Steering wheel vibrations at ~65mph only

[MrNotEnglish]

Hello, that was long time since my last visit here But I have weird problem now and need your help I have two sets of wheels, 18" with summer tyres and 16" (stock) with winter tyres. I was abroad in March, so I took off 18" and put 16" with winter tyres. Couple days ago I put 18" back, but those which were on rear went on front. Front ones had tyres worn pretty bad due to incorrect tracking before, so I got brand new tyres for them. So now 2 wheels from rear are on front, two from front are on rear with 2 brand new tyres. I didn't have any problems with my 18" before. Balanced perfectly. But since I put them 18" back, I got some vibrations at about 65mph, all 4 wheels were balanced at the time when 2 tyres were replaced, even replaced spigot rings for brand new ones at the same time. What could cause that steering wheel shaking? It doesn't happen when braking, brakes are fine, discs and pads replaced in March.
I'd appreciate any help

 

[freddofrog]

it could be several things, difficult to know from all that

Basically, try it when coasting (clutch pedal to floor, or go into neutral), if it continues when coasting then it will most probably be related to the wheels or suspension.

 

[accord_n22]

Might be driveshafts but highly unlikely due to it being the petrol 2.4
Have you checked the wheels for buckling or flat spots?

Might be worth getting the re balanced just to be sure. I have heard that tyres can deform and mishape when stored for long periods of time - it could be that.

 

[freddofrog]

Might be driveshafts but highly unlikely due to it being the petrol 2.4

that's why I suggest coasting to eliminate that (if it doesn't change when coasting then it's not driveshafts)
it is also a know issue on the 2.4 as well, ask Eric (toffee_pie) when he bought his CL9 (which I drove when he lived in Leicester, the car had terrible vibrations from driveshafts)

 

[MrNotEnglish]

Thanks for suggestions Forgot to add my cl9 has automatic transmission, and it has been remapped by ukcl9 (more than a year ago). Another thing I got Tein Street Basis installed last year in June. But I'll double check wheels, balancing etc, maybe swap them rear to front, because it was completely fine and fautless until the day I changed 16" with winter tyres to 18" with summer ones.

 

[freddofrog]

It probably isn't driveshafts , but it is possible to put an automatic into neutral at 65 mph to see if there is no change (if you don't like doing that, don't do it, any anyway it should be done on a straight section of dual carriageway or motorway where there's no other traffic)

 

[MrNotEnglish]

Problem solved, can't believe it was front left wheel slightly out of balance, even after it had balancing done week before. Balanced again and it's fine. Thanks for input