Rear Tire Pressure Survey

[Grumpy Goat]

Please take a moment to take this survey. Poll is up for 90 days from today.

[Ray]

I'm assuming you mean cold pressures. I've noted previously that we used to spend time looking at pressures once he tires were warmed up - especially at the track.

Or, do you mean the pressure from the sensor that is corrected for temperature?

Maybe I'm old fashioned....
What's the ambient temperature?
What time of day is it? Will the temperature be increasing by more than 15 dec C?
What kind of roads am I going to be on? Any dirt or gravel planned? Interstate miles?
How much of a load am I carrying?

All that said, it's a 240 kg bike. I have great respect for the engineers, so I usually try to keep myself sane and keep the TPM happy at 42 PSI.... Modern electronics has made a few things simpler for me.

[Grumpy Goat]

I'm assuming you mean cold pressures. I've noted previously that we used to spend time looking at pressures once he tires were warmed up - especially at the track.

Or, do you mean the pressure from the sensor that is corrected for temperature?

Maybe I'm old fashioned....
What's the ambient temperature?
What time of day is it? Will the temperature be increasing by more than 15 dec C?
What kind of roads am I going to be on? Any dirt or gravel planned? Interstate miles?
How much of a load am I carrying?

All that said, it's a 240 kg bike. I have great respect for the engineers, so I usually try to keep myself sane and keep the TPM happy at 42 PSI.... Modern electronics has made a few things simpler for me.

Actually I put up this poll in response to a request from Darrell, who was interested in knowing what the actual real-world cold pressure preferences among RS owners was. Knowing Darrell, it is probably the pressure manually taken in the garage before a ride.

As an engineer I also tend to adhere to manufacturer's specs, and tire pressures is no different.

[SauRoN]

I do my very best to keep my RDC pressure at 2.9 bar.

Whether right or wrong it’s the only eternal constant and that is more important to me that being correct.


Sent from my iPhone using Tapatalk Pro

[Ray]

Actually I put up this poll in response to a request from Darrell, who was interested in knowing what the actual real-world cold pressure preferences among RS owners was. Knowing Darrell, it is probably the pressure manually taken in the garage before a ride.

Thanks. Should be interesting.

[Duccrazydave]

I like how this evolved into specifics. If I'm riding loaded (meaning partially filled panniers or 2 up, not drunk) I'll always run the recommended pressure. But solo in the twisties, I tend to run F-34psi / R-38psi. I like the added compliance that slightly offsets the harsh compression damping, while in Dynamic mode.
With the same size tires on my Ducati (almost 100lbs lighter), I run F-32psi / R-34psi. On the track, less, as Ray has stated already.

[Grumpy Goat]

A good approach. The harder pressures are better for fuel economy while for the twisties you want the tires a little softer.

[runnerhiker]

I like how this evolved into specifics. If I'm riding loaded (meaning partially filled panniers or 2 up, not drunk) I'll always run the recommended pressure. But solo in the twisties, I tend to run F-34psi / R-38psi. I like the added compliance that slightly offsets the harsh compression damping, while in Dynamic mode.
With the same size tires on my Ducati (almost 100lbs lighter), I run F-32psi / R-34psi. On the track, less, as Ray has stated already.

This is what I do. I read an article by Dunlop on the Dunlop site (article no longer available) that explained that the recommended pressure by the bike manufacturer was to carry the maximum allowable load on the motorcycle. But that it did not mean that was the recommended pressure all the time for all circumstances. The lower the pressure, the lower load carrying capacity and the better the traction - they did not offer a graph or chart for guidance. As I remember, the only guidance was that around 30 psi would be as low as they would go, and that experimenting at a track was the best thing to do.

My biggest takeaway was that the 42 psi was important for a loaded bike and that anything lower than that would give better traction and do no harm if the pressure was not too low (like 30 psi).

[Grumpy Goat]

So far a surprising percentage of respondents are running 36 - 38 psi at the rear.

[darrell]

As Wayne mentions I am surprised people running the lower pressures. Since my bike was new 4 years ago I’ve been running 38 front, 42 rear psi regardless of load or atmospheric temps. I use calibrated gauges (calibrate against the dealer calibrated gauge) checking every single time I leave the garage at home and every other day when traveling unless I have significant elevation or temperature changes then check every morning. Tires are always checked first thing in the morning before riding. I adjust pressures if 0.5 lbs or more difference from the 38 or 42 psi.

Based on several of you running lower pressures I might need to reconsider what pressures I run at times.

[Lee]

So far a surprising percentage of respondents are running 36 - 38 psi at the rear.

At this time four voted for 36-38 and eight voted for 42-44.
Maybe you looked at the front tire survey?

