Speedometer diferential caused by non stock tires

[parkerbink]

Does this seem right? I want to know how off my speedo is so I know when I am speeding. If this is correct I have no worries. Gracias

[DanGillan]

didnt you just answer your own question?

[parkerbink]

I try not to assume, especially where dealing with law enforcement is concerned. I am asking if this assessment is correct.

Are you saying it is?? Are you saying anything really rly? o rly?

Thanks Dan.

[Mystikal]

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

[nando]

it's .1mph difference @ 60. your stock speedometer isn't even close to being that accurate anyway. so what do you think?

[parkerbink]

Thanks for link, the print screen in my original post is from them.

[Mystikal]

Oh shit, the pic seriously didn't appear for me the first time I opened the thread.

BTW, your stock tires were 195/65/14. There is quite a difference.

And FWIW, even with stock tires I've confirmed the E30 speedos read like 7-9% high. It's ridiculous.

[nando]

BTW, your stock tires were 195/65/14. There is quite a difference.

And FWIW, even with stock tires I've confirmed the E30 speedos read like 7-9% high. It's ridiculous.

yeah, I didn't notice that.. still, it's not a big deal, it's about the same difference as running 195/60s on a car that came with 205/55s. I just drive an indicated 5mph over and I've never had a problem.

[Scott314]

yeah, I didn't notice that.. still, it's not a big deal, it's about the same difference as running 195/60s on a car that came with 205/55s. I just drive an indicated 5mph over and I've never had a problem.

Going by one of those signs that tells your speed, 5 mph is about right for my car. Going an indicated 25 mph will give about 20 mph. Going an indicated 75 mph on a 70 mph highway will keep me with the rest of traffic. Kinda wierd, since I thought it would be off by a certain %, but it seems like its off by a constant value.