The ODO and the speedo are driven by the same electrical pulse so they both see the same number of pulses. If your tyres are 10% bigger (circumference) then yes you need to add 10% to the ODO figure to match the accuracy of pre big tyre readings.
My assumption is that the manufacturer intentionally makes the speedo read high, there's no reason these days for it to be inaccurate to the degree they are unless it's intentional IMO. Having the ODO under read by 10% wouldn't be good though so I would expect them to indicate the correct distance on the ODO but that is just supposition on my part trying to be logical about it.
My assumption is that the manufacturer intentionally makes the speedo read high, there's no reason these days for it to be inaccurate to the degree they are unless it's intentional IMO. Having the ODO under read by 10% wouldn't be good though so I would expect them to indicate the correct distance on the ODO but that is just supposition on my part trying to be logical about it.