[Grumpy Goat]

At this time four voted for 36-38 and eight voted for 42-44.
Maybe you looked at the front tire survey?

No, was the rear. Didn’t expect 30% of the people would be running that low.


Sent from my iPhone using Tapatalk

[Ray]

At this time four voted for 36-38 and eight voted for 42-44.
Maybe you looked at the front tire survey?

No, was the rear. Didn’t expect 30% of the people would be running that low.


Sent from my iPhone using Tapatalk

Gets back to your comment about loaded vs. unloaded. I almost always ride loaded. Should we factor in rider weight and luggage and average riding temperature and tire type when you update the poll in a few months?

[darrell]

I’ll watch closer in 2020 but at the last 3 Ride-In’s where 35 total motorcycles showed up I don’t remember 1 rider showing up, unpacking and then removing 4 psi of air from their tires. If they did at 0 Dark Thirty that night or the next morning I don’t remember anyone adding back those 4 psi they removed when they arrived the morning they left after packing up the bike. Just sayin”. It would be interesting to use the same calibrated gauge and do a pressure check on 15 bikes in a parking lot the morning after they arrive with no adjustments made from their ride in. Each owner write down what they think psi is before it is checked. I’d bet 20 of the 30 tires would be different by 2 psi or more from what the owner thinks it is. I know it has to be perfect temperature morning to match what BMW says their reading is compensated for but if not someone smarter then me should be able to figure that out.

[Grumpy Goat]

Good points Darrell.

[Duccrazydave]

Actually, I took care of that at the gas station across the street from the hotel

[Ray]

I’ll watch closer in 2020 but at the last 3 Ride-In’s where 35 total motorcycles showed up I don’t remember 1 rider showing up, unpacking and then removing 4 psi of air from their tires....
Just sayin”. It would be interesting to use the same calibrated gauge and do a pressure check on 15 bikes in a parking lot the morning after they arrive with no adjustments made from their ride in. Each owner write down what they think psi is before it is checked. I’d bet 20 of the 30 tires would be different by 2 psi or more from what the owner thinks it is.
I know it has to be perfect temperature morning to match what BMW says their reading is compensated for but if not someone smarter then me should be able to figure that out.

I agree with your thinking. These surveys are always fun, but can always be tweaked for a little more data.

Would also be fun to check the TPM data at the ride-in to see how well cold pressures agree with what we calculate the TPMs should show. Bet there's a little variation in calibration among the bikes - especially after a few years of use.

By the way, you might recall seeing me adding some air in the parking lot that first cold, wet morning in Eureka Springs.

My only point was that folks who tend to travel loaded might tend to keep pressures higher all the time. Folks who generally ride unburdened might find they naturally keep the rear pressure a little lower.

An old habit carried over from bicycle racing, I generally adjust pressures before every ride with a hand pump. If the ride is a 400 mile day with only a tail bag, I run a little lower in the rear than what I posted for the survey. (Front forces under braking are probabaly similar to those when loaded.) If the ride is going to be multiple days of carrying a load, I'll start the trip a little higher - but I'm only talking 5-10% difference.

(Fun facts to know and tell. I'll note that MotoGP runs pressures 10% higher front than rear (~2 bar vs. ~1.8 bar - that's about 29 pounds of pressure up front to help the carcass handle 2500 newtons (560 pounds) of force. For comparison, the rear will catch up to 2000 newtons in turns.)

Would be interesting if some of our TPMs are off by 10% - another explanation for differences in in the survey.

[Lee]

Actually, I took care of that at the gas station across the street from the hotel

I learned years ago to never check tire pressure unless I had a air hose close by you knew worked or had my own air pump.
It's a real bummer to accidentally let air out of your tire while checking pressure and not having air available to refill.

[Grumpy Goat]

I learned years ago to never check tire pressure unless I had a air hose close by you knew worked or had my own air pump.
It's a real bummer to accidentally let air out of your tire while checking pressure and not having air available to refill.

So very true. You only make that mistake once.

[darrell]

After the reminder I do remember in 2017 a rider showing up who I had never seen. The first morning he was out in the parking lot while it was cold and raining with a $4 bicycle pump attempting add some air to a tire. I assumed he had borrowed his dads bike, pulled the pump from his bicycle and took a day of vacation from riding his bicycle to his blue collar minimum wage job at some packing plant. Made this assumption based on the fact if he was a professional say in the medical field he would have the funds to have something more electronic to pump up his tires. Kind of like Lee, Terry or Wayne had with them.

In the other case I did not see the Lupin bike leave to go over to a gas station and secretly add air which was likely let out at O Dark Thirty after arrival. I will pay more attention in 2020.