Standard Tyre size speedo error etc

[Guest elandra]

Hello there,

 

I have a problem with speedometer and odometer error. The speedometer reads 10% too high ie 110km/hr when the vehicle is doing 100km/hr, 55km/hr when doing 50km/hr. I also found the odometer reads 3.6% too high. Reading the manual apparently a 10% speedometer error is right at the acceptable limit for accuracy which seems high to me. However I thought maybe the tyres are the incorrect size. The vehicle is a standard (as far as I can tell) 1995 n/a Supra japanese import. It has 16"x8" wheels all round with 225/50 tyres. All the info I have found so far suggests that the rear and front wheel sizes should be different. However this may relate only to US and UK models. Can anyone tell me if the Japanese SZ Supras came with tyres this size all round and if speedometer and odometers errors like this are common and what can be done about it.

 

Incidentally the measurements were taken with GPS.

 

 

Regards

 

Andrew

[heckler]

on stock 16" wheels, the wheels/tyres are the same size, the staggered (different sized) sizes wheels apply to the stock 17" which are the 235/45/17 and 255 /40/17 ( I think). Quite a few supras (SZ and RZ/GZ) came with 16's, but the 17's were an "option" and standard on UK spec supras, and at a guess USA spec too. If you were to stick some stock 17's on, you will still get an approx 10% speedo error! SO, yes, the 10% error is common

[stevie_b]

The stock 16" wheels can sometimes be different sizes too: I have 225/50/16 on the front and 245/45/16 on the rear. Mine's a Japanese SZ. Have a look at the sticker on the driver's door shut. Most of it's in Japanese but you can make out the size codes. I don't know much about wheels or tyres, but have a look at your alloys to see if they are "8J" on all 4 corners, or 8J at the front and 9J at the rear (as mine are).

Edited February 1, 2010 by stevie_b (see edit history)