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2005 R1200RT Cracked Rear Wheel Flange at the Wheel Mounting Studs

When these cracks first appeared in the '05 models, ( I had them on my 05RT) I wondered if it was from some old habits of folks/techs using 105Nm torque values of the previous series of drives on the new EVO drives. Basically doubling the value cannot be a good thing on that spider.

I had to pull the manual out on a fairly competent wrench who was still using that value on the 60Nm required torque. Steel bolts in a steel flange vs, steel bolts in that aluminum spider. He said I was wrong and he used the 105 setting on "everything" :banghead

The original BMWNA recommended fix for mine was to file the cracks smooth as no one had the equipment or knowledge on how to exchange the flange at the time:doh



Henzilla
It just goes to show what the truth is with these so called "perfeshunals" and "eggspurts".
dc
 
When these cracks first appeared in the '05 models, ( I had them on my 05RT) I wondered if it was from some old habits of folks/techs using 105Nm torque values of the previous series of drives on the new EVO drives. Basically doubling the value cannot be a good thing on that spider.

The photos show cracks around the brake rotor mounting holes, NOT the wheel mounting holes.
 
Well, duh...you are correct.

I guess I was thinking about wheel lugs.

I broke a Torx socket off in a 05RT wheel bolt the other day that someone put on with an air gun or at 105Nm...not mine...the wheel wasn't , the socket was. I had to use a breaker bar on the other 4 with another socket :banghead They were WAY too tight!
 
Part Replaced

Well it's fixed... I got the steel part in there with the spacer, a new lock ring and new rotor mounting bolts. Of the $502 it should of cost (debateable), BMW covered $101.87. Assuming I would not have received a discount on the parts, it cost me a Franklin to do the work. And that's fine by me. Not bad I guess for a seven year old bike with 40K+ miles.

Thanks to everyone who contributed to this thread. Nice to see I'm not alone. Now, what's all this talk about the fuel pump thing? A few of my buds said I should travel with a spare.

I think I'll go find that on another thread though.

Again... Thanks ya'll!
 
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I travel with a spare antenna ring (for the possible "EWS" failure) and a spare fuel pump CONTROLLER. I replace my controller with a new one (seems better made than the original) so I keep the working original under the seat.

I think I'm more likely to use these parts to rescue a fellow rider more than my own bike.

You can also buy, or make, a fuel pump controller bypass cable to use in an emergency. You'll find a lot posted on these topics.
 
Yes. Get a spare, or the bypass cable. I'm looking for a spare now. Mine went out Saturday. 50 mile tow. In Mexico.
I don't like the bypass cable. Might be a problem.
But do your research and planning on that fuel pump controller before it goes out.
dc
 
Subject drift... now talking about the fuel pump controller.

Yes. Get a spare, or the bypass cable.

Or learn how to bypass the fuel pump controller in the field[1]. You might also want to know how to bypass the side stand switch in the field.

[1] remove controller. Cut off connector that goes from controller to fuel pump. Wire said connector to the connector that normally feeds the controller:

brown (top connector) -> blue (bottom connector)
blue/green (top connector) -> yellow (bottom connector)
With this wiring the fuel pump will be controlled by the ignition switch, but will always be running at full power.
 
There are commercially available bypass cables. Some are direct drive onto the battery. But that means you have it running all the time, even with the bike off.
So the short method is the best.
Does anybody have the links for more on that, and the link for bypassing the side stand switch?
Thanks
dc
 
You don't have to be a professional metallurgist to see that these problems are caused by the same basic issue that leads to cracking of the plastic fuel pump flanges on various models as reported by many owners.

Someone ought to teach engineering 101 to the responsible Germans- namely that a screw thread is a levered wedge that exerts expansion pressure in whatever threaded bit is holding it. Therefore the receiver has to be strong enough to resist the force as installed plus whatever load increase it sees while in operation.

Just as the plastic pump flange is the wrong material (a new part has a metal reinforcing ring). this lightweight aluminum bit is also the wrong material in addition to being too thin at a critical point. Luckily, the manner in which it cracks is unlikely to cause immediate and potentially catastrophic separation. The receiver just "pops" to relieve the stress and the crack can't propagate for any distance. Even if all bolt locations were to crack simultaneously, immediate wheel separation is not probable.

