I upgraded to alum canyon wheels and 30" tires from 195/75R15 steel
wheels and tires. Does my speedometer need to be adjusted?

Has anyone done this?

Tom

 

Jeep speedometers generally read slow stock, you are probably closer to the
correct reading now than before. (but still slow)


"tk" <thomas_kessler@comcast.net> wrote in message
news:1169848358.200219.234310@j27g2000cwj.googlegr oups.com...
>I upgraded to alum canyon wheels and 30" tires from 195/75R15 steel
> wheels and tires. Does my speedometer need to be adjusted?
>
> Has anyone done this?
>
> Tom
>

 

Jeep speedometers generally read slow stock, you are probably closer to the
correct reading now than before. (but still slow)


"tk" <thomas_kessler@comcast.net> wrote in message
news:1169848358.200219.234310@j27g2000cwj.googlegr oups.com...
>I upgraded to alum canyon wheels and 30" tires from 195/75R15 steel
> wheels and tires. Does my speedometer need to be adjusted?
>
> Has anyone done this?
>
> Tom
>

 

Jeep speedometers generally read slow stock, you are probably closer to the
correct reading now than before. (but still slow)


"tk" <thomas_kessler@comcast.net> wrote in message
news:1169848358.200219.234310@j27g2000cwj.googlegr oups.com...
>I upgraded to alum canyon wheels and 30" tires from 195/75R15 steel
> wheels and tires. Does my speedometer need to be adjusted?
>
> Has anyone done this?
>
> Tom
>

 

Jeep speedometers generally read slow stock, you are probably closer to the
correct reading now than before. (but still slow)


"tk" <thomas_kessler@comcast.net> wrote in message
news:1169848358.200219.234310@j27g2000cwj.googlegr oups.com...
>I upgraded to alum canyon wheels and 30" tires from 195/75R15 steel
> wheels and tires. Does my speedometer need to be adjusted?
>
> Has anyone done this?
>
> Tom
>

 

You need to find a measured mile or use a GPS to see what it is now. I
have found that Jeep speedometers are calibrated for the largest stock
tire size so yours might be right on now.

Our XJ's became right on with 235's which are almost 30" tall.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

tk wrote:
> I upgraded to alum canyon wheels and 30" tires from 195/75R15 steel
> wheels and tires. Does my speedometer need to be adjusted?
>
> Has anyone done this?
>
> Tom
>

 

You need to find a measured mile or use a GPS to see what it is now. I
have found that Jeep speedometers are calibrated for the largest stock
tire size so yours might be right on now.

Our XJ's became right on with 235's which are almost 30" tall.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

tk wrote:
> I upgraded to alum canyon wheels and 30" tires from 195/75R15 steel
> wheels and tires. Does my speedometer need to be adjusted?
>
> Has anyone done this?
>
> Tom
>

 

You need to find a measured mile or use a GPS to see what it is now. I
have found that Jeep speedometers are calibrated for the largest stock
tire size so yours might be right on now.

Our XJ's became right on with 235's which are almost 30" tall.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

tk wrote:
> I upgraded to alum canyon wheels and 30" tires from 195/75R15 steel
> wheels and tires. Does my speedometer need to be adjusted?
>
> Has anyone done this?
>
> Tom
>

 

You need to find a measured mile or use a GPS to see what it is now. I
have found that Jeep speedometers are calibrated for the largest stock
tire size so yours might be right on now.

Our XJ's became right on with 235's which are almost 30" tall.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

tk wrote:
> I upgraded to alum canyon wheels and 30" tires from 195/75R15 steel
> wheels and tires. Does my speedometer need to be adjusted?
>
> Has anyone done this?
>
> Tom
>

 

I think your speedo will read SLOW now. When it reads 60, yoiur actual speed
will be 65, for example. (You'll need to take measurements to arrive at the
actual error.)

Your original tires were about 26.5 inches in diameter, the new tires will
be closer to 29.5. This gives a diameter increase of about 3 inches, which
will give a circumference increase of around 9 inches.

You will need to calibrate the speedo as a result. It ought to be as easy as
swapping a gear on the speed sensor in the transmission, or wherever they
mounted the sensor on your truck.



"tk" <thomas_kessler@comcast.net> wrote in message
news:1169848358.200219.234310@j27g2000cwj.googlegr oups.com...
>I upgraded to alum canyon wheels and 30" tires from 195/75R15 steel
> wheels and tires. Does my speedometer need to be adjusted?
>
> Has anyone done this?
>
> Tom
>