Jeff, 31's put the Wrangler speedo right on usually. The smaller tires
are the ones that are off. The next gear up will set the speedo for
33's from what I have seen. Someone put the next gear up in my CJ7 when
they put 31's on and it was way off. Exact for 33's though.

Same for the Cherokee. The top size listed for mine is 225's. When I
went to 235's, my speedo became right.

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)

Jeff Strickland wrote:
>
> You need a new gear in your tcase.
>
> Before you blow a gasket, the gear costs a few bucks, and you can put it in
> yourself.
>
> "Cal" <codom1*IHATESPAM*@triad.rr.com> wrote in message
> news:iE7Bg.13246$4c7.12659@tornado.southeast.rr.co m...
> > 97 wrangler, just put 31's (tires) on it. Speedo says 64 when actually
> > going about 70 now. Tire guy said may make 1-2 mile per hour difference,
> > but this is lots more! Any adjustment, or just get used to it?
> >
> > thanks
> >
> > cal
> >
> >

 

Agreed.

I think the OP's testing method leaves alot to be desired. The only way to
find the accuracy of a speedo is to find a measured mile, and run it at a
fixed speed while using a stop watch, then doing the math -- 3600 (or
multiples, depending on how many miles are involved) / time (in seconds) to
travel the distance = speed.

Of course, a GPS makes this much easier, but most of us already have a stop
watch and a calculator.

3600 / 45 = 80
3600 / 52 = 70
3600 / 60 = 60

My guess is that the pace car he is using is off, and the Jeep with the new
tires is closer to being right.




"Mike Romain" <romainm@sympatico.ca> wrote in message
news:44D89450.A0A4E8BA@sympatico.ca...
> Jeff, 31's put the Wrangler speedo right on usually. The smaller tires
> are the ones that are off. The next gear up will set the speedo for
> 33's from what I have seen. Someone put the next gear up in my CJ7 when
> they put 31's on and it was way off. Exact for 33's though.
>
> Same for the Cherokee. The top size listed for mine is 225's. When I
> went to 235's, my speedo became right.
>
> 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)
>
> Jeff Strickland wrote:
>>
>> You need a new gear in your tcase.
>>
>> Before you blow a gasket, the gear costs a few bucks, and you can put it
>> in
>> yourself.
>>
>> "Cal" <codom1*IHATESPAM*@triad.rr.com> wrote in message
>> news:iE7Bg.13246$4c7.12659@tornado.southeast.rr.co m...
>> > 97 wrangler, just put 31's (tires) on it. Speedo says 64 when actually
>> > going about 70 now. Tire guy said may make 1-2 mile per hour
>> > difference,
>> > but this is lots more! Any adjustment, or just get used to it?
>> >
>> > thanks
>> >
>> > cal
>> >
>> >

 

Agreed.

I think the OP's testing method leaves alot to be desired. The only way to
find the accuracy of a speedo is to find a measured mile, and run it at a
fixed speed while using a stop watch, then doing the math -- 3600 (or
multiples, depending on how many miles are involved) / time (in seconds) to
travel the distance = speed.

Of course, a GPS makes this much easier, but most of us already have a stop
watch and a calculator.

3600 / 45 = 80
3600 / 52 = 70
3600 / 60 = 60

My guess is that the pace car he is using is off, and the Jeep with the new
tires is closer to being right.




"Mike Romain" <romainm@sympatico.ca> wrote in message
news:44D89450.A0A4E8BA@sympatico.ca...
> Jeff, 31's put the Wrangler speedo right on usually. The smaller tires
> are the ones that are off. The next gear up will set the speedo for
> 33's from what I have seen. Someone put the next gear up in my CJ7 when
> they put 31's on and it was way off. Exact for 33's though.
>
> Same for the Cherokee. The top size listed for mine is 225's. When I
> went to 235's, my speedo became right.
>
> 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)
>
> Jeff Strickland wrote:
>>
>> You need a new gear in your tcase.
>>
>> Before you blow a gasket, the gear costs a few bucks, and you can put it
>> in
>> yourself.
>>
>> "Cal" <codom1*IHATESPAM*@triad.rr.com> wrote in message
>> news:iE7Bg.13246$4c7.12659@tornado.southeast.rr.co m...
>> > 97 wrangler, just put 31's (tires) on it. Speedo says 64 when actually
>> > going about 70 now. Tire guy said may make 1-2 mile per hour
>> > difference,
>> > but this is lots more! Any adjustment, or just get used to it?
>> >
>> > thanks
>> >
>> > cal
>> >
>> >

 

Agreed.

