Like if you upgraded you tires from a 25 inch to a 33 inch?
2007-05-12 16:42:08 · 23 answers · asked by Anonymous in Cars & Transportation ➔ Other - Cars & Transportation
Yes it can. You need to have it calibrated to match the tire size.
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2007-05-12 16:45:19 · answer #1 · answered by M00ND0CT0R 6 · 1⤊ 0⤋
Tire size will make a difference in how accurate the speedometer reads. It is not a set mph difference. it the circumference of your tires is 10% greater than the car was designed for...you'll be going 10% faster than your car thinks it is not just the speedometer but the wheel speed sensors as well. If the speedo reads 10 your doing 11 if it reads 70...you're doing 77...if it reads 100 ...you're doing 110. Just live with & know how this works. you're asking too much to try to reprogram. If your car is older and cable operated speedometer and you're not going to change that. (yes stewart warner made inline transmissions to do that but they've been discontinued for years)
2007-05-12 19:03:23 · answer #2 · answered by scottmandoo 1 · 1⤊ 0⤋
Yes it would. The speedo reads off a gear, based on the number of axle turns, not on the tyre, or actual road distance covered.
So if a 25 inch tyre made one full rotation you would have traveled around 79 inches. The same rotation on a 33 inch tyre would move you approximately 104 inches forward. But if the gear was set to read for the 25 inch tyre your odometer would tell you that you had moved only 79 inches (were they that accurate).
How does this translate to speed? If the car's speedo was geared to the 25 inch tyres and the speedo read 60 m.p.h. and you had 33 inch tyres on the actual speed would be about 30% more or over 78 m.p.h.
There are ratio changers available for adjusting the speedos, or electronic ones can be re-calibrated, so they read more accurately when you alter tyre size.
Hope this helps.
2007-05-12 16:57:17 · answer #3 · answered by Barb Outhere 7 · 0⤊ 0⤋
yes it does. A speedo does not measure speed, it calculates it. If you change the tire size, it screws up the calculations. Put a quarter on a piece of paper and mark the distance traveled 1 revolution, then do the same with a dime. The dime moves less of a distance, right??? If the coins were your tires, the car would still think it was moving the distance of the quarter, even if you bolted on the dimes. Get it???? You can adjust it, however, depending on the car and year. The older ones with cable speedos can have adapters made. You will need the old tire heigth, the new tire heigth, and the rear end ratio. On Cars with elect speedos, most of the time you can adjust it with a Hypertec or with a computer and the correct software. Good Luck
2007-05-12 16:50:02 · answer #4 · answered by dadforfive 6 · 1⤊ 0⤋
Take a look at the tire size calculator shown at the end of this post. With that, you can instantly see the amount of error you will have in your speedometer by changing your tire size to any size you choose. Best of luck.
2016-05-17 04:34:51 · answer #5 · answered by madeline 4 · 0⤊ 0⤋
Yes it does.
Your cars speedometer is calibrated for the standard sized tires meant for your car. If you go any bigger or any smaller there will be slight differences in your speedometer reading.
Each revolution of a bigger tire travels further than the smaller tire. The cars speedometer does not know that bigger tires are on the car.
I'm sure someone else can explain this better but I'm 100% sure it messes up your speedometer reading.
2007-05-12 16:47:55 · answer #6 · answered by Scooba Steve 3 · 1⤊ 0⤋
YES.
The bigger tire will make the speedometer think the car is going slower. Your actual speed will be 5-10 miles per hour faster.
I had a friend that played dumb with cops. Always just got warnings to have his speedometer calibrated. I'm not sure if he was ever given a ticket.
2007-05-12 16:48:56 · answer #7 · answered by powhound 7 · 1⤊ 0⤋
It will definitely make a difference of about 4 to 5 miles per hour. If your speedometer said 55, then you are really going almost 60.
2007-05-12 16:46:53 · answer #8 · answered by Anonymous · 0⤊ 0⤋
It depends. If you change the circumference of the tire, then it will surely mess up the speedometer. If you change the tire size then you will have to reprogram the computer to correct the speedometer ..
2007-05-12 16:47:06 · answer #9 · answered by Fordman 7 · 1⤊ 0⤋
Yeah, when I was in Alg. II/Trig and we were talking about this kind of stuff, my teacher told me about one of his students who got these huge-*** "pimp" tires on his jeep and he got a speeding ticket one day but didn't think he was speeding because the speedometer didn't correspond to his new tires. He was going like 15 or 20 mph faster than he thought. I think it has to be a pretty significant size difference though.
2007-05-12 16:46:40 · answer #10 · answered by Callie C 2 · 1⤊ 0⤋
Yes it does change the speed shown. Depending on type and age of vehicle you can take vehicle to transmission shop and have them reprogram computer to that size of tire and that will fix speedometer....
2007-05-12 16:47:11 · answer #11 · answered by Daniel S 2 · 0⤊ 0⤋