Speedo recalibration

[RichardK]

Having fitted 265 70 17's when I bought the D3 and having the Faultmate which I haven't explored nearly enough I thought it was time I recalibrated my speedo to account for the bigger tires. Seemed easy enough. just enter the rim size, width, width of the tyre, aspect ratio and dynamic rolling radius and write to the ECU. All done, now some how I have to find out if it worked........looks like a job for the GPS

Next job is to raise the suspension.

[NavyDiver]

Did it work?

[RichardK]

Yep, not a problem other than allowing for the wear to the tyre

[bee utey]

Yep, not a problem other than allowing for the wear to the tyre

Tyre distance travelled per revolution is mainly about the length of the steel belts. Tread contact is parallel to the road surface. This doesn't change so tyre wear has little effect on accuracy. Less than 1% in my careful checking over the years of travelling...

[rmp]

Tyre distance travelled per revolution is mainly about the length of the steel belts. Tread contact is parallel to the road surface. This doesn't change so tyre wear has little effect on accuracy. Less than 1% in my careful checking over the years of travelling...

yes, not much, but deep-tread tyres like muddies may reduce from 16mm to say 2 so that's 28mm total diameter loss. That can be significant. Road tyres aren't that deep to begin with. This is another reason why muddies are usually a greater diameter when new than roadies.

[RichardK]

Well, I put in the rolling radius as calculated by the tyre manufacturer but when I checked it out comparing my speedo to the GPS I ended up having to deduct 8 mm to get an accurate comparison