is there a need to have speedomoter done?

[Duality]

you guys running 33's, did you get your speedo adjusted? If not how far off are you?

Thanks for your time.

[SHNIPE]

4cyl, 33s, 410s and i was off about 8mph at 60mph never changed the speedo gear. Just checked it with one of those construction signs taht tells you your speed

[Bilt4Comfort]

V6, 35s, 4:10s and we're doing 70 when the speedo reads 65.

[RandyT]

never changed mine, just use my gps for acurate speed reading

[Crawldit]

lol you mean you're supposed to adjust your speedo :pinch: Mines off by 13%and has been for the past year and a half. After awhile you get good at doing the math in your head so you don't get busted for speeding all the time. When my speedo reads around 57-58 I'm really doing 65.

[Duality]

if it is that far off I need to change it. Your mileage will never be correct on the vehicle.

it is electronic on 03' right?

[TRLR8TDTJ]

What gears are you running?

Kyle

[Duality]

4.10... stock

[BKMCSO]

v6 4.56 gears and 33's it's about 9 mph slower than the speedo reads if i'm going 70 i'm really going 61.

[TRLR8TDTJ]

I have a 34, 35, 37 tooth speedo gear you might need the 36 though. The gears are not that much and very simple to install. See what gears four wheelers recommends. You are more than welcome to one of these if it will work. You moght be on the other side of the country though.

Kyle

[Andrew F]

I had 4.88s and 32s without the correct speedo gear in it a while ago. It read 96 mph when I has going 69mph. The engine cuts off at 96mph, made going down hills fun.

[neZZr]

I reprogrammed mine for the 33s, though it still read about 1-2mph slow. I attribute that to my tires not quite measuring up to a true 33" and the stock speedo not being that accurate to begin with.

Now that they're half worn, I'm a good 5mph off.

[Bilt4Comfort]

So we just put 35s on the JK and have the stock gears still....what do we need to do to make it accurate again? A new cable? Please advise.

[Duality]

on the JK my understanding is that is electric, as it is on all 02' and newer (someone correct me if I'm wrong.) So all it would take is a trip to Dick's Speed-o Tach on 7th Street and Campbell and about $100.

[Bilt4Comfort]

So if we're going faster than the speedo says, is the odometer showing + or - on the mileage?

[Duality]

If you are running + size tires, one revolution = more distance traveled, but your speedo sees one revolution as one revolution so you will be going faster than your speedo says.

[neZZr]

on the JK my understanding is that is electric, as it is on all 02' and newer (someone correct me if I'm wrong.) So all it would take is a trip to Dick's Speed-o Tach on 7th Street and Campbell and about $100.

For TJs, only the Rubicon is electronic. All other TJs use the speedo gear, including '03+ non-Rubicon.

I haven't tried it on a JK yet, but I imagine it can be adjusted by the dealer (to a point) just like my TJ was. I can't speak for other dealers, but where I work we wouldn't charge anything close to $100.

Unfortunately there are only a few choices that can be programmed into the cluster. Tire size could only be changed up to 33 or 35, and gear ratio had even fewer choices. Outside of that you just have to use an equivalent tire/gear combo to get the right speed.

[Bilt4Comfort]

If you are running + size tires, one revolution = more distance traveled, but your speedo sees one revolution as one revolution so you will be going faster than your speedo says.

OK...so my odometer will be adding less miles than actually traveled?

[KennethS]

Yep. You looking to keep the mileage low for resale (or warranty) purposes?

[Duality]

correct.

My 91' Yota with 38.5" swampers had 68K miles. Hmmm, I wonder why!

[Andrew F]

on the JK my understanding is that is electric, as it is on all 02' and newer (someone correct me if I'm wrong.) So all it would take is a trip to Dick's Speed-o Tach on 7th Street and Campbell and about $100.

Non rubi TJs just need a new speedo gear. Call 4 Wheelers or the dealership.

http://www.stu-offroad.com/engine/speedo/speed1.htm

[sms1688]

4.88's 35" tires and when it says I am doing 90 I am doing about 70. so I am a tad off then again I dont care how fast I am going my good looks gets me out of a ticket everytime.

[ltklein]

I have an '05 Rubi w/ 33's. Ran 3 mph off consistently. Put in a TruSpeed and dialed it in with my GPS. All good now..

If ya got a gear, Quadratec has a chart for the speedo gear you need that makes it pretty simple...