All right...with all this recent talk about the widest rear tire for an SF, I'd like to hear a little opinion on narrow tires. I picked up a couple 3.5-inch wide rear trials tires from CL on the very cheap. Unused. This guy wanted to put them on some electric bike and they were too wide. I'm looking to use them on trails. Gravel, rock, some sand, not too much mud, roots, climbing, and they'll probably get some commuting around town. What are the benefits and drawbacks of narrow rear tires, and in particular trials tires, for mainly off-road use? Ya, they may not look cool, but I don't care.

 

Other than in sand & mud (where you want some float) I think a narrow tire would be great. Smaller footprint = more pounds per square inch sticking you onto the planet. Who cares how they look if they work good! But are they taller than stock which would raise the effective gearing? Trials tires are quite sticky = TRACTION.

 

They could be, but not by too much just eying them. But that doesn't matter for me. I have 13, 14, & 15 counter sprockets with a 49 rear sprocket and change the counter depending on where I'll be riding. Right now, it's on the 14. The 13 works great for slow, technical work but bumps up to 8,000 rpm at 65 mph .

 

Man, Scott, I don't even know how to read English rated sizing in tires anymore. Plus, when most tires used that sizing, many were wildly exaggerated. Any idea what the metric numbers might be? Often when you still English sizing, the metric is occasionally on there too. I use a 100/100 rear Kenda Trakmaster, and as you saw even in the sand out at Fins & Things in Moab, it did quite well. You probably remember the big debate awhile back on bigger tires on the rear. Most of your racers know that big rears aren't the hot setup anymore. Even the current WR250F racing model only uses a 100/100 X 18. I guess it comes down to how that 3.5 tire actually relates to a metric sizing we can rely on. Even a pic might not do any good, as you know how hard it is to eyeball an uninflated tire.

 

3.5 inch x 25.4 mm/inch = 89. Call it a 90. That's only 0.44-inches narrower than your 100. If I recall, the marking on the tire is "3.5 x 18" but I'll look at it later.

 

A 3.5 may work on the rear of an S, and it may actually IMPROVE traction (indeed, that's the principle for winter tires on cars). But, it would be too narrow for the stock rear wheel of an SF.

 

And the SF uses a 17", doesn't it?

 

YES, 17" front and rear on an SF; they are the bane of any one trying to install knobbies on an SF!

 

BTW TNC, Imperial tire sizes are STILL wildly exaggerated judging by my Shinkos which measure ~1/4" narrower than advertised!

 

Looked at them again...

Golden Boy 3.5-18

And of course there are some other numbers, but nothing indicating a metric size that I can decipher. Golden Boy are apparently Shinko. I measured it at about 3 7/8" wide, laying flat with a straight edge. Will give one a try as soon as the MT21 goes away, which won't be too much longer. Looks like I'll get somewhere around 1,500 miles from it.

RMATV has Shinko SR241 for $38. Anyone running these?