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Hot Rods Coker Dirt Track Tires - Cured My Wobble

Discussion in 'The Hokey Ass Message Board' started by agshelby, Jul 25, 2016.

  1. agshelby
    Joined: Jan 6, 2010
    Posts: 463


    The tires on my 32 developed a serious wobble between 45-50 mph. It reached a point where the car was not drivable.

    Today I had the tires trued and speed balanced (on the car). At first the wobble was pronounced when the tires were spun - the tires were way out of round. I'm surprised that the tires only wobbled on the small window - they were REALLY bad.

    After shaving and balancing the tires are true and there is no wobble at all. I'll definitely get this done on my bias tires going forward.

    It's really a shame that these expensive tires come so far out of round -

    ImageUploadedByH.A.M.B.1469465778.493405.jpg ImageUploadedByH.A.M.B.1469465805.726396.jpg
    Tim likes this.
  2. silent rick
    Joined: Nov 7, 2002
    Posts: 3,913

    silent rick

    how much life did you need to remove to get them to run true?
  3. treb11
    Joined: Jan 21, 2006
    Posts: 3,290


    Looks like a cool old school shop. do they align I-beams? contact info? thanks
    Shaun1162 likes this.
  4. slowmotion
    Joined: Nov 21, 2011
    Posts: 3,094


    That's a damn shame, as proud as they are of their product, that it needs fixin' to be drivable. I've read (here) that their customer service is good. Do they compensate customers in a case like this?
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  5. agshelby
    Joined: Jan 6, 2010
    Posts: 463


    Too much ....

    I need tires for my '40 and I'm trying to find an alternative to Coker.
  6. So at first they didn't wobble, but now they do?

    I'm gonna say something you may not appreciate, but here goes:

    1st, I do not believe you have any idea how true those rims were to start with. That's a generalization to be sure, but most people don't give it much thought unless/until there is a problem. If I'm wrong, and you are one of those guys who used a dial micrometer on every rim - well then I'm wrong.

    2nd, the greater the offset and/or the wider the rims/tires, then also the greater any slight out-of-true will be. I-beam front axles - especially those with lots of KPI - makers it worse. All it takes is one hit to a curb or a chuckhole at just the right angle, and even brand new rims will go out by several thousandths.

    3rd, really experienced tire pros will look at a tire mounting if its far off balance, break it down and rotate a 1/4 turn to see if they can improve it before adding weights or going the shaving route.

    4th, it can and does happen with all brands - even Goodyear racing tires - which don't have much rubber on the tread to start with. And it was a given if we were doing a set for racing, the tires got shaved right from the get-go.

    Now, sure as shit I've said this, there'll be a whole slew of exceptions, but that's my say on it anyway.
    52plybizcoupe likes this.
  7. agshelby
    Joined: Jan 6, 2010
    Posts: 463


    Not sure on the I-beam. Truing up tires is fairly common with Heavy Trucks. I would recommend looking around Houston at the Semi tire service places.

    Here's the San Antonio location :
  8. agshelby
    Joined: Jan 6, 2010
    Posts: 463


    Stutzer - they checked the rims and they were fine. The wobble was there from the first - and got progressively worse. The shop said they have a lot of "old guys" that bring in tires to get balanced for antique cars. The shop guys are not into old cars at all - but they knew they were Coker tires and said that every Coker tire they had seen was way out of round.
    slimcat7m3 and C. John Stutzer like this.
  9. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 23,777

    Jalopy Joker

    as stated above, more than one problem can raise it's evil head to cause problems - and not just with tires - have had many various new parts that failed, or did not work, over the years - lucky that you found a place that does work on tires, not many around anymore
  10. deucemac
    Joined: Aug 31, 2008
    Posts: 1,006


    I bought a pair of 14x31 double diamond sprint car tires from Coker and mounted them on 15x12 steel wheels from Wheelsmith. The tire shop mounted and balanced the tires. They had to add 14oz. to balance one. I called Coker about it and was told it must be the rim. I replied that it would be rather obvious to find a pound of material on a steel wheel if it were the wheel. I took both tires to Fresno and had them look at it. They couldn't get it to balance either and I had them put another tire on. Presto! It magically balanced out with 2 1/2 ounces almost identical to the good wheel/tire. They acted as though this was something that could never happen with their tires. I wonder how much life would have been ground off that tire to reach a good balance. For the price of the dirt track tires they make, there shouldn't be problems like that. I used to race sprinters and used Firestones. Don't remember ever having that muscle imbalance when we raced the real ones. Or egg shapes either.
    C. John Stutzer likes this.

