Bigger Wheels / Tyres

[Mikebmth]

Hi all,

Always been a tad confused about the tyre size adjustments you are meant to make when running larger than standard wheels to keep the speedo correct so wondered if anyone could make a list for those fitting larger wheels and what tyres we need to run for clearance etc.

I have mk4 Astra sport 15" alloys and have 195/60/15 tyres on it, is this correct or will it through out my speedo reading???

[Cavalier342]

You know it's not correct dude, told you that ages ago Your speedo will be out anywhere around 15% now.

[planetc]

Google 'tyre circumference calculator', there is probably several but I have used one that came up top of the results where you can put in the original size tyre and alternatives and it will tell you how much larger or smaller they are.

[Gaz]

Your under the assumption that the cav dials read right in the first place....

[Mikebmth]

Google 'tyre circumference calculator', there is probably several but I have used one that came up top of the results where you can put in the original size tyre and alternatives and it will tell you how much larger or smaller they are.

Hmm I see, according to that I am 4.37% to large...lol...Speed difference +3.06 mph at 70mph

Closest I can get is 55 profiles which give a 0.97% and a speed difference of +0.68 mph at 70mph

Saying that though, I have never had a speed camera go off on me and I sit right on the speed limit through them

Used this: http://www.alloywheels.com/Tyre_Calculator