How far off is your speedometer?

[naford]

Speedo reads 3 to 5 mph faster than I'm actually going. Checked by GPS. What interesting is that a computer hooked to the OBDII connector shows right on the money.

 

[Il Brutto]

1 mph slow at 35. Not bad considering I put on a different tire size and a different rear end out of the 2.9 '88

 

[theAntihero]

Hmm, so all GPS units have a vehicle speed function in them? Im having a bit of problems with my speedo and wouldnt mind having a GPS in my work truck.

It looks like there is one for under 40 bucks at Walmart.

 

[shane96ranger]

My speedo reads fast by about 6%, and thats with larger than stock tires...

Here we are..... it's a percentage folks.

It doesn't just read XX mph faster at all speeds. It's a percentage at all speeds. At the 6% stated above, your speedo would read 3mph off at 50, and 6mph off at 100.

 

[4.0B2]

Here we are..... it's a percentage folks.

It doesn't just read ___ mph faster at all speeds. It's a percentage at all speeds. At the 6% stated above, your speedo would read 3mph off at 50, and 6mph off at 100.

yep..

however, mine is right. With a little math and the right gear in the t/case.. it works just fine.

 

[shane96ranger]

yep..

however, mine is right. With a little math and the right gear in the t/case.. it works just fine.

Yep, with a little research it's easy to correct it.

 

[Brownie Mobile]

Mines on the dot even after bigger tires weird thing is it was on the dot with the PO's smaller tires too lol i have no idea why that happened, i know im less than 1mph away cause like somebody else said i just went by those things that tell you your speed.

 

[triumphrider-1]

Yep, with a little research it's easy to correct it.

Yeah, I'm just not in that much of a hurry to correct it. The other t-cases and axles going in will be correct though.

 

[Thed]

Always slow, I just use my Ultra Gauge instead. Cheaper and WAY more useful than a GPS.

Can a GPS tell you how much air is going through your MAF? Cause Ultra Gauge can.
Can a GPS read and erase CEL codes? Cause Ultra Gauge can.

I think you can get what I'm gettin at here...

 

[4.0B2]

Always slow, I just use my Ultra Gauge instead. Cheaper and WAY more useful than a GPS.

Can a GPS tell you how much air is going through your MAF? Cause Ultra Gauge can.
Can a GPS read and erase CEL codes? Cause Ultra Gauge can.

I think you can get what I'm gettin at here...

What are you saying??
You're gonna buy me one??

 

[Thed]

What are you saying??
You're gonna buy me one??

Aww I would but Ultra Gauges work only on OBD-II vehicles, as it plugs in to your diagnostic port. Sorry bud.

http://www.ultra-gauge.com/ultragauge/index.htm

 

[David88]

Hmm, so all GPS units have a vehicle speed function in them? Im having a bit of problems with my speedo and wouldnt mind having a GPS in my work truck.

It looks like there is one for under 40 bucks at Walmart.

Most GPS units I have seen do. They would be more accurate since it's tracking how fast the unit moves across the surface via sat. Not much that can throw it off. Mine will even give me elevation, carbon footprint, MPG and has an ecobooster. The eco booster is a little leaf that changes color based on fuel economy. Red=worst, Orange=bad, yellow=okay, and geen=best. Then it fine tunes it with a number. I can usually run along at 96%.

Using it, I was able to get 22mpg from my Jeep on the hwy instead of the 20 it was rated for and 18mpg city instead of the 15 it was rated.

 

[SierraCanine]

Mines of by roughly 3%, after the larger tires and speedo gear change, so I just make sure a drive no faster than 62 on the freeway ( limit 65) and cruise right along. Otherwise I drive 1-2 under if I'm over 35.

I've tried the gps and it is spot on. Also for those of you who may be wondering an error of +5% is acceptable for factory vehicles.

 

[theAntihero]

Most GPS units I have seen do. They would be more accurate since it's tracking how fast the unit moves across the surface via sat. Not much that can throw it off. Mine will even give me elevation, carbon footprint, MPG and has an ecobooster. The eco booster is a little leaf that changes color based on fuel economy. Red=worst, Orange=bad, yellow=okay, and geen=best. Then it fine tunes it with a number. I can usually run along at 96%.

Using it, I was able to get 22mpg from my Jeep on the hwy instead of the 20 it was rated for and 18mpg city instead of the 15 it was rated.

Sweet! Im gonna have to rip apart the dash here shortly as my tach and speedo are going haywire but god do i want to put that off for as long as possible.

 

[4.0B2]

Aww I would but Ultra Gauges work only on OBD-II vehicles, as it plugs in to your diagnostic port. Sorry bud.

http://www.ultra-gauge.com/ultragauge/index.htm

ok? buy me one anyways... I use a 2004 f150 for my towing and daily driver sometimes.