Tire Pressures?

[globalrider]

Checked my Owner's Manual the other day and there is a single front and rear tire pressure for my 2016 R1200 GSA. And it looks like it is based on an all up weight.

Yet for my 1990 R100 GS and 2003 R1150 GSA, they list numerous pressures based on solo, dual and luggage. Go figure and yes, I realize I can reduce pressures, but why did BMW not list tire pressures as they did on previous models?

 

[stooie]

Since somewhere circa 2005 almost all new street bikes now recommend 36 front / 42 rear. As suspension guru Dave Moss points out, there is no way this is optimal for all bikes in all conditions. He recommends experimenting with different pressures to see what makes you happy.

On my '18 RT I've ended up with 38 front (gives better turn in) and 38 rear (gives a more compliant ride on my rigid-carcass Dunlop Roadsmarts). YMMV

Good luck!

 

[20774]

How much might be due to changes in tires over the years? IIRC the fender placard on the older Airheads showed 29 psi front and 27 psi rear!!

 

[globalrider]

As suspension guru Dave Moss points out, there is no way this is optimal for all bikes in all conditions. He recommends experimenting with different pressures to see what makes you happy.

Yes I have seen the Dave Moss video recently and in the past when I was trying to figure out tire pressures for my car. I'm a tech and I know about tire pressures and temperature changes from way back in school, but I was still confused about one aspect of it further discussed down this post.

As for tire pressures, I want long tire life in my everyday cars and motorcycles as I am not on the track with those vehicles.

But I was very surprised to see the following in the Owner's Manual for my 2015 Porsche Carrera 4 GTS. Note the temperature specification that I have never seen in any of my other cars from 1974 to present time.

So lets day the temperature increases by 30°F from 68°F to 98°F on a very hot day just parked in the driveway. And that tire pressures change by 1 to 2 PSI for every increase or drecrease in temperature by 10°F. So does that mean for that 30°F increase I should read an extra 3 to 6 PSI more than what is listed in the chart below.

 

[pglaves]

Yes I have seen the Dave Moss video recently and in the past when I was trying to figure out tire pressures for my car. I'm a tech and I know about tire pressures and temperature changes from way back in school, but I was still confused about one aspect of it further discussed down this post.

As for tire pressures, I want long tire life in my everyday cars and motorcycles as I am not on the track with those vehicles.

But I was very surprised to see the following in the Owner's Manual for my 2015 Porsche Carrera 4 GTS. Note the temperature specification that I have never seen in any of my other cars from 1974 to present time.

So lets day the temperature increases by 30°F from 68°F to 98°F on a very hot day just parked in the driveway. And that tire pressures change by 1 to 2 PSI for every increase or drecrease in temperature by 10°F. So does that mean for that 30°F increase I should read an extra 3 to 6 PSI more than what is listed in the chart below.

View attachment 93101

For as far back as I can remember "Cold" tire pressure was specified to be at 20C (68F) as a standard. But that would go up by about 1 p.s.i. per ten degrees F as the ambient temperature goes up. So for example if it is 90F outside with tires not ridden/driven on, one would increase the recommended pressure by about 2 p.s.i.

 

[globalrider]

For as far back as I can remember "Cold" tire pressure was specified to be at 20C (68F) as a standard.

They may have been "specified" somewhere but certainly not listed in the Owner's Manuals or stickers on the vehicle.

But that would go up by about 1 p.s.i. per ten degrees F as the ambient temperature goes up. So for example if it is 90F outside with tires not ridden/driven on, one would increase the recommended pressure by about 2 p.s.i.

I got that info from Google. I read between 1 PSI and 2 PSI per 10°F. Maybe it is time to get back into my physics book.

The Honda, Acura and Hyundai Owner's Manuals that I happend to have, do not mention a temperature, just "cold".

The Acura manual also states: "If checked when hot, tire pressure can be as much as 4–6 psi (30–40 kPa, 0.3–0.4 kgf/cm2) higher than if checked when cold." And of course that makes sense.

 

[20774]

The side of the tire has the maximum cold inflation pressure listed.

 

[Omega Man]

The When are tires considered cold question is a frequent topic in and on the RV forums.

I use the information on the frame of the bike as a reference and adjust for any front cupping or wear. Other than the stock as delivered tires, air pressure would be needed to suit based on the imprint information on the tire as tire designs, compounds and related change.

The motorhome tires will go from 90psi to 107psi on a hot day out on the highway. I have never seen arctic or desert specific tires. Too little air results in poor handling and excessive sidewall flex and frequently tire failure due to heat from flexing. Running at max air pressure when not needed for the specified weight can result in a harsher ride than needed.

"Tires are considered cold when the vehicle has been parked for three hours or more, or if the vehicle has been driven less than a mile (1.6 km) at moderate speed".

I tend to set 'em, and check 'em as needed.

YMMV

OM

 

[Hodadd]

Checked my Owner's Manual the other day and there is a single front and rear tire pressure for my 2016 R1200 GSA. And it looks like it is based on an all up weight.

Yet for my 1990 R100 GS and 2003 R1150 GSA, they list numerous pressures based on solo, dual and luggage. Go figure and yes, I realize I can reduce pressures, but why did BMW not list tire pressures as they did on previous models?

View attachment 93100

It's my belief that it has little to do with BMW and everything to do with the development of tire technology over the years.

 

[orforester]

I am with Bob from Salem, my front tire wallows with 36, I like 39 way better and still 40-42 in rear.

 

[brownie0486]

My mechanic always gives me both the 16RS and 11RT back with 38f/40r. I used to run 36/42. He's convinced me 38 up front prevents cupping later in in the tires lifespan. I still run 42 rear because I carry 45#'s of gear in the panniers and top box at all times.

This morning I aired up both motors in prep for riding this week. 38/43 [ it was 80f in the garage ] at the time. From my understanding, the 38f also gives better turn in's in the twisties.

 

[globalrider]

It's my belief that it has little to do with BMW and everything to do with the development of tire technology over the years.

Could be after installing a rear Michelin Anakee 3 on my 2016 R1200 GSA. I have been installing tires for nearly 50 years and I have never seen such a stiff rear tire. My reason for finally buying an OLMAX tire installer after doing it with plastic shims and tire irons.

 

[bigjohnsd]

I run Dunlop Trailmax Missions on my '21 GSA, they are quite stiff and bias ply vs radials. I run pressures a little lower than the 36/42 specified for the radials that come with the bike. I'm running 32/38 right now. I got over 14k miles on the last set running these pressures. No negative effects noted so far.
, and the ride is a little better.

 

[tepeterson7848]

I have had the same questions as the OP. I've had motorcycles for 50 years and my 2022 R1250RS is the first one to have the same recommended tire pressures regardless of load. This post detoured a bit into the subject of temperatures. The initial question still remains as to what happened to tires and suspensions that made this change in the last 10 to 15 years. An earlier reply suggested that tire technology has changed and that is what I suspect. I was hoping that a tire expert would weigh in on this one.

 

[globalrider]

The initial question still remains as to what happened to tires and suspensions that made this change in the last 10 to 15 years.

Looking up a recent Rider's Manual for an F800 GS, they listed various tire pressures based on weight. Go figure!