What is my speed? Got 3 readings!
 

Okay I have F-150 with aftermarket rims/tires, I need to know my correct speed. I havent done any changes to my gryphon and the speeds I get:

35 on grayphon
40 on the gauge
38 on garmin navi

which one should I use to align the rest with? :help:

Use your gps reading then adjust your tire size.
What is your tire size and value you are using?
If you post these up we can help you make sure they are right?

Try to get the Gryphon speed to agree with the GPS. That should still leave your dash speedo reading fast, but that 's just the "nature of the beast". Since the Gryphon reads slow right now, you want to increase your TS. However, I'd try to get them aligned at highway speeds, rather than "in town" speeds. I think the results might be more accurate that way.

- Jack

Here is a way to get your speedometer just about perfect. Use the odometer on the GPS and truck. Also to make sure you're making your changes correctly look at what Jack posted just before me on that thread.
http://forum.gopowerhungry.com/gryph...html#post23835

Thanks for the info guys, I'm using 33x12.5x20 Toyo Open Country MT's

I guess I cannot adjust the speed and other config until I choose one of the canned program, right?

I'm still running stock, waiting for my customs.

Yeah, pretty much. When you do decide to try a canned tune, try 2661 as your tire size and use the method I mentioned earlier (using the odometer) to get it even closer. Also, dont forget "load previous settings" no matter what your doing, and check the gear value to make sure that is right. You might also be able to get the dealership to recalibrate the speedometer but I dont know if it would be worth the price or trouble. I know a friend of mine got his truck recalibrated at the dealership(because he wanted to get out of a ticket, if the truck really was off then they would waive the fee).

I'm going to "qualify" something Longshot said - but overall, he's giving you good advice.

The FIRST time you program your vehicle to something better than "stock", there will be NO "previous settings" to load. In fact, if you do that first program the way we recommend, you won't even create a "previous settings" file, because you'll skip the "Custom Options menu" choice.

Then, if you DO elect to use the Custom Options menu the next time you load a tune, there will still be no "previous settings" file to load, even though the choice is there, but you will be creating one.

After this, you probably DO want to "Load Previous Settings" as your first step whenever you use the Custom Options Menu in conjunction with loading a tune.

- Jack

I didnt wanna start a whole new thread since I pretty much have the same question. My speedo and gryphon are off by about 3-5 mph from eachother depending if Im doing in town or highway driving. When you order custom tunes, on the order form it asks for stock and modified tire size. Does that mean the custom tunes come calibrated for any difference in tire size and adjusted for gear ratio?

Yes, the custom tunes files contain whatever info you put down on the order sheet. Some adjustment of the TS may be required one way or another.

ok, thanks 88. so which one is the more acurate one, and will they always be off regardless of any adjustments?