with good inventory control, the tires are not "in inventory" long enough for issues to evolve in more-normal types of tires.

Due to the way that Diamondback "makes" their whitewall tires, fusing white rubber onto the exterior of the sidewall (as I understand it, from prior posts on that subject) rather than grinding a thin layer of black rubber away to reveal a layer of white rubber below it, that might make them more susceptible to sidewall deformations if they were not stored horizontally.

Back to the wheel run-out issue. IF a wheel is out-of-spec in the lateral run-out spec, it'll be VERY visible to the naked eye. It'll be bad enough for the owner to say "I don't like that wheel!" But even with some of the older bias-belted tires, a wheel with a minor amount of visible run-out might make for a very slight "ride disturbance" at higher freeway speeds, but no more. This is the kind of thing which a radial's flexible sidewalls should, to me, mask nicely.

But in so-doing, it might also set up a "road force variation" situation which can be a very slight disturbance . . . enough to be a very minor irritant, but nothing more, which a balance job will not fully fix. We didn't start hearing about THIS until most modern cars had all-wheel independent suspensions and alloy wheels . . . in other words, not enough "machine weight" of heavier wheels and rear axles to override these things.

So . . . I'd recommend that you get your Diamondback tires to a tire shop which has an electronic wheel balancer that can check "Road Force Variation" (by way of an external cylinder which will roll against the tire's tread as the balancer turns the tire/wheel assy). It should give a read-out of how many "pounds" of RFV and also pinpoint the exact place of such just as it would tell you where to position the balance weights. There ARE also specs for RFV, too, depending upon if the tire is a passenger car tire or a truck tire. In prior times with bias-ply tires, seems like we used to term them "hard spots" in the tire's carcass?

As for the car, just reset the toe-in to the min-spec for the car. I have my own likes as to tire pressure, which can differ from what others might like. To me, what has been described sounds more like a tire issue than a vehicle issue.

One other thing . . . it's somewhat normal to rebuild the front suspension as a matter of course, but often not considered is that the rear suspension ALSO has rubber bushings and such which are just as susceptible to age and wear as their counterparts in the front suspension. Not only the control arm bushings, but also the TRACK BAR bushings.

Please keep us posted on how things turn out.

Just some thoughts and such,

NTX5467

Edited September 4, 2013 by NTX5467 (see edit history)

[TexasJohn55]

"Just some thoughts and such...." Let me condense that, You got some bad tires.

[TexasJohn55]

Balancing wheels on the car has it's merits. I think I have some drums out of balance, you can never account for that if the wheels are balanced off the car as is popular nowadays.

Be sure you distinguish "shimmy" from wheel bounce. Shimmy will cause the steering wheel to vibrate and pulse back and forth. If necesary, have someone shadow you while driving to determine what is happening.

Edited September 4, 2013 by TexasJohn55 (see edit history)

[dan at larescorp]

It's not a bad idea to have the car aligned to the positive side of the specs. when you switch to radials. It helps with shakes, and wandering conditions.

[old-tank]

What is the brand of tire that Diamondback used and the date code?

The tires I got from Diamondback were less than a month old when I received them (vs 2 years old from another vendor that I sent back); brand was Firestone FR380 (no longer made ). IF the tires are shown to be defective you should have no problem getting replacements (I had a cosmetic issue on one and a replacement was sent along with a return label for the old tire). The only good way to check the rims is to remove the tire...

[JohnD1956]

Before condeming the tires, may I ask what you meant in your original post when you said " Other than the typical bias tire issues" ?

[Guest Dave May]

Before condeming the tires, may I ask what you meant in your original post when you said " Other than the typical bias tire issues" ?

The bias tires provided a very smooth ride, but if they would catch a rut or seam in the road, the car would follow the rut or seam. It felt that the car would steer itself at times. The radials provide better road feel and control.

Diamondback provided Hankook radials, I haven't checked the date code on them.

Thanks for all the responses and great input. I'll be taking the car into the shop this weekend to see what might be the issue. I'll keep you all posted.

[JohnD1956]

Well, you replaced the shocks, Ball joints and upper control arms. That still leaves the tie rod ends, center link, idler arm, and lower Control Arm bushings, assuming the upper control arms had new bushings when you acquired them. Any of those parts can cause alignment problems that may not show till the conditions are right. And one or more could have lead to that feeling that the car was steering itself too.

Edited September 5, 2013 by JohnD1956 (see edit history)

[NTX5467]

Back 50 years ago, we drove cars on quality (and some not-so-quality) bias ply tires and thought nothing of it. But . . . the cars we're now dealing with were still relatively new with reasonably fresh rubber in the rubber suspension bushings and the other aspects of the steering system were still relatively "tight", including the steering gear. So why do these same cars now seem to display "poor" driving characteristics with bias ply tires? Plus "new" does not really mean "new" like it did 50 years ago, when those rubber suspension items were normally on the shelves of the auto supply stores/warehouses as a normal matter of course.

