Good vibrations...

[insideline]

My Mk1 has recently had a visit to WIM to apply the fast road settings and the difference is remarkable, much more composed on A and B roads and just like I expected the MX5 to be compared to what I actually had. So all in all a happy customer.

Whilst at WIM I asked Tony to look at the front wheel balance as my car was getting some serious vibrations at 75-80 mph +. They checked and balanced the wheels but unfortunately the problem is still there.

Does anyone have any pointers for what to look at next? I have considered the following...

Scuttle shake - would fitting a lower strut brace help?

Worn Diff mounts - apparently these contrbute to rear vibration (I'm not sure it is actually a rear vibration but you never know)

Tyres out of round - these are newish Yoko's so hopefully not

Over to the sage wisdom of the forum...

[71notout]

Warped discs?

[insideline]

Would warped discs cause the vibrations when not braking? I haven't noticed any evidence when braking tho' so probably not. Thanks anyway

[seismic22]

buckled wheels. I have to very so slightly bent wheels on the front. one a bit flat and the other a tiny bit twisted. had wheels balanced and this helped but no eradicated vibration - new wheels.

[tuttle]

seismic22 said:

buckled wheels. I have to very so slightly bent wheels on the front. one a bit flat and the other a tiny bit twisted. had wheels balanced and this helped but no eradicated vibration - new wheels.

+1. I had this exact same symptom at those speeds with a different car. One of the front wheel rims was very slightly 'D' shaped.

I had the WIM fast road settings done about 3 months ago. Made a great difference, number 1 recomendation upgrade IMHO.

Edited by tuttle on Monday 16th August 10:43

[Odie]

wheel balance
out of true wheels
damaged brake disc/s
bent drive shaft/s
scuttle shake
bad road surface
sligtly bent suspension

could be loads of things at that speed, really depends on the shaking, perhaps you could describe it further.

Front, rear? left or right? shaking steering wheel? bouncy shake or left to right shake? does the shake continue over 80 (im assuming its a track car)?

[A2Z]

Try rotating the wheels. I recently picked up a buckle in the front wheel. My alignment guy suggested putting it on the rear. Haven't done it yet though so no basis in fact.

[GravelBen]

At least with a buckled wheel on the back you wouldn't be feeling it through the steering wheel.

Out of interest does anyone know what the WIM settings are? Would be interesting to see how different they are to my own road/track concoction - I guess they'll be similar, the Flyin' Miata setup was pretty close to mine and its not rocket science.

Edited by GravelBen on Monday 16th August 12:30

[MX-5 Lazza]

WiM have a website with a forum. If you can't find the info on there I'm sure they would tell you if you posted the question

[insideline]

Thanks for the replies so far. To answer a few of the questions asked...
1. Wheels are brand new Mazda oem from mx5 parts last year, so I have ruled out buckled wheels as they have had only light use since and no pothole damage
2. The vibration is definitely felt through the steering wheel but also through the rest of the car in fact scuttle shake best describes it
3. Driveshafts/diff could be a possibility any simple ways to check these without access to a ramp?

Thanks