gtgt_bangbang
New member
Final drive TOOTH CONTACT / BACKLASH QUESTION
Does anyone know ;
HOW FAR DOES THE PINION GEAR -to- CROWN WHEEL TOOTH CONTACT SPOT MOVES, FOR EVERY SHIM INCREMENT ?
This is for the shim under the drive pinion bearing, which controls the PINION INSERTION DEPTH INTO THE HOUSING,
which controls the pinon to crown tooth patch.
I'd like to move the center of the contact patch a couple mm to center.
These shims come from 1.5 to 2.5mm in 0.05 increments.
Does any body have a stash of these shims , used, to sell swap or share ?
I'd prefer to get an answer and nail it, but I'd generate the useful data if I could get an assortment of shims .
fuller story -
The 'math' marked on my case & pinion indicate a 2.24mm shim required under the drive pinion bearing,
( +20 scribed on the crown wheel & 46 stamped on the case ,ie 77.70 - 75.46 = 2.24mm)
This unit had a 2.19mm shim (as measured, call it a 2.2) under it the pinion gear bearing upon tear-down,
I reassembled it with the same shim.
This part is actually called a (for instance) 33 12 1 231 239 COMPRESSION RING - 2,1MM
Reading the contact point with gear marking wax indicates an " thinner shim / deeper pinion required" error in the contact patch.
I'd like to move the contact patches centers , up to a couple mm
TYI to anybody with experience adjusting their Final Drive tooth patch..
BACK LASH ADJUSTMENT - CROWN WHEEL SHIM
I dont have the measurement jig to put a true number on back lash but its easy to see & feel this sort of movement.
I'd estimate the original backlash in this drive would have been easily over .010", if jig measured.
Clymer says the back lash should be "nil',
and the BMW manual says the backlash should be .004 to .006" ,
There was 2.09mm shim in there.
This shim is actually called a 33 12 1 231 239 COMPRESSION RING in max.
I got a nil+ backlash by substituting a ~1.93mm shim stack.
"stack" ?
I picked up a set of thin-stock shim washers to stack up / test / determine changes for set up.
You can search ebay for dimension ( 37mm x 47mm) pops up a number of english vendors
moakes-trading had the lowest shipping & total cost. Ran about $20 all in and mail was fast.
I bought their minimum (10x count) in each .1, .3, .5mm thickness, in order to make up a pretty comprehensive set of set up shims.
The shim stock isnt dead on those numbers but nothing majic about the exact numbers
FWIW, almost every shim I got from bmw has been off by a bit, but in the window. Good nuf for tractors like these.
I'll probably just use the stack of set up shims to run, but that brings up the next issue- bronze or steel ?
cos Im guessing some of the popular/low stock COMPRESSION RINGS are getting pretty spendy ,
and probably euro supply delays.
CROWN WHEEL SHIM MATERIAL ? Steel or bronze ?
these crown wheel shims for back lash adjustment are bronze at least according to Max catalogs
for instance ( 33 12 1 231 239 COMPRESSION RING, ) ,
The shim coming out of my bike was steel.
This is a sliding contact point and the bearing flanges/ shim were of course polished but not overly worn or not all destroyed.
I also see some of these shims in BMW packages elsewhere that appear to be steel.
Anybody know if BMW substitute material bronze vs steel ?
I could see why either material is acceptable, as the only load directly ON this back lash adjusting shim is
a) due to gear interactions & thrust reactions ( mainly the gears want to climb apart when loaded)
This means when the "climb apart" force is highest, the needle bearing shim is UNLoaded...
and
b) the combined effect of this shim and the large OD shim , ( for instance 33 12 1 230 540 SHIM - 90 X 99,8 X 0,750MM
This is the large shim between the 07 11 9 981 760 GROOVED BALL BEARING , and the inner cover.)
SO NOTE - Dont overlook; if you change the BACKLASH by swaping needle bearing shims as described above ,
you should also change that large, 99.8 OD shim to compensate, otherwise you'll be side loading the large ball bearing more than intended
This whole crown wheel assembly is one solid stack from needle bearing to ball bearing .
For example , reducing back lash requires a THINNER needle bearing shim ,
which then requires a THICKER ball bearing shim , to keep the ballbearing properly loaded.
The excess backlash in my FD may account for why the only bearing in my drive that felt sketchy was this bigass ball bearing.
Its rough, probably very noisy and I'm going to replace mine.
Boxer2valve shows how to take that bearing off with an large $$ puller,
but notice that the crown wheel has a set of holes intended to drive off the bearing ( the manuals agree) .
Hoping that some heat , a drift and a zealous hammer will allow removal. Would not be risky to cut if off, either.