Therefore, unless you can find somebody to make you some "fresh" suspension bushings one week and install them in your vehicle the next week, you're probably dealing with rubber items several years (even decades?) old, yet still "New-in-the-box" items. And, if they are true "New Old Stock", then you know they're several decades old, yet "new" rather than "used". To me, this is a reality issue which might not be really considered when purchasing these items. There might be some date coding on the box or on the part itself, but it can vary from manufacturer to manufacturer.

Certainly, the parts installed were "new", but if they might be "old", then possibly the elastomeric properties might have detriorated somewhat from their original assembly condition. But then, too, you can find many 20K mile cars at many vehicle auctions, with untouched suspensions, which are claimed to "Drive like a new car" (and they probably do!).

I might be splitting hairs on this issue, but it just seems a little odd that cars we eagerly drove and enjoyed, back then, on bias ply tires suddenly have a good bit of "bad behavious" on the more modern versions of bias ply tires we now have. Putting in new parts to replace "old" parts might be an improvement, but unless you consider ALL of the steering and suspension (front AND rear) rubber items in any suspension rebuild, you can still have spent money for little real benefit. And, of course, the many wear adjustments which the steering gear might need to be "as new".

Just some thoughts,

NTX5467

[JohnD1956]

And NTX just jogged my memory on something. I had a bad shock on the rear of my Wagon. My car would ride like a dream at lower speeds but just getting up to speed on the expressway on ramp resulted in massive vibration that I kept thinking was coming from the front end. All that disappeared when I got those rear shocks replaced.

I also had a later Caddy once with a bad vibration. I went through that thing several times looking for a vibration that turned out to be rotted brake drums in the back.

[Guest Skyking]

I suggest before anything else, try balancing them with a bubble balancer. That's all I use.

[Guest Dave May]

I suggest before anything else, try balancing them with a bubble balancer. That's all I use.

The first time they were spin balanced. The second time they were "Static" balanced. I assume that static balancing is the same as "bubble" balancing ????

[TexasJohn55]

Re: post 14. I would like to submit a friendly rebuttal to the presumption that "old rubber" is bad rubber. I have a small stock of old NOS parts from the '60's, at least 40 years old. My observation of old rubber parts, if stored indoors out of the sun, is that they are as good as anything I would get off the shelf now. I have a big box of original radiator hoses that are still supple and I would put on my car. Same goes for front end bushings and motor mounts, etc. Transmission rubber kit seals likewise. My opinion is that most but not necessarily all rubber components do not degrade just because they sat on the shelf for 5 yrs or so. My "barn parts" seem to have held up rather well. I have a '67 Harley with the original front tire but it is starting to show some age. Just some thoughts...

Edit: The exception would be belts, I have some NOS but they don't seem to age as gracefully. The type of rubber compound in the part is probably a major factor in aging.

Edited September 11, 2013 by TexasJohn55
disclaimer (see edit history)

[John_Maine]

My first try at radials was not good. My first new car was a '72 Ford Gran Torino. When the car had 23,000 miles or so, I decided to replace the original Firestone bias plies with new radials. I was very pleased with the difference in driving around town. A few days later, I took a short trip and as soon as I hit 50 mph, I got a terrible shake in the front of the car. The faster I went, the worse it got. It made driving on the highway almost unbearable. It shook like badly warped rotors only I wasn't braking. I went back to the tire store; they spun balanced the tires this time. I went out on the highway, very little change. Took the car back and they started from the beginning, demounted the tires, checked the wheels, re-installed and balanced them again. This went on for about a month when the tire place basically gave up. Fortunately, I kept the old Firestones so I had them re-installed. The shake was completely gone. The manager of the tire store gave me a full refund of the purchase price of the tires. When I went back a few weeks later for something else, he told me he re-sold the tires to a woman and put them on her '73 Montego wagon and they were fine. She had no complaints whatsoever. We both came to the conclusion that my Torino just wouldn't accept radials. I ran the original Firestones for another few thousand miles and replaced them with a set of General bias ply and had no issues with them or another set of bias ply that I put on at 70,000 miles.

Interestingly, I have radials on my '72 LTD and have had no problems with them. I replaced the '72 Torino with a '74 Torino that already had radials on it and they were fine as well. I just think some older cars are not accepting of radials.

[Guest Skyking]

I suggest before anything else, try balancing them with a bubble balancer. That's all I use.

Dave, sorry for this dumb post. In all the years I've been using mine, I never knew it was called "static: balancing. I guess we are never too old to learn.............I hope you solve your problem.

[60FlatTop]

I have two year old Coker Firestone 8.20 X 15 biased tires on my 1960 Electra. It rolls along just fine. In 1966 my 1960 Invicta had four 7.60 X 15 Firestone Deluxe Champion recaps it rode equally fine. I had a habit of pegging the Invicta speedometer at 120 fairly often. The Electra rarely goes over 85, where the speed reminder is set.

The Electra has had a pretty good grease flushing at all the joints since I have owned it. I lift the rubber seals up and pump until any water or dirty grease is displaced. I cleaned and adjusted the steering link cups.

When I do any work that twists the rubber bushings more than normal ride angles I loosen the through bolt and spread the suspension arm away from the serrations of the inner sleeve (keeps them from tearing).

