Kinda weird

So this is weird. My old stock (supposed to be accurate) Dunlop tires 245/75/16 when compared to my GPS was always off.

Now that I have the 265's on my speedometer is running perfect (Exact) with the GPS. According to the tire calculator it is supposed to run 3.9% too slow. I was wondering though. I thought my truck was supposed to be set for the 245's? But a lot of the Tacoma trucks come with the 265's stock. I'm thinking the 245 trucks are just off and go back to normal when you jump back up to 265?

Anyone else who has gone up noticed this? What do you think?

 

Mine came with the 265's and my GPS and my speedo have always agreed 100%. I think you may be on to something here.

 

Hey Maverick, I am a misplaced Jersey boy. I was noticing your Motorcycle. I have a Honda Shadow 750 & 1100. Gotta love those bikes man, they last forever! Nice color on yours by the way man.

As I'm writing this an almost gay thought just came into my head...

Weren't the pilots on Top Gun named Viper and Maverick??

 

Thanks for the compliment on the motorcycle. Yeah Hondas are indestructable. Got to love them.


As for Top Gun. I'm going to embarass myself here, but here we go:

Michael Ironside - Jester
Tom Skerrit - Viper
Tom Cruise - Maverick
Anthony Edwards - Goose
Val Kilmer - Iceman
Rick Roscovich (sp?) - Slider
Tim Robins - Merlin
Wip Hubley - Hollywood
Kelly McGillis - Charlie
There was also
Sundown
Cougar
and
Wolfman

But I forget who played them.

Ok let the ribbing begin.

 

Hey Viper, I had stock 246/75/16 and bought a pair of 265/70/16 using a tire calculator and they are almost identical (according to it). I do not have a gps but you post now makes me wonder ? The road performance seems the same but they do float a bit much when it comes to slush and snow.

 

i have the 245's and my speedometer is off almost 5 mph at 70. thats going with constuction speed signs but i'm guessing that those are pretty accurate... along with mile markers. so i took it in and they fed me this line about how all cars are off and they have a tolerance, (when i checked i was over the tolerance). so i told the dealer i would like for them to check it... like use a dino or something. so i bring it in and all he did was take it out driving for an hour an a half and came back and told me it was fine. so ended up losing a 1/4 tank of gas for nothing. and the waiting area had opra on the tv.

 

wow ! that's an hour and a half you'll never get back !

 

i know, right.

 

the 245 or 265 shouldn't make a diff. that is the width of the tire, the height should make a diff.

i am talking about this in another thread, but the point is i put on 33's, and according to a tire calculator, when my speedo says 70, i should be doing 75 or 76, can according to my gps, when speedo says 70, i'm doing 73....

i think before when speedo said 70, i was probably doing 67 or 68.... no point in getting anything recalibrated if it is just going to be off again.

what is everyone else's opinion on it......

and good job on the top gun trivia, u get the blue ribbon AND the gold medal maverick

 

Exactly....

I have stock tires/rims on my 2007 TRD sport and the truck speedo is reading 2mph faster than my GPS.

 

That is not entirely correct. The measurements in tire size are ratios to eachother. So if you increase one you will by default increase the other even though the measured ratio stays the same. Here's an example. I picked a model of Cooper tire at random, and cut and pasted the measurements for the same tire in various sizes.

Cooper tire in stock SR5 (6 lug) tire size

Discoverer AST II
245/75R16
Section Width 9.75
Overall Diameter 30.2
Tread Width 7.1

Increasing to a 265, but leaving the other numbers un-touched

Discoverer AST II
265/75R16
Section Width 10.6
Overall Diameter 31.32
Tread Width 7.8

Cooper tire in stock Off Road size

Discoverer AST II
265/70R16
Section Width 10.8
Overall Diameter 30.2
Tread Width 7.84

A different tire in the stock Sport size since the tire I started with is not made in that size

Discoverer ATR
265/65R17
Section Width10.71
Overall Diameter 30.55
Tread Width 8.75

Anyway you get the point. With the stated tire size measurements being a ratio, all the actuall measurements must change if one of them is changed to maintain the ratio.

And you can see how the speedometer can be off as even though the SR5 and offroad cooper tires are the same overall diameter, each of these packages uses a different manufacturer tire from Toyota.

Thanks. Top Gun trivia is part of where the sreen name comes from.

 

I can appreciate movie triva, my name comes from Cool Hand Luke, "we have here one lucas jackson....."

yeah, i know what you mean about the ratio thing, but i replaced 245/75's with 265/70's and kept the same height. i guess because 75% of 245 is about the same as 70% of 265.

 

ok... on the recalibration..
On my old Sierra with a 6in lift and 35s i used a scantool to tweak to performance as well as calibrate the speedo to the 35s.

Does the Taco have a similar tool out there? Is that the scangauge everyone uses? As i am running 285/70/17 which is off ~7% at 60mph from stock according to tire calculator.

 

The scangauge has a speedometer built into it, that you can adjust, but it has no effect on the truck's speedometer, I am not sure how you would go about fixing the truck's speedo. Nor am I sure that it is even worth it. Just figure out exactly how far off you are, find one of those police radar signs that says "your speed is" and go with that, and then just keep note of what how far off the speedo is.

just my $0.02

 

Holy Crap! I don't know whether to berate you for knowing all of this or to congratulate you.

 

No doubt on this, my tires clearly have more radius than before.

 

I do have another question about the OBD II on this truck. Why does my Acctron which has worked on every other OBD II for the last 2 years not work on this truck?

It is saying: Link error?

Wouldn't this be able to help me determine which tire it may be since the computer throws a code after 20 minutes if the TPMS light stays on? <---(run on sentence).

 

This has been great info gang thanks........And btw,I was a huge fan of TopGun back in the day.When Cruise was riding that 900 Ninja along the highway while the jet was taking off I sat in the theater and said...."I'm gettin' me one of those".I bought a 1000 Ninja shortly after and had a ball on it.....I guess I'm a sucker for marketing bacause when T2 came out and Arnie rode a black Fatboy,I sold the Ninja and bought one of those.

 

I also have noticed a difference between my GPS (Nuvi 660) and my speedo. I am running stock 245 tires and when I am up around 70 mph on the spedometer, my GPS is showing 66 -67 mph.

When I have my GPS in my wifes car (Nissan Pathfinder) I am right on the money but when I rented a Toyota and noticed the same 2-3 mph differance at higher speeds.

I took it into the dealership and they told me everything was accurate on my car and that my GPS must be off (?).

Not a big deal, but little things like that bug me since I have a background in field service and I know when things just don't add up.

 

Almost every car on the road's speedometer reads high. This is a great thing for the manufacturer. The majority of non thinking customers are happier getting slightly higher MPG's or slightly quicker 0 to 60 times while having their warranty expire earlier.