The RT and Tire Pressures.
It became quite apparent to me that the RT is very sensitive to tire pressure, that is, you will feel huge difference in performance of the bike along with different tire pressure, in particular the front tire! First, let's take a look at what BMW recommends for tire pressures:
For my prior '07 RT, BMW recommends:
31.9 psi (2.2 bar), Single rider, with cold tire
36.3 psi (2.5 bar), Driver with passenger and/or
load, with cold tire
36.3 psi (2.5 bar), Single rider, with cold tire
42.1 psi (2.9 bar), Driver with passenger and/or
load, with cold tire
For the 2015 RT:
Front: 36.3 psi (2.5 bar), with tire cold
Rear: 42.1 psi (2.9 bar), with tire cold
The above are direct copy from BMW's Riders manual, as printed.
I had always ignored the above recommendations, and had always ridden with my tires inflated at 40/42 (front/rear) from the very beginning, and had taken for granted as to how well the RTs had performed for me, in particular how the bike handle aggressive riding in curves. What caught my attention was that, many months back, Lee (LAF) had posted a comment that (for whatever reason) he had boosted up the front tire pressure from the recommended 36 to 40 psi, and found that the ride of the RT (wethead) to be totally different to what he had been experiencing! The bike became more nimble, and more sure-footed. I just took a mental note of this, since that had been what I thought about the RT all along. Then not too long ago (a couple of months?) a new owner of a '17 RT posted a thread asking what we thought was wrong with his RT, because when he picked it up from the dealer and rode the bike home on the interstate, he had felt very unstable. When he had gotten home, he looked over the bike and checked everything that would affect the stability. One of the thing that he did check, and reported on was that the front tire pressure was 34 psi, instead of 36 psi that the manual recommends. I told the fellow that probability is very high that the low front tire pressure was the cause of his instability, and suggested that he should get the pressure to the recommended spec. for a start, and see if he notice any difference. I also added that, people have noticed marked difference in boosting the front pressure up to 40 psi, and that he should try that while he was at it. The response, a day later, was WOW, it's like riding a totally different bike!
Now, that bring us to the present.....well, last month anyway. I had been visiting New Zealand for a little over a month, and the last part was to rent an RT (turns out to be a '17 RT) to ride around the south island for 10 days. one of the thing that was in my mind was to ask them to boost up the front tire pressure to the 40 psi that I am accustomed to, but I had forgotten about it until the day that I went to pick up the bike. On that day, I thought about asking them to add more air to the front, but then thought that I should ride at the BMW recommended pressure, and see for myself how much different the RT performs. One thing that you should note is that New Zealand roads are VERY hilly and winding. The perfect rider's dream, if you like riding the twisties! Anyway, as soon as I started to ride off, I noted right away that I didn't feel as sure-footed as I have been on my own '15 RT, but I chalked that up to the excitement. The feeling continued as I handle some of the curves, but again, I figured that I was just excited at doing the ride that I had been thinking about for a long time. However, when I came to a section where there was active roadwork, and several hundred meters were graveled (moderately), the "soft" front tire really shows its effect! Over here in Ohio, I had often ridden in deep gravel for more than 10 miles with greatest confident, and yet I can barely hold speed in 1st gear while riding that RT in moderate depth gravel. Several time I had to slow down so much that I had to grab the clutch, or fear that I would drop the bike. It was really bad!
Then, much further on, I had to cross a single lane bridge that has a railroad track down the middle of it. That bridge was actively shared between road and railroad traffic. I picked my path to the left of the tracks, which was narrow (no problems with that), but the wood planking had well worn asphalt over them, making the trail laid with regular bumps. Here again, the soft front tire accentuated the bumps by squirming side-to-side, enough to make the bike very unstable unless I slowed down to barely enough to hold speed in 1st. The next morning, I checked the tire pressure, and sure enough, the front tire was right on the BMW recommendation of 36 psi, and so I boosted it up to my usual 40 psi. To continue with my ride, I had to head back across that same bridge again, but this time, I breezed through in 3rd gear the whole way! Gravels? No problems, and I definitely felt very sure footed, and the curves were definitely more enjoyable to ride, with full confidence!
The point of this post is to share my experience. Not only what I have learned over the years of owning and riding the RT, but what I had just experienced for myself. I am NOT telling you that 40/42 psi (F/R) is the RIGHT pressure to use, because there are no right or wrong. All that I am saying is that for you to try and see how it works for you!
BTW, look above again at what BMW recommended for the hexhead ('07 RT) and the wethead ('15 RT). Why are they different, when the weight and geometry of the two bikes are basically the same?
Solon, OH, USA
2015 R1200RT (San Marino Blue Met.)
2014 R1200RT (Quartz Metallic Blue - Returned to BMW)
2007 R1200RT (Sold!)
Once Upon a Time........
1963 Norton Dominator 650 SS
1960 Triumph Bonneville (T120)
1960 Triumph Thunderbird (6T)
1952 Triumph Thunderbird (6T)
1932 Triumph 500
1952 BSA Goldstar