flixpink

I have 20' wheels an at 70 mph my rmp is reading about 2700 could any one help me out to what i need to fix this problem?

Lexbox

Sounds about right to me.

audax

iTrader: (10)

You have it backwards... your RPMs are not wrong but your speedometer is. Only the speedometer is affected by increasing the wheel size.

JeffTsai

iTrader: (1)

Actually the RPM's should get lower accordingly to your true speed. With a bigger overall tire diameter, there are now less rotations to travel the same distance. Say with the stock tires/rims and the speedometer is showing 60 you are going 60. Now with the 20's if the speedo is reading 60, you might be going 65 or something. So to achieve true 60mph...you will need to drive at a speed where the speedo displays 55mph and thus the engine spins at lower rpms for the same given real speed.

I hope I didn't confuse you too much

GS42NV

Your RPM's might be reading a little high if you're also carring a heavier load and its taking a little bit more power to achieve the speed you're looking for. For example, the added weight of the 20's might contribute to this. If you just put in a sub box that will also add some weight. If you have a packed car that will for sure increase your RPM.

As they say, its the little stuff that adds up.

JeffTsai

iTrader: (1)

I thought our tranny has a lockup torque converter? So the rpms shouldn't be jumping around once the car gets up to speed. He did specify 70mph.

flixpink

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