rotor bobbins on 1100RT, where to buy?

[KER]

im looking to replace the rotor bobbins on OEM discs on an 1100RT, i can get them from motobins for about $45 each rotor. Is there any place in the US to get these?

[Darren]

I have just received these from Moto-Bins,, half the price of BMW, although I have never seen them anywhere else

[Mark K]

I can't find my invoice just now, but my notes say I got the bobbins, washers and circlips for both sides for $63.60 plus tax from Chicago BMW. That was just over a year ago.

[smiller]

Why replace the bobbins at all? Looking at how everything is assembled it seems virtually impossible for the bobbins to actually wear enough to let go of the rotor no matter how sloppy they may seem. If you just want to address a purely aesthetic concern about the rotors rattling I guess I could understand that, but otherwise I don't see why the bobbins would ever need (i.e. for performance or safety reasons) to be replaced as a preventative measure... just do it whenever it comes time install new rotors.

[DavidEBSmith]

If they get really loose, so that there's rotational play, you can feel it in the front brake - you can feel the bike roll back and forth slightly while holding the front brake on. I don't know if this is a problem, but it feels like something that can't be good.

[bmwmick]

Seth,

Eventually the bobbins will wear through and separate. Not a good thing but it would take many thousands of miles AFTER they are worn out.

 

Mick

[smiller]

you can feel the bike roll back and forth slightly while holding the front brake on.

Yikes! OK, that's pretty loose, I'd probably go after that. But that must represent pretty far gone as mine are pretty sloppy but still no sign of actual play when the brake is engaged.

 

Eventually the bobbins will wear through and separate. Not a good thing but it would take many thousands of miles AFTER they are worn out.

That makes sense but it seems like the rotor would wear to replacement limits before the bobbins would actually wear in half.

[DEF]

If they get really loose, so that there's rotational play, you can feel it in the front brake - you can feel the bike roll back and forth slightly while holding the front brake on. I don't know if this is a problem, but it feels like something that can't be good.

 

David,

 

Have you checked everything else in the front brake such as the pads (do they have some slop in the calipers), the actual caliper fasteners? Rotor bobbins worn to that extent seems unlikely unless you got a set that was not properly heat treated....just thinking out loud here......

[KER]

thanks for eveyones input, looks like im going to be making my order with motobins. Thanks again

[bmwmick]

If they get really loose, so that there's rotational play, you can feel it in the front brake - you can feel the bike roll back and forth slightly while holding the front brake on. I don't know if this is a problem, but it feels like something that can't be good.

 

David,

 

Have you checked everything else in the front brake such as the pads (do they have some slop in the calipers), the actual caliper fasteners? Rotor bobbins worn to that extent seems unlikely unless you got a set that was not properly heat treated....just thinking out loud here......

 

The bobbins are not heat treated, they are rather soft aluminum. They are the wear item in the brake rotor suspension system. The anti-rattle springs take up the gap between the rotor and carrier until the brakes are applied. Once the rotor is solid to the carrier(brakes applied), the bobbins do most of the work transferring the stopping power to the carriers. Just replace them every 50K miles or so and don't forget to rotate the spring bobbins one hole either way to prevent wearing grooves in the carriers.

 

Mick

[GordonB]

Check the looseness of the bobbins (rotating the front wheel back and forth) AFTER you've ridden and the brakes are hot. They will tighten up a bit during riding, if they are still really loose then, replace em.

[Ziggy]

I bought a set from Moto-Bins and was not pleased. They are not identical to the OEMs. For example, there are no anti rattle "springs." The set I installed were snug, and the rotors did not float at all. The front wheel which previously spun free and easy would not spin a whole rpm with the new bobbins. A brief ride didn't help them "settle in," either. I called Moto Bins, confirmed the model and part numbers, but was not offerred any answers or relief. One guy there said they are purposely manufactured very slightly oversize on purpose, but that they should still have some movement. Not in my experience. After 25 bucks of overseas phone action, I called it a loss. Originals were re-installed, and a new set from Chicago BMW worked fine. I have done business with Moto Bins before with decent service and prices, but this experience was not good.

[smiller]

Just replace them every 50K miles or so and don't forget to rotate the spring bobbins one hole either way to prevent wearing grooves in the carriers.

Sorry, gotta ask... do we have record of so much of a single front brake failure due to worn bobbins... at any mileage?

[bmwmick]

Just replace them every 50K miles or so and don't forget to rotate the spring bobbins one hole either way to prevent wearing grooves in the carriers.

Sorry, gotta ask... do we have record of so much of a single front brake failure due to worn bobbins... at any mileage?

 

No, I have NEVER heard of a single failure.

 

I ignored my rattle for a long time. At 72K I replaced them on my K1100LT (same rotors) and a few of the bobbins were severely worn (I could punch a screwdriver through the wear marks).

Next time I replaced them at 130K and they were not as badly worn so I've decided the 50-60K mark is a good time to replace them and rotate the spring bobbins one hole. If you don't rotate them, the spring bobbins wear a groove in the carrier and they are almost impossible to get out.

 

Mick

[psyctrance]

Mine are toast, 97500 miles, started to get really sketchy towards the end of my cross country trip from Nashville, TN. The rotors, which are still good, sound like someone stuck a playing card in the spokes.

[smiller]

and a few of the bobbins were severely worn (I could punch a screwdriver through the wear marks).

OK, point made.