  11. Gotcha - well that's that then. Glad it worked out for you.
  12. Atwater Mike
    Joined: May 31, 2002
    Posts: 9,823

    Atwater Mike

    Yes, that is that.
    "Must be the wheel that's out of balance." I LOVE that one...14 oz., must be heavy metal on ONE SIDE!
    Thank the gods of common sense they replaced the tire!
    C. John Stutzer likes this.
  13. chopolds
    Joined: Oct 22, 2001
    Posts: 5,660

    from howell, nj
    1. Kustom Painters

    I'm still a huge fan of Coker, for all they do for the hobby. You DO have to remember, that they use the old original molds to repo the old tires. I'm sure that has a hand in the tires having issues sometimes.
    117harv and flatheadpete like this.
  14. I was responding to the first poster - you (I think) are referencing a second poster's story.
  15. blackout78666
    Joined: Jul 3, 2009
    Posts: 581


    I went to
    The same shop with the same problem. These guys are pros. Wobbled my ass up there about 40 miles. Took them about 4 hours. Glided home. Couldn't be happier. Coker should start doing this to their tires before they ship. Horseshit to get an out of round tire.
    PunkAssGearhead88 and Baumi like this.
  16. blackout78666
    Joined: Jul 3, 2009
    Posts: 581


    Quality control. "Using original molds" is no excuse for a defective product".

    One should be expected to have tires balanced. But to hunt down an obscure shop that has the know how and equipment to shave 1/4-3/8" off of brand new expensive tires to get them to roll straight is bullshit.
  17. missysdad1
    Joined: Dec 9, 2008
    Posts: 2,781


    I also run Coker dirt track tires on both ends of my coupester. Took three trips to the tire store to get them balanced properly. The problem was with the guy doing the balancing.

    Modern cars have so much rubber in the suspension that they can tolerate a fair amount of imbalance and still not be objectionable when going down the road.

    The tire machines have a "range" of acceptable balance and as long as the operator gets it within that range it's considered "balanced" even though it may be considerably out of balance.

    The cure for mine was standing over the guy's shoulder while he balanced each tire twice or three times until he got it right. It just took finding a tire guy who actually gave a shit.
  18. Had the same problem, never could get the wobble out. COKER TIRES ARE ABOUT AS ROUND AS A BRICK > F&CK COKER
  19. agshelby
    Joined: Jan 6, 2010
    Posts: 463


    I didn't start this to bash Coker - I was just highlighting a solution to a apparently common problem. I like the "look" but would have rather not spent half a day and 150.00 correcting a manufacturing defect. (150.00 sounds high - but they spent around 3 hours getting it right.)

    If there were a better option Id go there for my '40 coupe. Any recommendations ?
    C. John Stutzer likes this.
  20. Sometimes two (or more) ride disturbance causes are not addressed by the tire dealer, the tire shop trying to cure it or the end user/builder of the car.
    1. RUNOUT
    Is the rotating ASSEMBLY true, radially and laterally?
    The hub's rim locating seat and face, unequal torqueing of the lug nuts, physical runout of the rim measured at the bead seat, the tire's bead seating evenly on the rim when inflated, and any mold shift from the tire's build can individually or collectively contribute. The standard for ALL runout is zero, but is rarely obtainable. In the case of bias tires, they MUST be warmed up by driving before checking runout. Each component needs to be progressively checked: hub - bare rim- mounted tire.
    Who sets the standard? You do.
    2. BALANCE
    ANY out of spec assembly can be balanced, but that won't totally cure the ride disturbance. Rims will have a heavy spot, as will the tire (particularly bias), even if they are perfectly true. The objective is to get the two heavy spots opposite each other, by checking for imbalance and rotating the tire on the rim to reduce the weight required. Most tire shops are interested in getting it "in and out", not in blueprinting your assembly.
    Is the assembly being balanced static or dynamic? Modern computerized balancers can do both. Static balance just reads the radial imbalance, and dynamic averages the lateral and radial, and spots one weight in one spot. Has the balancer been calibrated by the manufacturer's tech?
    How is the assembly mounted on the balancer? Improper seating can cause runout on the balancer, causing it to read it as an imbalance, no matter how small, and compensate. Is the balancer a force balancer, does it actually place a load on the tire as it is being rotated? This simulates better the condition the tire is in when in use.

