Tire Pressure Question

[acguzzi]

going by temperature rise is the right way to do it if you know you get get your tires up to temp, and that is the problem. On the street you will probably not know if you are reaching the right temperature or if you do you will probably get a ticket. I would use what the tire manufacturer recommends as tire construction varies from manufacturer to manufacturer.

[bigbikerrick]

On an Ur-Eldo, I think you'll find 32 psi front and 36 psi rear to be a good starting point. That's what I use in all Loops.

                                                     

[Gliderjohn]

My Norge has a pretty wide low profile rear and the owners manual calls for 41 rear and 39 front. For what it is worth my T-3 seems to do well with 38 rear and 36 front.
GliderJohn

[chuck peterson]

Just off the top of my head without looking at my notes...........

Heavy vert, 38/42 cold, 42/46 after driving 1/2 hr

Light vert, 34/40 cold, 37.5/44 after driving 1/2 hr

v700 loop 32/36 cold, 35/39 after

Nevada 32/32 cold, 35/35 after

Honda 400f 26/28 cold, 28.5/ 31 after

Cal III full fairing loaded, 38/44 cold, , 42/48

1976 moped 24/24 cold, 26.5/26.5 after

All at medium temps. Colder weather? Start lower. Hi temps bump up a bit. The 10 % rise compensates for bike size, manufacturer, ambient temp, driving style, grip vs longevity. Today I can notice when it's down two pounds.

Try it, it feels good to me, and it's a no cost option to try

Your numbers depend on your conditions

[Moto]

My taste is to be analytical about this.

I think that tires hold the road better with less pressure, because they have a larger contact area and also because they get warmer from a greater internal friction caused by more flexing.

On the other hand, too much flexing can lead to too much heat and tire failure.

So the goal is to lower pressure to a point that helps roadholding but doesn't increase the risk of failure too much.

That goal is met, I believe, by looking for a 10% rise in pressure as the tire gets warm.

Running at the full load rating on the tire's sidewall means less traction. Lawyers probably influence manufacturers to recommend higher than optimal pressures in the hope of avoiding failures. I recently bought a bike that simply recommended the tire's full pressure rating on the sidewall, front and rear (36 psi), even though the loading on the tires was not much more than 50% of their capacity. This, in my opinion, is nuts, except from a liability lawyer's point of view!

I recommend following the 10% rule, and looking for specific recommendations for your bike or a similar one as a starting point. Usually the front needs 4 to 8 pounds less pressure than the rear.

I also think adding pressure to the rear is appropriate for hauling a passenger long distance, and that adding a couple of pounds front and rear is good for high speed highway travel.

Moto

EDIT: Another thing I think leads manufacturers to increase tire pressure recommendations is the evidence that the majority of riders ignore their tire pressures, letting them drop dangerously low between what checks they do.

[kingoffleece]

When the guys from the Dunlop MotoGP tire team came to our M/C club they recommended the 10% rule for street riders as a great starting point that will get very close to what the ideal pressure should be for a motorcycle.  Fine tune from there.
Good enough for me.