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Technical So....I'm learning a little about tires

Discussion in 'The Hokey Ass Message Board' started by trollst, May 1, 2020.

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  1. trollst
    Joined: Jan 27, 2012
    Posts: 1,848


    As some of you know, I've been chasing a vibration in my 36 for a long time. First, some history, although part of it is off topic, the info will be useful, aka, my expensive learning experiences. Pinto front suspension, 2 inch dropped spindles, pinto rear suspension, truck was built twenty years ago by me, 52 F1 frame, originally had a chev ten bolt rear end in it, I had the wheels reversed by a renowned shop, done professionally, driveshaft built by a driveline shop, wheels were done because the rear was slightly too wide, and it got me on the road, truck was built with very little cash, I was broke and did the best I could, it wore the cheapest new tires I could afford.
    At first, wow, I did a great job of building it, drove fantastic, till my first high speed jaunt, had a vibration, like an out of balance tire, shook the steering wheel, so, back to the tire store, rebalance all the wheels, stock 15 inch gm wheels with trim rings and hubcaps, same thing, tire guy says it must be the trim rings, vibration can be lived with, so....I do. Years go by, tired of the steering wheel shake, new tires, same thing, back to tire shop, no trim rings, spend a lot of time getting balance right, discover that one of the rear wheels is out of round after the pro shop reversed them, so, gotta be it, right? Have another wheel made, better, but still there. Frustrated, pull all my hair out, live with it, still not a lot of money to blow on a hobby car, get older, years go by, finally decide on getting some torq thrusts and good tires, discover a broken rear spring, replace both rear springs, and change rear end to a ford ranger 8.8, get her all done, bolted up, balanced, hit the road, still got a shake, although minor, but annoying.
    Up in the air, fire her up, put her in gear, crawl under, look at everything, notice what I think is a bent driveshaft, sure enough, my custom made, paid for in blood, never been off driveshaft is bent ever so slightly in the center. Twenty years, never been apart, gotta be it, 500 dollars later, new driveshaft, built to exacting standards, balanced, gotta be fixed.....right? No.....find old guy in the tire business all his life, says probably because I have no rag joint in the steering column linkage, I feel it all, but what does he know....I'm tired of the shake, shakes with one hand on the wheel, two hands makes it go away, gotta find it. Now, I should add, the dropped spindles make the front tires hard to balance, the a arms are close to the wheels and scrub off any weights placed near where they come close to the wheel, so the front balancing thing is always a compromise, so....brainstorm yesterday, balancing beads will fix this, right......? Off to same old bastard, peel all the weights off, pour beads into front tires, loads of confidence here, head out for the hiway......WORSE., back to the balance machine, gotta find it. I should add, everything is round, tire spins true, rotors are round, bolt pattern is round, NOTHING is off, I have checked everything.
    My roadster, also built by me, solid axles front and rear, split wishbones, four bar rear, is smooth as glass at speed, stock gm wheels, 15 inch, a delight to drive. I'll let you know..... DSC07687.JPG
  2. My wifes daily driver (a way off topic Nissan Murano) had a very annoying steering wheel shake at highway speeds for years. Chased tire balance, new tires, different wheels, new suspension and steering components etc. It finally went away after a good front end alignment. You have an ifs...maybe look at the alignment/specs?
    VANDENPLAS and chryslerfan55 like this.
  3. Elcohaulic
    Joined: Dec 27, 2017
    Posts: 1,418


    Find a tire balancing place that shaves the rubber off the tires..
    chryslerfan55 likes this.
  4. winduptoy
    Joined: Feb 19, 2013
    Posts: 2,191


    Good looking truck there.
    So, my OT van shakes the front end as you describe. I take it back to the tire shop. They assure me everything is balanced and round. No run out. I drive it home and it shakes worse.
    Decide to rotate tires around myself and the wheel bearing is so loose you can feel it grabbing the tire and pulling it side to side. Now this OT van has a swaged outer bearing...order whole front spindle assembly. Install and front end shake goes away not to return.
    Don't see that you mentioned checking spindle bearings and preload.
    Just a thought.
    By the way, after this, reset the preload on one of my model A's. Had to file the nut for the preload to be correct and the castle nut to line up for the cotter pin...
    Road walk disappeared along with some shakes
    Good luck

    Sent from my XT1585 using The H.A.M.B. mobile app
    Jet96, Hnstray, dirty old man and 3 others like this.

