Speedo Calibration

[Weasellee]

Easiest way to recalibrate speedometer on rubicon for tire size change?

Photo for the hell of it.

TIA

 

[Ashim]

HealTech SpeedoHealer from Poly Performance is what I used when I went to 35's years ago.

 

[Feralkid]

It's easier to recalibrate your mind and multiply the speedometer reading by the percent increase in tire size. You're not going faster than posted speed limits in a lifted TJ anyways unless you have a death wish.

 

[Apparition]

You're not going faster than posted speed limits in a lifted TJ anyways unless you have a death wish.

 

[Weasellee]

It's easier to recalibrate your mind and multiply the speedometer reading by the percent increase in tire size. You're not going faster than posted speed limits in a lifted TJ anyways unless you have a death wish.

You say that as today we went for a shakedown run from Poughkeepsie to Albany and back. Headed north speedo at 68-70 I said to Dave “she feels great wonder what 80 would feel like” he turned on gps and we were doing 80!! At 40 the gps said 45. This can’t be easily recalibrated in the head as cruising down the highway.

 

[Weasellee]

View attachment 576127

100%

 

[Ashim]

Recalibrating the speedometer is cheaper than a speeding ticket.

 

[Weasellee]

HealTech SpeedoHealer from Poly Performance is what I used when I went to 35's years ago.

This seems like a good way to go. $169 direct.

 

[Weasellee]

You're not going faster than posted speed limits in a lifted TJ anyways unless you have a death wish

Or you can build it properly and go 80 in a 55 through winding corners without even realizing it .

 

[J.Cain]

12 O’clock labs kit is what I used when I regeared to 4.88’s and 33”. Super easy plug n play system. Not the easiest to calibrate as it is done from a series of LED flashes but the online instructions made it simple enough.

 

[Weasellee]

Just to follow up. Ordered and installed the HealTech Speedohealer. Simple install. Simple programming. 100% recommend.

 

[Mudflat]

Recalibrating the speedometer on a TJ should be as easy as changing the speedometer drive gear as long as you know your differential gear ratios & tire diameter. I did this when I regeared my axles & my speedometer is dead on now.
Here’s the chart that will show you which drive gear to buy.

 

[mrblaine]

Recalibrating the speedometer on a TJ should be as easy as changing the speedometer drive gear as long as you know your differential gear ratios & tire diameter. I did this when I regeared my axles & my speedometer is dead on now.
Here’s the chart that will show you which drive gear to buy.

View attachment 580080

He has no drive gear to swap out, now what?

 

[Mudflat]

He has no drive gear to swap out, now what?

‘Not a TJ?

 

[mrblaine]

‘Not a TJ?

No, it is a TJ. It has the NV241OR 4-1 t-case which uses a tone ring to generate pulses to drive the speedo via the PCM.

 

[Weasellee]

Recalibrating the speedometer on a TJ should be as easy as changing the speedometer drive gear as long as you know your differential gear ratios & tire diameter. I did this when I regeared my axles & my speedometer is dead on now.
Here’s the chart that will show you which drive gear to buy.

View attachment 580080

This worked great for my Lj with the the 231 and Dave’s TJ with the 231 but once we got to Ben’s Rubicon with the 241 I looked for the next idea…. Thanks tho.

 

[John Cooper]

This worked great for my Lj with the the 231 and Dave’s TJ with the 231 but once we got to Ben’s Rubicon with the 241 I looked for the next idea…. Thanks tho.

And what conclusion did you come to??????

Wait, SpeedOHealer????

Did i guess correctly......

 

[Mudflat]

No, it is a TJ. It has the NV241OR 4-1 t-case which uses a tone ring to generate pulses to drive the speedo via the PCM.

OK. I didn’t know that. I stand corrected.
Thanks.