Speedo Error

[Doug C]

I just purchased an 05 SRT10 (6 speed). On the way home, I immediately noticed the speedo is reading fast by approx. 10 mph. The truck has a K&N setup and supposedly has had a tune done. There are no other mods that I'm aware of and I don't think the rear gear has been changed. Shows approx. 1500 RPM at a corrected 70 mph (I followed another car to verify the error).

I'd appreciate some input on how to correct this. I've no problem putting the tune back to stock, providing the K&N can be used with a stock tune.

Some input would be much appreciated.

 

[Gecko]

1500 rpm at 70 mph in what gear?

 

[Doug C]

Sixth gear.

 

[VPRPWRD]

What size tires are on the truck?

 

[VENOMOUS1 RACING]

Yup tire size is the only thing that's gonna change speeed.

 

[shorty]

Yup tire size is the only thing that's gonna change speeed.

Or Cuervo Gold :dontknow:

 

[Silver05]

Or Cuervo Gold :dontknow:

That always slows things down!

 

[shorty]

That always slows things down!

Not talking about Nam grass but the real gold stuff.

 

[Doug C]

Tires are factory size. 305/22. I'm wondering if someone has used the tuner to adjust for different size tires previously. I'm going to hook it up and try to adjust for the stock tire height and see if that corrects the problem.

And thanks for the advice, not withstanding the cuervo...

 

[VENOMOUS1 RACING]

Tires are factory size. 305/22. I'm wondering if someone has used the tuner to adjust for different size tires previously. I'm going to hook it up and try to adjust for the stock tire height and see if that corrects the problem.

And thanks for the advice, not withstanding the cuervo...

305/40-22? Not in the tune boss

 

[Doug C]

Thanks for the info. That leaves a rear gear change or a speed-o gear change as the only two possibly culprits? Am I missing anything?

Really appreciate this site, btw. Great info. The search function is terrific.