  5. trollst
    Joined: Jan 27, 2012
    Posts: 1,848


    So, heard about two guys in a tire store who are car guys and are the best, one being a front end guy. Ran over there, they dismounted the tires, checked the wheels for balance, all four, mounted tires, checked, dismounted and spun them on the rims till the least amount of weight was needed, told me to drive it. Same, minor steering wheel shake, their front end guy took it for a ride, gone a long time, came back, up on the rack, everything checked out normal, we talked and decided it was definitely a wheel shake, out of balance, but how? Rotors are stock ten inch pinto, very small, not enough mass to cause a shake, but the only thing never changed, no hot spots, no damage or indication anything wrong with them. I'll change them, could be a poor casting with too much weight on one spot, thats all our collective minds could think of. I'll let you know......
    Joined: Dec 14, 2009
    Posts: 2,849


    Alignment can do strange things.

    can you balance the fronts with sticky weights ?

    when is the shake ? At all speeds? Only certain speeds?

    Ya said pinto front clip, is it mounted straight? Secure? No flexing

    could your steering set up, shafts u joint etc. Be tonight n perfect , and your getting some flex somewhere and causing binding ?

    exhaust or engine mount “ grounding out” causing a vibe to be felt in the front ?

    amything through the floor or only in the wheel ?

    is it just a vibration or can you see the wheel moving ?
  7. Penetrator
    Joined: Aug 25, 2011
    Posts: 451

    from SK CAN

    Strut rod bushings? Excessive scrub radius?
  8. Budget36
    Joined: Nov 29, 2014
    Posts: 4,746


    Toss that POS truck, I've open arms waiting:)

    Seriously tho, I've an issue with my daily PU. Right front tire was cupping and vibrating. Moved front to back, etc,,,,now still does the same thing. So checked rotor for warpage, none...looked deeper....awww, see some odd wear on the strut...ordered new struts, so we'll see.

    So, may want to look at the shocks you have.
    trollst likes this.
  9. proartguy
    Joined: Apr 13, 2009
    Posts: 461

    from Sparks, NV

    The vibration problem in your ‘36 is similar to my ‘37 which has a similar running gear and suspension. Very frustrating to replace all rotating parts and not solve it. I ran out of ideas.
    trollst likes this.
  10. MAD MIKE
    Joined: Aug 1, 2009
    Posts: 570

    from 94577

    Is your front cross member square? Probably wouldn't cause a shimmy/shake, more likely to get dog walking.

    As mentioned have you checked the front wheel bearing play?

    Drive around town, car/truck is fine, hop on the freeway(even on a fresh flat repave) steering wheel starts to judder and shake.

    Most factory stated specs for setting the front wheel bearing preload is arbitrary or flat out wrong.
    Usually the spec is something to the effect of;
    That is not going to give you the correct setting/preload on the bearings.
    Tighten the nut to the recommended torque setting.
    Back it off.
    Snug it back up again.
    Install the wheel(preferably one with an open center to access the castle nut) with tightened lug nuts.
    Grab the wheel at 12 and 6 O'Clock.
    Wiggle the wheel and feel for any give.
    Snug up the nut until the wiggle is gone.
    Line up the cotter pin hole, preferably tighten the nut rather than loosen.

    Go for a drive.

    I've also seen the opposite, where guys will crank on the nut like its a stub axle nut. Don't do that, unless you like drag, wasted wheel bearings and a slower car.

