R12RT windscreen support arms??

[CopsRT]

Just found that both my upper support arms have cracked and snapped near the pivot point where they attach to the windshield assembly. In looking at them, it appears to be a weak spot. Also I found that it is a cast piece. Both are being replaced under warranty (21000 miles). I have been running with a Aeroflow windshield the last 17000 miles. Any others have the same problems?? Anyone think about having someone machine some replacements that would be heavier duty at the wink spot?? My dealer thinks that maybe BMW will redesign and strengthen these due to the fact that parts were backordered so there is a demand for them.

[keithb]

I just had the upper left support arm break two weeks ago riding with a buddy up around Lake Hughes here in SoCal. All of a sudden I noticed the CB windscreen was torqued to the left. When I stopped to check it out I thought a screw was loose and fell out. Upon closer inspection I realized the arm had actually broken. No worries. The bike is under warranty so they are replacing it. On the bright side I have the use of a loaner R12ST this weekend. It is fun, fast, and powerful.

[ChrisRappl]

This is not the first post concerning these arms breaking. Has anyone had a problem while running the stock windscreen?

[JohnBeaven]

Not me. 13500km and no problems.

[Illini]

The right side arm snapped at the lower mounting area. I have a Cee Bailey's +4 and +3 shield. I made a replacement out of wood (Walnut) until it gets replaced by dealer. I also JB welded the original arm and it feels pretty solid but I just don't want to remove and replace everything again just to see it fail at the weld spot. I think this piece needs to be made out of billet. If only I had a milling machine or CNC.

[Warren_H]

Both of mine broke in the same place at about 19,000 miles during a trip while I was in northern Indiana. CeeBaily +3 x +3 since about 4000 miles. I made some pads out of duct tape to raise the shield to the level I wanted and tied the mounting bracket to my BMR shelf with some zip ties. I called the three dealers in the Chicago area and nobody had them in stock. One dealer told me there were none in the country as of two weeks ago.

 

Went to the dealer yesterday and they've ordered two new supports under warranty. I can't see how the larger shield could have caused this, I doubt it's more sq. inches than the large BMW shield.

[St0nkingByte]

...I can't see how the larger shield could have caused this, I doubt it's more sq. inches than the large BMW shield.

 

Granted we've only seen 3-4 reports of this but so far it hasn't happened to anyone who didn't have an aftermarket windshield. You do the math.

[BrianT]

If you do have custom replacement support arms made, be careful that they aren't too strong. I don't know about the R1200RT specifically, but some motorcycle windshields are designed to break away by design if you crash and hit the windshield. It may be that this weak support is the part that breaks away so that the windshield doesn't add to your injuries and BMW just went too far making it breakable. If I remember right, on the R1100RT it was an internal part that the support connected to that would disconnect. On the old Kawasaki KZ1000 police bikes the windshields were mounted with plastic screws for this purpose.

 

Hopefully someone at BMW could possibly answer the question if this part is weak by design or if something else gives way internally that the support mounts to and it simply is a bad part. Either way it definitly shouldn't crack under normal use and should be brought to BMW's attention so they can update the design if it is a poor design. I hate to think what would happen if a bracket gave way while driving and the windshield came flying back at you.

[SteelD]

Hopefully someone at BMW could possibly answer the question if this part is weak by design or if something else gives way internally that the support mounts to and it simply is a bad part. Either way it definitly shouldn't crack under normal use and should be brought to BMW's attention so they can update the design if it is a poor design.

It is likely that BMW designed the brackets to work with their stock screen with which no faulures have been reported in this thread. If an aftermarket screen causes a failure that might be due to additional stresses caused by increased loading or minor variations in the tolerances of the mounting points then I don't see how this becomes BMW's problem. It seems more likely that the onus should be with the screen supplier to ensure that their screen is fully compatible in this respect or, at least, supply altenative brackets. If, as BrianT says, these brackets are designed to break on impact, you would have to trust that an aftermarket bracket also had this safety element designed into it. If not, it becomes a trade-off between comfort and preference in normal riding and the risk of increased injury in an accident situation.

