1999 R1100RT handling issues

[dp-R1100RT]

Hello all,

 

This is my third post, so please go easy on me.   I scrolled through the oil head forum until my finger hurt, and then I did a search for "handling issues", so if I missed it - then please just point me in the right direction.  Fair warning, this is going to be a bit of a long post:

 

I bought a new to me 1999 R1100RT in "excellent condition"  -  Meaning that it is a one owner bike and that all work has been done on schedule by the local BMW dealership.  The bike appears to be pristine.  Aftermarket items include: braided steel brake lines, cats dropped with after market exhaust, and Hyper-Pro aftermarket shocks/springs installed with minor overall custom build lowering.  The after market shocks have been rebuilt once.

 

The previous owner seems clueless about actual mechanical work that his chosen BMW mechanic does not actively bring to his attention - such as 40,000 mile transmission input spline greasing, and he already told me that he had a clutch problem on the road that he "adjusted out" at the clutch lever...  so, grain of salt here.   To his credit he did seem to do everything that BMW recommended for the last 20 years, and he wasn't afraid to spend the money to buy good parts - or to have all major work done at the BMW dealership.

 

I have minor handling issues.  The (Stock Metzler Z6) tires are in need of replacement, but not completely worn out...  cupping and wear patterns on the front - flat strip in the middle of the back tire.  The suspension seems to sag a bit, and is very choppy over washboard.  The main problem that I have is that the left grip pushes against my hand at slow speeds, and under deceleration.  The handling seems strange at slow speeds.  At higher speeds it seems pretty good.

 

Here is the problem:  I don't know what is normal for this type of suspension...  Maybe they are all "difficult" at slow speeds.  I am getting ready to do some tune-up related repairs, new tires, and minor suspension work - while I save major work like the transmission input shaft, new clutch, etc, for the fall tear down...

 

I guess that my question is: is it normal for the left grip to push on your wrist at slow speeds?  Do  these bikes just handle "flakey" and need more rider input at slow speeds?  Is there a know issue that I am missing, and I can easily fix while doing the minor overhaul for this season?  Is there something that I am missing that I need to address during the major winter overhaul?

 

During the winter rebuild I am looking at having the suspension rebuilt to the stock height, renewing and adjusting all bearings from end to end...  Maybe some other custom modifications...

 

Thanks in advance for any suggestions or comments.

[dirtrider]

14 hours ago, dp-R1100RT said:

 

I guess that my question is: is it normal for the left grip to push on your wrist at slow speeds?  Do  these bikes just handle "flakey" and need more rider input at slow speeds?  Is there a know issue that I am missing, and I can easily fix while doing the minor overhaul for this season?  Is there something that I am missing that I need to address during the major winter overhaul?

 

During the winter rebuild I am looking at having the suspension rebuilt to the stock height, renewing and adjusting all bearings from end to end...  Maybe some other custom modifications...

 

Thanks in advance for any suggestions or comments.

 

Is the grip push (directional pull) normal?-- Yes, some do it more than others,  as a rule 1100RT's without radios pull a little more than bikes with factory radios. The basic problem is called PTTR (Pull To The Right) so Google BMW PTTR or 'pull to the right'.

 

The basic problem is the motorcycle's  weight is not centered on the vehicles centerline, some of it  due to powertrain weight offset from centerline, some due to fuel tank design, & some due to rear wheel offset from centerline.

 

In your case you are not only fighting the basic PTTR trait but also fighting old worn tires that drastically change the bike's input response.

 

There are things at you can do to diminish the PTTR, like put bricks or lead in the radio compartment (if bike has no radio now), or play with the rear wheel offset with swing arm pivot spacers, rear wheel to final drive spacer removal, creative wheel machining. They all work to some extent (some more than others). The actual BMW rear tracking spec is pretty broad so I doubt  that you have anything out of actual BMW specification.

 

Bottom line-- you can spend a month or two trying to remove the basic PTTR, (OR), just put new tires on the bike then ride it for 2500 miles. After 2500 miles of riding (IF) it still bothers you then spend a lot of time & effort trying to remove it.

 

For most BMW 1100/1150 riders it becomes much less of an issue after riding the bike for 2500+ miles so most riders never take the time or effort to remove it.

 

Added: My first BMW 1100 bike had PTTR & it bothered me to no end when I first bought it. I spent hours & hours measuring everything, making rear wheel off-set changes, adding weighting, etc. (made it ride fairly straight)--- My last BMW 1150RT actually pulled to right  worse than any of my other 1100/1150 bikes (I owned many)  & I really didn't pay any attention to it as by then I was pretty immune to the PTTR issue so just rode the bike & enjoyed it. (the new owner rode that bike to every state  except Hawaii & always bragged about how well it handled compared to his other motorcycles and that bike had PTTR on the high end of specs)

 

 

[roger 04 rt]

[dirtrider]

27 minutes ago, roger 04 rt said:

 

 

Afternoon Roger

 

The link in that thread is dead.