    If the shake is still there.
    And if you have the Pinto/MII R&P rack installed.
    Raise the nose up.
    Remove the wheels and unbolt the outer tierod from the spindle.
    Feel for any clearance in the inner tierod, there should be none.
    If you can feel a slight click or in/out movement without steering change, most likely the inner tierod is worn out and needs to be replaced.

    It's comically well known that replacement 'rebuilt' racks for the 79-04 Mustangs usually come with blown inner tierods from most aftermarket vendors. I wouldn't be surprised if yours were already broken in on the Pinto/MII rack.

    You can check the strut rod bushings, if you are still using the rods rather than a lower A or V arm, but usually a wasted radius rod bushing will cause wandering, strange steering feel and vagueness. Less noticeable on smooth surfaces, usually shows up on rough or heavily grooved roads you will get a bit of tram lining. Or if you have to brake hard the vehicle will dart/dodge around.
    If the radius rod nut on front is snug and the bushings are firm yet pliable they are most likely fine. They usually don't matter until they are dry rotted or oil soaked and swollen into mush.

    One more thing, most likely not applicable to your situation.
    If using bolt on center caps, verify the bolts/screws used are not protruding past the wheels mounting surface.
    Recently was dealing with a buds car, had a significant shake.
    Faster we went the more wobbly the steering wheel would get.
    Strange, usually you have a constant wobble or you have a wobble that shows up at a given speed and then kinda just stays with you.
    Check lug nuts, half are loose.
    Tighten go for a drive.
    Wobble was gone, but a definite shimmy/shake throughout.
    Pull off the wheels to check the wheel bearings/grease and castle nut preload.
    Strange, a couple of the lug nuts are loosey goosey again.
    Go to take the center cap off the wheel for wheel bearing check, for wiggle/click test and adjust.
    Cap screws spin, but will not back off.
    Flip wheel over, screws were protruding past the mounting surface of the wheel.
    Pulled off all the hubcaps, 2/3s of the screws were stripped or spinning, luckily(somehow) the wheels were undamaged.
    Bolted the wheels back on and went for another drive without caps.
    Smooth running all the way to triple digits.
    Either the tire shop or a PO lost the correct hardware, we ended up replacing the screws with shorter ones.
    VANDENPLAS likes this.
  11. How’s the geometry on your front end?
    I’m talking nit picky stuff. Roll centers, right toe, left toe, total toe, scrub radius, gross difference in shims, ??

    So a wheel shake problem
    the shake starts at a very specific road speed.
    If doable the 1 2 3 gear makes no difference and
    Neutral makes no difference.
    Down hill coat with engine off creates shake at that road speed
    Once the spec start speed is reached going above that speed increases the shake frequency proportionately
    Maybe maybe not the shake goes away at a higher road speed.
    Some answers there will help.

    Going down the road wheels and tires do a lot.
    Wheels go around, so we check out of round. wheels go up and down, need good shocks.
    Wheels want to go side to side, so we set toe. Front and rear yes rear has a toe measurement.
    The tracking is important. front axle to rear axle as wholes and then getting nit picky there’s the left front to right front relationship.
    If tracking is off the tires will flex in the side walls then correct then flex and correct. That flex correct frequency can cause you vibrations. It’s a side ways movement and not what you’d normally expect tires to be doing.

    Getting the scrub radius off ,,, 5A1DA77D-2444-4C58-BEE1-5F0384E5FD7B.gif

    notably because of your interference at top ball joins right? Maybe you got the problem here . so the common sense correction is to fudge the offset to move the rim away from the ball joint. Doing that causes the scrub radius to move. The sweet spot on scrub radius is 2” and either positive or negative. The correct way to cure the wheel to ball joint interference is to manipulate the King pin inclination angle and that’s really hard to do with your spindles.
    winduptoy and VANDENPLAS like this.
  12. trollst
    Joined: Jan 27, 2012
    Posts: 1,848


