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Topic Review (Newest First)
08-15-2014 01:28 PM
Digger84 Works better from smaller so want a tooth count that if increased by 1/3 gives 35 so you

X. * 1.33 = 35
Same as X * 4/3 = 35
So

X= 35*3/4 = 105/4 = 26.25 go for 26 tooth gear
08-15-2014 10:47 AM
Digger84 So if you have a 35 tooth and you want speedo to read 33% faster you need 33% less teeth so you would want 23 tooth gear

Only need to know three things
Current tooth count and real vs indicated speed
The faster the better because at faster speeds small errors deciding where speedo needle is pointing are a smaller percent of total
08-15-2014 10:42 AM
Digger84 Screw the charts do the math

If you want your speedo to read x% higher get a gear with x% less teeth than your current gear

If you want your speedo to read y% lower get a speedo gear with y% more teeth
08-15-2014 09:57 AM
RobertTj98 Instal went great, then I checked it using a gps and it is worse than before. I got a 35 tooth gear because of 33's and 4.11. Lined up the numbers when I put the housing back into the TCase and it's worse than it was stock! Any ideas? Speedo says I'm going 30 when I am actually going 40.
08-07-2014 01:53 AM
CrimsnTide Anyone willing to trade a 39 tooth for what I have?

(I don't know what I have, but still need a 39 tooth.)
(Also need a 32 tooth for a friend)
03-11-2014 08:28 PM
Tiaan Hi guys, I have done everything the thread shows to the T. I am still off by 10 mph fast on my speedometer. I have d44 with 3.73 and 33s so I should run the 31 tooth speedo gear. The tab on the diff cover says it is a 3.73 but iam starting to question that now. Any advice would be greatly appreciated .
01-03-2014 06:09 PM
Sourmash Ok, so I reread the thread and found the ratio. I've got a '97 TJ, Automatic, Running 33" Toyo's, with 3.07 gear ratio. I see on the chart in this thread that it says 26 tooth, my question is almost every other chart I've seen doesn't show a size for the 3.07 and 33" tires, I dont fully understand gear ratios but can someone explain in layman's terms why they wouldn't have one for that combination? Is the 26 tooth the closest I will get to accuracy?
01-03-2014 03:49 PM
Sourmash At the risk of looking like a total idiot, can someone tell me how to confirm the gear ratio?
10-02-2013 05:14 PM
JT42 Ahhhh yeah I bet it is security since I pulled up the page from my work laptop. Appreciate the answer and the reposted picture. Cant wait to get this done. I will order the new gear tonight!
10-02-2013 04:20 PM
distortedtj Here is an attached photo of the ratio line up.

Find the numbers on your speedo falls under "tooth count".
Line them up at the 5 o'clock position of the hole. "also lines up with where the wishbone clamp sets in the plastic housing.

Since you have a 39tooth gear yours should look like this.....
10-02-2013 04:13 PM
distortedtj
Quote:
Originally Posted by JT42 View Post
Wow this is awesome! When I re-geared my Dakota I had to have the dealership do a flash and since they didnt have a chart it was trial and error until we got it right.

Since I have an 03 TJ Sport with 33's and 4.56's I understand I will need a short shaft 39 tooth. My only question is, did the original post intially have pictures to go along with the write-up or was it always just the step-by-step instructions? I am not sure I fully understand the rotation deal and think pics would help me before I tackle this.
There is still pictures with the original posts. If you can not see them try to adjust your security settings. All photos are linked from Photobucket.
10-02-2013 03:18 PM
JT42 Wow this is awesome! When I re-geared my Dakota I had to have the dealership do a flash and since they didnt have a chart it was trial and error until we got it right.

Since I have an 03 TJ Sport with 33's and 4.56's I understand I will need a short shaft 39 tooth. My only question is, did the original post intially have pictures to go along with the write-up or was it always just the step-by-step instructions? I am not sure I fully understand the rotation deal and think pics would help me before I tackle this.
07-23-2013 03:48 PM
InvertChaos
Quote:
Originally Posted by Rewind View Post
Yes it's a TJ.....According to the Vin I have a 3.07 axle ratio.
I would double check the ratio yourself. According to the chart, they don't make a gear small enough for you...

