Rims throwing off tac meter?
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Tach? Not gonna happen. If the rims and tires are not the same outside diameter as the stock tires and wheels, the speedometer and odometer will be off. See "Tire Calc" at the top of the page for more information.
The Standard One
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if you get something other then the stock tire size, it will "throw" it off. usually not by much. use the tire calc to get the tire size closest to stock. for example, for 18s, 215-35-18 are slightly smaller 215-40-18 are slightly bigger then stock. 225-35-18 is almost the same but you might have problems with 225 and a drop. i have 215-40-18 on neuspeed sports, no problems at all. see my members page for pics
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From: Milwaukee, Wisconsin, US
Rep Power: 0 No they wont, Vnlilman is wrong, it might throw off his odometer a lil bit, but it will not effect his tachometer whatsoever. His car is going to be slower cus of the 18s but his tach will not be off..
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From: Littleton, CO and Peoria, IL, Colorado, US
Rep Power: 0 tach sensor comes from either the ECU or the distributor, so putting different wheels on will not affect it in the least. if he's saying that because his engine speed at a given forward speed is different, tell him it's cause his speedo is off, not the tach.
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From: Connecticut, US
Rep Power: 0 Ahhhh! His tachometer will be different with a different diameter wheel. As you all know, the tach reads RPM...and since different size wheels = different RPMs why wouldn't the tach reflect that change? It will affect it...but it is still accurate.
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Quote
[hr]Originally posted by: PESTLNC
Ahhhh! His tachometer will be different with a different diameter wheel. As you all know, the tach reads RPM...and since different size wheels = different RPMs why wouldn't the tach reflect that change? It will affect it...but it is still accurate.[hr]
[hr]Originally posted by: PESTLNC
Ahhhh! His tachometer will be different with a different diameter wheel. As you all know, the tach reads RPM...and since different size wheels = different RPMs why wouldn't the tach reflect that change? It will affect it...but it is still accurate.[hr]
tachs display RPM of the ENGINE, not the wheels [IMG]i/expressions/face-icon-small-smile.gif[/IMG]
think about it, no matter what size wheels you have, and you're at a stop and you rev your engine, the tach will move.
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From: Connecticut, US
Rep Power: 0 Hmmm, this is getting more complicated than I thought it would.
OK...say this is my car and I suddenly have a smaller diameter wheel:
Speedo stock reads 80mph, tach reads 3100rpm
Speedo w/new wheels reads 80mph, tach reads 3100rpm; BUT I'm really only going say 75mph; therefore at 75mph the tach reads higher than it used to
Hmmm, now that I read back on my posts I'm a bit confusing...
OK...say this is my car and I suddenly have a smaller diameter wheel:
Speedo stock reads 80mph, tach reads 3100rpm
Speedo w/new wheels reads 80mph, tach reads 3100rpm; BUT I'm really only going say 75mph; therefore at 75mph the tach reads higher than it used to
Hmmm, now that I read back on my posts I'm a bit confusing...
The Standard One
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Rep Power: 416 yes you are confusing yourself.
keep in mind RPM and Speedometer are two sperate things.
you go 80 mph on stock wheels and it reads 3100rpms
you go "80 mph" on new wheels and it reads 4000rpms. why because your not going 80 but your going 90.
this would of course be measuring it at a constant speed in the last gear.
cause if your talking about 10 mph, you could be down in 2.5k in 2nd gear while in 6k in 1st. these are just exaggerations
keep in mind RPM and Speedometer are two sperate things.
you go 80 mph on stock wheels and it reads 3100rpms
you go "80 mph" on new wheels and it reads 4000rpms. why because your not going 80 but your going 90.
this would of course be measuring it at a constant speed in the last gear.
cause if your talking about 10 mph, you could be down in 2.5k in 2nd gear while in 6k in 1st. these are just exaggerations
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