Can anyone help I have an xs 250 project under way and I want to know will a Dunlop 4.00-18 tyre fit onto the front wheel ??

I currently have an Avon Road Rider 100/90-18 on the front the wheel is a 1.85-18, I have been told that a 4.00-18 you cannot get un yet I have seen a few bikes with these sizes tyres on with the same wheels,

I think the guy in the garage where I purchased the Avon from just wanted the sale and doesn't know the meaning of customer service, I was charged £90 for the Avon and since seen it on line a lot, lot cheaper, The tyre I am thinking of is a Dunlop 4.00-18 does anyone know if this will fit ????

I'd have a look at this chart.

http://dropbears.com/u/utilities/tyrerim.htm

you don't want to ride the tyre off the rim.

If you have spoked wheels then you can get a wider rim on

What's the standard spec sized tyre?

A 4.00 will be about the same width as a 100 but because the 100 has a 90 profile the 4.00 may have a bigger tyre wall.

4.00 means 4 inches across and probably a 4 inch tyre wall. 100/90 means 100mm across and 90% of the 100mm tyre wall. Imperial and metric tyres are measured at different parts of the tyre so it is not as straight forward as it seems.

Dirty DT, so do you think a 4.00-18 would fit on the front without the tyre touching the forks ??

its the mudguards that may touch. a 120 on the rear is max without the chainguard and 1mm from the drive chain

I have to agree with Drewps on this. The tyre is at the top end of the rim range but the tyre shape will be different. Drewps is out XS expert.

is that not a tad big for a front?