Topic 'Tire size question' in forum 'Automotive' - dslreports.com

Re: Tire size question

Wed, 01 Jul 2009 17:39:33 EDT

Doctor Olds posted : You are welcome! Glad to help when I can. :D

Re: Tire size question

Wed, 01 Jul 2009 17:25:08 EDT

pitroad01 posted : Well I purchased a set of P185/70/R14 and sold my old tires to a used tire shop for $40. I paid $336.82 for the new set ... so net paid to correct this mess was $296.42.
The car sure looks better with the taller tire and I took a drive with my GPS aboard and speed and distance are very close now. I think doc said "when your speedometer is reading 60mph you are actually traveling 59.96mph".

The info provided here saved me a lot of money
(I thought I would need to buy 15" rims and tires) and I do appreciate it.

Re: Tire size question

Wed, 01 Jul 2009 00:59:09 EDT

Its a Secret posted :

said by Doctor Olds:

Your vehicle has to be squirrelly in the rain and snow or on muddy streets.

Actually, rock solid in snow or rain, and I get the best (or worst) of both where i am. Not much mud though... :p

said by uber69er:

Having raced for decades I am quite aware of tire inflation characteristics.

I hear ya. Bike racer here. I go by the 10% pressure rise rule i.e. cold to hot shouldn't be more than a 10% rise in pressure. If so, it's under-inflated. But, I am a bit old school sometimes. :D
--
"In the future, that which is not mandatory will be illegal"
"Nobody knows the age of the human race, but everybody agrees that it is old enough to know better" - Anonymous

Re: Tire size question

Wed, 01 Jul 2009 00:26:08 EDT

uber69er posted :

said by Its a Secret:

Interesting Doc. I've filled my tires this way for years, and have never had a problem. They always run smooth, quiet and get exceptional mileage out of them. I've never experienced increased center wear either.

I've got the same experience and hundreds of thousands of kilometers to prove it in rain snow you name it.
Plus Canada to Key West every winter. I do drop down to 32 psi in heavy snow. Must be lucky so far too.
Having raced for decades I am quite aware of tire inflation characteristics.

Re: Tire size question

Tue, 30 Jun 2009 23:35:13 EDT

Doctor Olds posted : Your vehicle has to be squirrelly in the rain and snow or on muddy streets. You may have just been lucky up to now.

[att=1]

Re: Tire size question

Tue, 30 Jun 2009 21:30:09 EDT

Its a Secret posted : Interesting Doc. I've filled my tires this way for years, and have never had a problem. They always run smooth, quiet and get exceptional mileage out of them. I've never experienced increased center wear either.

While I value your expertise, my personal experiences have shown me differently. Puzzling.
--
"In the future, that which is not mandatory will be illegal"
"Nobody knows the age of the human race, but everybody agrees that it is old enough to know better" - Anonymous

Re: Tire size question

Tue, 30 Jun 2009 15:04:58 EDT

pitroad01 posted : Well I think I'm going with a set of Kumho P185/70R14. Can get a set installed/balanced/stems/tax for $340.85 'out the door'. Free rotation & balance for the life of the tire. It has a 85k mile warranty. Now I have to get rid of the P185/60/R14's that are currently on the car. Thanks for all the help.

Re: Tire size question

Tue, 30 Jun 2009 02:15:20 EDT

Doctor Olds posted :

said by Its a Secret:

One other thing... I run 70% aspect ratios myself, but fill them to 40 psi

40 PSI is a lot higher than most 70 Series as they have a 35 PSI (Some 36 PSI) Max Pressure. 40 PSI tire inflation is a bit past the dangerous side when the max inflation is 35 PSI.

