I have an 05 G35 coupe and will be getting new tires around 15K (I know it's ridiculous). The back will be replaced with the original size tires 245/40/19 but the front will be changed to 235/35/19 from 225/40/19. Will the speedometer read slower anyway because the front axle is off or will be it accurate since the rear wheels are the same and it's a RWD vehicle? Thanks in advance.
Is the speedometer based on the rear wheels for a RWD car?
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There used to be a cable that ran to the transmission where it was geared to the output shaft. Haven't checked, but it could all come out of the ECU now. It still will be based on the output of the transmission. So sticking with the same size rear tires on a RWD car shouldn't change the speedometer too much.
Guess I could check my $130 worth of factory shop manuals for my 02 Cavalier. I don't even remember a cable for my 81 Phoenix.
Guess I could check my $130 worth of factory shop manuals for my 02 Cavalier. I don't even remember a cable for my 81 Phoenix.
should either have a sensor on the tailshaft of the trans, or else it is based off the VSS readings of the tires.
A moderator on a G35 answered...it takes signals from all four wheels. I guess I'll just have to live with having mile on the odeometer, I didn't drive. Don't matter though...I'll be driving this into the ground.
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Hmmm ...that would work well for ABS ..but using all four wheels for the impulses for the speedo
Anything to make things more complicated.
We do not know for sure. Look for the usual suspects ie; ABS Hub/Wheel Bearing sensors, Transmission based sensor etc.
On a car with staggered wheel / tire sizing, it'd have to be a transmission sensor, unless they went through the trouble of routing front and rear wheel speeds through the ECU and having it provide the speedo with the average of the two. My bet is an output shaft sensor.
It all depends on the vehicle. My 95 Grand Cherokee (ZJ style 93-98) has an output shaft sensor. Our 2000 Grand Cherokee (WJ style, 99-04) takes ABS impulses.
Last I saw with RWD, when the tires were spun, like in the rain or snow/ice, the speedometer jumped up. Just try that and see.
But that won't answer the question whether the speedo takes the signal from all wheels or just rear wheels alone.
I would guess if there is a mechanical cable running from the transmission to the speedometer, it is the rear wheels only. If a bundle of wires is all that runs to the speedometer, who know? Check your shop manual.
At one time, odometers went backwards in reverse. You could chuck the cable in an electric drill and run as many miles off as you wanted. That has been defeated. Complicated electronic systems are more of a challenge.
At one time, odometers went backwards in reverse. You could chuck the cable in an electric drill and run as many miles off as you wanted. That has been defeated. Complicated electronic systems are more of a challenge.
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