What profile of tyres are best.

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Robsey
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What profile of tyres are best.

Post by Robsey »

I am looking to fit a pair of 15" Dippy Fanblades to my Cav.

I have had slightly lowered Spax springs fitted (30/40mm drop).

I see from Haynes that the standard tyres should be 195 / 60 R15's.

However my alloys have 3 different profiles fitted.
2 are 60's
1 is a 55
And 1 is a 50 % aspect ratio.

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I am going to fit fresh rubber all round after the wheels are refurbed.

So what profile should I fit? - and why?

Bear in mind that upto now the Cav has been fitted with standard 175 width 14" steelies.

I suspect that 195/50-15's will give the least difference in indicated road speed compared to the 14" steels.
although I have an Astra digi dash, so can flick the little red switch to suit 15" wheels if necessary.

I want a happy balance between handling and comfort.
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James McGrath
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Re: What profile of tyres are best.

Post by James McGrath »

Keep it standard; 195/60/r15 should be fine.
have a look here:
http://www.willtheyfit.com/

Anything less than a profile of 60 will make the fan blades look really small in your wheel arches.
Lots of people make the mistake if putting on tyres with too low of a profile and it just looks stupid in my opinion.
It will also put your speedo out of calibration.

Going from 175 to 195 makes a big difference to the handling, no need to lower the profile further.
iangsi
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Re: What profile of tyres are best.

Post by iangsi »

Your supposed to go with wider tyres when lowering the profile GSI tyre size is 205 55 15 I think they will look OK on a slightly lowered car as GSI's are lower from the factory.
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Robsey
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Re: What profile of tyres are best.

Post by Robsey »

The nearest comparisons to the original wheels 175/70r14

Are:-
185/60r15
This provides 0.4% road speed difference and 1.2mm difference in ride height.

195/55r15
Is the next closest, at about 0.8% speedo error and 2.34mm higher ride height.

195/60r15 gives almost 2.5% speedo error and 7.2mm increase in ride height.

195/50r15 gives 4.3% speedo error and a reduced ride height of 12.3mm

So there you go - I hope that helps with your own wheel and tyre considerations
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Envoy CDX
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Re: What profile of tyres are best.

Post by Envoy CDX »

195/55/15 is what I have on the Corsa currently and they are spot on in terms of speedo reading matching most road scope things as well as 3 different sat navs.
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