Some possibilities,
1) No amount of balancing will make a buckled or deformed tyre ride smoothly. If you are confident that you can do it safely, jack up each corner of the car, and spin the wheel - make sure each runs true. Check carefully for bulges in the sidewall.
2) Any flat spotting should be seen during step 1, and *may* be reduced by going on a longer run, and getting the tyres warm, so that they can return to their previous 'round' shape.
3) Tyres are usually marked at their light spot - usually a red dot. This should be positioned near the valve during fitting to reduce the need for balance weights. Check to see if your tyres were fitted properly.
4) 60g is quite a bit - although not unknown. This is the tyre I would check out most thoroughly.
5) If all the above get you nowhere, make a note of where the balance weights are for each wheel. Take them all off. Take your car and have them all balanced again. See if the new weights go back where the old weights were removed from.
Number_Cruncher
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well front 2 are new tyres.
It's not uncommon for new tyres to slip round on their rims due to the lubricant the garage use when fitting a new tyre. Might pay to have them re-checked when they've bedded themselves in.
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hi again,
i'm currently in the process of trying every wheel with the spare (mondeo has full size spare).
so far i have tried the 60g one with the sapre and it was the same ride, shame. I also span it when jacked up and it wasn't deformed.
then a rear (older tyre) and it was the same ride.
so the other left to check.
bear in mind the seats especially the upright back is vibrating/wobbling at 60 and above getting worse the higher you go.
i'm right in thinking a new car wouldn't do this at 100mph?
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The only time I've had exactly the symptoms you describe was with old tyres. Worn suspension joints won't help either. Although they looked perfect and were balanced the two rear tyres has gone out of round probably simply due to old age. In my case new tyres & the vibration was gone.
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I had the same symptoms with nearly new tyres on a (then) recently purchased Granada Scorpio.
It was simply down to the cheap (Tigar) tyres self-oscillating at that speed and they had to be replaced.
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funnily enough they put what i would class as cheap SUNNY tyres?
anyone heard of them?
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Sunny tyres appears to be South China Tyre & Rubber Co. www.cec-ceda.org.cn/english_version/enterprises%20...m
Although anything Chinese these days seems to mean better engineering than the Germans!
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hi,
current situation is i've checked 3 wheels and none are buckled or out of shape.
problem is, the problem isn't going when putting the spare on, no change what so ever, as i have 2 older tyres and 2 new cheap brand ones, but only 1 spare??
so not sure how i'm going to narrow it down between the 2 potential problems
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i've checked 3 wheels...
Keep going, check all 4. I think the substitution testing method you are using is a good idea.
Number_Cruncher
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not good news
after swapping out all 4 wheels the problem is still there, none are visibly buckled or out of shape.
so now i'm stuck.
I have 2 new cheap tyres and 2 4 year old tyres and have only done 20k
But 1 spare!!!!
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You have arrived at step 5 of my earlier plan - unlucky! I had hoped that you wouldn't get this far and still have the fault!
If possible, find a place that can balance your tyres on the car, i.e., with the wheel and hub rotating just as it while driving. Sometimes this process can find another rotating component that is out of balance, when used in conjunction with ordinary balancing. You balance the wheel normally, off the car, then spin it up on the car. If you then find that an out of balance condition, something else that is rotating is out of balance.
This is a more diagnostic procedure than most tyre places will be staffed for, so I think you will most likely be able to get this done at a well staffed and equipped independent garage.
Beyond this, the other fault I have seen a time or two is a bent driveshaft. This can be checked for visually, again by spinning the hub, and watching the shaft.
I hope this helps you sort out the fault.
Number_Cruncher
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to your first suggestion, are you implying something none wheel related is spinning, as i've substituted each wheel.
we are getting to the realms of actual car problems now not wheels.
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Hi Andy,
By swapping your tyres one by one for the spare, you have ruled out the possibility that *one* tyre is causing the problem. Unless, of course, your spare was badly out of balance as well!.
You have carefully, visually, checked all your tyres for deformation that could result in uneven running.
There is still the possibility that the two older tyres are flat-spotted, as Cheddar suggests above, although I would have hoped that you would have seen that while inspecting the tyres.
I did deal with a Cortina (you can tell how far back in time I'm going) with about* 1mm of run out on one of the steel wheels, which was causing a vibration at speed. As the owner was a particularly style concious individual, we fixed the problem by swapping to alloys!
*I say about because we checked it using nothing more than an axle stand, a pencil, and rule!
Although it is a possibility that something else rotating is causing the problem, this is really quite unusual in a front wheel drive car. With RWD, there is a long prop-shaft which introduces a number of opportunities for vibration problems.
Wheels and tyres usually bear the brunt of any damage due to potholes and kerbing, and are a good place to check carefully.
It is not unknown for balancing to be in error.
Number_Cruncher
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just to rule out, for flat spotting I should probably look at the top or bottom of tyre and spin it. the reason I ask is i might of saw something but it was on all 4 so never thought anything of it.
by the way the sunny sn3900 new tyres i have are budget, but branded with a speed rating of V so hopefully ok, I saw them on another website at £50 each.
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depending on how bad the tyre/wheel is ie normaly fronts only cause steering vibration..rears being off balance will cause body to shake but not affect the steering.So it is possible for a bad tyre/wheel on front and back to cause the problem together.But another possible is drive shaft out of balance this will affect both
--
Steve
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i think i may have made some progress, put the older quality tyres on the front, and 1 new cheapo and 1 spare (quality) on back
i noticed no steering wheel vibration at 75pmh but the passenger seat was vibrating at 75mph.
i'm thinking its the cheapo tyres or the wheels on the cheapo's
this is because the front quality one have hardly any weights on a 15g on one side and nothing on the other, and on the other wheel a 20g and nothing on the other side.
But, on the cheapo's one had a 40g and 30g and the other wheel has 60g and 30g
ie quality tyres spin properly.
think i'm barking up the right tree?
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Yes, I think you are onto something - I agree with Steve's comments about the location of imbalanced tyres and the resulting type of vibration given above.
Are you considering ditching the cheap tyres?
Number_Cruncher
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i noticed no steering wheel vibration at 75pmh but the passenger seat was vibrating at 75mph.
That would indicate that one or both rear tyres are out of balance, and nothing wrong with the front tyres.
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