ND stock alloys 'buckled'?

Technical Area Wheels, Tyres & Brakes
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  1. My model of MX-5 is: __1.5 ND2 2019
  2. I’m based near: __Yorkshire
  3. I’m looking for technical help or recommendations on: __Alloy wheels

Hello all,

I recently changed all four tyres from the stock Yokohama V105 to Kumho HS51 after the NSR tyre developed a buble after what must have been a massive pothole. This car was bought half a year ago as a Mazda approved used car.

The car has developed a vibration in the floor at 68-75mph since changing the tyres. I’ve had a 4 wheel alignment done since the tyres were changed too.

Went to another garage today (didn’t trust the garage which changed my tyres to do a good job), the mechanic told me both rear wheels were ‘slightly buckled’ and was therefore unable to balance them completely. He seemed to be unable to identify the buckle. They also commented on how much weights the front wheels needed to be balanced. The balancing maching read “15; 65” and “10; 70” on the OSF and NSF, respectively. For reference, the rear wheels were “15; 95” and “15; 120” for the NSR and OSR.

I am hoping to hear if anyone has experienced such mild ‘buckling’ of the wheels which prevents proper balancing of the wheels?

Thank you.

2

They are talking cobblers, you can balance a biscuit tin if you wanted. The wheel could be square and it will still balance. The algorithm used in the machines is very clever, but basically the machine is looking for the very slight speed variations due to weight as the wheel rotates. The weights simply balance out these variances. A vibration at a certain speed is very typically a harmonic situation because they have not taken the time to properly balance it. Many do not check, once the machine has told them where to put weights, that the wheel is actually balanced.

3 Likes
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Thank you.

Do you think that is a lot of balancing weight for the wheels? I remember thinking that to myself when I bought it, but they all seem to be opposite the TPMS sensor, which makes sense.

4

:joy::joy::joy:

5

It could be a number of things

It could be the tyres, the brake disk or the wheels (or wheel bearings) These are the only things that rotate while the car is moving

If the wheels are buckled you can see it if they mount it on the balancing machine without the tyre and give it a spin.

Whether its the tyre (or wheels) if there’s a lot of weight to balance its an indication there’s something wrong.

Its not difficult to bend a 17" wheel especially if you have stiff suspension.

My guess is that its likely the wheels, maybe the brake disk is corroded and that induce vibration or last its possibly you got faulty or oval tyres.

Check tyre pressures as well.

6

Thank you.

My car is stock and 16 inch so the ride is full of lean in the corners.

Plan to go back to the garage which changed the tyres and see if they can identify the source/possible bad batch of tyres.

7

It could be/likely that you buckled the wheels when you damaged the tyre. You can check the ‘run off’ by jacking up each corner and bodging up a simple ‘dial guage’ and rotating the wheel.
Vertical out of balance should be cured by weights as indicated by a wheel balancing machine but longitudinal (side to side) shimmy caused by the buckle may be more difficult to cure with just weights. My understanding of physics is ‘basic’ at best so what do the ‘experts’ think.
If you have caused a bubble in a tyre by hitting a massive pothole you could have damage any part of your suspension as well so it may not be as simple as ‘a faulty tyre or balance’.
:heart:

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That’s the most likely explanation I think.

Also been advised to contact the company which sold the tyres as it might be a bad batch of tyres given how the other wheels are requiring a lot of weights to be balanced.

The suspension should be ok. The 4-wheel alignment was done by a very respected man in this community and he mentioned that the components were fine.