Thanks to all, I have what I need.


Jerry



"c" <c@me.org> wrote in message
news:Wc0hc.71356$YC5.16824@twister.rdc-kc.rr.com...
>
> "Jerry Newton" <leaveme@lone.net> wrote in message
> news:40848b95_1@newspeer2.tds.net...
> > I have been googling my *** off, but can't come across the reference
chart
> > for selecting the appropriate speedo gear by tire size and gear ratio.
> > Somebody help a poor dude out here, I gotta get the speedo back into the
> > ballpark.
> >
> > Jerry
> >
>
> Just a follow up to that chart. You can do it mathematically as well using
> the formula:
>
> Gear Teeth = Axle ratio * 280 / Tire Diameter
>
> Chris
>
>

 

Raingler's chart is OK, and I've seen others, but none of them specify
which year TJ/YJ they are talking about. I've seen references
suggesting the older TJ's have a stock 27 tooth gear, but my 2004 TJ
has/had a 29 tooth gear. When I timed it on the road and did the math,
I needed a 35 tooth gear.

the math:

3600/mile time= miles per hour (mile time=time in seconds to cover a
mile)

Number of gear teeth=(old gear number)x Speedo reading/actual speed.

(ie--if the actual speed is lower than the speedo reading, you end up
with a larger gear).

I usually average the times over 2-3 miles using mile markers on the
highway.

tim

 

Raingler's chart is OK, and I've seen others, but none of them specify
which year TJ/YJ they are talking about. I've seen references
suggesting the older TJ's have a stock 27 tooth gear, but my 2004 TJ
has/had a 29 tooth gear. When I timed it on the road and did the math,
I needed a 35 tooth gear.

the math:

3600/mile time= miles per hour (mile time=time in seconds to cover a
mile)

Number of gear teeth=(old gear number)x Speedo reading/actual speed.

(ie--if the actual speed is lower than the speedo reading, you end up
with a larger gear).

I usually average the times over 2-3 miles using mile markers on the
highway.

tim

 

Raingler's chart is OK, and I've seen others, but none of them specify
which year TJ/YJ they are talking about. I've seen references
suggesting the older TJ's have a stock 27 tooth gear, but my 2004 TJ
has/had a 29 tooth gear. When I timed it on the road and did the math,
I needed a 35 tooth gear.

the math:

3600/mile time= miles per hour (mile time=time in seconds to cover a
mile)

Number of gear teeth=(old gear number)x Speedo reading/actual speed.

(ie--if the actual speed is lower than the speedo reading, you end up
with a larger gear).

I usually average the times over 2-3 miles using mile markers on the
highway.

tim

 

Raingler's chart is OK, and I've seen others, but none of them specify
which year TJ/YJ they are talking about. I've seen references
suggesting the older TJ's have a stock 27 tooth gear, but my 2004 TJ
has/had a 29 tooth gear. When I timed it on the road and did the math,
I needed a 35 tooth gear.

the math:

3600/mile time= miles per hour (mile time=time in seconds to cover a
mile)

Number of gear teeth=(old gear number)x Speedo reading/actual speed.

(ie--if the actual speed is lower than the speedo reading, you end up
with a larger gear).

I usually average the times over 2-3 miles using mile markers on the
highway.

tim

 

it's in the dealer parts catalog look up speed o gears

Jerry Newton wrote:

> I have been googling my *** off, but can't come across the reference chart
> for selecting the appropriate speedo gear by tire size and gear ratio.
> Somebody help a poor dude out here, I gotta get the speedo back into the
> ballpark.
>
> Jerry

 

it's in the dealer parts catalog look up speed o gears

Jerry Newton wrote:

> I have been googling my *** off, but can't come across the reference chart
> for selecting the appropriate speedo gear by tire size and gear ratio.
> Somebody help a poor dude out here, I gotta get the speedo back into the
> ballpark.
>
> Jerry

 

it's in the dealer parts catalog look up speed o gears

Jerry Newton wrote:

> I have been googling my *** off, but can't come across the reference chart
> for selecting the appropriate speedo gear by tire size and gear ratio.
> Somebody help a poor dude out here, I gotta get the speedo back into the
> ballpark.
>
> Jerry

 

it's in the dealer parts catalog look up speed o gears

Jerry Newton wrote:

> I have been googling my *** off, but can't come across the reference chart
> for selecting the appropriate speedo gear by tire size and gear ratio.
> Somebody help a poor dude out here, I gotta get the speedo back into the
> ballpark.
>
> Jerry