Need help with a wheel package question

I have a 2004 Jetta Gls 1.8T, the stock wheel and tire size is 195/65/15. I am looking to plus 3 size to 225/40/18, my questions is; will I have to change anything to accomodate for correct mph? for example, the speed controler.

My previous vehical I had the same senario going from a 15" to 18" and I needed to change the speed control.

one problem there is no way that is avalible that would change the vehicle speed as it is a program setting based by wheel speed and input speed of trans vss.
you will not be off by much.
good luck

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http://www.vortexautomotive.com

The rolling radius of a 195/65 15 tyre is not much different to the rolling radius of a 225/40 18 tyre.

65% of 195mm = 126.75mm

This is your profile size.

126.75mm into Inches = 5.7"

5.7" * 2 + 15" = A wheel/tyre Diameter of 26.4"

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40% of 225mm = 90mm

This is your profile size.

90mm into Inches = 3.6"

3.6" * 2 + 18" = A wheel/Tyre Diameter of 25.4"

So you will be reducing your overall Diameter by 1 Inch by fitting the 18" wheels.

This will cause your speedo to Over Read. So you will be safe in terms of speed traps etc. Just your top speed will be slightly optimistic. Wink

All the best

Ben

Oh, and just because im bored, I worked this out too.

225/45 18

The overall diameter is 26.1 Inch.

So maybe better going for 45 profile tyres. Will make the change less dramatic.

Thanks, can I pick your brian? What series would be better for performance and gas 40 or 45?

	dybarra wrote:
	Thanks, can I pick your brian? What series would be better for performance and gas 40 or 45?

Entirely depends on what tyres your putting on there mate.

You will get 45 profile tyres cheaper than 40 profile tyres.
A set of 225/45ZR18 Michelin Pilot sports would out perform a set of 225/40ZR18 Pirelli P Zeros. And they will be a similar price.

The taller profile will give you a smoother ride, And you will also get a VERY SLIGHT AMOUNT more MPG as they will cover more ground with less revolutions. But it wont be that noticeable to be honest.

I cant recall what the golf comes with standard. Ive a feeling its 225/40ZR18. Going for the 45 profiles might result in slight arch/wheel contact on full lock.

Thats about as far as I can assist you mate.

Ben

You have such great knowledge on the subject...one more question please, My Jetta is a stock 1.8T, i want to get just a little more out of the performance, I've been looking at a cold air intake (or just a performance filter) as well mods to the computer (different chip) and turbo. Have any suggestions that are easy, bolt on and such? Very Happy

just get a performance intake and chip.. unless you're willing to dump thousands into a turbo and boost and controllers etc.

i gained a good amount of HP just by adding a chip, air intake, and near spark plug wires / plugs. - simple and cost effective Smile

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my mkTHREE

No, I've already done that on my last car. But is there something that can be done with the stock turbo?

	itscarve wrote:
	just get a performance intake and chip.. unless you're willing to dump thousands into a turbo and boost and controllers etc. i gained a good amount of HP just by adding a chip, air intake, and near spark plug wires / plugs. - simple and cost effective

Where is a good place to buy a chip and intake?