Air Pressure - Correct, Underinflated and Overinflated
»www.tirerack.com/tires/tiretech/···techid=1

Unless you have ordered and installed "extra load" tires (that designation would be stamp into the sidewall), you are driving under dangerous conditions. You have less tire contact patch with the road, you have increase noise and you have a higher risk of a blow out from foreign object impacting the tire as it is beyond it designed stiffness not to forget the accelerated wear of the center of the tire taking away any partial MPG increase you may see. Saving $10.00 to $15.00 on gas isn't smart when you throw away $50.00 to $75.00 worth of tire wear/tread life.

North American Load and Pressure Markings
»www.tirerack.com/tires/tiretech/···echid=21


Sizing System   Tire Load Range      Load Pressure  
P-metric         Light Load                35 psi
                 Standard Load             35 psi
                 Extra Load                41 psi
 
Euro-metric	 Standard                  36 PSI
                 Reinforced or Extra Load  42 PSI

--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time?

Re: Tire size question

Tue, 30 Jun 2009 00:54:10 EDT

Its a Secret posted : One other thing... I run 70% aspect ratios myself, but fill them to 40 psi with nitrogen to minimize sidewall flex, and get great wear life. Just a thought.

Re: Tire size question

Mon, 29 Jun 2009 23:35:17 EDT

Its a Secret posted : You'll get better gas mileage as well. :)

Re: Tire size question

Mon, 29 Jun 2009 21:21:23 EDT

pitroad01 posted : yea maybe the P185/70/R14
It would probably look a lot better then a really wide tire (225)

Re: Tire size question

Mon, 29 Jun 2009 21:19:57 EDT

Doctor Olds posted :

said by BonezX:

if it doesn't clear the brake calipers or impedes proper cooling of the brakes it is a problem.

also having smaller tires effects braking, as well as other things

He already has had the 14" Rims and has been driving on them since he got the car and changing the tires size will not make any changes to the existing rims dimensions. The Value Edition Model in 2005 comes with the same 14" Rim.
--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time?

Re: Tire size question

Mon, 29 Jun 2009 21:16:50 EDT

Doctor Olds posted :

said by pitroad01:

So what you are saying is that I could correct my problem with a 225/60/14 ...... I wonder if that tire would fit on my current 14" rim ?

Actually the 70 Series fits better with the closest to the original revolutions per mile.

This helps visually:

»www.miata.net/garage/tirecalc.html

Tire Size Comparison Specification  Sidewall  Radius  Diameter  Circumference  Revs/Mile  Difference195/60-15         4.6in  12.1in    24.2in         76.1in        833        0.0%185/70-14         5.1in  12.1in    24.2in         76.0in        834       -0.1%

The second choice 225/60-14

Tire Size Comparison Specification  Sidewall  Radius  Diameter  Circumference  Revs/Mile  Difference195/60-15         4.6in  12.1in    24.2in         76.1in        833        0.0%225/60-14         5.3in  12.3in    24.6in         77.4in        819        1.7%

--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time?

Re: Tire size question

Mon, 29 Jun 2009 21:13:17 EDT

BonezX posted :

said by aurgathor:

Wheel diameter is mostly irrelevant, it's the outside diameter of the tire that matters.

if it doesn't clear the brake calipers or impedes proper cooling of the brakes it is a problem.

also having smaller tires effects braking, as well as other things

Re: Tire size question

Mon, 29 Jun 2009 21:04:52 EDT

pitroad01 posted : So what you are saying is that I could correct my problem with a 225/60/14 ...... I wonder if that tire would fit on my current 14" rim ?

Re: Tire size question

Mon, 29 Jun 2009 20:47:06 EDT

Doctor Olds posted : If you want the same width tire then:

Original tire [195/60-15]
Sidewall: 4.61 in
Radius: 12.11 in
Diameter: 24.21 in
Circumf: 76.07 in
Revs/mile: 832.96

New Tire [215/60-14]
Sidewall: 5.08 in
Radius: 12.08 in
Diameter: 24.16 in
Circumf: 75.89 in
Revs/mile: 834.86

Speedometer reading with new tire is 0.23% too fast.
When your speedometer is reading 60mph you are actually traveling 59.86mph.

