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Rig Front Tire options??

Okay, let's talk about front tires for your rig.

The Gold Wing 1800 uses a 130/70-18 MC tire on the front. Being a rounded MC tire, the actual wear width is only 2.5 inches. So of the 130 mm tire width (roughly 5.12 inches), only half of the available tire surface is the actual contact patch.

Would a 4.00-18 Heidenau K-28 with its flat profile be a better front tire?  Though a narrower tire, the actual contact patch would be much larger.

How does one find the aspect ratio of a 4.00-18 tire?  ...and the diameter?

NOTE: the found 135/70-18 auto tires were all space saver tires with shallow tread.

What say our tire experts? 

A 4.00x18 measures out to roughly 102/95-18 but this will vary from mfg to mfg and from model to model. It's really more of an "indication" of size rather than an actual size.  However, doing the math suggests the sidewall height on a 4.00x18 might be about 97mm.  The sidewall height of a 130/70-18 is about 91mm.  So you have to look at the clearance between your fender and tire.

I think it would probably fit OK because the Heidenau is not really much taller than the outer edge of its sidewall because of the square profile of the tread.  The center of the tread of a moto tire with its rounded tread profile will be of course much higher than the sidewall.  I guess what that means is that you need to find out the actual diameter of the Heidenau.  I looked online and I found one website saying it 27.44 inches but I found no confirmation for that and that number looks to me like two inches too much.  Maybe there's a Ural guy with that tire who could go out to the garage and measure it?

By the way, how tall is the tire you have on there now?

The K28 is a hard-wearing tire with a great footprint but, for me, I wouldn't want a tube-type tire on my 'Wing.  Instead, I use a 130/70-18 bias-ply rear tire which gives me a wider contact patch and a tougher carcass than a 130/70-18 front tire. Easy steering, excellent braking, and I've never noticed any slip during cornering though, admittedly, I don't drive my 'Wing rig like a hot rod either. YMMV.

CCjon has reacted to this post.

Car tire on front the answer is often to change wheel doing the home work you can often go to a 16 inch wheel and with the right car tire come out he same height.

Bit harder on front.

130/70 18

DIA  25.7

Width 5.5

Sidewall 3.8

Circum  80.6

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 Biggest issue with getting car tire in front is width. many end up going with a wide front end and that is not cheap.

You will see wider car tires on some GW rigs with front end work. Another option is a rear tire in front run backwards.

There just are not  a lot of options for a 18 inch wheel.

 On the rear I was facing 180/55 18. Nothing would work. The answers was go to 16 inch wheel and 195/65r16 tire results was same height and 6 tenths of an inch wider. A 195/60R16 would have worked also but was a little lower width cam out about the same.

If you have time playing with this tool and trying different wheels and tire will help get you going in the right direction. It does not madder if they are car or motorcycle tires the math still works.

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