    Yeah, first, I built the truck twenty years ago, 52 F1 frame, stock pinto-mustang II crossmember, used stock strut rods I made mounts for, all stock components set to 77 pinto specs, only change made was the purchase of five lug rotors with a chev bolt pattern. Over the years, worn parts replaced as per usual wear, nothing altered, still stock specs. Truck drives fantastic and always has, but for a slow shake that comes on at around 58 mph, not enough to shake the truck, only the steering wheel, put two hands on the steering wheel, is enough to dampen the shake and make it stop. Remove one hand, you can feel a shake in the steering wheel, let it go, you can see it. Minor. Shake increases with speed, it is a rotational problem.
    It has been there since day one, through four sets of tires, three sets of rims, many tire balance attempts, many pressure ranges tried, countless checking of components, never any odd tire wear, the only thing never changed is the rotors, I've never heard of it, but years of experience and three great minds today have all arrived at the same conclusion, a heavy spot on one of the rotors.
    I installed the clip, like I have done many times without an issue on other builds, very confident in my work, nothing has ever broke anywhere on the truck, replaced the u joints this last fall, first time in twenty years of use, driveline angles correct, everything is square, well used but square, this is a well travelled hot rod that has seen tons of miles, just two weeks ago, six hours straight through mountain passes, it never whimpers , never has failed me, has killed a million bugs, and I love her aside from this annoying problem.
    Last edited: May 1, 2020
  13. trollst
    Joined: Jan 27, 2012
    Posts: 1,848


    Answers, neutral makes no difference, zero scrub issues, engine off, engine on, no difference, Stock A arms, two inch dropped spindles, top A arm has tons of clearance, bottom A arm sits a half inch from the inside of the rim, Three sets of shocks, varying quality, I cut the clip out of a never hit, low mileage grampa's car, red in colour, too nice to cut up, low mileage. The only change made was from four stud to five stud rotors. Vick, you'd love this truck, great driver, hot rod front to back.
    Last edited: May 1, 2020
    VANDENPLAS likes this.
  14. seb fontana
    Joined: Sep 1, 2005
    Posts: 6,695

    seb fontana
    from ct

    Did you/could you install a rag joint? Done everything else..
    Old wolf likes this.
  15. warped rotors
    Old wolf likes this.
  16. I’m sure I would!!! Bring it down and I’ll sort this thing out for you :)

    So swap rotors and find out.
    there’s some talk of bolt patterns not centered so check that out on your new ones.

    Wheel shake is almost always worn front end parts. Or something fighting between left and right. Did you Try throwing a little more caster at it? A steering stabilizer?

    Balance issues are mostly up and down and movement. If you’re having up and down movement that’s causing wheel shake I’d be looking at some bump steer aspects too.

    Sooooo anyways all of the related stuff to your issue was deleted out of the thread. But I built 100% of the front suspension for the orange 54. The guy is picky and this is what he said. “ my truck is old, it’s loud and has some rattles but I love it that way. As far as going down the road, it drives better than my wife’s brand new caddy.” There’s much to it.

    Throughout my travels I’ve found most unsolvable problems have a false assumption at the root.
    Baumi, trollst and David Gersic like this.
  17. trollst
    Joined: Jan 27, 2012
    Posts: 1,848


    Thanks for the opinions guys, the purpose of this thread was not to canvass you all for answers, it is to teach what I have learned, chasing an invisible issue that should be simple, but has turned out not to be. Its not the style of suspension, I've gone from....maybe I didn't do something right, to faulty work I have paid for, to bad parts, gradually narrowing this thing down to what I hope it to be.
    I built a fast, solid hot rod in my own style, one that I can, and enjoy getting into for many hours at a time, reliable and fun. Everything on this truck is right, nothing worn out, everything tight, good rubber, very predictable, solid, good driver, that I'll never sell, but every now and then we'll come across a head scratcher that is hard to figure out. If I find this weirdness, it'll educate us all to our benefit, I have had the most experienced people in the front end business help me find it, and all their collective wisdom hasn't worked. I'll let you know.
    Jet96, VANDENPLAS and David Gersic like this.
  18. trollst likes this.
  19. hemihotrod66
    Joined: May 5, 2019
    Posts: 261


