ADVrider

Go Back   ADVrider > Bikes > GSpot > GS Boxers
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 11-18-2013, 08:40 AM   #1
bcostell OP
Gnarly Adventurer
 
Joined: Jun 2005
Location: San Fran Bay Area
Oddometer: 192
1150 Final Drive Pre-Load Tool

Having read through the BMW service manual, viewed you-tube vids and looked at various articles written on the topic I've had a go at putting together a tool that I can use in the field to accurately measure and correctly set up the final drive main bearing. I want to be able to set up the correct pre-load without removing the final drive from the bike.

To 'correctly' set up the bearing pre-load you need to know the size of the gap between the face of the bearing outer race and the inside face of the final drive cover - all when it's assembled. Once you have that you select a shim that is that size plus a bit for pre-load.

But how to measure?

Well, it looks to me like you have two choices at the moment, both of which involve the use of either a set of BMW measuring tools or a heat gun, dial gauge and a fridge. The common wisdom is if you experience bearing failure on the road you just pop a replacement bearing on and carry on until you're someplace where you can do the job properly. Common wisdom also has it that the dimensions of the bearing races are held to a pretty tight tolerance so what you put in should be the same as what you take out. There are two problems with this logic however. 1). Was the shimming correct to start with and 2). Are the dimensions really the same?

I don't doubt that the race dimensions are always going to be within 1 tenth of a gnats cock of each other, but I'm not so convinced about the axial play in the bearings.

If you just pop another bearing on you then are stuck with one of the currently accepted methods of setting things up properly at a later date. My thinking is to find a way of figuring out what the correct shimming should be in advance of a trip, or once a failure has happened be able to determine what the shims need to be so that you can 'quickly' add the correct shims later. By quickly I mean with the final drive still assembled to the bike.

The approach is to be able to take and calculate a bunch of measurements using a feeler gauge and a simple tool. The key measurements you need are:

1). Dimension FROM the outer mating face of the crown-wheel (where the big bearing inner race mates) TO the mounting face for the big bearing inside the cover.

2). The bearing race dimensions including the axial play. The axial play can be measured by laying the bearing on a flat surface and pushing feeler guages under the inner race while holding the outer race against the flat surface.

By making up a bearing plug, with known dimensions, that is a close, but sliding fit you can assemble the drive without a bearing and measure the play. By then doing the calculation:
Assembly play + thickness of the plug + axial play
And then subtracting the thickness of the bearing race
you then have the gap between the bearing outer race and the final drive cover mating face IF it were all assembled without a shim(s).

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? Here's some pictures which 'might' help.

The Tool


Fitting the bearing blank to the crown-wheel


Fitting the cover and measurement plate


Measuring the gap with the crown wheel in the lower position


Measuring the gap with the crown wheel snug up against the outer cover


Subtracting one from the other gives the total play of the assembly - used below.

Measuring the axial play in the new bearing


All of the above takes about 5-10 minutes. And it's done without keeping parts hot or cold.

Here's my calculations:

Play measurement (in thou) 0.032" 0.8128mm
Blank thickness (in thou) 0.695" 17.653mm
Bearing thickness (in thou) 0.7075" 17.9705mm
Bearing axial play (in thou) 0.007" 0.1778mm

Total gap of assembly 0.0265" 0.6731mm

Pre-Load (mm) - Low Side 0.05mm
Pre-Load (mm) - High Side 0.1mm

Shim Min 0.7231mm
Shim Max 0.7731mm

Required shim 0.75mm

As I hinted earlier, all of these measurements with the exception of the bearing axial play, can be taken with the final drive still mounted to the bike, and in the field. As the tool is the approx the same size as the final drive bearing and made of alloy you should be able to find a home for it in your luggage if you want the insurance. Btw, I'm not selling the tool, it's just something I made up for my personal use, thought I'd share and take comments
bcostell is offline   Reply With Quote
Old 11-19-2013, 05:49 AM   #2
Dan Căta
Beastly Adventurer
 
Dan Căta's Avatar
 
Joined: Jun 2008
Location: Cluj, Romania
Oddometer: 1,576
This is interesting and I really appreciate the effort you took into building this.
It would have been more relevant if you could have also measured the needed shim thickness by the old micrometer/comparator gauge and see if there were any differences in thickness.

But I have to agree that this is a simpler method.