You've got a 34.4" tire http://www.quadratec.com/jeep_knowle...article-46.htm
07-23-2013 03:35 PM
Rewind Yes it's a TJ.....According to the Vin I have a 3.07 axle ratio.
07-23-2013 03:22 PM
InvertChaos
Quote:
Originally Posted by Rewind View Post
How do I tell which speedo gear I need to compensate for the larger tires (315/70-17)
There is a chart floating around somewhere. You have a TJ correct? Also what gears do you have in the diffs?
07-23-2013 03:18 PM
Rewind How do I tell which speedo gear I need to compensate for the larger tires (315/70-17)
07-23-2013 01:43 PM
AlexS put your transfer case in neutral. jack up the rear end of your jeep. Spin your rear tire around once and count the number of times the drive shaft spins. That will roughly tell you what gears you have
07-23-2013 12:22 PM
Rewind
Quote:
Originally Posted by AlexS View Post
Your PO had to have regeared if your running 35s on 3.07. I have 33s on 3.73 and its a bit sluggish!
Maybe not.........I think mine is a bit sluggish too.
07-23-2013 12:03 PM
AlexS
Quote:
Originally Posted by Rewind View Post
Ok, this is interesting........there is no speedo gear tooth count listed for my set up. I have (according to my vin) a 3.07 axle ratio and I'm running 35's. Any ideas on which one I need?
Your PO had to have regeared if your running 35s on 3.07. I have 33s on 3.73 and its a bit sluggish!
07-23-2013 11:15 AM
Rewind Ok, this is interesting........there is no speedo gear tooth count listed for my set up. I have (according to my vin) a 3.07 axle ratio and I'm running 35's. Any ideas on which one I need?
07-20-2013 10:20 PM
RevCo666
Quote:
Originally Posted by distortedtj View Post
Yes Sir.
Thanks for clarifying that! I know running 31's is messing my milage readings but its always better to be accurate non the less. I'll check at parts store for prices since everywhere else seems to want to charge me 25$ for shipping and up for a 40$ part online.
07-20-2013 09:58 PM
distortedtj
Quote:
Originally Posted by RevCo666 View Post
So in my case I'm looking at a short shaft version? 2001 TJ
Yes Sir.
07-20-2013 03:56 PM
RevCo666
Quote:
Originally Posted by distortedtj View Post
Year and model of the T-case.

ALL TJ np231j cases use a short shaft.
All TJ rubicon np241 do NOT use a gear driven speedo. But a tone ring. You must have a dealer reprogram the comp to the correction or use a aftermarket programmer to adjust it yourself. "i'd use the programmer'.
So in my case I'm looking at a short shaft version? 2001 TJ
07-20-2013 01:23 PM
distortedtj
Quote:
Originally Posted by RevCo666 View Post
How does one know if you need a short or long shaft version of a speedo gear??
Year and model of the T-case.

ALL TJ np231j cases use a short shaft.
All TJ rubicon np241 do NOT use a gear driven speedo. But a tone ring. You must have a dealer reprogram the comp to the correction or use a aftermarket programmer to adjust it yourself. "i'd use the programmer'.
07-16-2013 02:05 PM
RevCo666 How does one know if you need a short or long shaft version of a speedo gear??
04-17-2013 12:16 AM
MissingMyYj
Quote:
Originally Posted by MissingMyYj View Post
let's bring back a dead thread....

I just bought a 1993 jeep wrangler with a 4.0l with 35" tires and 4.11 gears. I wondered if my speedo gear was swapped out so I crawled under it and yanked the gear out. Turns out it was changed to a number 35; this doesn't line up with the chart though.



How will this affect my current millage and mpg? Should I swap it for a 34? When I used my gps and compared it to my speedometer I am going 1.11 miles for ever 1 mile shown on the speedo.

Thanks!
Actually i have 4.10 gears in the rear
04-16-2013 10:01 PM
MissingMyYj let's bring back a dead thread....

I just bought a 1993 jeep wrangler with a 4.0l with 35" tires and 4.11 gears. I wondered if my speedo gear was swapped out so I crawled under it and yanked the gear out. Turns out it was changed to a number 35; this doesn't line up with the chart though.



How will this affect my current millage and mpg? Should I swap it for a 34? When I used my gps and compared it to my speedometer I am going 1.11 miles for ever 1 mile shown on the speedo.

Thanks!
03-08-2013 08:56 PM
871kevin Does anyone know if there are numbers on speedos that are cable not electronic? I don't know what to turn it to
02-28-2013 04:47 PM
distortedtj
Quote:
Originally Posted by Sinister6 View Post
So this will NOT work if you have a JK or the RUBICON version of the TJ? Just want to clarify this....I saw it won't work for a JK but seemed to miss the RUBICON...
I have an 06 Rubicon manual transmission...
-EXCELLENT WRITE-UP BTW!
Correct. The Rubicon does NOT use a speedo gear in the t-case tail housing. To correct the speedo with a rubi t-case you will have to purchase a programer to recal it or have a dealer reflash the computer to correct it.

"Tru-speed" I believe it is called made by superlift is a decent speedo recalculator.
02-28-2013 03:32 PM
Sinister6 [QUOTE=distortedtj;2615886]As noted before. The Rubicon 241 t-case uses a tone ring. You can only fix the speedo with a computer flash or programmer that has the option to adjust the speedo gear for tire size.



So this will NOT work if you have a JK or the RUBICON version of the TJ? Just want to clarify this....I saw it won't work for a JK but seemed to miss the RUBICON...
I have an 06 Rubicon manual transmission...


-EXCELLENT WRITE-UP BTW!
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