speedometer reads faster than im actually going.
#1
Registered User
Thread Starter
Join Date: Dec 2007
Location: Baldwin Park, California
Posts: 97
Likes: 0
Received 0 Likes
on
0 Posts
speedometer reads faster than im actually going.
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.
#2
Registered User
Join Date: Jul 2009
Location: florida
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
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
#4
Registered User
Thread Starter
Join Date: Dec 2007
Location: Baldwin Park, California
Posts: 97
Likes: 0
Received 0 Likes
on
0 Posts
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?
#5
Registered User
Thread Starter
Join Date: Dec 2007
Location: Baldwin Park, California
Posts: 97
Likes: 0
Received 0 Likes
on
0 Posts
#7
Registered User
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
Trending Topics
#8
Registered User
Join Date: Feb 2009
Location: Milwaukie, Oregon
Posts: 63
Likes: 0
Received 0 Likes
on
0 Posts
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
#9
Registered User
Thread Starter
Join Date: Dec 2007
Location: Baldwin Park, California
Posts: 97
Likes: 0
Received 0 Likes
on
0 Posts
so the smaller the tires the worse the speedometer reads??
#10
Contributing Member
Join Date: Feb 2010
Location: Pagosa Springs, CO
Posts: 260
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
#11
Registered User
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.
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.
Last edited by Hadmatt54; 07-04-2010 at 03:32 AM.
#12
Registered User
Thread Starter
Join Date: Dec 2007
Location: Baldwin Park, California
Posts: 97
Likes: 0
Received 0 Likes
on
0 Posts
the ratio ishow many turns of the input shaft (pinion) it takes to make the ring gear go around one time. if you didnt change tires sizes and went from 4.10 to 5.29(?) then you are going slower than the spedo says cause now yoru driveshaft is turning more than one turn more than it did before you did sas in order to move the tires the same distance.
if you dont change tire sizes=
4.10 means teh driveshaft makes 4.1 turns for each 1 turn of the ring gear
5.29 means the driveshaft makes 5.29 turns for each 1 turn of the ring gear
so that means the driveshaft turns 1.19 more turns with 5.29 than with 4.10 gears with each turn of the tires and that makes the transmission and spedo gear turn faster and your spedometer read faster then you are really moving.
if you dont change tire sizes=
4.10 means teh driveshaft makes 4.1 turns for each 1 turn of the ring gear
5.29 means the driveshaft makes 5.29 turns for each 1 turn of the ring gear
so that means the driveshaft turns 1.19 more turns with 5.29 than with 4.10 gears with each turn of the tires and that makes the transmission and spedo gear turn faster and your spedometer read faster then you are really moving.
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.
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.
#17
Registered User
#18
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.
#19
Registered User
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.