Thanks,
Dan.
Dan Căta is offline   Reply With Quote
Old 11-19-2013, 07:00 AM   #3
bcostell OP
Gnarly Adventurer
 
Joined: Jun 2005
Location: San Fran Bay Area
Oddometer: 192
Yup, that would have been a great exercise. But as I built this for myself and not with the intent of marketing it I just used a line of logic/reasoning to satisfy myself
bcostell is offline   Reply With Quote
Old 11-19-2013, 10:56 AM   #4
EKinOR
Gnarly Adventurer
 
Joined: Mar 2012
Location: Central Oregon
Oddometer: 242
Very cool! Can you post the dimensions of the bearing blank?
__________________
- Eric
2002 BMW R1150GS
EKinOR is online now   Reply With Quote
Old 11-20-2013, 07:04 AM   #5
GS Addict
Pepperfool
 
GS Addict's Avatar
 
Joined: Sep 2006
Location: Sunshine Coast B.C.
Oddometer: 3,502
Nice job but I just use the 1mm dia solder method. Simple and accurate.
__________________
Old enough to know better....
Young enough to try it again
GS Addict is offline   Reply With Quote
Old 11-20-2013, 07:42 AM   #6
Ravenslair
Gnarly Adventurer
 
Joined: Feb 2012
Location: Placer County, California
Oddometer: 455
Quote:
Originally Posted by GS Addict View Post
Nice job but I just use the 1mm dia solder method. Simple and accurate.
Not sure I have heard of this. Please do tell.
Ravenslair is offline   Reply With Quote
Old 11-20-2013, 07:50 AM   #7
GS Addict
Pepperfool
 
GS Addict's Avatar
 
Joined: Sep 2006
Location: Sunshine Coast B.C.
Oddometer: 3,502
Quote:
Originally Posted by Ravenslair View Post
Not sure I have heard of this. Please do tell.
Remove all shims, place bits of 1mm solder in 4 places in place of shims - space every 90 degrees (a dab of grease will hold in place) , assemble with new bearing, torque cover to spec.
Open, measure the solder thickness with a micrometer, calculate required preload.
__________________
Old enough to know better....
Young enough to try it again
GS Addict is offline   Reply With Quote
Old 11-20-2013, 08:13 AM   #8
stefan1150
Adventurer
 
Joined: Jan 2013
Location: cluj
Oddometer: 40
The method looks very effective. The play of the main bearing can be more accurately measured if it's outer race is clamped to a perfectly flat surface and 2 similar feeler gauges are used 180 degrees apart. Could you tell us the dimensions of the spacers and the part which replaces the bearing?
stefan1150 is offline   Reply With Quote
Old 11-20-2013, 08:50 AM   #9
Ravenslair
Gnarly Adventurer
 
Joined: Feb 2012
Location: Placer County, California
Oddometer: 455
Quote:
Originally Posted by GS Addict View Post
Remove all shims, place bits of 1mm solder in 4 places in place of shims - space every 90 degrees (a dab of grease will hold in place) , assemble with new bearing, torque cover to spec.
Open, measure the solder thickness with a micrometer, calculate required preload.
That seems like a very straightforward approach. That will go into the toolbox for future reference. Much appreciated.
Ravenslair is offline   Reply With Quote
Old 11-21-2013, 04:33 AM   #10
ragtoplvr
Beastly Adventurer
 
Joined: Oct 2007
Location: S. W. Mssouri
Oddometer: 5,671
Quote:
Originally Posted by GS Addict View Post
Remove all shims, place bits of 1mm solder in 4 places in place of shims - space every 90 degrees (a dab of grease will hold in place) , assemble with new bearing, torque cover to spec.
Open, measure the solder thickness with a micrometer, calculate required preload.
+1000

I verified that solder does not rebound, put solder on ground hard plate, between 2 0.020 inch feeler gauges. top with another plate. Crush in arbor press. Measure solder. It was 0.020. Cheap. works. My old shim was correct.

Before mine failed I had dealer install 75-140 oil. that is rumored to be a cause. I also had the final drive gear diameter the bearing installs on kind of oversize, it got polished down some. I now use 75-90 oil. There has not been another failure, so I do not know which it was. I am not planning to use the other oil just to find out.

Rod
ragtoplvr is offline   Reply With Quote
Old 11-21-2013, 08:02 AM   #11
GS Addict
Pepperfool
 
GS Addict's Avatar
 
Joined: Sep 2006
Location: Sunshine Coast B.C.
Oddometer: 3,502
Quote:
Originally Posted by ragtoplvr View Post
+1000


Before mine failed I had dealer install 75-140 oil. that is rumored to be a cause.