 

I remember reading your write-up & it was on point so if you still have that write-up somewhere could you post it here? 

 

(a lot of older links are dead since the migration to the new system here) 

[Michaelr11]

Welcome DP.   All bets are off until you replace the tires with new rubber.  Worn out tires can give you so many false handling issues, you would be chasing ghosts.

 

When you get the new tires, run them higher than the spec pressures.  I run mine around 38F/40-41R.  Some folks run them at the sidewall max pressure (42?) but I find that makes for a very harsh ride and the tires can slip and skip easier at max pressure.

 

Your shocks might not need a rebuild, they may just not be set up properly.

 

If you fill out your profile with more info, you might find another 1100RT rider nearby that will ride your bike and let you know if it's in the normal range or feels off.

[dp-R1100RT]

Thanks dirtrider - that was some awesome information that I may never have found on my own. 

 

Some have suggested that I use the new Z6 tire that I have and use a Z8 for the back.  I think that the handling characteristics might be different enough to cause more problems.  It looks like I will need to start with some tire research and pick up a new matched set of tires.  I agree that the handling is light years better than my Goldwings, and knowing that it is a known issue makes it much easier to deal with than wondering if something in the suspension is trying to break on me.  (Murphy says it will happen at 80 mph in the twisties. lol) 

 

Thanks to all of the members for your many useful replies, and words of welcome.

 

~dp

[dirtrider]

5 minutes ago, dp-R1100RT said:

Thanks dirtrider - that was some awesome information that I may never have found on my own. 

 

Some have suggested that I use the new Z6 tire that I have and use a Z8 for the back.  I think that the handling characteristics might be different enough to cause more problems.  It looks like I will need to start with some tire research and pick up a new matched set of tires.  I agree that the handling is light years better than my Goldwings, and knowing that it is a known issue makes it much easier to deal with than wondering if something in the suspension is trying to break on me.  (Murphy says it will happen at 80 mph in the twisties. lol) 

 

Thanks to all of the members for your many useful replies, and words of welcome.

 

~dp

 

Afternoon dp-R1100RT

 

You don't need to match the tires exactly, I have mixed the front Z-6 with a rear Z-8 a few times on the 1200RT with great handling & no issues so they do get along with each other just peachy.

 

In fact the Z-6 is one of my (personal) favorite tires but they are getting difficult to find now as they are out of production.

 

The Z-8 rear does have one advantage over the Z-6 as the rear Z-6 had poorly thought out tire wear indicators (wear indicators were put in a spot on the rear tire that typically didn't wear very much. So basically the main wear indicator on the Z-6 rear tire was when the air started showing.

 

 

[roger 04 rt]

4 hours ago, dirtrider said:

 

Afternoon Roger

 

The link in that thread is dead.

 

I remember reading your write-up & it was on point so if you still have that write-up somewhere could you post it here? 

 

(a lot of older links are dead since the migration to the new system here) 

 

Hi DR,

i dug it out, here’s the original: https://www.bmwsporttouring.com/topic/69612-r1100rt-pull-to-the-right/

[AndyS]

15 hours ago, dp-R1100RT said:

 

Some have suggested that I use the new Z6 tire that I have and use a Z8 for the back.

 

You could mix the tyres, but what's the point? Just purchase a new pair of the same and go from there. Either way it is an unknown. But you need to establish a baseline to go forward and tyres are that starting point. However, at this stage, mixing them isn't the right thing to do.

[Jim Moore]

16 hours ago, dp-R1100RT said:

Thanks dirtrider - that was some awesome information that I may never have found on my own. 

 

Some have suggested that I use the new Z6 tire that I have and use a Z8 for the back.  I think that the handling characteristics might be different enough to cause more problems.  It looks like I will need to start with some tire research and pick up a new matched set of tires.  I agree that the handling is light years better than my Goldwings, and knowing that it is a known issue makes it much easier to deal with than wondering if something in the suspension is trying to break on me.  (Murphy says it will happen at 80 mph in the twisties. lol) 

 

Thanks to all of the members for your many useful replies, and words of welcome.

 

~dp

If you're using your RT as a track bike at knee-dragging speeds you might need to be concerned with the differences between a Z6 and a Z8. If you're not, "round, new, and from the same manufacturer" is plenty good. 

[Woodchips]

Welcome to the RT world DP

 

Just to add my two bits to the discussion, I have now reached 215,000 Kilometres on my 96 RT. Over the years I too have felt the PTTR with varying degrees depending on the the wear of the tires and offset loading of the saddle bags, and of course the severity of the crown of the road.

Just before installing new tires last month, I removed the spacer from the rear wheel and immediately felt a reduction in the PTTR. After the new tires were installed there was virtually no pulling at all. I now have about 4000 K’s on the tires and do not notice any difference. Needless to say, the spacer is staying on the shelf.

Now if the woes with my other RT could be solved so easily.