    To bad you can't find an old tire shop that spin balances the tire on the car....That use to be and I think the best system to check for problems...
  20. Bird man
    Joined: Dec 28, 2009
    Posts: 593

    Bird man
    from Milwaukee

    Got an El Camino, OT by just a couple of years. Had to replace a 12 bolt axle & found a great used one.
    Axle flange is bent, you can see it clear as day.
    30 mph, no shake, 60 mph, same. 90 mph, smooth as glass.
    Just bizarre!
    winduptoy likes this.
  21. Rickybop
    Joined: May 23, 2008
    Posts: 6,737

    from Michigan

    Picture threads are awesome.
    But the tech threads, especially the diagnosis threads can really help to save a lot of time, effort and money for the rest of us.
    Thanks, trollst.
    Looking forward to the answer.
    winduptoy and trollst like this.
  22. Rickybop
    Joined: May 23, 2008
    Posts: 6,737

    from Michigan

    That's what I was thinking.
    If rotors don't help.
    trollst likes this.
  23. trollst
    Joined: Jan 27, 2012
    Posts: 1,848


    Thanks Vick, confirms my thoughts, good video. Guys, I have looked high and low for a guy with a spin balancer, lots of tire guys don't even know what they are. Vick, get busy on that coupe, it turns my crank in a big way. LeRoy.
    Last edited: May 2, 2020
  24. roadsterdonpat32
    Joined: Apr 16, 2008
    Posts: 78


    I chased a shimmy a long time, talked to ECI and Ralph said to check if the lug studs were concentric, they were way off. I had bought them from a name co. who was buying junk and making a good profit off of them. Bought a set from ECI and are either USA or Canadian made, problem gone.Just saying.
    46international and partssaloon like this.
  25. I built an MII equipped '36 Ford for my wife and set the front end alignment to stock MII specs (I think it had about a degree or 2 of positive caster)..drove the car that way for many years and many miles. On a whim, I adjusted the caster up to 4-5 degrees positive...what a change that made! We could let go of the wheel on the highway for miles! Loved it!
    31Vicky with a hemi likes this.
  26. winduptoy
    Joined: Feb 19, 2013
    Posts: 2,191


    I recall out of my dark past..reaching back into the cobwebs, that dad used to take the car to OK Rubber Welders.
    They would jack the front end up both tires off the ground
    They had a motorized shaker that they would attach to the front end of the car and they would get the tires rotating and mark where they stopped at the bottom. Heavy spot. Repeat and then get to turning the tire with indexing the heavy spot at 90 degrees from the mark on the bottom and watch it rotate again. Started adding weights to balance. This was the whole rotating assembly. Kind of rudimentary but you don't need much of a high dollar balancer.
    Well I'm thinking something like this might work for you to verify that the rotating assembly has a heavy spot. Might point to the right or left side as well.
    I just hate changing components without some kind of knowledge based decision though I realize you've done some process of elimination.
    Vibrations bug me too
  27. Have you tried a truck shop for a spin balancer?
    john worden likes this.
  28. BamaMav
    Joined: Jun 19, 2011
    Posts: 4,577

    from Berry, AL

    I haven't seen an on the truck spin balancer in a truck tire shop in years. They all have spin balance machines that balance a tire off the truck. Might be one in some small independent shop somewhere, but I haven't ran across one in 25 years or longer...
    trollst likes this.
  29. eaglebeak
    Joined: Sep 17, 2007
    Posts: 1,142


    Have you had the frame checked for square?
  30. trollst
    Joined: Jan 27, 2012
    Posts: 1,848


    I've checked the frame for any movement, bent crossmembers, cracked welds, under it with a flashlight, checked everything the eye can look at, both while in gear and static. Nothing wrong.
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