tyres!

would it make a big difference to anything if i was to use 195/55/15 instead of the 195/50/15 which is on the car or on my other car 175/60/14 changing to 195/60/14?

The sidewall height of the 195/55/15's is 195 X 0.55 = 107.25mm. The 195/50/15's = 195 X 0.5 = 97.5mm. So these new tires you're proposing are about 10mm larger radially. I'd crank my wheels either direction and see whether that 10mm would be getting the tire close to anything it shouldn't. I would guess it wouldn't be a problem.

If you know someone who has a GPS unit, it might be a good idea to go check your speed afterward. I've checked my speed and found that the speedometer reads 2-3mph slow, so I'm really only going 67mph or so when it indicates 70. With bigger tires (er, tyres ) you'll be going faster than what your speedometer says because you'll be covering more ground per revolution.

Thanks for the reply, would you think that it would be a problem putting 195 on the rim as they were originally 175?

Again, clearance might be an issue. Perhaps more likely in this case than in the other.

Also, a rim designed for a 175 mm tire may be a bit narrow for the 195 mm tire. The sidewalls will be angled inward a bit compared to being mounted on a rim designed for 195s.

That could cause some handling or durability issues. A reputable tire shop might be able to tell you for sure.

how much of a difference?
get to see this ,you will now know.

good link, thanks