Designing a different mousetrap - Final Drive Bearing Tool for 1150's

[MikeP]

Agree, taking tools and spares is a pain in the arse. Doing the quick and dirty is an easy solution and no doubt gets you home and on your way quickly. I guess there are only a relatively low percentage of riders who might consider it worthwhile: the anal (me), those who might be in the 'at-risk' category (high load, rough surface), those doing a lot of distance away from home base or BMW parts who want to do the bearing swap 'right' and not as a get you home repair. I guess the trade off is about 3 oz of weight and maybe 10mins of measuring time - all about personal choice I suppose

I always carried the spares when I owned my 1150GSA. I never needed them but I advised others to carry them even if they didn't know how to fit them - chances are that someone nearby would know once they were shown the parts. Not having the parts is likely to be more of a problem even in places with good dealership back-up.

 

[bcostell]

Brand new from motorworks. Great!, also, they sent me a 17 ball version. As I said, I'm putting in angular contact bearings in my bikes.

That is a knackered ball race with .007" of axial play

 

[Smug]

The way that you are measuring with a feeler gauge on one side is measuring tilt and not axial play. You must measure with the same size feeler on opposite sides.

 

[bcostell]

Yup, see posts 2 and 3

The way that you are measuring with a feeler gauge on one side is measuring tilt and not axial play. You must measure with the same size feeler on opposite sides.

 

[Aidan1150]

I must admit that for a repair on the road, I'd probably just use the original shim and trust that it lasts long enough for me to complete my trip

if the "incorrect" shimming lasted several thousand miles before it spat its guts, why drag around a tool to measure it at the roadside? Just do what has been done often enough in the past, stick a new bearing in and carry on.

I guess it all depends on IF you're the sort of person who carries a spare bearing with them on a trip.

I was unlucky enough to have FD bearing failure in Creede Colorado on a coast to coast ride and I have to say that the shimming of the bearing was the last thing on my mind. All I wanted at the time was to rebuild the FD and carry on as soon as possible.

Taking the time to shim the bearing in the shed at home is probably good practice but I am inclined to agree with MikeP and accept that it is probably the result of a design flaw. I am though prepared to accept that I may have to change the bearing every 75000 miles or so.

 

[DrFarkoff]

Looks like a good idea but if a bearing gets you 50,000 miles then fails

Would it be wrong to expect 50,000 from the next bearing

I have come across some right cock ups of incorrect reassembly that put pressure on the bearing because it wasn't seated correctly against the shims in the aperture

I've Also come across Aidans where a bit of material jammed the alloy cone whilst the crown wheel kept on driving

Yes its important to know the axial float but this is a C3 bearing with extra clearances

I think its more important to get a clean and precise build with quality bearings and to check for damage outside normal use

 

[MattW]

Interesting discussion in this thread.

In the end, as I said earlier, on the road I'd just put the new bearing in and finish my trip but at home it would be good to at least check the shimming using bcostell's technique. I have a lathe, so I'll probably make up a kit of parts as in his original post.

My original bearing is coming up to 50k so yes, I'd be happy to get 50k + from the next so perhaps mine was 'nicely' shimmed in the factory? Then again, I've always been careful with paralever bearing adjustment...

Who knows?...

 

[kennyc]

Interesting discussion in this thread.

In the end, as I said earlier, on the road I'd just put the new bearing in and finish my trip but at home it would be good to at least check the shimming using bcostell's technique. I have a lathe, so I'll probably make up a kit of parts as in his original post.

My original bearing is coming up to 50k so yes, I'd be happy to get 50k + from the next so perhaps mine was 'nicely' shimmed in the factory? Then again, I've always been careful with paralever bearing adjustment...

Who knows?...

my original lasted 66K if I get 66K from the new one it will probably mean the bike is 32 years old! if I was so Anal as to want to measure the shimming whilst on a trip, I wouldn't wait for a trip! the sucka would be out on the floor and a new bearing and shim would be sitting in the FD! then I could leave all that extra luggage behind and carry more important stuff, pies, beer etc

 

[Fanum]

How often, out 'in the field', will you find a guaranteed flat smooth surface to measure your axial play?

Nice work, but I suspect you're answering a problem which isn't worth asking.

 

[Timolgra]

My thinking is if I carry a spare bearing with me I will of course pre-measure the bearing dimensions and axial play, all I need to worry about in the field is the calculated play of the assembly. If I prefer I can pull the drive apart before I set out and do all of the measurements in advance and if there is some difference in bearing axial play I can just take the required shims with me. Confused yet?

I think he's already answered that Bill

 

[bcostell]

let me explain a bit....

I live in th US (ex-pat). I have a gs in the US. I also have a GS currently parked up in
Malaga between trips. I have no 'home' in europe, nowhere to go to after a ride for repairs. So, for the next 3 yrs my bike is 'on the road'. If i do a quick bearing swap there's no 'home' for me to get to to fix later in the garden shed. So, fix it right first time.

I think my original intent of the post has been lost here. I didn't intend a discussion about bearing failure or the wisdon or otherwise of carrying tools and spares - although that's all good stuff. My personal intent was to share a design that I thought would be easy for the home mechanic to use and very cheap to make (maybe less than $20) in the event somebody wanted to either make some up or make one themselves. For me personaly it achieved my goals of being very easy to use and obviated the need for either BMW service tools or removal from the bike.

