wheels making the car slower?
Thread Starter
Registered!!
iTrader: (2)
Joined: Aug 2005
Posts: 550
Likes: 1
From: Riverside, CA
Rep Power: 0 
wheels making the car slower?
ok so i bought this thing with 14s on it it has 16s now, when i set the cruise its not the same as other people so say i set it at 75, cars also set at 75 are passing me, so i can only conclude that that speedo is off or something due to the wheel size.
Ive heard of this before but i couldnt get the search to yeald anything helpful.
is there anything to do to correct this?
Ive heard of this before but i couldnt get the search to yeald anything helpful.
is there anything to do to correct this?
Back From The Banned!
iTrader: (13)
Joined: Nov 2002
Posts: 5,226
Likes: 0
From: Queens, New York, US
Rep Power: 339 http://www.7thgencivic.com/index.php?page=tirecalc
use that to help calculate whats going on..... wheels dont make the car go slower unless the wheel and tire are significantly heavier than stock, such as 17 inch wheels and up.
use that to help calculate whats going on..... wheels dont make the car go slower unless the wheel and tire are significantly heavier than stock, such as 17 inch wheels and up.
Registered!!
iTrader: (14)
Joined: Nov 2004
Posts: 1,864
Likes: 0
From: Toronto, Canada
Rep Power: 281 
Total wheel diameter will make your speedo "lie".
Heavy wheels will make car slower, but its slower to accelerate. Looks like you're thinking about slow as just less mph..
Heavy wheels will make car slower, but its slower to accelerate. Looks like you're thinking about slow as just less mph..
Thread Starter
Registered!!
iTrader: (2)
Joined: Aug 2005
Posts: 550
Likes: 1
From: Riverside, CA
Rep Power: 0 it says my speedo is 9.74% too fast. Im not good at math so maybe someone out there whose a wizz with it can tell me what that translates into
and in case you need it for figuring its a 2001 ex 2dr MT
and in case you need it for figuring its a 2001 ex 2dr MT
Originally Posted by ryangt
it says my speedo is 9.74% too fast. Im not good at math so maybe someone out there whose a wizz with it can tell me what that translates into
and in case you need it for figuring its a 2001 ex 2dr MT
and in case you need it for figuring its a 2001 ex 2dr MT
thats a huge difference
Joined: Sep 2002
Posts: 51,241
Likes: 20
From: NV
Rep Power: 812 it means if you're going 65mph according to the speedo its more like 58 in real life. when you're going 75 according to speedo, you're really going 67. your odometer will also record miles wrong.
Joined: Dec 2003
Posts: 4,773
Likes: 0
From: IL
Rep Power: 320 
mines 0.96% too slow. which is funny because compaired to my friend's car he claims that his speedo is 3-4mph faster than mine while he's staying behind me. around 72-75 its not even 1mph off tho.
however he has a 90s probe. so yeah.
however he has a 90s probe. so yeah.
Last edited by shmik1; Jan 2, 2006 at 02:58 PM.
Back From The Banned!
iTrader: (13)
Joined: Nov 2002
Posts: 5,226
Likes: 0
From: Queens, New York, US
Rep Power: 339 ^^^ yup, or simply put when youre driving about 100 (not recommended) youre speedo will read 109.74MPH. Also this puts false miles on to your odometer but not motor.
Registered!!
Joined: Aug 2005
Posts: 132
Likes: 0
Rep Power: 0 
changing the speedo gearing is anything but easy. don't even think about it.
easiest thing to do, if you are hard up to get the exact odometer correct with mileage being spot on, get a digital speedometer/odometer aftermarket gauge that has an adjustment screw/**** for gearing differences (where you set the number of wheel rotations per mile at a dyno shop... they usually don't charge too much).
pain in the *** to get it exact. most people just leave it and do the math in their head, gettin used to what equals what on the highway.
easiest thing to do, if you are hard up to get the exact odometer correct with mileage being spot on, get a digital speedometer/odometer aftermarket gauge that has an adjustment screw/**** for gearing differences (where you set the number of wheel rotations per mile at a dyno shop... they usually don't charge too much).
pain in the *** to get it exact. most people just leave it and do the math in their head, gettin used to what equals what on the highway.
i'm 1.29% too slow. It seems if i were to get 205/40/18 tires size then it would be exactly at 0%.
so since it says i'm 1.29% too slow then doesn't that mean if i'm going 65 mph then i'm actually going a LITTLE bit faster?
so since it says i'm 1.29% too slow then doesn't that mean if i'm going 65 mph then i'm actually going a LITTLE bit faster?
Last edited by D5cIvIc; Jan 2, 2006 at 04:25 PM.
Registered!!
iTrader: (14)
Joined: Nov 2004
Posts: 1,864
Likes: 0
From: Toronto, Canada
Rep Power: 281 Overall aftermarket tire diametr should be equal to factory tire diametr. This will keep spedo happy.
If overall tire diamert smaller, means wheel rotating faster and it will show "faster" speed than it actualy is. Example: If your speedo reads 75mph, you may be going 70mph...
If overall tire diamert smaller, means wheel rotating faster and it will show "faster" speed than it actualy is. Example: If your speedo reads 75mph, you may be going 70mph...
Registered!!
Joined: Feb 2005
Posts: 77
Likes: 0
Rep Power: 0 Above post brings up a critical point. The tire calculator just shows how far off your tire size is from stock tire size. There are a few major problems here;
1. This is assuming all tire manufacturers make exactly the same size tire (they dont, go and measure if you dont believe me.
2. This does not take treadwear into account. Say your tread depth is .4" brand new. If the tire was completley worn out, your tire would be .8" shorter.
3. Stock speedo IS NOT accurate. It is off. Because of above factors, and others.
4. Speedo is not mechanical, it does not use gears, it is an electronic sensor somewhere with a reluctor ring, usually in tranny or at wheel hub.
5. THE ONLY WAY TO HAVE A 100% ACCURATE SPEEDO IS TO USE A GPS SPEEDOMETER.
So, next time you drive by a law enforcement radar set up somewhere, look at what it reads, and look at your speedometer and go from there. Remember, it is a percentage, so if it reads 5mph off at 70, it will not read 5mph off at 40. Your speedo wont read 5mph when you are stopped, will it.
That is all.
1. This is assuming all tire manufacturers make exactly the same size tire (they dont, go and measure if you dont believe me.
2. This does not take treadwear into account. Say your tread depth is .4" brand new. If the tire was completley worn out, your tire would be .8" shorter.
3. Stock speedo IS NOT accurate. It is off. Because of above factors, and others.
4. Speedo is not mechanical, it does not use gears, it is an electronic sensor somewhere with a reluctor ring, usually in tranny or at wheel hub.
5. THE ONLY WAY TO HAVE A 100% ACCURATE SPEEDO IS TO USE A GPS SPEEDOMETER.
So, next time you drive by a law enforcement radar set up somewhere, look at what it reads, and look at your speedometer and go from there. Remember, it is a percentage, so if it reads 5mph off at 70, it will not read 5mph off at 40. Your speedo wont read 5mph when you are stopped, will it.
That is all.
Registered!!
iTrader: (1)
Joined: Jul 2001
Posts: 324
Likes: 0
From: Centreville, Virginia, US
Rep Power: 0 ^def interesting
...the bikes i've owned have all had speedos that read faster than it really is...and people i've talked to say the same.
well i'm def curious as to how accurate the speedo is in our cars.
...the bikes i've owned have all had speedos that read faster than it really is...and people i've talked to say the same.
well i'm def curious as to how accurate the speedo is in our cars.
Thread
Thread Starter
Honda Civic Forum
Replies
Last Post
