Anyway to recalibrate speedo besides programmer

[Kevn]

Thinking of putting my truck back to stock and getting rid of my bullydog but keeping the bigger tires

 

[BlownGP]

I've read the dealership can do it. For a price I assume.

 

[VolsRam]

Any reason you want to get rid of the tuner?

 

[Kevn]

Moved out to BC and only use my truck now to haul the sleds and quads to the bush, all short trips. Would like to do some perf mods to the rzr instead. Gonna sell the programmer, vararam and 87mm tb.

 

[VolsRam]

In that case, do like I did in my old truck. Find one of those speed traps that shows your speed while driving and determine how off it is. My truck went 5 mph slower than the speedo read. So I knew I could drive 5 mph faster (according to my speedo) to be in the speed limit. Plus, if they're only short trips, it shouldnt be a big deal.

 

[Gardenfan]

A good dealership will charge you little to do so. Like 25 bucks, and it's done. Takes 5 minutes.

 

[sausec17]

What size are your tires? Dealership cant re-calibrate anything over stock sizes

 

[WhiteExpress]

I have this strange feeling there is a lot of opinion in the thread.

I have heard both ways, I have never personally attempted to get my speedo recalibrated at a dealership.

We aware, that just because at X MPH your speedometer if off by 5MPH, does not mean it's off 5MPH across the board. It's all a function of circumference.

 

[Lawhand]

math is fun

 

[sausec17]

A good dealership will charge you little to do so. Like 25 bucks, and it's done. Takes 5 minutes.

You've personally had this done to a 4th gen ram 1500?

 

[Kevn]

Interesting...mines a 2500, not that it would make a difference though

 

[sausec17]

Yea shouldnt matter.

From 2 dealerships I've been to and 3 others I've called, they can only adjust the speedometer to different stock size tires.

 

[BlownGP]

In that case, do like I did in my old truck. Find one of those speed traps that shows your speed while driving and determine how off it is. My truck went 5 mph slower than the speedo read. So I knew I could drive 5 mph faster (according to my speedo) to be in the speed limit. Plus, if they're only short trips, it shouldnt be a big deal.

Once you have the tires size, they have calculators to determine how fast or slow you are really going.

 

[Gardenfan]

You've personally had this done to a 4th gen ram 1500?

Yes to my 2012. I only went from the stock 31s to 33s. Not sure if they can do bigger though, forgot about that. Wouldn't hurt to call and ask. I had a diablo at the time and still do but support had just arrived and tire adjustment didn't work yet.

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[sausec17]

Yes to my 2012. I only went from the stock 31s to 33s. Not sure if they can do bigger though, forgot about that. Wouldn't hurt to call and ask. I had a diablo at the time and still do but support had just arrived and tire adjustment didn't work yet.

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Ok. That makes sense. Those are both stock sizes.

 

[Kevn]

I'm just running 275/70r18, roughly a 33", probably wont make much of a difference. I'll check with the dealer here
Thanks for the info

 

[BlackRamHemi]

I'm just running 275/70r18, roughly a 33", probably wont make much of a difference. I'll check with the dealer here
Thanks for the info

What was your stock tire size?

I believe LT275/70R18E is a stock size on the Laramie 2500's

if your stock size was 245/70R17 then the difference is 8.7% (reads too slow if tires are larger than stock)
(Speedo will read approx 87 mph when your actually doing 100 mph) (fewer revolutions per mile)
....half of that for 50 mph (43.5) since its a percentage and not a constant.

 

[Kevn]

Stock was 265/70R17 (31.6") compared to what I have now 275/70R18 (33.2")

 

[BlackRamHemi]

That's about 5%

Some times stock if off by that much,
so you probably dont' need to do anything.

Like I said borrow a hand held GPS or find a set of highway mile markers
to confirm just how far out your are first. might not be enough to worry about.
(at 50 MPH on your speedo, you'd be moving about 52.5 by my calculation)

Link: http://www.miata.net/cgi-bin/tirescgi

 

[huff2462]

If you have a smartphone, you can download a speedometer app for free. They use GPS to measure your speed and they're surprisingly accurate.

At least that'll let you know for far off you may be.

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