advantage of smaller wheels?

so, i heard an 18" rear wheel is used on enduros because it has better traction. is this the advantage? wouldnt switching from a 19" to an 18" have a similar effect as adding a tooth to the rear sprocket?

i want to switch to a 20" front and 18" rear for better traction off road, and hopefully a slightly lower seat height. would that drop the seat height much at all? these bikes are pretty tall. thanx for any info :thumbsup:

My understanding of wheel size. The 18 inch wheel has a taller side wall. The inside diameter is the 18. The outside diameter is the same for both 18 and 19 inch tires.

So for 18" or 20' fronts the theory follows-

Plus side-The taller side wall allows less pinching of the tubes and dinks to the wheel.

Minus side- Because the side wall is taller it allows more flex when cornering, this equates to less precise steering.

Some of the pros played with a 20 inch front in MX but it has all but gone away. I think that speaks to it's effectiveness.

Edog's pretty much correct... :thumbsup:

I would have thought that a larger wheel (tyre OD) would have better traction. The larger the tyre OD, the more rubber is on the ground. The run 17's on motard bikes to lower the C of G and for the far better tyre choice.

Along with taller sidewalls, you have less pinch-flats with a smaller

wheel. :thumbsup:

I would have thought that a larger wheel (tyre OD)

This is correct but the measurements here is the rim to outside of the tire measurements. The foot print measurement, distance accross the tire is what your looking for. On Dunlops it's the first number on the tire 110/100x18. So a 120/100x18 has a bigger foot print.

Now if you go bigger for traction you give up some too. The minus is clearance issues, cornering won't be as quick, and you will be carrying more weight on the end of the swing arm.

I have a 20" front on my 03 YZ250F and love it. Excellent traction, front end feels more planted and no or less pinch flats. Tire selection is very important, my current favorite front is a M59 Bridgestone. I tried a 756 and it was horrible.

my 110/90 x 19 works perfect on an mx track. launching, cornering and acceleration all seems just right in mx. my problem is when i go off road, i feel like ive got an odd type of traction when taking off. in the sand i just spin and spin, yet i can chunk a soft terrain tire in no time at all. am i looking for a different size tire (110, 120 or 18", 19"), or should i looking at different tread patterns for my 19"?

seems to me a 18" rear have more air volume than a 19", allowing a lower tire pressure :thumbsup:

It is a fact that a bigger wheel diameter allows for more traction for the same width (print). Think about farm tractors.... they have really tall rear wheels.

Then if the sidewalls of a 18'' makes the outside diameter the same as an 19. Then they are both the same in traction if the width is the same.

The 18'' rim is tougher than the 19. The larger the circle is, the easier it is to deform.

Then, I agree with endurodog on everything he said. :thumbsup:

The main way to get more traction is 2 fold, width of the tire, and lower tire pressure.

The minus of that is lower pressure can equal more flats. Wider tires, 120's or higher, are heavier and will be somewhat harder to turn.

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