Speed test with new wheels

[andys101]

Well I have just put the 14" alloys on and carried out a calibrated speed test

Indicated speed 13"steels 14" alloys

.....30.......................26............28

.....40.......................35............37

.....50.......................45............47

.....60.......................54............58

.....70.......................63............67

Much more accurate Yippie!

Edited October 28, 2008 by andys101

[Niche]

Wheel sizes make some difference but the main thing that affects the speedometer is your tyre profile.

What was your tyre profile on both wheels?

[andys101]

Wheel sizes make some difference but the main thing that affects the speedometer is your tyre profile.

What was your tyre profile on both wheels?

Both 175/65

[Niche]

The difference in percentage is 4.48% which is quite a bit.

I think you may have had the wrong tyre size on your old steels.

My 14" steels give these results...

30....29

50....48.5

70....68

I can't remember what the tyre size is though.

[andys101]

The difference in percentage is 4.48% which is quite a bit.

I think you may have had the wrong tyre size on your old steels.

My 14" steels give these results...

30....29

50....48.5

70....68

I can't remember what the tyre size is though.

Factory fit tyre sizes.

My wifes 1400 s has the same size.

How did you get your results??

[andys101]

1

Edited October 28, 2008 by andys101

[deathhead]

How much will my speedo be out going from 15 inch rims on 195 45's to 13 inch rims on 175 50's?

[Silver!]

Have a play here to get the effects on speedo reedings of different size wheels and tyres...

http://miata.net/garage/tirecalc.html

Standard Lupo/Arosa tyre sizes:

155/70/13

185/55/14

205/45/15

[andys101]

How much will my speedo be out going from 15 inch rims on 195 45's to 13 inch rims on 175 50's?

There will be a 9.1% difference from your current size down to your new size - however if we take your speedo to be set simmilar to mine it will give you a 13.38% difference.

my speedo reads 2.9% over. Add that to the 13.38% difference gives you a 16.28% over speed reading, so at an indicated speed of 70mph you will actually be travelling at 58.6mph.

Great for not getting caught by speed cameras but rubbish for fuel economy.