    Having addressed 100's of ride disturbance issues and balanced 1000's of assemblies, there is WAY more to eliminating ride disturbances than throwing a tire on a balancer.
    IMHO, to the OP, any passenger tire that would require truing when new on a round rim and hub, or required MORE than one wheel weight per side, should be rejected back to the supplier.
  21. Atwater Mike
    Joined: May 31, 2002
    Posts: 9,823

    Atwater Mike

    Yes, C.John, second poster. (to paraphrase, 'that was that' was simple satire attached to the '1 pound outa round...probably yer rim!'
  22. gnichols
    Joined: Mar 6, 2008
    Posts: 10,550

    from Tampa, FL

    I had a similar problem with one front tire on my truck. Truing it took off a lot of rubber but it worked... for awhile... So now I'm wondering if, like motorcycle front tires, if once your tires get out of round they are pretty much junk even if you might be able to save them once or twice by shaving / rebalancing? Thoughts? I'm also wondering if that - assuming a good alignment - that incorrect spring rates / shocks might create a situation where the wheel and tire assembly are not adequately controlled (ie everything is too stiff) which would allow a little bit more wheel hopping or bouncing than you would desire, and that might eventually let the tire get out of round beyond comfortable limits. Idears? Gary
  23. ^^^^^^Exactly^^^^^^
    Soft suspension without adequate rebound control (shocks) can contribute to starting a wear pattern in the tire, particularly at constant speeds (Interstate driving) As upward force is put in to the tire (bumps, joints, ripples, imbalance), it tries to lift up, changing the footprint, and will cycle until the energy dissipates, or is dampened (shock). Continuous cycling wears a spot out in the tread, the assembly is now out of balance as well as out of round, and the cycle progresses elsewhere on the tire, and eventually overcomes the shock's capacity to dampen. Conversely, too stiff suspension makes the tire overflex leading to tread squirm, sidewall fatigue, overheating and fast wear rate.

    Comfortable ride is always paramount, but sometimes it is a trade off for poor tire wear, which leads to a ride disturbance. Keeping a constant sized rectangular footprint is the key to long tire wear, and requires the right spring weight, correct rebound control (shocks) and inflation vs. load. But, even though the tire wear is close to perfect, the assembly needs a rebalance occasionally, as the total weight has reduced as the tread is worn off.
    Last edited: Jul 26, 2016
  24. ottoman
    Joined: May 4, 2008
    Posts: 274

    from Wisconsin

    We seem to forget the Bias ply tires never were all that good back in the day either... why do think all the good shops had tire truers (shavers)? All the issues I read about on Coker threads have always been problems with bias ply tires.. then and now. Either your lucky and get a good set or you have to spend money to make them work.
  25. Baumi
    Joined: Jan 28, 2003
    Posts: 2,200


    Over the last 15 years I have bought 6 brandnew sets of Cocker tires, all of them 5.60-15s up front and L78-15 rears. 4 of the 5.60s and 3 of the L78s needed shaving. A set is close to 1000 Euros over here, probably more now, and it really hurts to see what amount of rubber is being cut down during the process...but what can you do. .. I really love to go fast without rattling all of my teeth loose, so I am happy there is a solution for edgy tires.
  26. Crease
    Joined: May 7, 2002
    Posts: 2,879


    Coker will be happy to warranty the tire if you take them to a professional, get a computer read out on the tire run out, and ship it back to them. Of course your out a tire for weeks, have to pay to have the new tire mounted and balanced and there's (in my experience) a 25% chance the new one won't be any better. Shouldn't take a rocket scientist to mount a tire with good results.

    Sent from my iPhone using The H.A.M.B. mobile app
  27. A HAHAHAHahahah!!!! Coker said from the beginning "Not For Street Use". I have them on a 29 with a 425 nailhead and went up th the market parking lot and did burnouts til they were round, they're so good looking, just take out your false teeth so they don't rattle and punch it!!!
    Finding guys with a good balancing shaving machine is the tough part.
    52plybizcoupe likes this.
  28. I don't believe that they use the original molds to make the tires, only to use as patterns to make new molds - correct me if I'm wrong?

  29. DDDenny
    Joined: Feb 6, 2015
    Posts: 12,724

    from oregon

    These are "real" Firestones I got many years ago, one of them was quite lumpy.
    Bought them from Weisel Firestone in Pennsylvania, when I called he asked what compound I wanted, I told him it didn't matter and he asked what are you using them for.
    I told him a street roadster and he said "I didn't hear you say that".


  30. Pete
    Joined: Mar 8, 2001
    Posts: 4,490


    99% of thair tires are out of round. I sent back many sets but only got slightly better ones in return.

    Kinda sucks because the tires are expensive and can render your car undriveable.
    PunkAssGearhead88 and Baumi like this.

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