Author Topic: Rolling radius...  (Read 975 times)

Offline Jack3559

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Rolling radius...
« on: 04 January 2011, 01:49 »
At the moment I'm running a 60/R14...

How would the speedo/brakes do with a 40/R16?

I've been told a difference of more than 3.2% is bad and I think the difference is about 8%...

Is there a way round this problem or does it actually not matter at all?

Offline justalex81

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Re: Rolling radius...
« Reply #1 on: 04 January 2011, 02:41 »
on a mk3 if you're running 16's then the profile should be 45. If you're running a 40 profile then you're speedo is out in the right direction. i.e you're going slower than the speedo says you are. very slight improvement on acceleration and a slightly lower top speed. shouldn't make much of a difference to brakes and i'm guessing by the fact you're running r14 wheels that it's a slow boat you've got

Offline les.tansey

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Re: Rolling radius...
« Reply #2 on: 04 January 2011, 02:55 »
Hi mate, although the width of the tyre doesn't change the rolling radius it can affect your speedo.

use this website to work out how it will affect your speedo:
http://www.kouki.co.uk/utilities/visual-tyre-size-calculator

Presuming that the width of your current tyres is 185mm and that when you get your new wheels, the your new tyres will be 205mm; according to the kouki tyre convertor your cars rolling radius will be 1.2% less than indicated which is fine.

Hope this helps,

Cheers, Les.


(As above) Golf MK3 & genuine BBS RX 16"wheels, now for sale separately - Just ask for details - Thanks, Les

Offline Wayne

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Re: Rolling radius...
« Reply #3 on: 04 January 2011, 07:55 »
215/40/16 was standard on Anni's you can also use 205/45/16 or 195/45/16 all these should leave you speedo / gearing all ok.