or

Original tire [195/60-15]
Sidewall: 4.61 in
Radius: 12.11 in
Diameter: 24.21 in
Circumf: 76.07 in
Revs/mile: 832.96

New Tire [225/60-14]
Sidewall: 5.31 in
Radius: 12.31 in
Diameter: 24.63 in
Circumf: 77.38 in
Revs/mile: 818.85

Speedometer reading with new tire is 1.72% too slow.
When your speedometer is reading 60mph you are actually traveling 61.02mph.

or 65 series (not as wide)

Original tire [195/60-15]
Sidewall: 4.61 in
Radius: 12.11 in
Diameter: 24.21 in
Circumf: 76.07 in
Revs/mile: 832.96

New Tire [205/65-14]
Sidewall: 5.25 in
Radius: 12.25 in
Diameter: 24.49 in
Circumf: 76.94 in
Revs/mile: 823.45

Speedometer reading with new tire is 1.15% too slow.
When your speedometer is reading 60mph you are actually traveling 60.68mph.

or 70 series

Original tire [195/60-15]
Sidewall: 4.61 in
Radius: 12.11 in
Diameter: 24.21 in
Circumf: 76.07 in
Revs/mile: 832.96

New Tire [185/70-14]
Sidewall: 5.10 in
Radius: 12.10 in
Diameter: 24.20 in
Circumf: 76.02 in
Revs/mile: 833.50

Speedometer reading with new tire is 0.07% too fast.
When your speedometer is reading 60mph you are actually traveling 59.96mph.
--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time?

Re: Tire size question

Mon, 29 Jun 2009 20:02:55 EDT

pitroad01 posted :

said by Doctor Olds:

said by markwp2001:

I believe he got the 7% figure

The difference value is seen in the post directly above yours which was determined by »www.tiresizecalculator.info/ after the tire sizes were posted.

That's a neat site. I'm sure their numbers are correct. I guess I'm stuck. I was hoping they could make a change in the car processor to calculate speed and distance with a 14" tire but evidently they can't. I wonder if there is a certain size 14" that would work ?

Re: Tire size question

Mon, 29 Jun 2009 18:54:03 EDT

Doctor Olds posted :

said by markwp2001:

I believe he got the 7% figure

The difference value is seen in the post directly above yours which was determined by »www.tiresizecalculator.info/ after the tire sizes were posted.
--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time?

Re: Tire size question

Mon, 29 Jun 2009 18:10:28 EDT

pitroad01 posted :

said by markwp2001:

said by Doctor Olds:

said by pitroad01:

Well I found out that running 14" tires on a car that was built for 15" causes the speedometer and odometer to error. The tire size is programed into the cars processors. So my speed and mileage are off by about 7%.

You are leaving out what size the Tire is that is installed on the 14" rim. Without knowing that and without knowing a few other factors you are possibly incorrect about the 7% difference.

I believe he got the 7% figure by comparing his odometer reading to the GPS reading of miles driven.

I threw out the figures I had recorded for the trip but it came to like 93% .... + or - a little.

Re: Tire size question

Mon, 29 Jun 2009 17:27:50 EDT

markwp2001 posted :

said by Doctor Olds:

You are leaving out what size the Tire is that is installed on the 14" rim. Without knowing that and without knowing a few other factors you are possibly incorrect about the 7% difference.

I believe he got the 7% figure by comparing his odometer reading to the GPS reading of miles driven.
--
Into music? tealeafgreen.com

Re: Tire size question

Mon, 29 Jun 2009 17:09:08 EDT

Doctor Olds posted :

said by pitroad01:

My Civic is a 4DR EX SE (4 speed automatic)
I have the original sticker and it says :

The sticker says it had P195/60 R15 87H All-Season Tires.

Then you should have returned to Dealer when you determined the tires/rims were not the correct OE size.