Rod
I heard that as well
__________________
Old enough to know better....
Young enough to try it again
GS Addict is offline   Reply With Quote
Old 11-21-2013, 08:57 AM   #12
bcostell OP
Gnarly Adventurer
 
Joined: Jun 2005
Location: San Fran Bay Area
Oddometer: 192
The spacers are made of 3/4" stock - I used stainless, but pretty much any metal will work. This stock size fits very snug in to the cover counter bores. The length is 21mm. I drilled a 10.5 hole down the center. These dimensions allows clearance in both the up and down positions of the crown-wheel. For the bearing blank, I just took a couple of thou off of the 'real' bearing outer dimension, added a couple for the inside dia and took off about 10 thou for the width. With these dimensions the blank is a close sliding fit.

bcostell screwed with this post 11-21-2013 at 10:14 AM
bcostell is offline   Reply With Quote
Old 11-21-2013, 01:51 PM   #13
vagueout
Beastly Adventurer
 
vagueout's Avatar
 
Joined: Mar 2010
Location: sydney, east
Oddometer: 1,529
Quote:
Originally Posted by GS Addict View Post
Nice job but I just use the 1mm dia solder method. Simple and accurate.
Did a pre-emptive bearing change almost two years ago, tried the "solder" method, failed to get consistent thicknesses due to super gluing the short strips onto the race. Then set up with borrowed dial gage using the "d man " method, for me a big fail, could not get a consistent reading. Opened the bugger up again this time using thinner solder strips with grease, very carefully and incrementally torqued the cover, let it sit for a coffee, opened it up and all the strips (4) still sitting as placed , all measured absolutely consistent, telling me that my factory shim was by memory .004" fatter then the squashed solder, hence just at the upper tolerance of pre-load, a beautiful and confidence inspiring moment . As to oils (sorry, couldn't leave it out of the thread) i use a straight 90 GL5 gear oil with a squirt off additive (nulon brand). Changed it's oil last week, a touch of sludge on the mag plug, the oil was pristine and no silver at all under a very strong light. I applaud BCOSTELL for his talent and effort in sharing his work with us, i value these type of threads above all others, but in my case the solder method was (almost) foolproof, no cost, no set up, just a micrometer or vernier required.
__________________
i just seek clarity
vagueout is offline   Reply With Quote
Old 11-21-2013, 02:05 PM   #14
GS Addict
Pepperfool
 
GS Addict's Avatar
 
Joined: Sep 2006
Location: Sunshine Coast B.C.
Oddometer: 3,502
Quote:
Originally Posted by vagueout View Post
Did a pre-emptive bearing change almost two years ago, tried the "solder" method, failed to get consistent thicknesses due to super gluing the short strips onto the race. Then set up with borrowed dial gage using the "d man " method, for me a big fail, could not get a consistent reading. Opened the bugger up again this time using thinner solder strips with grease, very carefully and incrementally torqued the cover, let it sit for a coffee, opened it up and all the strips (4) still sitting as placed , all measured absolutely consistent, telling me that my factory shim was by memory .004" fatter then the squashed solder, hence just at the upper tolerance of pre-load, a beautiful and confidence inspiring moment . As to oils (sorry, couldn't leave it out of the thread) i use a straight 90 GL5 gear oil with a squirt off additive (nulon brand). Changed it's oil last week, a touch of sludge on the mag plug, the oil was pristine and no silver at all under a very strong light. I applaud BCOSTELL for his talent and effort in sharing his work with us, i value these type of threads above all others, but in my case the solder method was (almost) foolproof, no cost, no set up, just a micrometer or vernier required.
Just be sure to use 1mm solder, not thicker.
Works like a charm, after all we use plastiguage for main bearings - Right? Same principal.
Note: If anyone wants any 1mm solder they can send me a self addressed envelope and i will gladly send them some to do their FD.
Just PM me.
__________________
Old enough to know better....
Young enough to try it again
GS Addict is offline   Reply With Quote
Old 11-21-2013, 04:30 PM   #15
bcostell OP
Gnarly Adventurer
 
Joined: Jun 2005
Location: San Fran Bay Area
Oddometer: 192
What a great piece of lateral thinking (solder method)! Simple and elegant (and cheap). Could this be done of the bike or does the final drive have to be removed? - I'm wondering if there's a way to keep the solder in place if the face is vertical (as it is when on the bike).

My design parameters were to negate any measuring tools other than feeler gauges when on the road - although the bearing would need to be pre-measured with a micrometer if desired. I also wanted to be able to do the shimming on the bike - without having to remove the final drive. But carrying around a micrometer and some solder is a smaller footprint than my approach - if you do indeed want to carry spares on a trip.
bcostell is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 07:02 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014