Speedometer correction

T

TexasA&M

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Getting ready to put a lift and step up to 285s on my '05 4Runner. For you guys have have put bigger tires on, have any of you corrected the speedo? This is my wifes car, so I'd rather have the speedo be correct than just do the math in my head (I already do this on my '86 Chevy).

How do you go about correcting the speedo? Do you have to take it to Toyota?
 
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TexasA&M said:
Getting ready to put a lift and step up to 285s on my '05 4Runner. For you guys have have put bigger tires on, have any of you corrected the speedo? This is my wifes car, so I'd rather have the speedo be correct than just do the math in my head (I already do this on my '86 Chevy).

How do you go about correcting the speedo? Do you have to take it to Toyota?
Click to expand...

Take it to a reputable shop and ask for the speedo to be recalibrated.
 
Very interesting. Thanks for the link. Anyone have a write up about pulling the instrument cluster out? I've been wanting to drop in a cluster from a limited anyway (because of the cooler gauges), so this might be a good time to do it.
 
TexasA&M said:
Getting ready to put a lift and step up to 285s on my '05 4Runner. For you guys have have put bigger tires on, have any of you corrected the speedo? This is my wifes car, so I'd rather have the speedo be correct than just do the math in my head (I already do this on my '86 Chevy).

How do you go about correcting the speedo? Do you have to take it to Toyota?
Click to expand...

Mike07SE said:
^^^ Negative. Read this article.

Speedometer correction - Toyota 120 Platforms Forum
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I've been running 285's for about a year or so now,i use my GPS to verify my actual speed for reassurance.... :police: I noticed the speed indicated on the speedometer is approximately 4-5 mph SLOWER than what is indicated on my GPS unit,due to the taller wider tires.I also agree on the Speedo Healer thread that was linked above.
 
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So this is weird, I think at one point in her life, someone had bigger tires on my truck but switched to 31x10.5x15's because my speedo is doing the exact opposite of everyone elses. It says that I'm going 4-5mph faster than I actually am. (I pretty much use my gps as a speedo) Anybody have any idea how to re-calibrate the speedo if you don't know the old tire size?
 
Getting closer to doing this mod and wondering if anyone out here has instructions on how to pull the main cluster out. I read through the Speedo correction thread link above several times, but I'm still confused on how to get the cluster out. All it says is 'pop out the bezel' and then to remove a couple of screws.

Also, anyone know if an instrument cluster from another vehicle can be plugged in without issue? I want to put a limited cluster in my vehicle because of the cooler gauge needles.
 
I wonder if the dealer could perform this through the obd connection. There has to be a tire diameter adjustment in the settings.

IMO the speedohealer that 4Mudder installed is probably a less expensive and better option. You can change tire sizes at will with that box and at no additional cost.
 
The correct way to have the speedo work with taller tires is to change the diff gearing. That's what what Toyota does on their 31" tire pkg. That way not only is the speedo accurate, but more importantly the engine operates in it proper bandwidth for optimum power and MPG.
 
Mike07SE said:
Speedometer correction - Toyota 120 Platforms Forum
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Best option in my opinon.

fourwd1 said:
The correct way to have the speedo work with taller tires is to change the diff gearing. That's what what Toyota does on their 31" tire pkg. That way not only is the speedo accurate, but more importantly the engine operates in it proper bandwidth for optimum power and MPG.
Click to expand...

That's not entirely true for the 4th Gen. As far as the optimum power and MPG, a regear is probably a good thing. The speedo however is controlled by individual sensors on each wheel IIRC. So regear wouldn't change the speedo at all. Someone correct me if I'm wrong.
 
kylebacc said:
Best option in my opinon.



That's not entirely true for the 4th Gen. As far as the optimum power and MPG, a re-gear is probably a good thing. The speedo however is controlled by individual sensors on each wheel IIRC. So re-gear wouldn't change the speedo at all. Someone correct me if I'm wrong.
Click to expand...


Interesting info. No idea if speed is measured at the wheels or at the tranny/tcase. Either way, re-gearing is not an option as it is out of the budget. I don't mind installing a speedohealer type of thing, but I just want to make sure it is the easiest/best way to go about it. I'd also like to find some good instructions for tearing apart the dash so I don't mess anything up while I'm working in there.
 
Seth. Ditto. I read 70 on the speedo, and GPS says 62. I think mine came with 31's and now is seriously downsized.
Im a cheapskate, so Im not getting bigger tires till these are shot, and they're mostly new. The speedohealer sounds like an answer.

Why is it, now that I have discovered the speedo miscalculation, cops are tailing me almost daily. Nerve wracking to not know my true speed when I'm being followed. Speedohealer would be cheap piece of mind.
 
Before I went to 265/70/17's from the 265/65/17's my speedo was 1 mph too slow, now it is 1 mph too fast. Not a real concern, but a nuisance. I use the Garmin GPS in my Kenwood 5140DNX and the speedo reading in the Scangauge II to keep me accurate.

It would be cool to simply reprogram it via the OBDII though.
 
martini said:
Maybe one of you would know the answer to this question: http://www.toyota-4runner.org/perfo...1130-265-65r17-vs-265-70r17-2.html#post557776, why the FJ with the same 3.73 gears has a 267/70 option while the 4Runner has 3.73 gears and 265/65?
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Probably because while the 4runner and FJs have the same options for engine and gear ratios, they are different vehicles with different weights so the overall torque/power is not the same. Toyota may have put smaller tires on the 4runner to make the FJ and the 4runner perform more similarly.
 
Those tire sizes are so close together that the question is really irrelavent. 4Runners themselves came with several different tire/wheel combos but only one gear ratio (that I know of).
 
Speedohealer installed!

FYI, I installed a speedo healer on my 4Runner tonight and now my speedo is right on with the GPS. It was a fairly simple mod, but it's a little nerve wracking to cut into the wire bundle behind the cluster. The hardest part was actually finding a keyed power source. I wanted to tap into the fuse box, but the back of the box is closed, so I wasn't able to do that. I finally found a wire and just tapped into it.

Anyhow, it's a pretty cool mod that will allow your speedo (and odo, etc) to be accurate, no matter what size tire you go to.
 
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