Heres the story, 39 ford, m2 front. 8 year old car, 18k miles. I have always had a shake at hwy speed. not crazy bad, just annoying. for a few years i had american racing aluminum wheels all around. a couple of years ago i switched to 11" drums on the front so had to get a new wheel so I just went with used steels, then new steels because the old salvage yard ones were not true. last year I went to big O tires and had them weight match the new wheel and tire( where they mark the wheel and tire and re-mount for minimum runout). that was the best my car has ever done. after 18k of driving miles on the car, this was the first time I was finally happy with it. Now My question. I had a very slight shake this spring, so I figure get them re balanced. I had them check them first and all 4 were a little out. I drove it to work tonight and SHAKE CITY between 55-65. has anyone else had this kind of trouble. It just drives me nuts!!!!!!!! I think I am feeling the out of roundness in the tire because I know they balanced out to -0-. the tires are just 2 years old. and not a hight dollar tire, but not the cheapest either.
Has anyone checked or is there any chance that one or more of the tires may have broken plys. It used to be and probably still is a problem with steel belted radials. especially one that may not be running @ full or close to max tire pressure.
If they re-balanced the tires you could have possibly thrown a weight if they put the wrong style on it. I've balanced tires before they came out good then i test drove them and had them shake, pulled it back into the shop, re checked them, and they suddenly had run out? and had to match them to the rim. How are they balancing them? Static balance? Road force balancing?
they just did a weight balance. and cant remember what brand, some no-name. last year they really spent a lot of time on them to get them right. I will have them check the tires good tomorrow for broken belts, but I really dont think thats it. Its just crazy that every year is tire balance hell. I put the car on blocks in the winter, so I dont believe its flatspots. I only put about 3k miles a year on.
Radials don't get the flat spots like the old nylon bias plys got. I have seen broken belts on radials with less than 5 K on them. I think they have gotten better though. I actually had one so bad on an old C-10 that it looked like an S when you stepped back and saw it., it was like driving a rattle snake.
Sephilis, having sudden runout sounds like what I am dealing with. It feels to me that I am feeling a runout problem rather than a balance problem, if that makes any sence. would a bettter quality tire stay more true? probably a stupid question since you get what you pay for.
Quality and price do not always run hand in hand but a resounding a better quality tire is going to give you better performance. Performance in this instance being related to less maintenance. Here is something that I have experienced maybe not on topic for this thread but worthy of mention is that a radial tire often does not perform well on an early non safety bead rim. They have a tendency to slip around a little. Like I said maybe not pertanent to this thread but worthy of mention.
You have to have them "Road Force" balanced. You can static balance the tire / wheel combo all day long and it will be zero but still shake. The road force balance will find stiff spots, flat spots, heavy spots or out of round tires. Depending on the suspension in your car determines how much you will feel. On the back of my 1 ton 4x4 I have a tire that has 110 lbs of road force. I hardly feel it. on the rear of an 04 cadillac deville with a swing style rear suspension you will feel 10 lbs right at 55 - 62 mph. Steel wheels lend themselves well to "match mounting" which is marking and spinning the tire so them "heavy" spot on the tire is opposite the "heavy" spot on the rim. This cancels itself out. Aluminum rims are almost always very close to true (unless they were wacked at some point) so if you have a bad tire there is not much you can do about it. In the 12 years with a cadillac dealer I dealt with this on a daily basis. Old people drive right in the 55-62 mph zone where most of the shake shows up. This topped with ultra quiet cars makes for a warranty nightmare! These days with all of the china tires on the market it is hard to get a good tire. Michelins are very good but they are expensive. You buy a Sunny (china tire) and it is terrible and will last about 10 K miles before it is junk if that. Always ask the shop if they have a road force balancer. Most dont as they start at $10K. Hope this helps.
