bigger wheels - smaller tyres = stock size.

Post by **ally** » 01 Aug 2006, 23:06

hello

im thinking of alloys, but i notice its best to keep the same diameter of the stock wheel.

So if i go up to 16inch alloys, what size do the tyres have to be?
etc

Or the cheapest option is 15inch alloys, what tyre size on them?

Cheers

aLLY

Post by **HarryMann** » 02 Aug 2006, 09:26

On the linked page below (mainly an Excel workbook) look for the TRC Calcaulator (blue font) and click that wherein a Tyre Rolling Circumference calculator will magically appear... you could use this to help match up the wheel and tryre sizes to your originals.
You might also err on the larger TRC size, as your speedo already over-reads considerably, if mine is anything to go by. It is now exactly correct (by two different GPS checks) with 15" wheels and 205/75 off-road tyres - quite surprising.

MPH per 1000 rpm

Post by **lhd** » 08 Aug 2006, 22:36

I have a set of 16" borbets, the tires are 215,50,16 and they have a -5% difference in circumference...
ie, at 100 mph speedo reads 95.......
If I ever got to 100 mph that is.....

lhd.....................

Post by **Reg** » 10 Aug 2006, 18:40

this might be helpfull just type in your wheel size and what tyres show you the difference in size and the %of speed
http://www.discountpartcenter.com/tirecalc.html

Post by **HarryMann** » 10 Aug 2006, 19:43

Or even our own one

http://www.club80-90syncro.co.uk/Syncro ... ulator.htm

Or download the MPH/1000 rpm spreadhseet

http://www.club80-90syncro.co.uk/Syncro ... nloads.htm