Speedo Recalibration

[Dinks66]

Hi, does anyone out there know if the speedo takes it's info from the front or rear wheels. I am putting new wheels and tyres on which are different sizes to the standard ones and want to know what values to input into my Dreamscience XCT tuner. Front or rear size ?? If no-one can help I can do the trial and error method I suppose. I have ordered some Project 6GR Fives and hopefully they should be here by the end of the month with a bit of luck. Thanks for any advice !!:cheers:

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[willisit]

Everything I've read points to the rear ABS sensor(s). Go outside and do a line-lock and see if the speedo reads

 

[Enoch]

What sizes are you going to run??

 

[Gibbo205]

It is rear and SCT can no longer re-configure the rolling revolutions like it could on S197.

You need Whipple flare tool, or regular Ford cable and canbus tool.

It is possible but quite a bit of hassle.

Your speedo will be off as will your track apps.

 

[Cati]

Check rolling radius... probably makes little impact on speedo accuracy. Unless your going gangsta and 26 inch dubs bro...

Otherwise gps phone calibration check

 

[Dinks66]

What sizes are you going to run??

Hi Enoch,
I have gone for 285/35 on 20 x 10" fronts and 295/35 on 20 x 11" rears. All Michelin PS4's.

 

[Dinks66]

It is rear and SCT can no longer re-configure the rolling revolutions like it could on S197.

You need Whipple flare tool, or regular Ford cable and canbus tool.

It is possible but quite a bit of hassle.

Your speedo will be off as will your track apps.

Cheers Gibbo,
I rang Dreamscience and the young guy on the phone was going to check whether it was front or rear and get back to me but he never did. This would probably explain that the XCT isn't able to do it and why he didn't bother to get back to me. The speedo shouldn't be too far out going by google online tyre size comparators but it would just of been nice to have it bang on. Not to worry and thanks for the info. I will post pics once the wheels are fitted !!!:cheers:

 

[plc268]

It is rear and SCT can no longer re-configure the rolling revolutions like it could on S197.

You need Whipple flare tool, or regular Ford cable and canbus tool.

It is possible but quite a bit of hassle.

Your speedo will be off as will your track apps.

Whipple flare is probably the easiest way, but there's another way by modifying your as-built:

http://www.mustang6g.com/forums/showpost.php?p=1556321&postcount=987

and read this thread for more info:
http://www.mustang6g.com/forums/showthread.php?t=61773

 

[Enoch]

Hi Enoch,
I have gone for 285/35 on 20 x 10" fronts and 295/35 on 20 x 11" rears. All Michelin PS4's.

Based on those sizes I wouldn't worry about speedo error

Speedo reads slightly high anyway...my speedo shows 72 when sat nav is reading 70... (on standard tyres)

Based on this with your sizes I'd take a guess that you're readings will be closer to actual.... i.e. Actual 70 on sat nav will be 70 on the gauge

 

[willisit]

Based on those sizes I wouldn't worry about speedo error

Speedo reads slightly high anyway...my speedo shows 72 when sat nav is reading 70... (on standard tyres)

Based on this with your sizes I'd take a guess that you're readings will be closer to actual.... i.e. Actual 70 on sat nav will be 70 on the gauge

If that IS the case, it's well worth checking against a GPS as, although entirely unrelated, my old Monaro is calibrated exactly and so the usual "I'll do 33mph here as I know I'm doing 30mph" can get you in a bit of bother (I know because I didn't have any idea until I was "told off" for speeding) ;)

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