tyre sizes

[minge]

will tyres off 7x15 alloy rims fit on 6x15 rims?Tyres on 7x15 rims are 195/45/15 are to replace tyres on 6x15 rims are 195/65/15

[woodchopper]

They will fit but will cause tyres to roll, ( move sideways ) on the rims which you dont really want to happen.
And will most likely throw the speedometer out as well due to the different profile being fitted.

[rdv]

The recommended rim size for the 195/45 is 6" to 7.5" so thats fine in fact many Golf GTIs had 195s on 6" rims as original. The gearing and speedo reading will be affected. The 45s have an overall dia. of 557mm and the 65s are 635mm