In this case, they took the cheap and easy way out for the fix, apparently, with a steel part (both more ductile and stronger so unlikely to crack) rather than using a more expensive solution which could also have been a proper alloy forged aluminum piece.

Germans do a pretty good job at a lot of stuff but the number of basic engineering goofs on R models demonstrates an organizational weakness at BMW- failure to do adequate team-based engineering reviews prior to approving bits for production. Too much reliance on what's drawable in a CAD system and not enough on human knowledge based review to ensure it will work and be durable.

One has to wonder how many of this type of silly choice is buried in the design of new and untested models like the K1600.

Racer7 has it right. If you look at the right side of the lug (as shown in the photos), the hole almost breaks out of that undercut. That's a bad design detail (large stress concentration for the engineers in the audience) which will contribute to fatigue cracks and premature failures. I'd be interested if the new hub removed that undercut in addition to just changing the material.

Sometimes even good engineers make mistakes. The best ones learn something from them.
 
Sometimes even good engineers make mistakes. The best ones learn something from them.

:lurk
Know a few German engineers...they do not make mistakes:nono
and even if it were possible, getting them to say those words...priceless

:D
 
:lurk
Know a few German engineers...they do not make mistakes:nono
and even if it were possible, getting them to say those words...priceless

:D


It's a complicated process, modern engineering - of modular subsystems that are supposed to integrate seamlessly and reliably.

The client is supposed to write a requirement document for the salable product. Think GS vs. RT. A company i worked for did not know/realize this should be a mission statement rather than a top-level spec.

Systems engineers spec the product and postulate one or more sets of subsystems that will satisfy the requirements. If there is insuffificient traceability from reqirements to system spec, something will be missing. The system test plan should be traceable back through the system spec to the requirements so nothing will be missed. This was news to my employers too, but they did approve a $50K expenditure on a specialized database called DOORS to ensure this traceability was documented.

Each subsytem has its own spec and test plan, traceable all the way back to requirements, ideally. Then, relatively junior engineers develop the item and test it. If the traceability is not complete ... . If the design reviews miss something... If the Risk Program is not done right ... If the Value Engineering Program suggests plastic instead of aluminum, wrongly ...

The Systems Engineer and specialist engineering support should catch the problems, but they are human ... .

Yes, this is Aerospace doctrine, but many firms have adopted this level of philosophy.

It should be clear that a company that has not done so and produces complex products that could kill a human when failure occurs may have liabilities. That's why developing our toys can be expensive and still may have regretable cobsequences.

Oh, i have known accountants who are comfortable doing systems engineering ... And, i have known Program Managers who buckle.

Theory and practice still are often not in sync.

And, this is a very condensed summary of the process, so if you comment, please remember my caveat. I'm trying to show a "designer" doing detailed work may not have all the info and not be involved in all the decisions, and could build in a problem that goes undetected, or even is told to design the wrong thing.
 
I'm almost afraid to ask this out of fear I could jinx myself. Is there anything about your riding you would consider out of the ordinary for an RT?

I ask this because I too have a 2005 RT however I have 85,000 miles on mine. After reading your post and seeing the pictures I went out and checked my motorcycle for similar cracks. Everything appeared normal.... no sign of cracking or fatigue.
 
You are not jinxed, but, well ...
Ah, I mean no. Absolute not. There is nothing in anyone's riding of that motorcycle that could possibly crack that flange. Other than running it into a tree ... backwards.
It is a faulty part.
Listen to the engineering knowledge above. The part is faulty.
dc
 
stress cracks

Yep, after visiting my local and friendly servicing shop today here in rainy SoCal [http://valdis-motozone.com/] I not only saw several different bikes and vintages with said cracks, but I went home to discover one on my coveted and well maintained RT that has 105k on the odo.

Pinnacle after market insurance will get a call from me on Monday. For those interested, they have paid out $3 for every $1 I invested in their premium, and they still have 2 1/2 yrs to go on the coverage!
 
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