I was sent this information by an Avon Motorcycle Tires USA rep regarding their suggested pressures for those of us using their Azaro sport touring series.  Perhaps it would be useful if information of this sort was gathered for other brands and models of tires - the pressures suggested in the owner's manual for the OEM tires are far lower than suggested for these aftermarket tires, and I would never have thought to set my tire pressures this high on my own.  All I had to do to get this info was shoot an email to Avon - those of you running Michelins, Pirellis, Bridgestones, etc. might consider doing the same (ask for appropriate ranges for tire pressures for your model tires - specify the year and model of your bike, the OEM tire sizes, and the tire sizes you're currently running) and posting the info here.

Quote
Hi Ryan, Keith here.

The non OEM sizes make this a little tricky.

The front 110/80R17 replacing a 110/70R17 sizing, the 80 series tire is
taller.

The rear 140/80R17 replacing a 130/70R17 sizing. The 140/80 is one size
wider and taller by twice.

The whole motorcycle has been raised up with the rear even taller. Center of gravity has been changed and steering geometry (steering quicken, less frt. length contact pattern).

OK, p.s.i. question time!

The 110/80R17 and 140/80R17 are non OEM sizes. So we will need to review general tire p.s.i. guidelines. But this will be still trial and error for the right p.s.i. for your motorcycle because of these non OEM sizes.

                     General Sizes/Pressure Chart

Code Select Expand

  Front          Solo         2 up light       2 up heavy
 3.25-80/90      32-34           32-34             34-36
 3.50-100/90     32-34           34-35             35-36
* 110/70-120/90   34-36           36-38             36-38
 130/60-150/80   34-36           36-38             38-40


  Rear
 4.00-100/90     34-36           36-38             38-40
 4.25-110/90     34-36           36-38             38-40
 120/80-130/90   36-38           38-40             40-42
 The next two your rear sizing is in between them.
* 140/70-190/50   36-38           38-40             40-42
* 140/90-200/50   38-40           40-42             40-42

Note: This is a wide range recommendation for average conditions only. High speed riding and high road temperatures may require a moderate increase in pressure.

Thanks, Keith

I have played around with my tire pressures over the past few days, which have seen a range of temperatures and road conditions (it's been raining off and on) and have found the best combination for road feel at my weight (180 with gear) is 35 front 38 rear.  Previously I was running 32 front 35 rear and there was more noticeable rolling resistance when moving the bike around in the garage and parking lots, and the bike really liked to follow ruts on the highway.  Now the ride is a bit firmer, but the bike doesn't squirm as badly on poor roads, and I don't get  "greasy" feel from the tires when turning when they're cold.

Interesting info!

Looks like you went from "1 under the recommended" to "2 over the recommended".

Here's the sticker on the swingarm of my '99.  (On my '96 I believe it was below the seat.)

I will check that out before i go riding again. When your tires are off by that much Psi can you tell visibly.

They have to be pretty damn low for you to see the difference...  Unless you're the head mechanic at Aurora Suzuki (he can see it from 20 yards).

Also, note that you want to increase your tire pressure for riding in the cold, because the tire does not expand as much, or enough, to obtain it's proper shape and maintain it's traction qualities.

Now, what I want to know is, what Keith (the guy who replied to Jazzz) means by 'less frt. length contact pattern', by raising the rear?

Good call on the pressures. I went out for the first time last weekend and neglected to check mine, bike felt really strange when cornering, so I decided to check i was down about 10 in the rear and 5 in the front . Glad I checked that now