Speedo way off

[spamalope]

Ok, I've got an '85 p-type auto and the speedo's off by quite a bit. it's always seemed fast sence I've got it and i drove past one of those speed trap thingies and it said 24 while my speedo said 30 adn I gassed it up to 40 on my speedo and it read 31 on the trap. It's got stock wheels and 235/60-14's on it so I dont know why it would be so off unless somebody pulled the 4.10 gears out and put something taller in there before I got it. What taller gears would through it this far off? Thanks in advance

[Keyfoo]

I changed my tranny and my speed o is also off. I heard the gear in tranny to speedo cable can make a diff.

check out this site. lot of info on rear axel ratio and trannys used with codes.
also color codes interior codes ect...

www.xprt.net/~willber/supra.htm

found this today hope it helps

[airwhirlybird]

i also have the same problem on my 84. i read 70, and my friend behind me in his volvo says i'm going 60. at the track i make passes on my speedo at 95, and my slips say 90 or 91. if you find out why this is please pass it on.

[spamalope]

Well, reading 95 and traping 91 isn't that bad but with how off mine is when it reads 90 I'm really only doing around 70... that a good deal off... but the funny thing is it really doesn't feel like It's that high off on the top end. It seems like it's not of by a % that much as it almost seems like it's off at a flat rate of around 10mph. I might just be crazy though.

[spamalope]

Well, according to my speedo at 3000 rpm I'm going 84mph... sound right for an '85 suto P-type??? Let me know, thanks.