2004RT Steering Characteristics

[AlanBrown]

I don't know whether this has been discussed before, but the handling of a 2004 1150RT while cornering appears to be radically different to the 2003 version.

 

My own 2003 RT is in the local BMW repair shop, and they have organised a like-for-like temporary replacement - a 2004 RT. My bike has 43,000 miles on the clock, and this one has only 4,300. Great, I thought: a chance to experience a newer machine, and compare the two. Well, I don't know whether the lack of miles on this new bike has anything to do with it, but apart from it feeling very tight (that's the best word I can find to describe it), it has this unnerving characteristic when cornering. As I begin to lean into the corner, the body of the bike seems to want to remain standing up, and at the same time the handlebars take a distinct turn into the corner. (And this is happening at speed, not at walking pace.) The feeling is the same as you get when trying to turn at slow speed using the handlebars only, and you aren't giving it enough throttle - the bike seems to be ready to tip over. I have to make a conscious effort to countersteer my way out of this sensation, i.e. turn the bars in the opposite direction. And it's an effort because the bike is resisting it.

 

I would appreciate your thoughts / comments / experiences on this one. Thankfully my own bike should be back on the road soon (with most of the right side essentially replaced, from mirror to pannier), so I won't have to concern myself too much longer, but I would be interested to hear whether it's a common thing.

[stu650]

As I begin to lean into the corner, the body of the bike seems to want to remain standing up, and at the same time the handlebars take a distinct turn into the corner.

 

I had those exact symptoms on a (second hand) 2002RT, but my (new) 2004RT has never displayed anything like it.

 

I know that does not help you but I have sometimes thought that it is a factor of how the bike is set up - i.e. suspension, tyre pressures etc - or that something is out of alignment. I did not get chance to find out on the 2002 due to an accident eight weeks after I bought it.

 

I am sure that there are members out there with a lot more technical knowledge that might be able to explain it.

[ShovelStrokeEd]

Sounds to me like tire pressures are way off.

 

At 43K miles you stock shocks are done for and that certainly will give you a different feel.

 

Have you tried countersteering from the start?? At anything over a walking pace, you shoudn't be turning the bars into a turn but rather counter steering from the initiation of the turn to completion of the leaning process. You then should, assuming proper body position, be able to remove all pressure from the bars and just arc around the corner. A slight increase in throttle as the bike bends in will stabilize the suspension and allow the bike to hold its arc.

 

There are no mechanical differences between an '03 and an '04 to account for what you are experiencing.

[Ken H.]

There were no suspension or geometry changes from '02 - '04, so I have to think what you felt is tire, suspension adjustment, or wear related.

[BobFV1]

Alan - I have to go with Ed and Ken on this one - what you are experienceing is not a difference in the bike, but in the setup of the bike and probably tires/suspension.

 

First and easiest "suspect" to check, cold tire pressure of the loaner - compare it to your normal tire pressure. Also amount of wear and type of tires - are they different than your bike.

 

As has been stated, your bikes shocks, at 43K, are TOAST if they are stock shocks, and this will account for handling differences.

 

One other factor you shouldn't discount is seating position. While it is not likely to account for the entire difference you feel, differences in seat height, rear shock height, even windshield height will cause you to position your weight differently on the bike and cause the handling to feel different.

 

I've also noticed that my bike handling changes as I get heat in to the tires.

 

Countersteering is really something I use every time I turn this bike in all but low-speed, nearly stationary manuvers.

 

Let us know what you discover after checking this stuff out and getting your bike back. You are obviously a veteran rider if you have put all 43K miles on your 03 and I would be interested in hearing "the rest of the story"

 

Bob

[AlanBrown]

Bob (and everybody else who commented):

 

Spot on. You all pointed out the likelihood of tyre pressures being the culprit, and just 10 minutes ago a work colleague walked by and said "Alan, your rear tyre looks low. You might want to check it out."

 

I also take note of your comment on the shocks having given up the ghost, and will have it looked into when I get the annual service done. I bought the bike earlier this year with 35k on the clock, but I have added another 8000 miles in 6 months already.

 

And finally, Bob - your coment about the seat height was spooky. First thing I noticed when I got on the loan bike was the high seat. However, virtually all my "bike time" is in the dark (early morning, late evening), and I never got round to looking at it. I'll do that before I hit the road again tonight - promise.

 

Thanks everybody.

[BobFV1]

Alan -

 

Glad we could be of some assistance! I am a nut about tire pressure - I check my cold pressures at least twice a week, but there is always a temptation when picking a bike up from the shop to just assume that the tech at the shop has already done so - this is bad voodoo - always check them, especially when picking up from the shop!

 

Ride safe and njoy your bike!

[Pilgrim]

I agree with Ed and Ken about pressures, with this additional factor.

 

Depending on who rode the first 4,300 miles and where, and what tire it is, the rear tire may have developed a flat spot across the tread. A soft tire on straight roads at speed will develop one pretty quickly.

 

That leaves what amounts to an "edge" on each side of the flat spot. As the bike leans over it will come up on that edge, perhaps even pass it, and the handling will be distinctly, uh, "different".

 

Pilgrim

[SWB]

I've also noticed that my bike handling changes as I get heat in to the tires.

 

Alan: What tires do you have installed on your RT? If the 2004 still has stock tires (Dunlop 205s?) and you've put after market tires on your 2003 RT, that may account for the difference. My retired RTP came with original Dunlops, and I almost low-sided into a corner when the rear tire lost traction one early morning. I learned (the hard way) that those Dunlops take a while to get up to operating temps, and until then, you might as well have rocks straped to your wheels - those suckers are hard!

 

After I switched out the Dunlops with Metzeler Z6's, my RT cornered like an entirely different bike in all temperatures.

[BobFV1]

What Scott said - exactly!

[AlanBrown]

Problem solved: You all got it right first time. It was the tyre pressures. I went straight to a filling station from work yesterday evening and checked them. Front was OK-ish at 35 psi, but the rear I'm ashamed to say was indicated as 15 psi!!

 

A quick refill and the problem has disappeared. The bike handles exactly as expected. Many thanks to all who responded so quickly.

 

PS. Seat height was at its lowest already, just like mine. Probably a different make.

 

PS2. I will wholeheartedly endorse the comment made earlier - just because it came from the shop, doesn't mean it's safe to ride. Always, always check for yourself.

[Mark P]

I've experienced this characteristic when the front tyre pressure on my bike was way down on what it should have been and I had overlooked to check it.