Install of that bearing is a simple " heat it up / install on cold crown wheel" job
Does anyone know ;
HOW FAR DOES THE PINION GEAR -to- CROWN WHEEL TOOTH CONTACT SPOT MOVES, FOR EVERY SHIM INCREMENT ?
This is for the shim under the drive pinion bearing, which controls the PINION INSERTION DEPTH INTO THE HOUSING,
which controls the pinon to crown tooth patch.
I'd like to move the center of the contact patch a couple mm to center.
These shims come from 1.5 to 2.5mm in 0.05 increments.
Does any body have a stash of these shims , used, to sell swap or share ?
I'd prefer to get an answer and nail it, but I'd generate the useful data if I could get an assortment of shims .
fuller story -
The 'math' marked on my case & pinion indicate a 2.24mm shim required under the drive pinion bearing,
( +20 scribed on the crown wheel & 46 stamped on the case ,ie 77.70 - 75.46 = 2.24mm)
This unit had a 2.19mm shim (as measured, call it a 2.2) under it the pinion gear bearing upon tear-down,
I reassembled it with the same shim.
This part is actually called a (for instance) 33 12 1 231 239 COMPRESSION RING - 2,1MM
Reading the contact point with gear marking wax indicates an " thinner shim / deeper pinion required" error in the contact patch.
I'd like to move the contact patches centers , up to a couple mm
TYI to anybody with experience adjusting their Final Drive tooth patch..
BACK LASH ADJUSTMENT - CROWN WHEEL SHIM
I dont have the measurement jig to put a true number on back lash but its easy to see & feel this sort of movement.
I'd estimate the original backlash in this drive would have been easily over .010", if jig measured.
Clymer says the back lash should be "nil',
and the BMW manual says the backlash should be .004 to .006" ,
There was 2.09mm shim in there.
This shim is actually called a 33 12 1 231 239 COMPRESSION RING in max.
I got a nil+ backlash by substituting a ~1.93mm shim stack.
"stack" ?
I picked up a set of thin-stock shim washers to stack up / test / determine changes for set up.
You can search ebay for dimension ( 37mm x 47mm) pops up a number of english vendors
moakes-trading had the lowest shipping & total cost. Ran about $20 all in and mail was fast.
I bought their minimum (10x count) in each .1, .3, .5mm thickness, in order to make up a pretty comprehensive set of set up shims.
The shim stock isnt dead on those numbers but nothing majic about the exact numbers
FWIW, almost every shim I got from bmw has been off by a bit, but in the window. Good nuf for tractors like these.
I'll probably just use the stack of set up shims to run, but that brings up the next issue- bronze or steel ?
cos Im guessing some of the popular/low stock COMPRESSION RINGS are getting pretty spendy ,
and probably euro supply delays.
CROWN WHEEL SHIM MATERIAL ? Steel or bronze ?
these crown wheel shims for back lash adjustment are bronze at least according to Max catalogs
for instance ( 33 12 1 231 239 COMPRESSION RING, ) ,
The shim coming out of my bike was steel.
This is a sliding contact point and the bearing flanges/ shim were of course polished but not overly worn or not all destroyed.
I also see some of these shims in BMW packages elsewhere that appear to be steel.
Anybody know if BMW substitute material bronze vs steel ?
I could see why either material is acceptable, as the only load directly ON this back lash adjusting shim is
a) due to gear interactions & thrust reactions ( mainly the gears want to climb apart when loaded)
This means when the "climb apart" force is highest, the needle bearing shim is UNLoaded...
and
b) the combined effect of this shim and the large OD shim , ( for instance 33 12 1 230 540 SHIM - 90 X 99,8 X 0,750MM
This is the large shim between the 07 11 9 981 760 GROOVED BALL BEARING , and the inner cover.)
SO NOTE - Dont overlook; if you change the BACKLASH by swaping needle bearing shims as described above ,
you should also change that large, 99.8 OD shim to compensate, otherwise you'll be side loading the large ball bearing more than intended
This whole crown wheel assembly is one solid stack from needle bearing to ball bearing .
For example , reducing back lash requires a THINNER needle bearing shim ,
which then requires a THICKER ball bearing shim , to keep the ballbearing properly loaded.
The excess backlash in my FD may account for why the only bearing in my drive that felt sketchy was this bigass ball bearing.
Its rough, probably very noisy and I'm going to replace mine.
Boxer2valve shows how to take that bearing off with an large $$ puller,
but notice that the crown wheel has a set of holes intended to drive off the bearing ( the manuals agree) .
Hoping that some heat , a drift and a zealous hammer will allow removal. Would not be risky to cut if off, either.
Install of that bearing is a simple " heat it up / install on cold crown wheel" job
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