Is my Speedo off?

[aceofspades]

so there's my line up! 1987 turbo 4 runner! swapped to manual not done by me!
had a 430 in the rear! but was 410 in front so i fixxed that now its back to factory 410's! like engine bay tag says!

I'm running 30x9.50 tires on 15's

and has digital dash!

At 2000 RPM in 5th i'm doing about 49 to 51mph!
At 3000 RPM in 5th i'm doing 69 to 70 miles per hour!

does that sound right

of do i have the wrong speedo gear?

 

[2ndGenToyotaFan]

Yes!

So the truck came with 4.10's and an automatic tranny? That doesn't sound right to begin with...

The best thing to do is have someone with a newish car set it at say 60 with the cruise on and you pace it.

Then divide the pace car's speed by your speedo number and that will tell you if you're over or under and how much...

My truck comes out to 1.16 which means I'm going 16% faster than my speedo says.

If you have a manual tranny and 4.10's (A very common stock set up) and 30 inch tires... Reason says your'e going about 6% faster than your speedo says... So 20 on the speedo is closer to 21 and 100 (Yeah right) is about 106...

Here's some reading:

https://forum.ih8mud.com/showthread.php?t=169817&highlight=tire+size

 

[aceofspades]

hmm not by much so where can i get a speedo gear for the trans to make it close to the speed i'm doing

 

[2ndGenToyotaFan]

I have no idea..... maybe Marlin Crawler or Advance Adapters.... If you find a place, let us know!

 

[fourwd1]

The auto should have come with 4.30's, not 4.10's. What is the axle code on the firewall plate?
Either way larger tires than stock will throw the reading off.
Marlin used to sell replacement gears for the sending unit in the t-case. Check his site.

 

[aceofspades]

The auto should have come with 4.30's, not 4.10's. What is the axle code on the firewall plate?
Either way larger tires than stock will throw the reading off.
Marlin used to sell replacement gears for the sending unit in the t-case. Check his site.

It was a factory auto turbo with 4 runner with 410's thats what the code on the plate says look up my old post about having 2 different gear sets!

 

[Foreigner]

The easiest way I know to check the speedo is to go 60 and run a stopwatch against the mile markers. Or if you're in a hurry, do it at 75 (48 sec to the mile).

 

[a85toy]

You can just borrow a GPS unit from someone and check your speed with that.