Does Anyone Understand What Tire Sizes Mean???????

I have an 01 YZ250F.When I got it it had an 80/100-21 dunlop 739 tire on it.I went to an 18" rear wheel. I noticed that they put 110/90-18 size rear tires on the wr models.basically I would like to stay as close to those two sizes as I can.However, in the summer I run Michelin S12s. They have wierd tire sizes.On the front I run a 90/90-21 and on the back I run a 130/80-18 (which I guess its like a 110/100-18).Are these my closest match as far as stock tire size(and still stay with S12s)?Also, I run Trelleborg ice tires in the winter.I'm running a 434 front size:80/100-21 and a 244 rear size 4.40-18.Are these sizes pretty close to stock?Trelleborg doesn't have many choices in tire sizes.Basically The diferent brands of tire sizing is getting me confused.How technical is tire sizing as far as handling is concerned?Thanks guys.

Most tires will have the same overall dimentions.

19 to 18" tire will make the biggest difference in handling. More rubber sidewall means more walk and more flex in turning.

The width of the tire is the second most important handling concern. Too wide a tire, and the bike will not turn as well. Too narrow a tire, and you get less hookup and it probably would feel "floppy" in a turn.

A 130 michelin is a 110 Dunlop, Bridgestone, Maxxis, ect....

ok hutch,i use to work in w/sale m/cycle parts which included tyres.i have a wr25001 so i can help you out with your questions.i run 80/100-21 front and 100/100-18 rear but sometimes 110/100-18 depending on the terrain as pirelli dont make the 100/100 in an mt 32 inter.i dont know if you understand what the numbers mean or not so i hope you dont think im dribbling [censored].the first number(110)is the width of the tyre in mm,the next number is(100)the height ie from rim to the top of the tread pattern,and the last digit is of course the diametre(18)but this is measured in inches????i use pirellis most of the time as i can get them cheap but the 739 is a good all round tyre.the 130/80-18 is miles to large a tyre for you.i hope i have managed to help you??

The S12 Michelin rear tire says 130/80-18, but the sticker on the tire says 110/100-18 on it. I'm thinking the size on the tire is some kind of european sizing and the sticker is what it compares with US tire sizes.Would that still be too big of a tire since Michelin doesn't make a 110/90-18???

The second number is the aspect ratio which indicates tire height as a % of tire width. In other words if your tire cross sectional area is 120mm and the aspect ratio is 80 (80%), the height is 96mm. 120*.8= 96. Don't be mislead into thinking that the second # is height in mm! Not all manufacturers measure th tire the same. Some measure outside the tread for width and some measure the casing width.

Thanks hoov165x. I never paid any attention to it for too long. The local shop explained it to me. You did a better job. I did not know if they measure the casing or the knob either. Good post

So is a 4.40-18 too big of a tire for the YZ250F?

All I know is 'SIZE DOES MATTER"

Now regarding tires

Here is a good chart for you to determin that for yourself. But keep in mind a bigger tire doesnt mean more traction, it could hinder the bike in many ways.

Such as Power to the ground, cornering and speed. Its called drag.

I know that will start a debat, well what about dragsters, race tires and so forth. well the quick anser is Application / HP

It may b a little big

if you go by the chart

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now