right guys im gonna give these a shot but 1 thing im a bit unsure about is the

4.75 -17 (120/90-17) as the size of my metzler tourance is 130/80/17 also
is the 4.75 reffering to rim width :(

What bike are you fitting them too?

As I've already said, it is sometimes possible to fit slightly different tyres to bikes. My XT6 has 120/90 17 Rear 90/90 21 Front. I have been informed that it is possible to fit 130/80 17 to the rear wheel. Aparently, the width is used in the height or vice versa... Not quite sure of the science here.

I'm sure someone else (more technically minded) will be able to help you out here... That's what this thing is for after all. It would certainly help if you could tell us what model bike you have. :thumbup1:

oops thought i had it in my sig 2002 xt600e

That helps....

The standard tyre size for a XT600E is -

Front - 90/90 21
Rear - 120/90 17

I presume your bike is completely standard. It sounds like someone has in the past fitted a different tyre size! Perhaps before you had it?

I would try stick to STANDARD sizes if possible. The 130/80 17 you refer to can be fitted according to some odd people. A different (non-standard) size MAY adversely effect handling etc...

The Michelin website actually recommends fitting either tyre size!!!!!!!!!!! - Michelin offers

I opted for the STANDARD size SIRAC's (120/90 17 - 90/90 21).

I believe that Trellesport do manufacture Army Specials to all those sizes.

well i got the tires today and got em on the bike handy enough.
tell ya what going from a 17" moto wheel with a road tire to a 21"wheel with a nobly on it is so weird hte steering feels so tight at the bars as in to pull left or right requires a tad more effort nothing to silly but noticeable none the less
tire sizes r as kentfallen says 4.75 -17 (120/90-17) the 4.75 had me a tad confused but it be on with no probs

hopfully this weekend ill get a chance to do a bit of offroading at the local leadmines if so ill tell yas how they go

plus once i get my hands on a mobile with a decent cam on it ill get a few pics up for yas (lost my sony k800i on a building site :oops2:) does look well with noblys on it :mchappy:

Glad to been of help here. Ride safely...:scooter:

Righto, now the technical stuff.

These tyres are dual marked - that is they show you the size of the tyre in 2 ways.

A tyre size is defined by three characteristics, the nominal section width, the aspect ratio and the rim diameter it suits. That's why you see three numbers on a modern tyre size description.

The metric marking is the 120/90- 17 marking. The 120 is the nominal section width in millimetres. (The width of the tyre), the 90 is the aspect ratio, expressed as a percentage of the nominal section width, (the height of the tyre as a percentage of it's width, so in this case 90% of 120 mm = 108mm high), and the 17 is the rim diameter in inches. (Yeah, I know that's not metric, but that's the way it's measured).

The nominal section width is the width of a fitted, unloaded but inflated tyre. Squat behind the bike, and picture the sectional view of that tyre, if you cut sideways, along the plane of the axle. The widest point (not neccesarily the tread, could be the sidewall, and not including any raised lettering etc) is the sectional width.

The aspect ratio is the nominal section width, divided by the nominal height of the tyre, expressed as a percentage. The sectional height is measured again as fitted, inflated, but unladen, and is the measurement from the lowest part of the tyre section (usualy the bead heel, where it sits against the rim) in a straight vertical line to the highest point of the tyre, (usualy the top centre of the tread).

The rim diameter is not the diameter of the hole in the middle of the tyre, but the wheel diameter it should be fitted to, measured at the point that the tyre bead heel sits.

Imperial is the 4.75 - 17 marking. The 4.75 is the nominal section width in inches, (how wide the tyre is), the 17 is the rim diameter in inches. The lack of an aspect ratio figure implies an aspect ratio of 80%. Traditionaly all tyres had an aspect ratio of 80%, so no one bothered to to mention it.

So the definition of a low profile tyre is one with an aspect ratio of less than 80% - good for feedback, handling and stiffness, bad for comfort noise and rim protection.

An awful lot of work is done by the big tyre manufacturers with the vehicle manufacturers to get the right tyre for the requirements of the vehicle. The tyre manufacturers are the people to ask about which tyre to fit. Std size is best 99.99% of the time. Unless it's on it's original tyres, check what they should be with the tyre manufacturers. They may be more than one recommeded size, and they will feel very different on the bike. Michelin have technical helplines (local rate numbers) where real people will tell you what tyre options there are for your bike, and what pressures you should be running in what conditions. I assume the other big manufacturers do the same. The web sites should give you some good advice too.

Hope this helps.

well guys i had em of road over the weekend and they performed tops i managed to claber a m8 that was trailing me from head to toe with puty like mud so they get full marks in that section (woodland and rocky terrain )

also as far as onroad use goes u do become used to them they felt odd as fook to start with but a few hours with em and there spot on (wet roads still to happen)

1 thing that did cause a bit of a hickup was the gear stick getting bent back 90 degrees luckily enough it was steel and could be re shaped

Nice to hear that the tyres are performing so well... Keep us informed of any developments. I'm giving serious consideration to fitting a pair when my Michelin Sirac's need replacing...:thumbup1:

ENJOY:scooter: