Speedo recalibration

[JennaBear]

Your speedo is pretty close already are you running different size tires?

 

[drperry]

You could look into finding a used hypertech programmer and compensating for different tire size...

Or, take your cluster apart and fix your needle position

 

[Bernie]

Your speedo is pretty close already are you running different size tires?

Nope, stock 225/75R16

It's just irritating to have to remember to go a few MPH above the limit to actually do the limit.

And yeah, I could pull the cluster and move the needle, but that's a PITA with all the wiring this truck has.

 

[Zembonez]

Since your difference in MPH is consistent from low speed to high, the needle is just off. Recalibration would do you no good. A speedo needing recalibrating will be off by a percentage (and therefore a growing amount).

20 MPH - off by 2 MPH
40 MPH - off by 4 MPH

Etc.

 

[Bernie]

Since your difference in MPH is consistent from low speed to high, the needle is just off. Recalibration would do you no good. A speedo needing recalibrating will be off by a percentage (and therefore a growing amount).

20 MPH - off by 2 MPH
40 MPH - off by 4 MPH

Etc.

Ah well... It would have been worth the cost.

Anything to avoid pulling that cluster and all the extra wiring under it.

 

[Zembonez]

I certainly understand! Some GM clusters allow you to remove the front bezel and then the lens. That might be all you need to do to get to the needle. Those instrument clusters plug in.

 

[Bernie]

I certainly understand! Some GM clusters allow you to remove the front bezel and then the lens. That might be all you need to do to get to the needle. Those instrument clusters plug in.

I'll have to take a closer look at it tomorrow, after I do the rear shocks, but I'm thinking I might have to pull more than that to get to it.

Then again, I could fix the fuel gauge at the same time...

(Photo attached showing the truck at idle with slightly less than full tanks)

 

[hotrodpc]

Since your difference in MPH is consistent from low speed to high, the needle is just off. Recalibration would do you no good. A speedo needing recalibrating will be off by a percentage (and therefore a growing amount).

20 MPH - off by 2 MPH
40 MPH - off by 4 MPH

Etc.

You are exactly right Bonez, and why I suggested 3 off at 65 is not bad at all, so broken down, he is 1mph off at every 20mph increment,

20mph = 1
40mph = 2
60mph = 3
80mph = 4
100mph = 5
And most speedo shops say 5% + or -. I do believe, some maybe 3%. So you'd be doing 95 if your speedo says 100mph Bern.

 

[Zembonez]

I certainly understand! Some GM clusters allow you to remove the front bezel and then the lens. That might be all you need to do to get to the needle. Those instrument clusters plug in.

I'll have to take a closer look at it tomorrow, after I do the rear shocks, but I'm thinking I might have to pull more than that to get to it.

Then again, I could fix the fuel gauge at the same time...

(Photo attached showing the truck at idle with slightly less than full tanks)

Once you pull that front surround, you can get to the lens bolts. Not as bad on those as you might expect!

 

[Bernie]

Since your difference in MPH is consistent from low speed to high, the needle is just off. Recalibration would do you no good. A speedo needing recalibrating will be off by a percentage (and therefore a growing amount).

20 MPH - off by 2 MPH
40 MPH - off by 4 MPH

Etc.

You are exactly right Bonez, and why I suggested 3 off at 65 is not bad at all, so broken down, he is 1mph off at every 20mph increment,

20mph = 1
40mph = 2
60mph = 3
80mph = 4
100mph = 5
And most speedo shops say 5% + or -. I do believe, some maybe 3%. So you'd be doing 95 if your speedo says 100mph Bern.

No, I'd be doing something really nasty in my pants because at 80 this truck is flat out, balls to the wall. The only way this thing could do 95 is off a cliff... with a tail wind.