Beastang

I BOUGHT A USED GT SOME TIME AGO. WHEN I AM DOING 60MPH THE TACH IS AT 2750. HOW DO I FIGURE GEAR RATIO BASED ON THIS OR CAN I?

JOHNNYB

have you looked on the hoghead to see if the sticker is still there, my friends 07 gt has a white sticker on the right rear of the hoghead that says 3.31, i wouldnt have thought that the sticker would last long but his had 13k on it when he bought it, and i just looked under it to see what the ratio was last fri night, sticker looks brand new, if thats no longer on it, or you suspect it is not factory i know there is a formula but i dont know it off the top of my head..i am sure someone on here can tell ya tho

Beastang

THANKS IT'S AN 05 SO I KNOW THE STOCK WAS 355 I WRECKED MY OTHER O5 BACK IN AUGUST BUT I DO NOT REMEMBER DOING 60 AND REVVING AT 2750

drbobvs

Since the new speedo's are electronic and can be calibrated for any gear ratio, it is impossible unless you know your speedo is properly calibrated to the gear ratio you have. 2750 sounds like a lot for 5th gear at 60mph. You either have 4.30's in there, or you have a lesser gear and your speedo is off.

howarmat

05 GT is 3.55 manual and 3.31 auto

if you are turning 2750 going 60 you have aftermarket gears in there (4.30) and have the smallest tires in the world....i suggest go and read the RPMS again for 60 in 5th gear......it cant be that high IMO

Beastang

I AM SORRY IT IS A MANUAL AND THAT WAS RUNNING IN 4TH GEAR 5TH DRONES TO MUCH AT 60.

GidyupGo

Jack up the rearend, put in Neutral, make chalk mark on driveshaft, count how many times DS goes around when the tire is turned only one complete revolution. Guestimate the fraction but if it is about 3.5 times, there you go.

Beastang

THANKS MY BRAIN MUST BE IN A FOG

howarmat

you have 3.55

Beastang

I ASSUME YOU REV AT THE SAME SPEED. THANKS