I think the OP's testing method leaves alot to be desired. The only way to
find the accuracy of a speedo is to find a measured mile, and run it at a
fixed speed while using a stop watch, then doing the math -- 3600 (or
multiples, depending on how many miles are involved) / time (in seconds) to
travel the distance = speed.

Of course, a GPS makes this much easier, but most of us already have a stop
watch and a calculator.

3600 / 45 = 80
3600 / 52 = 70
3600 / 60 = 60

My guess is that the pace car he is using is off, and the Jeep with the new
tires is closer to being right.




"Mike Romain" <romainm@sympatico.ca> wrote in message
news:44D89450.A0A4E8BA@sympatico.ca...
> Jeff, 31's put the Wrangler speedo right on usually. The smaller tires
> are the ones that are off. The next gear up will set the speedo for
> 33's from what I have seen. Someone put the next gear up in my CJ7 when
> they put 31's on and it was way off. Exact for 33's though.
>
> Same for the Cherokee. The top size listed for mine is 225's. When I
> went to 235's, my speedo became right.
>
> 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)
>
> Jeff Strickland wrote:
>>
>> You need a new gear in your tcase.
>>
>> Before you blow a gasket, the gear costs a few bucks, and you can put it
>> in
>> yourself.
>>
>> "Cal" <codom1*IHATESPAM*@triad.rr.com> wrote in message
>> news:iE7Bg.13246$4c7.12659@tornado.southeast.rr.co m...
>> > 97 wrangler, just put 31's (tires) on it. Speedo says 64 when actually
>> > going about 70 now. Tire guy said may make 1-2 mile per hour
>> > difference,
>> > but this is lots more! Any adjustment, or just get used to it?
>> >
>> > thanks
>> >
>> > cal
>> >
>> >

 

Agreed.

I think the OP's testing method leaves alot to be desired. The only way to
find the accuracy of a speedo is to find a measured mile, and run it at a
fixed speed while using a stop watch, then doing the math -- 3600 (or
multiples, depending on how many miles are involved) / time (in seconds) to
travel the distance = speed.

Of course, a GPS makes this much easier, but most of us already have a stop
watch and a calculator.

3600 / 45 = 80
3600 / 52 = 70
3600 / 60 = 60

My guess is that the pace car he is using is off, and the Jeep with the new
tires is closer to being right.




"Mike Romain" <romainm@sympatico.ca> wrote in message
news:44D89450.A0A4E8BA@sympatico.ca...
> Jeff, 31's put the Wrangler speedo right on usually. The smaller tires
> are the ones that are off. The next gear up will set the speedo for
> 33's from what I have seen. Someone put the next gear up in my CJ7 when
> they put 31's on and it was way off. Exact for 33's though.
>
> Same for the Cherokee. The top size listed for mine is 225's. When I
> went to 235's, my speedo became right.
>
> 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)
>
> Jeff Strickland wrote:
>>
>> You need a new gear in your tcase.
>>
>> Before you blow a gasket, the gear costs a few bucks, and you can put it
>> in
>> yourself.
>>
>> "Cal" <codom1*IHATESPAM*@triad.rr.com> wrote in message
>> news:iE7Bg.13246$4c7.12659@tornado.southeast.rr.co m...
>> > 97 wrangler, just put 31's (tires) on it. Speedo says 64 when actually
>> > going about 70 now. Tire guy said may make 1-2 mile per hour
>> > difference,
>> > but this is lots more! Any adjustment, or just get used to it?
>> >
>> > thanks
>> >
>> > cal
>> >
>> >

 

