Warning - Rear Wheel Bolts - Mono

[kutter]

Just thought I would relate a tale of an exciting event that happened to
me shortly after I had bought my R80 in July.
I was still in Central Australia when I purchased the bike, only seen in photos
from the mate of a mate.
My mate handled the cheque and had the bike delivered and stored under his house
until we got home and went up in early October and trailered it the 320km home.
Did all the paperwork had the rego transferred insurance arranged etc.
It was suggested that I could catch a bus up and ride it home but I didn't fortunately.
It was still in the PO's name no insurance or bike gear.
I was coming home from visiting my aged parents one Sunday morning when
I felt the back was "squirmy" aha I thought "Flat tyre".
Stopped had a look - Tyre not flat.
Took off again, stopped at lights rode off- something not right here.
Pulled off the road again, had a closer look - Rear wheel bolts backing out.
Walked a couple of kilometers home, got the Toyota and spanners came back
tightened bolts, and rode cautiously home. Picked up the Toyota later when
Mrs kutter got home.
Bloody PO hadn't tightened bolts ? No that was not the cause.
These bolts need to be tightened to 78ft/lbs. As much as some heads bolts on cars.
Three of the bolts would not tighten so I removed them.
The top bolt in the picture below is the original (25 yrs old??) Note the stretching and waisting!
The lower is a new R Series bolt. Slightly different design.(Improved?)



Rang The BM Shop in Brisbane to order new bolts. "What do you want them for? We've never had an order
for them before".
They rang back later can get some from Germany $18.00AUD+ Each.
Rang back again compared dimensions etc and they have some K series wheel bolts
which will need to be shortened 4mm. Do K series bikes have more problems with
wheel bolts than R's?
Cost is $2.50 each + postage. Bolts arrived a couple of days later, modified and installed
to 78ft/lbs.
Photo below showing bolts drilled and wired for extra insurance!
Have not seen this problem mention in any of the BMW forums
that I have searched. Has any body else had this problem and lived?

[Jeff in W.C.]

Bloody PO hadn't tightened bolts ? No that was not the cause.
These bolts need to be tightened to 78ft/lbs. As much as some heads bolts on cars.
Three of the bolts would not tighten so I removed them.
The top bolt in the picture below is the original (25 yrs old??) Note the stretching and waisting!
The lower is a new R Series bolt. Slightly different design.(Improved?)

I'd say someone replaced them with the best alternative rather than OEM. I have an 88 R100 RT, and the bolts do not look like the top one. They look like the bottom one. In any case, glad to hear everything worked out OK. However, given that the PO replaced the bolts with some that appear to be of questionable quality, you may want to go stem to stern on the bike making sure everything is as it's supposed to be.

[vanzen]

kutter,
Any identification markings on the head of the stretched bolt ?

[Bob Bennett]

G'Day kutter,
My bike,R80, was made in 3/85 as well, and I think Jeff is probably correct as my rear wheel bolts
are the same as your new ones. The black ones are most likely substitutes for whatever reason.
Very nice bike you have though.

[richard t]

I had new tires put on my K75 last May at a shop I hadn't used before because my reguar shop didn't have my size in stock and I was getting ready to go to Ken's rally, I rode about 200 miles before I left for the rally. 20 miles into my trip at 70mph the bike went to a serious shimmy and shake, I thought I had blown a rear tire, I discovered all the lug bolts had backed out, I tightened them and went on stopping ever 50 miles and checking them, they stayed tight, I used Ken's torque wrench and they've stayed tight ever since. My fault, I guess I'll check them my self next time I let a shop put tires on. I don't want to experience a wheel comming loose again. Since then I heard about a guy who's wheel came completely of a K100,

[barndeadr80]

Mine was made 2/85 and the fubar bolt does not look familiar at all. Some potential excitement to look forward to in any case. In the late '80's I headed down an off ramp and grabbed the front brake. Nothing. Picked up something off the road with the front tire and it took out the steel crossover line under the fender. 20+ years later on the same ramp on the same bike I grabbed the clutch. Nothing. The adjusting bolt had backed out of the clutch linkage. If my wheel is going to fall off at least I have a good idea where it will happen.
Glad you suvived that.

[kutter]

The only markings on the old bolts is a
number 9 or 6 in the centre of the head.
The K series bolts I used look much the same
as the new R series (Motobins UK) only
4mm longer.

[Motu]

Rang The BM Shop in Brisbane to order new bolts. "What do you want them for? We've never had an order
for them before".

If they were a problem they would order every week and have 3 sets in stock.As has been mentioned,they are the wrong bolts and someone has cranked them too tight.

[ME 109]

I was on a ride one day on a k100rs.....rear wheel bolts loosened right off.
Hot dang tomales I said to my mate who was riding a much newer 1150 rt.

Later that day, the same thing happened to the 1150rt...

[vanzen]

The only markings on the old bolts is a
number 9 or 6 in the centre of the head.
The K series bolts I used look much the same
as the new R series (Motobins UK) only
4mm longer.

I have a BMW lug screw from a Paralever GS that very closely resembles the "stretched" one,
including the shorter length of the head.
The one exception will be that the non-threaded portion
is significantly longer (@ 2/3 the length of the screw) than the "stretched one.
The "dished" head of this BMW screw is embossed with "6.0' that refers to the length of the screw – 60 mm.
(to differentiate it, I will assume, from the 55 mm screws used on other models)