Bad Vibrations

Can anyone through some light on my problem.

I have just fitted a set of BK Racing Wheels and a new set of Toyo Tyres. They were balanced when the tyres were fitted and again after a couple of hundred miles because  there is a horrible vibration going through the car. The second time the tyre fitter (a different garage) said they were well out and I must say the vibration is marginally less but still uneccaptable.

The problem does not start untill around 65 / 70 and probably gets worse the faster I go. I am unable to drive through the vibration  as in my experience with  balance problems  another 5 / 10 miles an hour usually sorts it. This seems to stay up to a point where it feels i would not like to go any faster and of course it’s over the legal limit.

There is no excessive wobble on the steering wheel just a comlete vibration through the seat of my pants if you know what I mean.

The original wheels were 14".185. 60 The new ones are 15". 195. 50 …

I would like a few ideas before I return to where I bought them as I can imagine the response I am likely to get

 

 

hi Billy, the speed the vibration starts  sounds like a balance/buckled wheel problem, but as you say usually able to drive through, but not always, if steering wheel is not vibrating(?) then defo from rear wheels only (since tyres/wheels fitted) if ya wanna make sure wheels/tyres r the prob swap fronts to rears steering wheel should now vibrate, hope this helps

 

Thanks for your reply goochie
I will try swapping the wheels around to see if that has any effect.

I was wondering if the tyres may be a problem as I think I heard a tale of new cars having a similar problems & one or more of the tyres were defective. It is a shame as I had Goodyear F1s on my 14"s and the car was as steady as a rock.

Update

Went back to BK Racing where I bought wheels & tyres. They took them off & re balanced them again saying they were well out. With not much hope I drove away & tried it out on the Express Way & it seems to have solved the problem. Who would believe it would take three tries to get it right.

I am still surprised though how different the car feels on this setup. Some tracking on the tarmac joints in the centre of the road & a harder ride. This is not to any extreme you understand it just feels different.