Topic: nice speedo!

[Loke Groundrunner]

well,...lazy fargin' bastadge that i am...i FINALLY got around to changin' my speedo gear. earlier this year i'd installed 31" BFG AT treads and really thought my mileage had taken a gigantic pooper (i was "guestimating" the effect of the larger tire on my mileage). my FIRST tankfull (since changing the gear) netted me an ACTUAL 20 mpg (with 80% city, 20% hwy). Jesus...what a relief!  i'd thought i was baggin' about 13-14 mpg's. i am nominating myself for "Numb Nutz of the Year" for not changing out the gear sooner. LESSON LEARNED: Change out yer Friggin Speedo when you lop on bigger chunks of rubber!! INCIDENTALLY,..the speedo gear swap (for any other "relative" noobs out there) is embarrasingly easy to do  (although the first write-up i found was a bit misleading on the postioning of the gear in the socket). NOW...on to the hard-top insulation and the cargo rack. cheers! 

[Jeffy]

well,...lazy fargin' bastadge that i am...i FINALLY got around to changin' my speedo gear. earlier this year i'd installed 31" BFG AT treads and really thought my mileage had taken a gigantic pooper (i was "guestimating" the effect of the larger tire on my mileage). my FIRST tankfull (since changing the gear) netted me an ACTUAL 20 mpg (with 80% city, 20% hwy). Jesus...what a relief!  i'd thought i was baggin' about 13-14 mpg's. i am nominating myself for "Numb Nutz of the Year" for not changing out the gear sooner. LESSON LEARNED: Change out yer Friggin Speedo when you lop on bigger chunks of rubber!! INCIDENTALLY,..the speedo gear swap (for any other "relative" noobs out there) is embarrasingly easy to do  (although the first write-up i found was a bit misleading on the postioning of the gear in the socket). NOW...on to the hard-top insulation and the cargo rack. cheers! 

You mean you didn't use MY writeup? 

[Loke Groundrunner]

You mean you didn't use MY writeup? 

apologies, Jeffy...i reckon i didn't search the "banger" forums thoroughly enough.

P.S. that emoticon () looks like the "Blue Man Group" doing a Don King impersonation. 

[jcoleman]

just out of curiosity what tooth count did you use?

[Bounty Hunter]

The wrong speedo gear can affect your mileage as it sends the wrong signal to the ECM, a signal needed for the engine to run at optimum performance.

[lax22]

So according to the chart in jeffy's post, If i have stock 4.11 gears and 33 inch tires i should be running a 35tooth gear? I cant tell if i am reading the chart right or not Also i have a 97. How do i know if i have a short or long shaft.....and i dont mean that shaft

[GreenBayjeeper]

To chime in with queries of my own....

I have a 98 tj.  How do I determine what gears I have, or the existing speedo gear tooth count?  My tj is bone stock as far as drive line goes, and the new meats are Goodyear MT/a 31s.

[Jeffy]

To chime in with queries of my own....

I have a 98 tj.  How do I determine what gears I have, or the existing speedo gear tooth count?  My tj is bone stock as far as drive line goes, and the new meats are Goodyear MT/a 31s.

More then likely you ahve 4.10/4.11 gears if it's a manual.  Automatics come with 3.73's.  You can double check by looking at the differential cover.  There is a metal tag on the diff cover with some numbers on it.  In the middle will be the three numbers seperated from the others.  307, 354, 373 or 410 usually.  Those are your gear ratios.  If you have 410's then you most likely have a 41T speedometer gear.

[GreenBayjeeper]

Thanks! Again.