question about tyres?

Question

the tyre size on my standard alloys is i think 185,55,14 ive bought a set of alloys 16'. ive been told 205,40,16 i will need but i would like to go a bit wider to 225,40,16. would this affect the driving in a bad way. does anyone know the tyre size i should have.

Answer 1

A 205/40R16XL 83 is the ideal +2 application from a 185/55R14 80. You only have to increase the air pressure 2 PSI to maintain the same load carrying capacity as the smaller tire and the overall diameter is very close with the 16-inch tire being only slightly larger so your speedometer and odometer readings should hardly be effected. Depending on the vehicle they are being installed on you should have the least problems with interference with this size as well.

If you are going to use the 225/40R16 85 size I would suggest test-fitting one tire and wheel first to make sure you don't have any clearance problems before mounting up the rest. And again, depending on the application, this may be too much tire for the car from a performance standpoint. The 205/40R16 could actually offer better grip.

Answer 2

The first number in the tire size is the width in mm. The second number is called the "aspect ratio" it is a percentage meaning the distance between the rim and the tread is what percentage of the tread width. The last number is the rim size in inches.
So your first tire 185/55R14 the tread is 185mm wide, and the distance between the rim and the tread is 55% of 185mm and it is on a 14inch wheel.
It is a very skinny short tire on a small rim.
You can easily figure out the total overall height of any tire by using a metric conversion. First figure out what 55% of 185mm is. Then multiply that number times 2 because the distance between the rim and the tread will be on the top and bottom of the tire. Then convert the number to inches, and add it to the rim size.
That will give you the total height of the tire, and you can also convert the 185 width to inches. Most tire manufacturer websites like goodyear will list tire dimensions in inches for each size.

As far as how it will affect the way the car drives, a wider tire will give better traction, and usually add to cornering stability, but the wider tire reduces increases resistance to roll therefore your fuel economy will go down.
Tires with a lower aspect ratio have a much stiffer ride and do not absorb bumps, impact and road imperfections well.

I went from 195/75R14 to 205/65R15, and it wasn't too bad, but then when I put 225/60R15 it cornered really nice, and had a really nice ride on really smooth freshly paved roads, but the suspension was designed to work with the taller tires, so the suspension was strange on bigger bumps and just road absolutely terrible on even slightly worn roads.

Wheel offset is also another dimension to be aware of, also called back spacing. If your wheel is 8inches wide and you have 3.75inches of back spacing it means that the wheel will stick out 4.25inches from the mounting face. So where it mounts is not in the center. If you go too low on the back spacing your wheels will stick out very far and have adverse effects on wheel bearings due to the added stress on them.
Most factory wheels have most of the width inside so the face of the wheel is usually pretty flush with where it is mounted, most people go to like a 3.5" or 3.75" wich will make the wheel stick out a little wider, and because you have a wider stance you have better stability on corners. However if you need to tuck the tires inside the fenders like if your factory clearence from the tread to the fender is already pretty close you may want to keep the factory back spacing, or possibly even go with more backspacing.

Also with back spacing if your tire is too wide, and your back spacing too little the inside edge of the tire will probably rub on the car's frame when turned all the way. With too much back spacing if you have close clearances with your fenders or bumper the center of the tread will probably rub on the bumper or back sides of the front fenders when turned, or rub on the rear fenders when you go over bumps and the suspension dips.

Also if the total height of the tire is alot taller than what came from the factory it will be harder to stop, and wear your brakes out alot quicker, so you may want to upgrade your brakes, especially if you are going with a larger rim diameter that can fit larger brakes.

Sorry this didn't answer your question, but at least it provides you with information so you can figure out the answer yourself. There are entirely too many variables to give you a definate yes or no answer.

oh yeah, last things, you will need to get an alignment because your suspension will be off even if it does not pull one way or the other, also a good alignment will give you the best fuel economy, ride quality, and cornering. If the tire is a different height than stock. your speedometer will be wrong, so you will need to ask a performance shop for a different speedometer gear to obtain the correct speed, unless it is electronic, then there is usually other ways they can calibrate it

Answer 3

First off make sure the tire will fit in the wheel well.

The first number represents the tread width in mm. The second number is the height of the side wall it is a percentage, ie. 40 equals 40% of the tread width. 16 is the rim size in inches.

The car will handle and perform differently with the change in tire size.

Steering will not be as responsive. Wider tires will tend to follow ruts or grooves int the road.

A lager tire diameter on your drive wheels will require more power to turn them. It is like increasing your drive ratio. The car will have a higher top speed but less acceleration. Your speedometer will also be incorrect. With a larger wheel diameter the speedometer will register a lower speed than actual.

Answer 4

How tall is the profile of the tires more the car will swing over them. How wider less you need to turn the wheel drive to make turns, but its going to be havier and the fuel consumption will grow up. So when you use low profile and wider tires you will loose confort, but you will have a more precisely and safe drive.
The suspension will pay the cost. So the size depends of your needs. Don´t forget that should use a tyre that fits good and safety to your wheels.

Answer 5

the cross section of the tyre depends on the width of the wheel(the 205 bit) if the wheels are 7inches wide you will require a 195 to 205 cross section tyre if it is 7.5 inches to eight inches you will require 205 to 215 tyres to big a cross section and the tyers probably wont seat properly and look shockingly horrible if they do. if youve got a small hatch back vehicle and the wheels are 7x16 inche i recomend 195/45/16 tyres this will give minimul scrubbage if any at all then i recomend lowering the cars suspension 30mm so it doesn't resemble a land rover

Answer 6

The overall tyre diameter of a 185/55x14 is 559mm.
The overall tyre diameter of a 205/40x16 is 570mm.

The difference is about 2%. The recommended maximum difference is ±2.5% when changing wheel sizes, so that looks about right.
(Assuming there are no wheel arch clearance issues).

The 225/40x16 is 586mm and nearly 5% more, so you'll have a bit of a gearing problem, if nothing else.

Answer 7

You will have problems steering and with tyres rubbing against the wheel archers if you go bigger than your cars spec!
Go to a tyre specialist and ask advice! Its Free!
Grrrrr! 225 is the width 40 is the depth 16 is the rim size!

Appart from that! Your insurance company will laugh at you if you exceed your cars spec and try to make a claim!

Answer 8

I've got 265-75-16's on my half ton GMC Z71. A stock 3/4 ton GM can take 285's with some fender modifications to keep them from rubbing. It gets to a point where it will affect the driving but with my 265's I find it handles just fine both on and off road. If you put a lift on you can get some bigger tires under it. It all depends on what you have for a vehicle. I'm talking trucks but if you have a car I have no idea.

Answer 9

The driving will be fine, the biggest issue is wheel well clearance. Since we don't know what you are driving the answer will have to be provided by a tire shop. They have experience fitting tires and wheels to a variety of cars and will know what you can get away with.

Answer 10

this is TIRES u are talking about? not only would it affect your driving like your toe in and toe out it would damage the front suspension and your front end would need to be lined up often as well as your speedometer.your speed would be greatly affected by that large a tire and your fuel consumption would increase dramatically