Gears 3.73?
07-26-2011, 02:22 PM
#1
Thread Starter
Join Date: Jun 2011
Location: Pennsylvania
Posts: 33
Gears 3.73?
Hello,
So I was driving yesturday at 50mph with rpm around 2200-2350. I used the rear-axle gear calculator and it estimated it at 3.73.. would that mean I have aftermarket gears then?
I posted a few days ago about my issue of me doing 75mph but actually i was only doing 65. but 75mph was what the speedometer was reading at the time.
I do have aftermarket wheels. American Racing 18" I don't know if that has anything to do with the errors. Can u please fill me in. Thanks
So I was driving yesturday at 50mph with rpm around 2200-2350. I used the rear-axle gear calculator and it estimated it at 3.73.. would that mean I have aftermarket gears then?
I posted a few days ago about my issue of me doing 75mph but actually i was only doing 65. but 75mph was what the speedometer was reading at the time.
I do have aftermarket wheels. American Racing 18" I don't know if that has anything to do with the errors. Can u please fill me in. Thanks
07-26-2011, 03:21 PM
#4
4th Gear Member
Join Date: Sep 2009
Location: NC
Posts: 1,481
Your car came from the factory with 3.27 gears.
What gear were you in at 50mph and 2200rpms??? NOT 5th I'm sure. 3.73 gears in my car puts me right at 2000rpm at 60mph in 5th gear.
If your speedometer reads 75mph when you are actually going 65mph, that would indicate that you have 3.73 gears and no correction has been made to the speedometer.
If your tire diameter is different than the stock tires that came on your car, that would also cause some error in your speedometer.
If you can provide a little more information, we may be of more assistance to you.
What gear were you in at 50mph and 2200rpms??? NOT 5th I'm sure. 3.73 gears in my car puts me right at 2000rpm at 60mph in 5th gear.
If your speedometer reads 75mph when you are actually going 65mph, that would indicate that you have 3.73 gears and no correction has been made to the speedometer.
If your tire diameter is different than the stock tires that came on your car, that would also cause some error in your speedometer.
If you can provide a little more information, we may be of more assistance to you.
07-26-2011, 03:30 PM
#5
Thread Starter
Join Date: Jun 2011
Location: Pennsylvania
Posts: 33
Thank you. sorry if im not much help lol.. im new to this..
Im pretty sure i have 245/35/18? don't quote me, but does that sound legit.
I was running in 3rd gear (auto) when i hit 50mph on speedometer just about over 2000rpms. if there are any questions that can make it easier for me to know if i have aftermarket gears ill b gladly to answer them or give u more info on helping me know if i have aftermarket gears or not..
Im pretty sure i have 245/35/18? don't quote me, but does that sound legit.
I was running in 3rd gear (auto) when i hit 50mph on speedometer just about over 2000rpms. if there are any questions that can make it easier for me to know if i have aftermarket gears ill b gladly to answer them or give u more info on helping me know if i have aftermarket gears or not..
07-26-2011, 08:19 PM
#6
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
Thank you. sorry if im not much help lol.. im new to this..
Im pretty sure i have 245/35/18? don't quote me, but does that sound legit.
I was running in 3rd gear (auto) when i hit 50mph on speedometer just about over 2000rpms. if there are any questions that can make it easier for me to know if i have aftermarket gears ill b gladly to answer them or give u more info on helping me know if i have aftermarket gears or not..
Im pretty sure i have 245/35/18? don't quote me, but does that sound legit.
I was running in 3rd gear (auto) when i hit 50mph on speedometer just about over 2000rpms. if there are any questions that can make it easier for me to know if i have aftermarket gears ill b gladly to answer them or give u more info on helping me know if i have aftermarket gears or not..
Ignore this, I had not done the math on the 245/35-18 tires and realised that they are smaller diameter than the stock 245/45-17s--24.75" vs. 25.7" respectively...
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¹ - What does "pretty sure" and "don't quote me" mean? Look at the tires and the size will be clearly indicated in great big letters.
Last edited by cliffyk; 07-27-2011 at 03:51 AM. Reason: bad advice/numbers
07-26-2011, 08:21 PM
#7
when i bought my car i had similar size rears, 3.73's, and no calibrations. when my speedo said 85 i was actually doing right between 70-75. at that speed my rpms, if i remember right, were right around 2600 or so. now i have 4.10's and at 75mph i'm at 2900.
