speedometer question

[71cruiser71]

i put a 4 inch lift on my 40 with larger tires...33's and i just drove it for the first time since and it feels like im going a lot faster than what the spedo says. if i had 31's on before if i was going 65 before... how fast would i be going if i had 33's?

just thought someone out there should know something like this? thanks!!!

 

[vk7ybi]

=33/31x65

6.45% faster.

 

[KOOTENAY KRUZER]

IIRC the stock tire diameter was 29" so with the 31s and reading 65 on the speedo you were doing app. 70 and with the 33s you are doing app. 74.

 

[71cruiser71]

perfect... 55 on my guage feels like a comfortable speed. purs along well.. just wish the rpms wernt so high 3K. is that normal?

 

[vk7ybi]

What are your diff gears?

 

[71cruiser71]

stock dif. stock 3 speed and stock 3 t case

 

[vk7ybi]

So assuming you have a 71, stock for that year is 4.11?

According to my math, at 65 with 33s the motor is turning at about 2720rpm..