I also agree. Putting 235s on my 2002 TJ put the speedo spot on.
Tomes

"Jeff Strickland" <crwlr@yahoo.com> wrote in message
news:OtSdnUKFrqyIAUXZnZ2dnUVZ_r6dnZ2d@ez2.net...
> Agreed.
>
> I think the OP's testing method leaves alot to be desired. The only way to
> find the accuracy of a speedo is to find a measured mile, and run it at a
> fixed speed while using a stop watch, then doing the math -- 3600 (or
> multiples, depending on how many miles are involved) / time (in seconds)
> to travel the distance = speed.
>
> Of course, a GPS makes this much easier, but most of us already have a
> stop watch and a calculator.
>
> 3600 / 45 = 80
> 3600 / 52 = 70
> 3600 / 60 = 60
>
> My guess is that the pace car he is using is off, and the Jeep with the
> new tires is closer to being right.
>
>
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:44D89450.A0A4E8BA@sympatico.ca...
>> Jeff, 31's put the Wrangler speedo right on usually. The smaller tires
>> are the ones that are off. The next gear up will set the speedo for
>> 33's from what I have seen. Someone put the next gear up in my CJ7 when
>> they put 31's on and it was way off. Exact for 33's though.
>>
>> Same for the Cherokee. The top size listed for mine is 225's. When I
>> went to 235's, my speedo became right.
>>
>> 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)
>>
>> Jeff Strickland wrote:
>>>
>>> You need a new gear in your tcase.
>>>
>>> Before you blow a gasket, the gear costs a few bucks, and you can put it
>>> in
>>> yourself.
>>>
>>> "Cal" <codom1*IHATESPAM*@triad.rr.com> wrote in message
>>> news:iE7Bg.13246$4c7.12659@tornado.southeast.rr.co m...
>>> > 97 wrangler, just put 31's (tires) on it. Speedo says 64 when
>>> > actually
>>> > going about 70 now. Tire guy said may make 1-2 mile per hour
>>> > difference,
>>> > but this is lots more! Any adjustment, or just get used to it?
>>> >
>>> > thanks
>>> >
>>> > cal
>>> >
>>> >
>

 

I also agree. Putting 235s on my 2002 TJ put the speedo spot on.
Tomes

"Jeff Strickland" <crwlr@yahoo.com> wrote in message
news:OtSdnUKFrqyIAUXZnZ2dnUVZ_r6dnZ2d@ez2.net...
> Agreed.
>
> I think the OP's testing method leaves alot to be desired. The only way to
> find the accuracy of a speedo is to find a measured mile, and run it at a
> fixed speed while using a stop watch, then doing the math -- 3600 (or
> multiples, depending on how many miles are involved) / time (in seconds)
> to travel the distance = speed.
>
> Of course, a GPS makes this much easier, but most of us already have a
> stop watch and a calculator.
>
> 3600 / 45 = 80
> 3600 / 52 = 70
> 3600 / 60 = 60
>
> My guess is that the pace car he is using is off, and the Jeep with the
> new tires is closer to being right.
>
>
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:44D89450.A0A4E8BA@sympatico.ca...
>> Jeff, 31's put the Wrangler speedo right on usually. The smaller tires
>> are the ones that are off. The next gear up will set the speedo for
>> 33's from what I have seen. Someone put the next gear up in my CJ7 when
>> they put 31's on and it was way off. Exact for 33's though.
>>
>> Same for the Cherokee. The top size listed for mine is 225's. When I
>> went to 235's, my speedo became right.
>>
>> 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)
>>
>> Jeff Strickland wrote:
>>>
>>> You need a new gear in your tcase.
>>>
>>> Before you blow a gasket, the gear costs a few bucks, and you can put it
>>> in
>>> yourself.
>>>
>>> "Cal" <codom1*IHATESPAM*@triad.rr.com> wrote in message
>>> news:iE7Bg.13246$4c7.12659@tornado.southeast.rr.co m...
>>> > 97 wrangler, just put 31's (tires) on it. Speedo says 64 when
>>> > actually
>>> > going about 70 now. Tire guy said may make 1-2 mile per hour
>>> > difference,
>>> > but this is lots more! Any adjustment, or just get used to it?
>>> >
>>> > thanks
>>> >
>>> > cal
>>> >
>>> >
>

 