 

David

[gezerbike]

A friend of mine had his left support arm break on his way home from Vermont..........and he too has and aftermarket screen as well.

[marcopolo]

I find it somewhat amusing that we all get on BMW's case to have them make their bikes lighter, then when they do, we all try to come up with ways to make them heavier again. You have to appreciate the irony in that. I presume BMW went to some trouble to design a support arm that would withstand the stresses of their stock shield, not larger (heavier?) aftermarket ones. Sometimes you just can't win.

[keithb]

Here is an update on the broken left support arm on my 05 RT. Apparently there are NO support arms in the U.S. 2 week backorder from Germany. It appears several of us are experiencing this problem. Could be another recall? I guess we will have to wait and see.

[Warren_H]

It would only add an ounce or two of weight to make the supports durable enough to last for the life of the bike. If they're not strong enough for the aftermarket windscreens I doubt they are strong enough for the BMW large shield either.

[Ken H.]

If an aftermarket screen causes a failure that might be due to additional stresses caused by increased loading or minor variations in the tolerances of the mounting points then I don't see how this becomes BMW's problem.

Exactly. All this talk of poor design, time for a recall, etc. If it breaks from an aftermarket windscreen, why is this BMW's fault?

[CopsRT]

The only problem is this. They are breaking!! Is this caused by after-market shields? We don't know. We have seen where one rider has 13,500 Kilometers on his-with a stock shield and they are fine (works out to 8,388 miles). Mine were fine for twice that distance (17,000 miles) with my Aeroflow before they went. In having a machinist look at the part, it is made out of a cast piece of metal, or what they seem to like calling pop metal. There are several areas that it could very easily be redesigned to be stronger and I am considering having him make me replacement parts for my bike. Before any of us can start saying that it is due ONLY to after market shields we need a whole lot more data such as who has had them break, how many miles, what speeds you are running, where you primarily ride (plains vs mountains) and what angle you normally have the shield at when at highway speeds.

[Ken H.]

Before any of us can start saying that it is due ONLY to after market shields we need a whole lot more data

True. But so far the only people who have reported them breaking are people with larger aftermarket screens. Hardly a scientific study, but certainly some anecdotal evidence.

[velomoto]

The only problem is this. They are breaking!! Is this caused by after-market shields? We don't know. We have seen where one rider has 13,500 Kilometers on his-with a stock shield and they are fine (works out to 8,388 miles). Mine were fine for twice that distance (17,000 miles) with my Aeroflow before they went. In having a machinist look at the part, it is made out of a cast piece of metal, or what they seem to like calling pop metal. There are several areas that it could very easily be redesigned to be stronger and I am considering having him make me replacement parts for my bike. Before any of us can start saying that it is due ONLY to after market shields we need a whole lot more data such as who has had them break, how many miles, what speeds you are running, where you primarily ride (plains vs mountains) and what angle you normally have the shield at when at highway speeds.

 

Some other variables for those who like to ponder such things...

 

Typical height and angle of windshield. I find I keep my CB +3 windshield raised about 60% of maximum. Had I purchased a +2 height then I'd probably have had it raised nearly 100% which would have been at a much more upright angle, possibly less aerodynamic and possibly more force on the bracket.

 

Windspeed - Out here in the Colorado/Wyoming area it can get pretty windy. Never experienced ANYTHING like it while living on the East or West coasts (PA, NJ, NY, CA). On windy days it is not uncommon to get gusts in excess of 60mph. Also if one tends to ride on high speed interstates which are heavily used by truckers, the bike will undergo much more buffeting than if riding in nice clean air on rural highways. Additionally, interstate speeds vary from state to state - typical speeds of 65 to 70 mph in some states will be much easier on the bike than out here where speeds are frequently 80 to 85 mph.

 

Just some food for thot...

Greg

[gfountain]

15,000 with stock windshield. Just checked. No problems.