[norwegianE46]

I've got a virtually new Gran Turismo 318da, and have put 7000miles on the clock since picking it up this summer.
It's now got 225/45R18 expensive Nokian winter tires on the original 18's, and rides smooth as nothing I've driven before.
BUT, yesterday after a calm business trip of about 100 miles, when I set back on the 100 mile Return, there is now a very noticeable vibration in the front, at above 60-70mph , why? I've driven veeeery calmly and fuel-economy focused, and have not hit any pot holes or ridden any curbs, so what's up!?

Surely the wheels can't go off balance suddenly like that? The air pressures are Perfect in both fronts. Any tips??

[turbolag]

Rebalance?

[norwegianE46]

I was thinking a rebalance, but it seems a bit odd as I've driven at least 600 miles on these winter tyres with whisper smooth cruising, so why would they go off balance on their own?

[Orjan]

Snow/ice in the wheels maybe?

[norwegianE46]

Good point, but the roads are still completely dry here :-).. Could the balance weights have fallen off one wheel?

[Zamorskii]

it's not uncommon for a balance weight to fell off, so check those first.

[DesertSmokeBBQ]

Re-balance. Dollars to doughnuts a weight has spun off...