CBNBAC

Just ordered some 275/60r20 tires for my truck. I'm currently riding on the stock 18s so there's going to be a pretty significant difference with the speedo. Most folks here are riding bigger than stock and I did some searching, but couldn't really find a definitive thread on this.

How did you correct your speedo(dealer, tuner/speedo calibrator, nothing at all)?
If you had the dealer correct it - what'd they charge and what tire size selection did they use?

tonhe

SCT Tuner...

Z7What

According to my dealer they can only calibrate tire sizes that are available on the F150. 275/60R20 not being one of them. I have that size on my truck and got a custom SCT tune to correct the speedo.

If you wondering the 275/60R20 is 32.99X10.83

Wayne

CBNBAC

What do you think of the SCT Tuner? Do you reflash to stock every time you goto the dealer?

Z7What

SCT is the best Ford tuner! Period!

As for going back to stock? No, but I have never had my truck in for work that would require them to hook the computer up.

Wayne

CBNBAC

Which tuner do you have? I see a few options on the SCT website.

tonhe

I have the SCT x4 - I purchased it from Stage3 Motorsports. Only had it a week, but so far I'm quite happy with the results I'm seeing.

gouldje

check your speed first with a GPS, i put on 305/65/18's and at 60mph i was only off 1mph, so i think the speedos are off to start with

Z7What

X3, X4, Livewire. They all will tune your truck kit fine.

X3 holds 10 tunes and to datalog you need to have a lap to do so.

X4 holds 10 tunes and has a display that will show you datalogs in real time but isn't a mountable unit.

Livewire also holds 10 tunes and has a display to datalog but it is mountable to always have parameters at a turn of the head.

But they all need a laptop to datalog long enough to send to a tuner and you mount the Livewire be prepared I lose have your view area through the windshield, I think it's huge!

So with that all being said go with either one you can find cheapest!

Wayne

FordEver

My stock height tire was 32" (275-55-20) Went to a 34" (275-65-20) My speedo was off by 6-7%. Asked dealer to flash for me, was told could not be done for those tires. I asked about a tuner, wasw told it may void warranty. So rather than argue, I will put up with it. It throws off your MPG and stuff, but I can live with that.


Weird thing is, my speedo is off by 6-7%, but my mileage is off by 10% So effectively, I am getting 10% more warranty, cuz a 1000 miles/kms on my truck is only showing me 900 miles/kms.


When I calculate my MPG with the bigger tires, I have lost maybe 1MPG.....MAYBE!!!!!


So OP, if you can live with your speedo being off by approx 3%, I wouldn't even screw with it...... But thats mee