I went through about 8 rims to find a set I was happy with the chamfered bolt holes. A lot of wheels had been horsed down by good old boys with 150 PSI on the impact wrenches. They tear those holes up pretty bad. You might want to check that.

That story I tell about having the priest spray holy water on my windshield when I test the windshield wipers, well, I don't even let him tighten the lug nuts; no one but me.

Bernie

[buick5563]

FWIW, I vote for one of the wheels being out.

Just sayin'

[TexasJohn55]

Bernie, I'm with you on the rubber A arm bushings. First set I put in as a youngster, had the car off the ground on jack stands, pulled control arms (69 Pontiac) and pressed in new bushings, put 'er back toghether and fully tightened the A arm end nuts. Put the wheels on and dropped it to the ground. A few months later I was under it checking things out and noticed the new bushings were ripped out. That is learning the hard way.

Same here on lugnuts. I make Discount Tire hand tighten all mine, no impact. I had one garage put them on so tight with an air wrench, I had to use a 2 ft cheater on my 1/2 in ratchet to get them broke loose, thought something was gonna break! I have no faith in those so-called "Torque sticks" they use that supposedly limits the torque applied.

[TexasJohn55]

Sorry, Weren't we waiting to see why his tires bounced or was it shimmy? I don't think THAT has even been determined.

[Matt Harwood]

Tire balancing is more of an art than science, despite the machines they use today. I had a client with a 1948 Lincoln Continental that had wide whitewall radials on it and it wandered all over the place. He swapped on a set of bias-plys and wheels from his '42 Continental convertible and the sucker tracked straight as an arrow. Swapped the radials back on, and it was back to wandering. I have exactly no explanation for this.

I have also been struggling with balance issues on my 2004 Audi allroad. I bought a set of 18-inch OEM wheels brand new and kept the original 17-inch wheels to use with snow tires. New wheels, out of the box, with brand new tires were prone to vibration. I blamed the tires and tried at 8 different shops to get them balanced, and they ALWAYS balanced perfect on the machine. But the car vibrated. I blamed the tires.

So I recently replaced the tires and the vibration continues. I complained to Goodyear and they sent me to corporate HQ here in Akron and 1) gave me another new set of tires and 2) comprehensively tested and balanced the tires. They found nothing wrong with the tires or the car (I've replaced everything in my quest to cure the vibration). The new tires are 90% better, but the vibration is still there, and it's worth noting that the snow tires on the original 17-inch wheels, which have been battered and abused, ride perfectly. Somehow, some way, the wheels are defective in a way that machines can't detect but shows up as a vibration on the road.

My point? Maybe it's the tires, maybe it's the wheels, maybe it's the combination of the two. See if Diamondback will replace the tires, but if the new ones also vibrate be prepared to either change other parts on the car or throw away the brand new tires and buy a new set of bias-plys or simply live with the vibration as I have learned to do. I grit my teeth as I drive, but hey, at least in November I get to put the snow tires on and it'll be smooth again...

Holy cow I have bad luck with tires.

[NTX5467]

As a side note . . . a friend used to run a Firestone store (in the 1980s) and also did aluminum "mags" from various manufacturers. You'd think that a machined aluminum wheel would balance perfectly, but sometimes they would not. Seems that there could be lumps of material on the inner sides of the wheel, where it was "as cast" rather than "machined". The wheels which were fullly-machined, front and back, usually balanced with very little weight, but the ones with the lumps took LOTS more weight . . . when he found that situation, he reached for another wheel rather than more balance weights. He showed me the backside of one of those wheels and I was shocked at how much extra material was in that lump! Yet the front side looked fine.

I concur on the "tork sticks" issue! I never did understand how they limited ultimate lug nut torque from an impact wrench, but they were "all the rave" for a time in the 1990s. On the issue of lug nut torque. . . it's strange how that we normally had lug nut torques in the 65 lbs-ft range in the middle 1960s, yet my '77 Camaro specs at 90 and many later model vehicles (with factory allow wheels) spec toward 150. Best to always check the factory service information before torqueing lug nuts!

Enjoy!

NTX5467

[Guest Dave May]

Follow up,......I jacked the front of the car up and fashioned a stable straight edge which I positioned very close to the edges of the tires and then spun them. Each tire showed a " high spot", but not more than 1/8 in. run out at the thread. Each high spot was on the opposite side of the balancing weights.

I then brought my 2 front tires/rims to my local Discount Tire outlet who Lugcentrically, Road Force balanced them. One tire exhibited 24 pounds of force in one area of the tire and the other showed 54 pounds of force. Both tires were corrected by balancing. The tire with 54 lbs. of force was able to be corrected down to 24 lbs. I was told that anything corrected down under 30 lbs. is acceptable. They did not notice any tire defects,...other than the 54 lb force, if that is considered a defect.

This greatly improved the ride, but there is still a bit of vibration at 50 mph. I plan to bring in the back tires for road force balancing and baced on the results, move the tires with the least amount for exhibited force to the front.

[NTX5467]

Thanks for that update! I'm glad things are getting better! Please keep us posted.

NTX5467