Ford Transit Speedometer Calibration

[BillsPaseo]

This may be interesting for Ford Transit owners who have upgraded to larger tires... the newest version of FORScan (2.3.29 beta) has added the ability to access a bunch of parameters in the BdyCm Central Configuration (Main) module of the Ford Transit, in particular Tire Circumference.

We upgraded our Transit T350HD from the stock 195/75R16 to 215/75R16, and this knocked our speedometer, odometer and fuel economy gauge off by roughly 10%.

Today I followed the procedure in FORScan and found that my factory setting for tire circumference was 2115 mm, and was able to change it to 2260 mm (the max setting available), a difference of 6.8%. This should reduce the error to only 3.2% based on the experience of others who have tried it. I will report back when I get some highway miles on it.

Lots of info on the Ford Transit forum. Warning, the procedure is not for the faint of heart. The good news though for those that don't want to tackle it themselves, is that the setting is available, and a Ford dealership should be able to change it for you.

https://www.fordtransitusaforum.com/...ensions.78826/

https://www.fordtransitusaforum.com/...sort-of.78984/

Attached is a picture of the bigger tires that caused me to go down this path...

[oilman]

What was the reason you switched to larger tires, looks, ground clearance or something else??

[BillsPaseo]

Mostly for ground clearance. Got really tired of dragging the rear of the van over every little bump.

The combination of bigger tires, Sumosprings and Supersprings had resulted in a total difference at the rear hitch of about 4", and has eliminated that grinding noise at every gas station entrance.

[BillsPaseo]

Got a chance to check the results last night. On the freeway with cruise set to 60, GPS is reading 62. Before the change, it would have been reading 66-67. So big improvement.

[Jimbo614]

Looks like the larger tires would affect your gear ratio as well. A 3.75 rear would effectively become 3.60 Maybe better mileage. Do you notice any change in performance? Do you have the ecoboost ?

[BillsPaseo]

Originally Posted by Jimbo614

Looks like the larger tires would affect your gear ratio as well. A 3.75 rear would effectively become 3.60 Maybe better mileage. Do you notice any change in performance? Do you have the ecoboost ?

I do have the EcoBoost. And the taller vehicle from the combination of supersprings, sumosprings and larger tires did change gas mileage, slightly worse. Lost about 0.5 MPG at 60 and 1 MPG at 75 MPH. That is after taking into account the error in the odometer.

[@Michael]

Bill,

Do you have a before and after measurement at the hitch? I'm curious to know how my Crossfit compares to where your Paseo was and is now.

Mike

[BillsPaseo]

Originally Posted by @Michael

Bill,

Do you have a before and after measurement at the hitch? I'm curious to know how my Crossfit compares to where your Paseo was and is now.

Mike

Mike, before any changes, my rear hitch height was a little under 12". After doing the SumoSprings and SuperSprings, the rear went up to 14". And then when I did the larger tires tires it went up to a little over 15.5".

So total clearance gain at the hitch was almost 4".

Biggest benefit of the suspension changes was the reduced bouncing on bumps - no more bottoming out the suspension on every little dip in the road.

[@Michael]

When full of water and ready to camp my Crossfit is 11.25 to the bottom of the hitch. The sewer holder is even lower.

I'll have to come up with a plan for getting the back end higher.

[BillsPaseo]

Originally Posted by @Michael

When full of water and ready to camp my Crossfit is 11.25 to the bottom of the hitch. The sewer holder is even lower.

I'll have to come up with a plan for getting the back end higher.

I only had about half a tank of water when I did my measurements, and my trailer was not hitched up. I'd guess it's about half an inch less when fully loaded. Trailer tongue weight adds about 250 lbs, and that alone drops the hitch a little over 1/4".