artofliphkd

i recently did a sas on my 90 pickup with 5.29 gears and 33's soon to be 35's. and my speedometer is way off! i used to have ifs with i believe it was 4.10's on 33s and the speedometer was accurate. when im on the fwy it says 80 but im going like 67! i used my gps and i even found speed traps on the streets! and its says 55 on my speedometer and 45 on my gps/and speedtraps! is there a way i can fix this? or am i screwed.

calcuta

There is no way it was right with 4.10s with 33 s I have 33s and 4.10 s on my 91 it is off don`t know exactly how much but for every 3 miles on the odometer i have too add 1 one. you may be able to change the speedo gear in the transmission

85gijunk4x4

i think you can buy different sized speedo gears to accomadate a larger or smaller tire size...weird though...

artofliphkd

maybe it wasnt then. im not sure if it was 4.10 since i was the third owner and the speedometer gear in the tranny? is that expensive?

artofliphkd

lol yea im like confused on the fwy sometimes. idk how fast or slow im going.

85gijunk4x4

i dont think the speedo gear should be that expensive...i mean, its just a dinky little peice of plastic

85gijunk4x4

do you have a cable driven speedometer? if you dont, you will have to get an electronic re-calibrator, wich are far more expensive then just a new speedometer cable gear

DoveGray85

My 85 truck speedo reads high with 5.29 gears and 35's. Your speedo will be closer with the 35's but will still read high. 37's would be perfect. Now, there's an excuse to buy some new tires

artofliphkd

im not sure? how could i find that out? is it visible?
so the smaller the tires the worse the speedometer reads??

coops2k

at one time there where gears for the speed cable, might still be, I just don't know.

My 87 has 31 and 4:10 and the speedo is off, reads 70 when doing 65-66, checked with a GPS. The original owner had a correction gear put in way back when, but they put in the wrong gear. If I pull the correction gear out, it will read slow ie: 60 and doing 65. I estimate the gear is good for 33's which I am not getting anytime soon, so I live with it.

Try a local transmission shop and see if they can help you.

Hadmatt54

You can also add in the tire factor! A tire that has a larger diameter will cover more distance for one revolution than a smaller tire, because the circumference is larger too!
So with taller gears (more turns of the driveshaft) and larger tires (greater distance for each revolution of the tire) your actual speed and registered speed are out even further.
In the 80's the 22re manual Pickups/4Runners had 235/75/R15 tires and 4.10 gears. Autos had the same tire but 4.30 gears from the factory. In the 90's when Toyota offered 31" tires as an option, manuals had 4.30 gears and autos had 4.88 gears. The autos were given a taller gear than the manuals to make up for the 20-25% loss in power due to the torque converter, (but with the same size tire), so Toyota would install a different speedometer gear to allow the speedometer to read accurately. The V6 trucks had even more speedometer gear options. For example from toyodiy.com for a 87 4Runner (22RE) it lists a different gear for a manual than an auto. For a 91 (22RE) there is a gear for a manual and one for an auto, but for a V6 there are 3 different gears for the manual and two different gears for an auto. These different gears were used to match the different tire options. Oem prices are from $28-$33.
A recycle yard would be the place to start to obtain different gears to try to bring the accuracy of your speedometer back in line.

artofliphkd

man you guys are smart! i'd like to thank everyone for all the help! and i will post on this thread again once its fixed!

Tofer

what year is your truck? i have 5.25s and 35s and its just a hair faster than actual.

Fink

Just get yourself a cheap GPS and use that.
Or go with the old "Officer, I was just trying to keep up with traffic..."

Fink

87hillbillyoter

i got 4.10s with 33s and it reads about a mph slow. at least thats what i think.

RustBucket

iTrader: (1)

Just write in new numbers on your speedometer.

xxxtreme22r

hahah booty fab I love it.

on a side note, the above explanation answers a question I think I had asked quite awhile ago as to why no one makes speedo adapters for our trucks. Great info !!!!

clydehatchet

now, i might be way off, but cant you go to the dealer and have them recalibrate the system to accommodate for the gear change and tire size change? I know that with newer vehicles you can buy re programmers.

xxxtreme22r

unless it's factory I doubt they would even touch it. But even if they did, probably cost you quite a bit to have them do it.

clydehatchet

no kidding! yeah, like i said, somehow, somewhere, someone told me that. most probably BS, being that we are runnin primarily mechanical setups, not electronic.