Adjust speed readings according to tire size

[Alexandru]

Hello all,

 

I am thining about changing my 14 inches standard wheels - 185/ 60, to a set of alloys, 15''. Due to the fact I like a more comfy ride, I will not fit the recommended ones - 195/50, but I will get something about 195/60 or somewhere around. Will it be possible to adjust the instrument panel according to the new tires, so my speed, mpg and everything else will keep recording correct data?

I found this and this, but I am not sure...

Have anyone tried this before? 

[Benjiman]

I've gone up a profile size on my 16"s - a 3.4% increase in overall diameter, and my speedo now reads about spot on.
 

Tyre calculators suggest that going to 195/60/15 instead of 185/60/14 is an increase of 6.4% overall diameter.  So will read a little slower than you are actually going, but useable.

 

As for 'real' mpg figures from the dash, that's a debated topic in itself! (I find mine to be +/- 5 to 10% out).  Hopefully someone who knows VCDS can help to answer if correctios can be applied in VCDS..

[SkUG]

Just to give you the heads up, They will rub on the rear arch and touch the pointless bit of metal that sticks out behind the liner - I used an angle grinder to remove the metal lip and no more scrapey noises! speedo reads spot on with sat nav too!

[ifbravadoasks]

AS Skug says... I agree

[Alexandru]

If the manual says that I should fit 195/50 tires on 15'' wheels, will I break anything if I will go with 195/60 ? I am talking about the drive shafts, wheel alignment - angles - that will have to be reworked and all the suspension components also. I'm driving about 6000-6500miles/year, 80% the city.

Edited 30 July, 2014 by Alexandru

[Huskoda]

There will be additional strain on the components due to the larger torque needed for the larger wheels. I doubt you'll break anything, but I've driven a car on oversized wheels and it was sluggish. It was much better when back to standard. Your insurer may not like the change either.

[stuart vrs]

I've dropped down to size 195/45/16 summer tyres and use 205/55/16 winters tyres, better ride on the 55, but not accurate on the speedo, just drive tad slower during the winter.

[giandougl]

Correct size tyres fitted, my TomTom sat nav reads 2mph lower than my speedo.. one must be wrong..but which one ??

[Huskoda]

Correct size tyres fitted, my TomTom sat nav reads 2mph lower than my speedo.. one must be wrong..but which one ??

The speedo. They cannot underread by law, so they're set to overread.

[Tech1e]

Correct size tyres fitted, my TomTom sat nav reads 2mph lower than my speedo.. one must be wrong..but which one ??

 

You speedo isn't that accurate. You will get a bigger variance from a new tyre to an old tyre.

[KillerShark1978]

If the manual says that I should fit 195/50 tires on 15'' wheels, will I break anything if I will go with 195/60 ? I am talking about the drive shafts, wheel alignment - angles - that will have to be reworked and all the suspension components also. I'm driving about 6000-6500miles/year, 80% the city.

 

If that's what the manual say I would imagine that's what you should do, it just makes scene to lower the profile of your tyre if your increasing the size of your wheel or lowering the car, 

[Rooted]

http://kouki.co.uk/utilities/visual-tyre-size-calculator