Imperial to metric tyre sizes?

[KX500]

Looking to shod the xr650 with some new tyre's, says in book the recommended tyres sizes are

Front: 3.00-21 51P
Rear: 4.50-18 70P

Anyone know what the equivalent metric sizes are please ?


Cheers

[grusomhat]

Front: 75 / 100 21
Rear: 115 / 100 18

I wouldn't quote me on that though.

[YellowDog]

I suspect this is the standard:

Front 120/80/17
Rear 140/80/17

But it does depend upon your rims.

[KX500]

Cheers


At the moment the below tyre sizes are fitted so close to what YellowDog has quoted, I suspect with Honda taking years to produce the final product despite pressure that the tyre size will all be part of the total plan so curious to the exact equivalent, an imperial to metric calculator be a fine thing. (mate got same bike so want the edge, especially on the tar )

90/90-21
140/80-18