If you can find someone who can spin balance them on the car have them do it. Quite often the drum,rotor or hub is just enough out of balance to cause problems. You didn't say that you put hubcaps on the car with the steelies but if you have full hubcaps on it you might want to pull them off and take a run down the road to see what it feels like. It's doubtful on that car but I have seen cars with mud settled and dried inside the rim that threw the wheel and tire out of balance. As P-n-B said radials can break belts or get a separation at any mileage. I've seen it on week old cars with only a couple hundred miles on them before. The car was stored with the tires off the floor so flatspots shouldn't be an issue no matter what tires it has. On this one when it comes and goes at a certain speed I'm still thinking balance.
jfg455, yes that helps. I just remembered the tires are a "multi-mile" brand. and the wheels are new wheel vintiques. I know they checked the road force last year and had to index the wheel and tire, so sound like I need them to revisit that on my tires. I always try to buy american, heck-i work at ford motor co., but I tried to go cheap on the hot rod for some reason. I was always afraid to drop a lot of money on tires. the first ones i had on the car were bfgoodrich and they didnt ride that good, but i believe maybe part of it was in the wheel. like I said earlier, i have never been happy with the smoothness of the ride. I know its a hotrod, but on a 3 hr trip I dont need steering wheel shake.
If a radial has a belt laid less in less than perfect alignment when its built, it will develop a variable lateral(side to side) force as it rolls down the road. The tire industry has a machine called Akron Standard that will meausre all these forces on a loaded tire, but its not something you'd find in a tire shop unless they've got an extra half million bucks they don't need. The road force balancers strictly measure variations in radial forces, so they can't detect lateral force variation. It'd probably be worthwhile though to get them checked on a roadforce balancer since that would give you the best balance of anything commercially available. At the least, it would confirm or eliminate radial force variation as the problem. Its been about 20 yrs since I worked in the tire industry, and I haven't kept up with it much since then. Used to be, there were tire truing machines that would cut out any runout in a mounted tire/wheel assembly. Don't know if they're still used or not, but they were pretty effective in correcting out of round conditions on mounted tires. We also did a bunch of testing one time to determine whether a tire mounted using rubber lube would stay in the same place on the wheel if you do any hard starts or hard braking right after its mounted. Found they will move quite a bit on painted steel wheels unless you let them sit for a half hour or so after mounting, or you avoid any hard starts or stops for about that same amount of time. Of course, if they move on the wheel then the balance job is messed up, so you need to either take it easy or let them sit for long enough for the rubber lube to dry. All this aside, going thru some rebalancing act once a year sounds more to me like the tires are changing shape somewhat over time, and that would indicate there's some problem with the belts or other structural parts of the tire like beaner mentioned.
I hope they cut me a deal tomorrow. they charged me $8 a tire to balance, and I already had them off the car. at least once a day I say" that use to not cost that much". about something. maybe in getting old like jfg said. I usually drive between 55-62. :\
In most normal diameter passenger car tires for full size cars, imbalance or force variations or most anything else that makes the car want to shake will show up worst in the 55-62 range just like he said. That's because the tire is spinning in an rpm range near a resonant frequency. Vibrations at resonant frequencies in anything that's spinning become more noticable because the resonance allows the vibration to actually make itself worse by using its own force to excite itself. Fortunately, tires just shake and jump around for the most part. Things like flywheels with an imbalance operating at a resonant speed can rip themselves free of their mountings or even explode.
i am a firm believer in on the car spin balance,with a strobe light. you might try a place that does big trucks. not a lot of places that does that around here now. have them trued(sp) also but don't sob while they are cutting the rubber off. good luck and let us know how it works out.
here is the latest. I went to big o this morning. they re-indexed the front tires. looking at them on the machine they had a little run out. nothing crazy bad, but not perfect. i drove it and the same shake. I took it up and let the manager drive it and he instantly said it had FRAME SHUDDER. Last year was the first time it did really well on the road. but I have had 3 different sets of tires and wheels on it and it has always been the same. I really cant augue that he is wrong. I have had this problem since i built it. the frame is stock 39. the front is boxed only in the front where the m2 is. it is stock from there on back, with parallel leaves in the rear. so what do you think? im thinking box the frame up and see what it does.