»www.tiresizecalculator.info/

quote:
Original tire [195/60R15]
Sidewall: 4.61 in
Radius: 12.11 in
Diameter: 24.21 in
Circumf: 76.07 in
Revs/mile: 832.96

New Tire [185/60R14]
Sidewall: 4.37 in
Radius: 11.37 in
Diameter: 22.74 in
Circumf: 71.44 in
Revs/mile: 886.89

Speedometer reading with new tire is 6.08% too fast.
When your speedometer is reading 60mph you are actually traveling 56.11mph.

--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time?

Re: Tire size question

Mon, 29 Jun 2009 16:59:40 EDT

pitroad01 posted : My Civic is a 4DR EX SE (4 speed automatic)
I have the original sticker and it says :

Special Edition Features Include:
AM/FM 6-Disk in-dash CD audio System with 6 Speakers & MP3 Playback
Leather-Wrapped Steering Wheel
15" X 6.0" 15-Spoke Alloy Wheels
Wing Spoiler

The car was built in Canada and sold at a dealer in North Carolina. A private Honda garage was able to research the VIN and found that it was built with 15" wheels. The sticker says it had P195/60 R15 87H All-Season Tires.

Re: Tire size question

Mon, 29 Jun 2009 16:31:23 EDT

Doctor Olds posted : And this is a Civic 4-Door Sedan, correct?

Which one in the Yellow highlighted image below is yours?

[att=1]

There is a 185/70-14 that is used on these 2 Models:

»www.tirerack.com/tires/SelectTir···ModClar=
Original Equipment Sizes for 2005 Honda Civic Value Package Coupe
Description Size
Original Equipment Size 1: 185/70-14

»www.tirerack.com/tires/SelectTir···ModClar=
Original Equipment Sizes for 2005 Honda Civic Value Package Sedan
Description Size
Original Equipment Size: 185/70-14

Re: Tire size question

Mon, 29 Jun 2009 16:22:42 EDT

pitroad01 posted :

said by Doctor Olds:

You are leaving out what size the Tire is that is installed on the 14" rim. Without knowing that and without knowing a few other factors you are possibly incorrect about the 7% difference.

The tires are P185 60 R14 .... 14" tires

Re: Tire size question

Mon, 29 Jun 2009 16:18:17 EDT

Doctor Olds posted :

You are leaving out what size the Tire is that is installed on the 14" rim. Without knowing that and without knowing a few other factors you are possibly incorrect about the 7% difference.
--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time?

Re: Tire size question

Mon, 29 Jun 2009 16:11:35 EDT

pitroad01 posted : Well I found out that running 14" tires on a car that was built for 15" causes the speedometer and odometer to error. The tire size is programed into the cars processors. So my speed and mileage are off by about 7%. I took a 400 mile trip and used my GPS to monitor speed and distance against the cars speedometer and odometer. I really don't care about the speedometer being off but I do about the odometer. I am logging 7% more miles then are actually being driven. Sucks .... expensive to correct and put 15" wheels and tires on at this point. Best I can find are 15" used Honda aluminum wheels for $150.00 each and then I have to buy tires.

Re: Tire size question

Wed, 17 Jun 2009 19:06:25 EDT

aurgathor posted : Wheel diameter is mostly irrelevant, it's the outside diameter of the tire that matters.
--
And the winner is:

Re: Tire size question

Tue, 16 Jun 2009 15:33:07 EDT

Doctor Olds posted : »consumerguideauto.howstuffworks.···ivic.htm

quote:
The Si includes a sport suspension and 16-inch wheels. Wheels are 15 inches for LX and EX models, 14s elsewhere. The new top-line Civic is the EX-based Special Edition coupe and sedan.

Its possible it came from the Dealer that way even though the EX is supposedly fitted with 15" wheels. It shouldn't cause any issues.
--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time?

Tire size question

Tue, 16 Jun 2009 14:45:09 EDT

pitroad01 posted : The 2005 Honda Civic Ex SA I just bought calls for 15" tires. The vehicle has 14" tires on it. Does that throw off anything or is it OK.