 

[Timolgra]

let me explain a bit....

I live in th US (ex-pat). I have a gs in the US. I also have a GS currently parked up in
Malaga between trips. I have no 'home' in europe, nowhere to go to after a ride for repairs. So, for the next 3 yrs my bike is 'on the road'. If i do a quick bearing swap there's no 'home' for me to get to to fix later in the garden shed. So, fix it right first time.

I think my original intent of the post has been lost here. I didn't intend a discussion about bearing failure or the wisdon or otherwise of carrying tools and spares - although that's all good stuff. My personal intent was to share a design that I thought would be easy for the home mechanic to use and very cheap to make (maybe less than $20) in the event somebody wanted to either make some up or make one themselves. For me personaly it achieved my goals of being very easy to use and obviated the need for either BMW service tools or removal from the bike.

Yes, sorry about that ...we often get off track on this forum

My interest though is, have you noticed a variation in axial play between various bearings to the extent that 'could' cause failure if the shimming is left alone?

 

[Steptoe]

Lets hope it's not raining and the night is closing in when you decide to start any shimming exercise at the side of the road.

And you may need a large selection of shims if you don't know what shims are already fitted.
In which case i suggest you dismantle and check. In which case you may as well stick another bearing in while it's apart. In which case you shouldn't need to carry all this stuff in the first place....... just saying......

 

[bcostell]

As I mentioned earlier, even if you don't have the right shims you can at least determine what they should be BEFORE you fit the new bearing, so that when you do obtain the correct one it's a very quick job to pull the cover, pop off the crown wheel and fit the shim. The reassemble. Does this not have value?

I think there's a lot of discussion about the efficacy of doing things on the road - hassle, need, etc. That's for the individual to decide for themselves. If we take it as a given that some percentage of bearings do indeed fail I'd really value a critique of the tool itself. Is it any easier or convenient for the average mechanic to use? Could Motorworks for example sell it for say 20 quid along with a 50 quid bearing with some instructions - would that help riders who need to fix their rear bearing - and not have to trust the local BMW mechanic to do the job right or at BMW service prices?

Lets hope it's not raining and the night is closing in when you decide to start any shimming exercise at the side of the road.

And you may need a large selection of shims if you don't know what shims are already fitted.
In which case i suggest you dismantle and check. In which case you may as well stick another bearing in while it's apart. In which case you shouldn't need to carry all this stuff in the first place....... just saying......

 

[cookie]

I'd really value a critique of the tool itself. Is it any easier or convenient for the average mechanic to use? Could Motorworks for example sell it for say 20 quid along with a 50 quid bearing with some instructions - would that help riders who need to fix their rear bearing - and not have to trust the local BMW mechanic to do the job right or at BMW service prices?

having recently replaced one of theses bearings and checked the shimming, i'd say your tool would make life easier. if it could be had cheap enough, i might even buy one if i had to do the job again. i do wonder about the way the measuring bar thing is mounted though. what with it sitting on spacers on rough cast ali + paint, it can't be level - so any measurements would need to be done in the same place every time?

more useful though IMO is a puller that would get behind the bearing to pull it off. beating it with hammers and chisels is not the sort of thing i enjoy.


also, i wouldn't be worrying myself about play in the bearing and factoring that into the process. i can't help thinking BMW might already have taken that into account with their preload tolerance?



ps. the one i did, and it was only one, was shimmed up fine AFAICT.

 

[Timolgra]

i do wonder about the way the measuring bar thing is mounted though. what with it sitting on spacers on rough cast ali + paint, it can't be level - so any measurements would need to be done in the same place every time?

.

Look at the photos again Cookie, the spacers sit in the machined recesses, hence my question about making sure the depths were equal

 

[MattW]

i do wonder about the way the measuring bar thing is mounted though. what with it sitting on spacers on rough cast ali + paint, it can't be level

Don't the spacers sit in the counterbores for the cover bolts?

Edit: Tim beat me to it

 

[cookie]

Look at the photos again Cookie, the spacers sit in the machined recesses, hence my question about making sure the depths were equal

you're right. didn't see that


anyway, i like the idea. doing it the way i did it is a PITA. i think it would cost more than £20 for the tool though.

 

[bcostell]

The spacers are machined square and the counter-bored holes in the cover are square, so I think it fits pretty square. You are correct though about the wisdom of measuring in the same place. That way any out of square inconsistencies are negated.

i do wonder about the way the measuring bar thing is mounted though. what with it sitting on spacers on rough cast ali + paint, it can't be level - so any measurements would need to be done in the same place every time?

 

[bcostell]

I had my parts made up by a local machine shop close by my local airfield. They are not the cheapest place around. For a one off all the parts were about $75. I figure that a cheaper place and a run of say 20 parts they could be run off much cheaper. You can always use a bunch of flat washers instead of having machined stainless spacers made up. As long as you measure in the sames place and all is snugged down that would work just as well. I had the shop knock me out a part for the the bearing puller for a couple of dollars.

you're right. didn't see that


anyway, i like the idea. doing it the way i did it is a PITA. i think it would cost more than £20 for the tool though.