I also agree. Putting 235s on my 2002 TJ put the speedo spot on.
Tomes

"Jeff Strickland" <crwlr@yahoo.com> wrote in message
news:OtSdnUKFrqyIAUXZnZ2dnUVZ_r6dnZ2d@ez2.net...
> Agreed.
>
> I think the OP's testing method leaves alot to be desired. The only way to
> find the accuracy of a speedo is to find a measured mile, and run it at a
> fixed speed while using a stop watch, then doing the math -- 3600 (or
> multiples, depending on how many miles are involved) / time (in seconds)
> to travel the distance = speed.
>
> Of course, a GPS makes this much easier, but most of us already have a
> stop watch and a calculator.
>
> 3600 / 45 = 80
> 3600 / 52 = 70
> 3600 / 60 = 60
>
> My guess is that the pace car he is using is off, and the Jeep with the
> new tires is closer to being right.
>
>
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:44D89450.A0A4E8BA@sympatico.ca...
>> Jeff, 31's put the Wrangler speedo right on usually. The smaller tires
>> are the ones that are off. The next gear up will set the speedo for
>> 33's from what I have seen. Someone put the next gear up in my CJ7 when
>> they put 31's on and it was way off. Exact for 33's though.
>>
>> Same for the Cherokee. The top size listed for mine is 225's. When I
>> went to 235's, my speedo became right.
>>
>> 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)
>>
>> Jeff Strickland wrote:
>>>
>>> You need a new gear in your tcase.
>>>
>>> Before you blow a gasket, the gear costs a few bucks, and you can put it
>>> in
>>> yourself.
>>>
>>> "Cal" <codom1*IHATESPAM*@triad.rr.com> wrote in message
>>> news:iE7Bg.13246$4c7.12659@tornado.southeast.rr.co m...
>>> > 97 wrangler, just put 31's (tires) on it. Speedo says 64 when
>>> > actually
>>> > going about 70 now. Tire guy said may make 1-2 mile per hour
>>> > difference,
>>> > but this is lots more! Any adjustment, or just get used to it?
>>> >
>>> > thanks
>>> >
>>> > cal
>>> >
>>> >
>

 

I also agree. Putting 235s on my 2002 TJ put the speedo spot on.
Tomes

"Jeff Strickland" <crwlr@yahoo.com> wrote in message
news:OtSdnUKFrqyIAUXZnZ2dnUVZ_r6dnZ2d@ez2.net...
> Agreed.
>
> I think the OP's testing method leaves alot to be desired. The only way to
> find the accuracy of a speedo is to find a measured mile, and run it at a
> fixed speed while using a stop watch, then doing the math -- 3600 (or
> multiples, depending on how many miles are involved) / time (in seconds)
> to travel the distance = speed.
>
> Of course, a GPS makes this much easier, but most of us already have a
> stop watch and a calculator.
>
> 3600 / 45 = 80
> 3600 / 52 = 70
> 3600 / 60 = 60
>
> My guess is that the pace car he is using is off, and the Jeep with the
> new tires is closer to being right.
>
>
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:44D89450.A0A4E8BA@sympatico.ca...
>> Jeff, 31's put the Wrangler speedo right on usually. The smaller tires
>> are the ones that are off. The next gear up will set the speedo for
>> 33's from what I have seen. Someone put the next gear up in my CJ7 when
>> they put 31's on and it was way off. Exact for 33's though.
>>
>> Same for the Cherokee. The top size listed for mine is 225's. When I
>> went to 235's, my speedo became right.
>>
>> 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)
>>
>> Jeff Strickland wrote:
>>>
>>> You need a new gear in your tcase.
>>>
>>> Before you blow a gasket, the gear costs a few bucks, and you can put it
>>> in
>>> yourself.
>>>
>>> "Cal" <codom1*IHATESPAM*@triad.rr.com> wrote in message
>>> news:iE7Bg.13246$4c7.12659@tornado.southeast.rr.co m...
>>> > 97 wrangler, just put 31's (tires) on it. Speedo says 64 when
>>> > actually
>>> > going about 70 now. Tire guy said may make 1-2 mile per hour
>>> > difference,
>>> > but this is lots more! Any adjustment, or just get used to it?
>>> >
>>> > thanks
>>> >
>>> > cal
>>> >
>>> >
>