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View Full Version : Bigger tyres/whees = slower speed and or speedo error?



robfd
12-03-2015, 06:37 PM
I just got a new set of wheels (17x7) with 215/45/17 Nitto nt555 tyres put on my FD civic. Car originally came with 16 inch wheels.

When I drive it, it feels like it's become a bit slower for some reason? I've been told if you get bigger wheels, it takes more time to for power to go through the wheels or something? Haha.

I'm not too sure.. Could someone point me in the correct direction please?

Cheers!

3K9
12-03-2015, 07:01 PM
That's right.

The wheels are unsprung weight. In your case, it's a reduction of rotating mass. I dunno the exact value, but I think unsprung weight is like x2/x3 the normal weight.
Not only are the wheels a bit heavier, the extra width on the tyres creates more rolling resistance (drag).

bennjamin
12-03-2015, 07:37 PM
the same mass at the wheels or along the drivetrain has more effect that the same mass anywhere else on the car.

ECU-MAN
13-03-2015, 07:26 AM
The change in tyre diameter effects the cars roll-out, thus the speedo accuracy is also effected.

Haanda
24-03-2015, 05:16 PM
Have a read through this page. Some excellent info as what effect different wheel and tyre combos will have on the accuracy of a cars speedo reading.

http://www.carbibles.com/tyre_bible_pg4.html

NightKids
25-03-2015, 02:36 PM
Your new rims are heavier therefore you can feel your car being slow because Honda's hardly have any torque.

Get some 17" lightweight JDM rims and you can still retain the bigger wheel look.

#broscience

RenzokukenJ
25-03-2015, 02:50 PM
Because JDM right?

SHOGUNOVDDRK
25-03-2015, 02:53 PM
Because JDM right?
Maaaaaaaaaaaaate


#broscience

cbauto
25-03-2015, 03:00 PM
the replies in this thread are very confusion.