dose any one know the standard rim size on the 1998 altera's when they came out, i was just wondering because i want to put 17'' rims on i was just wondering if it would knock my speedo out, thanks :)

go outside and have a look at yours?

*does, does, does, does, does, does

First, go here, and find out what it came with.
http://www.bridgestone.com.au/default.aspx
Then use this to figure out the difference to what you're fitting.
http://www.miata.net/garage/tirecalc.html

Answers: 205/65 R15
You're probably getting 17s with 235/45R17s, although you haven't told us that, but assuming you are, the speedo will read 0.6% higher than previously. So if your speedo was dead accurate now (it's not), and you were doing 100km/h, your speedo would read 100.6

And, next time, what Liverpool said.

Parently when i put 20's on mine..came with 17" rims stock, it put my speedo out 1.3%, which is still negligeble considering most speedos are 3 kph under what they're showing. dw you not going to be going 80kph and the speed saying 60kph. lol

Another good Rim/Tyre comparison site...
http://www.wheelsmaster.com/rt_specs.jsp

P.S. Quick personal suggestion - Please consider more informative Thread Titles.
Things like "help please" and "does any one know" don't help much when searching or reading thread titles.

P.S. Quick personal suggestion - Please consider more informative Thread Titles.
Things like "help please" and "does any one know" don't help much when searching or reading thread titles.Seems to happen a lot in SA - never noticed it as much elsewhere. People will come into a shop and say "can you help me with something?" Er, well it'd make a lot more bloody sense if you stated the problem first, then asked if I can help you.

thanks everyone i thought the altera's came out with 15'' stock ??? i have 16'' on my car now and i'm going to buy my mates 17'' rims not sure on the brand but there comeing off a tj executive. so my speedo will be out.

http://i658.photobucket.com/albums/uu308/evoz10/22052009025.jp

http://i658.photobucket.com/albums/uu308/evoz10/22052009025.jp

there the rims i currently have..

*cries*

I ALREADY TOLD YOU WHAT TYRES WERE ORIGINAL EQUIPMENT FOR YOUR CAR. Please read. Which, yes, are 15s. Muzzi's car came with 17s stock. Not yours. As for the picture of the rims you have now, that does not help at all, go read what it says on the tyre.

If you can get the tyre sizes (eg. 205/65/15, 225/50/17, 235/45/17 or whatever) and either post them up here or enter them into the website I posted earlier, it'll tell you how much the speedo will be out.

Next time mate on't make four posts in a row, use the Edit button and add it to your previous post.

If you want to find out the size of your standard wheels/tyres, it should be mentioned on the tyre placard that's in the driver's door.

It doesn't matter if it throws your speedo out a little -there's a legal tolerance for it. In SA, "the overall diameter of alternative tyres must be not more than 15mm larger than the largest O.E. size or 15mm smaller than the smallest O.E. size." So use the tyre calculator that Mofo posted up and make sure the diameter hasn't changed by -/+15mm (just to keep it simple). If it's already on another Magna it should be fine, assuming your mate bought correctly sized tyres.

i'm sorry i'm only new to hear and i still getting used to it, thanks everyone for your help :)