Stock Speedo + 33"s = ?

[Boze]

I was wondering how much faster I am going actually going with the new 33's compared to what the speedo says. I know there is a hoo****y you can install that gives you the adjusted speed, but I have more important stuff to spend my hard earned dough on, (like and SYE and lockers :shades. Anybody have a guesstimation of what I should add to what the speedo says?

 

[Bounty__Hunter]

Simply change the speedo gear to correct your speedometer, they run from $15-$25 and takes about 5 minutes to change.
Changing Your Jeep Speedometer Gear
http://www.go.jeep-xj.info/HowtoSpeedoGears.htm

I've got quite a few speedo gears on hand if you're able to determine which one you need. Use the charts on the above pages to determine which gear works with your gear ratio and tire size.

 

[southtj]

I can't answer your question but if you or a buddy has a GPS that would give you an accurate read of your true speed.

 

[TerryMason]

Do you guys think a speedo change is needed for 31's?

 

[Bounty__Hunter]

Yes. You also want a correct reading as the ECM uses the VSS input in its operation.

 

[Boze]

And for us Dumb dumbs ECM and VSS would be... what exactly?

 

[pitbulld45]

Good to know Thanks Bounty.

 

[SteelHeadz]

The VSS(Vehicle Speed Sensor ) is an Input to the ECM(Electronic Control Module) and ABS (Antilock Braking System) Module if equipped. If the VSS signal is not true to actual speed, it will greatly affect ABS engagement, Transmission shift points(if automatic).. That's a Good Info. from Bounty_Hunter, I didn't know that..i learn something new everyday..

 

[TerryMason]

Just an FYI - The Jeep dealer near me can order a new speedo gear for $80.35, but Quadratec sells them for just $20.

 

[Boze]

HA! That's sounds about right for the Dealer's 465,892% markup! Scumbags. Thanks for all the help guys.

 

[redwrangler02]

I have 33"s on my 02 tj and ive driven next to friends while talkin to them on the phone and figured out that my speedo was aroung 5mph slower than i was actually driving. So, if my speedo said 50, i am actually going about 55. Get a friend to drive beside you at equal speed and see how fast theyre going.

 

[Bounty__Hunter]

That'll get you close, but you are relying on the accurateness of your friend's speedo and any minute change in speed. I've found a GPS in the rig is a lot more accurate.

Tacoma Speedometer - Home is a great company to get speedo gears from, cheap and fast.

 

[southtj]

Do you guys think a speedo change is needed for 31's?

When I put 31's on mine I checked it with a gps to know how far off it was and it was dead on. I've checked it with another gps and now a second set of 31's and still dead on.

 

[TerryMason]

I ordered a new one from Quadratec, waited a day then my order was canceled because they are no longer in stock

 

[Bounty__Hunter]

Tacoma Speedometer. Or I may have what you need. Which gear?

 

[TerryMason]

The chart says I need a 33 tooth gear (3.73 with 31s)

Any idea what the stock gear or tire size would be on my 2005 SE / auto?

 

[Bounty__Hunter]

Probably a 35 or 36. It's one 1/2" bolt to pull the speedo sending unit and check out the gear, the tooth count is stamped into the gear.