Vibration at speed, only on certain motorways?!

[sfish95]

So had 4 new tyres fitted and balanced can see they've changed the weights about. On some motorways I can feel a slight vibration through the steering wheel only. If I go a bit faster than I should it gets worse. So I thought they've not balanced them properly. However, went onto a different motorway shortly after. No small vibrations and even when I gave it some no vibrations either. So I'm curious is this just the road surface I can now feel through these tyres (Conti Premium contact 6) or does this point to another issue?

[GreenV8S]

If it depends on the road surface I'd have thought it was more likely a characteristic of the tread than a balance issue.

[sfish95]

GreenV8S said:

If it depends on the road surface I'd have thought it was more likely a characteristic of the tread than a balance issue.

Was thinking the same, I will check the pressures are right. Not ideal if it is due to tread though it's quite unsettling.