I had an experience3 in a off topic car ( 1993 Jaguar.) My step dad gave me his car collection of 1950 on up Hotrod books. 13 boxes!!!! I loaded 7 boxes in the back seat and trunk. Each box weighed over 100 lbs and the car vibrated soooooo bad at 55 but was better at higher and lower speed. When I got home from the 400 mile trip, I removed the boxes and the car was back to smooth. It had to be due to the axle shafts in the rear end not being in line. Sort of like pinion angle as the car was squating bigtime!!! Check your drive shaft angle.
I readjusted the drive shaft angle a couple of years ago and all is good. at least it was good? i am thinking i will put some 1/4x2 angle inside the frame rails, and bolt it in , plus another cross brace somewhere in front of the back axle to see what happens.
I had a 56 ford pu with shimie and did just about everything. The rubber gromits top of shocks were loose you will get it. May want to get new shocks.
Just a shot in the dark, but check for a 'tight universal'. Had this on an OT daily factory lowered (ZQ8) and it drove me nuts for a while, chasing tire balance (on brand new T/As). Very slight shudder around 55-62.
when i first put my a sedan on the road about 4 years ago it had a shake also. tried rebalancing and that didn't help. took it down to a friends who is 68 and has been building hot rods and racecars since he was 16 or so and told him what was happening. he grabbed a jack, and put the front end up in the air. he crawled under and backed off the brakes so the wheel would spin free. after spinning the tires numerous times and finding the heavy spots he hammered on some weights. couldn't believe it. the shake was gone.
The problem isnt as rare as it seems, Slight vibrations can also be caused from a tight or stuck u-joint, often occuring from storage. If you have any rust residue around the caps, thats perhaps your culprit. Often tire shops when rotating will rebalance your tires every or every other change, and some times when an issue arroses they will x the rotation. you can only x or reverse radials one time. (little known fact). another is, if the tires is in balance, then its not the cause of the vibration, if you lift the car have someone rotate the tire while you look head on at the treads. a slipped or seperated tire tread usually appears with a slight S in the tread pattern. If all else fails rotate the tire 180 deg on the rim and re balance... Like I said, if its in balance, it may be a U-joint frozen...
I will check the ujoints tomorrow and see how they look. I am also thinking about having the driveshaft checked, but the next 2 weekends I have 10 hrs of driving to do in it, so Im not sure If I will have time to take the driveshaft to a shop. rustrunner, thats a cool story. thats the way is should be!! I might just try that.
I have a irritating slight vibration on my 70 torino. Did everything including a master bearing kit in the rear end. So, i'm pointing at the drive shaft now which i had this same experiance with a dodge dakota i had. Same thing at the 60 mph range. The dakota was fixed with a balancing but yet to do the torino.
Never heard of "FRAME SHUDDER". I would put that up there with muffler bearings. I would be looking at my driveshaft and universals also. I had a car once with a 9" Ford and where the universal went in to the rear yoke it looked like it would seat in but the universal was a few thousands to wide and you couldn't tell until I pulled the driveshaft and saw where the cup had a slight distortion on it.
I think what he ment by frame shudder, is that the vibration seems to be through the whole car. he said for that kind of vibration the wheels would have to be stupid out of balance. he offered to rebalance again but I kind of agree, I have been chasing this too long for it to be all tire related. I just think these tires on a late model car would be fine. once again, its not crazy bad, but on a trip on the interstate its very annoying. A car should be smooth!! I will post my progress as I go, or until i give up!!!!!!!
George, you may be right!! I just remembered that in the past I have put the rear on jack stands and run it up to speed with no vibration. That may not be a 100% test, but I would think would rule out a driveshaft balance issue.
The Jalopy Journal
