Tyre sizes and advice

What tyre size should I be running - I am new to bay windows - and the garage recommended I get bigger tyres than I currently have to increase the gear ratio so I can cruise easier at 55mph - due to small tyre sizes revs are a bit high. I have just purchased 15'' fuchs from SSP - so what tyre size do I need to go for. I am going to keep the original size at the front - so the tyres will be bigger on the back than the front - will this cause any major problems anyone can think of? my van is quite low so I do not want to start risking tyres rubbing etc on the front.

 

I want to keep them as narrow and as tall as possible!! so they will fit in the arches without any rubbing

 

On a standard unmolested van if you run 15's you need 195/70/15 to be as near as damn to 185/14 standard, I'm afraid I have no idea what size will fit on a bus that's been lowered

 

I'm with Ricky, I dont know what size will give you clearance, but if you bear in mind the rolling size of the 195/80 14 (stock) and look here: http://www.etyres.co.uk/how-to-change-your-tyre-size/
you can work out how much bigger your wheel will be!

 

thanks guys that's all I needed to know - I am going to adjust the ride height at the back to fit to get it back on standard sized wheels - to get the gearing back to normal

 

as @zed corrected me last night standard is 185/r14c 80 is more like 82 and not mentioned.

 

2mm difference in the diameter of the wheel between 185/r14c 85 & 195/80 14
16mm difference between 185 80 14 and 195 80 14

 

When I had 15" alloys on I was running 195/70/15's on the front and 205/70/15's on the back, My speedo was spot on with the sat nav speed. I have now put my steels back on but wanted to keep the gearing up a bit so I put 205R 14 van tyres on, The speedo now runs about 4mph slower than the sat nav

 

205/70 15 are about 16mm bigger than stock the 70 or 65 or 85 etc is the percentage of the width (205 etc) that denotes the height.

 

i run 225/75/15's on the back of my bay

 

I think on those wheels you will probably run:

175/55/15 on the front to keep it low, (your speedo will be out)

195/65/15 on the rear I am certain will clear the arch, As said above it would be better to run 195/70/15 or 205/70/15 if they will fit.

 

What make did you fit? You still happy with the set up. Need to swap mine before i go any distance as the fronts are on the way out. Putting the steels back on for now.