I know its already posted somewhere, but......

[johnhunter44]

I just got a new 2009 RT and curious about what tire pressure is best to run? I am not a very aggressive driver and ride one-up mostly. I want to get the highest mileage I can, so what is the best pressure for this? Been running 40 front, 42 rear. Any suggestions?

[RodB]

Those are the pressures I run with pretty much the same conditions as yours, except I do ride 2-up a lot.

[OlGeezer]

I just got a new 2009 RT and curious about what tire pressure is best to run? I am not a very aggressive driver and ride one-up mostly. I want to get the highest mileage I can, so what is the best pressure for this? Been running 40 front, 42 rear. Any suggestions?

 

10% Rule

[JayW]

That 10% rule makes a lot of sense, though I I don't know why it is 10% and not, say, 7% or 13%.

 

You can get the best mileage by increasing pressure to the maximum the tire will allow for, but then the tire will have less carcass flex and thereby less road contact surface area which may reduce traction below a safe threshold. Maximum tire life is a great goal, but don't forget the safety factor.

 

Jay

[Paul In Australia]

+1

Very true. I am totally surprised at the mileage some people get from tyres ( allowing for climate, road etc). My analysisi suggests they must have pretty high pressures to get the quoted life.

I am happy with 7K to 7.5K miles and also have great traction. Each to their own.

best regards

Paul

[dirtrider]

Morning John

 

The BMW suggested tire pressures are in your riders manual. I’ll bet they (BMW engineering) put some time and effort into testing those recommended pressures, at least on the OEM furnished tires.

 

Excess tire pressure is not always the answer as that puffs the tire center out more so you get more center tire wear. Too high of tire pressures can also cause more tire slippage on braking, acceleration and rough roads. Remember your tire pressures are also part of the motorcycle overall spring and shock system so the tire pressures can slightly effect the stock shock control and spring rates.

 

Personally I use the BMW recommended tire pressures to start with then check that against the 10% rule. So far on all my late BMW’s the riders manual recommended tire pressures are fairly close for the roads in my riding area and my riding style.

 

I have always wondered if the same riders that don’t trust the riders manual on tire pressure recommendation also add a little more oil than recommended at oil change time or put a few more ounces of oil in the final drive at final drive change time or tighten the bolts and nuts to a little higher torque than the manual recommends.

 

[Don_Eilenberger]

The 10% rule is almost worthless with radial tires. Actually - I'd say it's totally worthless.

 

Example - yesterday started out about 59F and drifted up to 69F mid-day. I have a tire-pressure-monitor where I can monitor in real time, tire temp and pressure.

 

At 59F - I had about 33F and 37R. As the tire warmed up, it went up to eventually about 101 degF front, and 99 degF rear - where the pressures were 38F and 42R. But - that was high-speed highway temps. On local roads at 30-40MPH the tires cooled off a bit (probably around 80/82F) - and pressure was around 36F/40R..

 

So where do you draw the 10% rule when the actual pressures can vary that much with difference in temperature (which doesn't have to be caused by riding - ambient temps in NJ certainly cover those ranges, and can on a single day..)

 

I tend to agree with the factory pressure, but at the moment I'm trying about 3PSI more just out of curiosity. It felt OK yesterday, but this AM when it was 41F it felt rather squirrelly..

[dirtrider]

Afternoon Don

 

I apply the 10% rule at the hottest the tire gets, never on a local or slow speed run.

I usually take the pressure reading after a long high speed run on a warm day.

Worst case = 10% pressure build or under.

 

Hot high speed running is where you get the heat build up. Slow speed on a cold road won’t tell you much.

 

The only time I might raise the tire pressures above the recommended is in the spring when the pot holes are out in force as a coupler of PSI extra can sometimes protect from a bent rim.

 

Can’t say I get the best tire mileage but I do get pretty even tire wear with no cupping or feathering and the tires stay fairly quiet until just near the end of life cycle.