Just changed wheels on my wife’s car over to the winter set we bought last year. These were new Alloy wheels and winter tyres. Maybe did about 4500 miles with no issues before putting summer ones back on.
Now we are back on the winter set, there’s a clear vibration that wasnt there before. More evident above 50mph, but worse when coasting and less obvious when under power. Tyres are directional and are all on the right way round. I’ve checked wheels are properly seated and all wheel bolts properly tightened. Tyres aren’t unevenly worn in any way, and pressures are correct.
Only thing I can think of is one or more of them need rebalanced. The little weights are stuck on and while I can’t see any missing spaces where one might have fallen off, I suppose it is possible.
Anyone got any bright ideas? Should I just take to a garage and get wheels rebalanced?
Car is a Merc GLC, tyres are Nanking Snow SV2

From what you’re saying about the issue being speed related it sound like one of them could be out of balance. Have you checked that there’s no obvious damage? IE a bubbled sidewall/deformation. I’d start with getting them balanced again.

Checked sidewalls and nothing obvious

Stone(s) stuck in tread?

Common with winters, affects balance to some extent.

How were they stored?

What Scotroutes said. They should be stored flat, not upright.

Stored on their sides, no stones in tread

Have you put the previous rears on the front?
The rears could have been out of balance but you wouldn’t notice until they are on the front.

Check they are still round, I had a tyre recently go out of shape with a bulge in the tread area that gave similar symptoms to yours. It took me ages to find as I was checking sidewalls, balancing weights etc but all were fine. Eventually I ran my hands around the tread areas and found the problem. Was worse at speed (nothing around 30) and went if the car was loaded and lessened under acceleration. The tyre was otherwise in fair condition with plenty of tread

If they were stacked did you rotate them and set pressure at about half on car inflation?

Vader, hadn’t seen a bulge but will check again
Bsims, stored at pressure they came off the car at, on their sides. Why would you need to reduce pressure or rotate? The pressure will be less off the car than with the car sitting on them?

Are the centre spigots the correct size on the ‘new’ wheels and did you tighten the bolts in the correct pattern i.e. 1 – 3 – 5 – 2 – 4.

Also I don’t think its common but if the garage don’t let the tyre completely deflate after popping the bead on and balancing the wheel, the bead may not be even. As you’ve stored them at lower pressure the bead may have relaxed into the wheel lip and put the balance out.

The instructions I was given were to rotate if stacked so as to not damage the bottom sidewall on the floor – think weight and cold rough concrete. Also reduce pressure as unweighted tyres with higher pressure suffer ply damage in the side walls. It was 8 years ago I first got mine so I could have remembered those points wrong.

Most likely rebalance will solve the issue.

Edit . What spooky says makes sense. Maybe they said increase the pressure by half 8 years ago. I have followed those instructions and never had a problem.

A quick google says pressure should be lowered to prevent uneven pressure on the unfitted wheel causing distortion.

It’s the Stans gone solid in the bottom.

Hmmm, the spigots are different, but I have spacers and these are fitted fine, in any case, they were on before with no issues. Nuts tightened up in correct sequence. I have not however reduced pressure or changed storage with rotation. I’m resigned to getting them balanced again on Monday.

I stored my own wheels in exactly the same way, swapped them over at same time, and mine are fine. So it’s not all bad!

I’ll assume Stan’s comment is a joke.. 😊

I had the same at 70mph. the balancing on one wheel was out. easy to sort. Are you sure they are mounted correctly with the nuts tightened evenly? does the steering pull under braking? if so then the tracking is to blame.

Just go n get them balanced

I’ve had this with an egg in my tyre.

I don’t know how much difference it makes, if any, but I try to always put the locking nut in the same position on the wheel, on the basis that it was originally balanced like that. It is heavier than the standard nuts, but being so close to the hub may make that irrelevant.

They don’t balance them on the car. Wheel goes on a balancing machine with a massive wing nut to hold it on the spindle, so you’re right, locking nut position is irrelevant. 😊

Iveco recommend the gold standard of wheel balancing, there is a machine that does the balancing on the vehicle so the wheel weights also balance the hub and brake disc. Presumably this is why my hubs have extra pins so you can only fit the wheels in the correct orientation.

Iveco also produce the only automatic gearbox I’ve ever driven that is possible to stall the engine with on a hill start. **** awful engineering.

Anyway; OP, get your wheels balanced again. A weight has probably dropped off.