My Fatboy, in common with my former ride (2014 XLT 1200T Sportster) has tires specified at 42PSI for the rear tire and 36PSI for the front tire. I check the pressure every Saturday morning before my weekend riding, and happily the pressure is usually just about perfect; maybe 40-41 PSI and 34-35PSI. I naturally add a few seconds of air to get them exactly to spec. Of course this is done when the bike is "cold" -- not having been ridden for at least 12 hours or more. Here in Southern California right now my garage is about 75 degrees, by the way.

My question is a little silly, but I have been reading various threads that seem to recommend going a bit above factory specs for tire pressure. I was going to discuss that with my mechanic, but I was curious what you fellows all thought about that. I am a "by the book" guy and I am reluctant to deviate from spec and certainly have no plans to do so, but what do you all think?

Related question: what is tire "cupping"?

Thanks guys (and ladies) -- I have learned a lot from this forum during the 2 years I've been a member.

 

Can't speak to the tire pressure issue (don't exceed the pressures listed as max pressure on the tire sidewall for liability purposes).
Cupping is a tire wear pattern. Instead of even wear around the circumference of the tire, the tire wears in a wavy pattern. Not unusual for heavy bikes. Goldwings are especially susceptible (my GL1500 had it bad, so far, no problem on my GL1800). Often related to underinflation and/or head bearing wear.

 

Correct on the description of cupping, and its typically caused by an out of balance wheel - best look at dynamic balancing such as RideOn or Dyna Beads.

I run 36 psi front and rear, and when I had 42 psi in the rear the ride was hard and the centre strip wear was unacceptably high.

 

On my '94 Heritage, I keep the front tire inflation up and my head bearings are perfect. Still, every front tire I've run on this bike (all 20 of them) will cup given enough miles. I've also been told it's a natural consequence of using the front brake (which I always do). It also may depend on the type of tire. I don't know.


I seem to get the best tire life on my bike running 36 front, 38 rear (solo). as always, YMMV.

 

I prefer slightly lower PSI also....low to mid 30's.
Run her at 40 or 42...too firm, harsh. Squeek out just a few PSI and "ahhh..that's better!"

 

I find that if my front tire is too soft or hard that the bike wallows at speed. I found 40/36 to be the best combination.

 

You know you lose a pound or two checking. That is why you are down. I check mine in March when riding starts, and mid-summer. Never down. If you are loosing air every week you got a problem with sealing

 

More often than not, front tire cupping is due to under inflation. When the front brake is applied on an under inflated tire, the center of the tire "folds" in and leaves the outsides of the tread to do the majority of the braking. Thus, wearing in an uneven, "cupped" or "scalloped" pattern.

 

Yep, agreed, under inflation is the more likely cause followed by poor shock absorbers and imbalance.

The installation of Monotubes might be the reason why my current front wheel shows no sign of cupping.

 

The factory engineers know best. Put in what is recommended for your bike. Beware...not what is labeled on the tire. The tire label is maximum pressure.

The higher the pressure, the harder the ride, and the smaller the contact patch. Also, a harder tire will be easier thrown when hitting objects such as stones. The engineers are much more qualified to optimize tire pressure than any mechanic. With all due respect to mechanics...