April 10, 2020
This question has been asked before but there has never been a reply as to why this shim/s is required to be fitted. So…..
Looking at the workshop manuals B175, D14, etc they all mention a shim on the front wheel spindle between the shoulder on the brake side of the wheel spindle and the bearing.
The shim is part number 90-5722 and is listed/ shown in the relevant parts books. Looking on the T’internet it looks like this, so just a thin washer.
Apologies for the poor drawing but should be enough to get the idea of what i am going on about.
Here’s my take on the setup:
1. The brake side outer bearing race butts up to a shoulder in the hub and is held solidly in position, in the hub, by the bearing locking ring (LH thread) shown in blue. The precise location of this bearing is therefore fixed by the shoulder machined in the hub.
2. The wheel spindle is clamped solidly to this bearing’s inner race by the spindle nut which clamps the spigot on the inside of the brake plate (shown in red) against the front of the bearing inner race and the shoulder on the spindle against the rear of the inner race. The location of the spindle is therefore fixed by the location of the bearing.
3. There is NO shoulder in the hub for the opposite bearing. According to the manual this bearing’s position is determined by pressing it in until it is just possible to fit the dust shield and the circlip. Whilst there is a small machining lip on the spindle on this side (not a proper shoulder as on the brake side the manual does not suggest the bearing is fitted up against this ‘lip‘.
4. Fitting my bearings and spindle in this way (as per manual) results in a gap of 0.10″ (1/10th inch) between the inside of the opposite bearing inner race and the small ‘lip‘ on the wheel spindle. This gap can be measured by undoing the spindle nut and pushing/ pulling on the spindle.
5. In my view this gap is of no relevance to the correct operation of the front wheel bearing assembly as the wheel spindle is already firmly clamped/ located in position, within the hub, by the brake side bearing as explained in 1 and 2 above.
6. So onto the ‘shim’: It is supposed to be located between the brake side inner bearing race and the shoulder on the spindle As far as I can see, all that a ‘shim’ in this location can do is move the wheel spindle across towards the non brake side by the thickness of the shim…but what does this achieve?.
7. Regarding the number of ‘shims’ the parts book says “as required”. Does this means that no shims may be OK, or 1, or multiples of one? To make up the 1/10th inch more than one would be needed.
There was no shim present on my front wheel spindle and i just can’t see what fitting one will achieve.
So what do you chaps think? Quite a few of you have B175’s and D14’s ….so is this shim always fitted and if so only one?
Cheers
Alan
1939 Ariel VH, 1942 Ariel WNG, 1951 Triumph 6T Thunderbird, 1970 BSA Bantam B175, 1980 Honda CB250N, 1986 Yamaha SRX600
September 30, 2011
Hi Alan.
Very interesting, not something that I have thought about before. It’s 10 years since I rebuilt the front wheel on my D14 and cant remember if there was a spacer in it or not.
I have just read the workshop manual and it refers to the spacer and implies that there will only be one. As you say, it seems to serve no purpose.
It would probably make more sense if there were different thickness shims available to set a small amount of preload to the bearings but no mention of it anywhere that I have seen. So got to say, I just don’t know.
Mike.
November 6, 2016
Excellent diagram by the way. I have always put my hubs back exactly as I found them. Having ensured that the new bearings are the same thickness as the originals. If a shim was present I have put it back in as found. It must be there for a good reason and I have never had any corresponding problems with wheel bearings and brake plates to date.
I guess that you could also use these shims to ‘align’ / centralise the rim in the forks during chassis set up but its probably better to do it the traditional way by ‘pulling’ the rim over to get a perfect alignment.
I am unable to offer mush else by way of help.
Sponge
April 10, 2020
Thanks for the input chaps. I think its good every now and again to have something to keep the grey matter working
Measured my spindle endfloat again this time with a dial gauge. With both bearings mounted as per manual, but no shim and no brake plate, it is 2.40mm / 0.094 inch. So again, as shown in my drawing, with the spindle and brake plate assembled this (0.094″) is the distance between the non brake side bearings inner race and the small lip on that side of the wheel spindle.
I think its worth mentioning that it is desirable for there to be a gap at this point (non brake side bearing inner to spindle lip) because…as I found out…if you drive the non brake side bearing in by its outer race (the correct way to fit a bearing) until the inner race contacts the lip this puts a side load on the bearing/s making the balls bind in the race. However, this bearing never gets this far if you fit it as per the manual, so that it just clears the dust shield and circlip. So…fully taking up this gap with shims at the other end of the spindle would not be the way to go.
Spoke to Draganfly and the 90-5722 shim is 0.90mm / 0.035 inch thick. Therefore, fitting one shim does not make any significant difference to the lateral position of the spindle when it is tightened up against the brake plate and certainly does not take up the available spindle endfloat. You would need to fit two and even then you would still have a gap.
So…if the shim does nothing significant regarding the assembly of the hub/spindle/bearings IS the shim required to get the wheel centered in the forks as has been suggested?
Reading through all the relevant posts here and elsewhere there is little in the way of a definitive offset (drum edge to rim) measurement for the single sided hub on a B175. Mine (no shim fitted) was 15mm and I have read that the correct measurement per CWC is 5/8″ (16mm). So the thickness of a single shim different…interesting?
So…really not much further forward as to why that shim is needed. The same shim is listed on the brake side for B175, B175 Bushman, D14, D14 sports full width hub, D14 bushman full width hub and the D10. And on the D10 sports full width, as well as one on the brake side, there is also one shown on the non brake side between the outside of the bearing and the dust shield!
I think I’ll just fit one and be done with it. Onward and upwards
Cheers
Alan
1939 Ariel VH, 1942 Ariel WNG, 1951 Triumph 6T Thunderbird, 1970 BSA Bantam B175, 1980 Honda CB250N, 1986 Yamaha SRX600
February 7, 2013
Hi All
When I first read this topic I went and had a look in my B175 parts list book to see where the shim/washer went.
I agree with Sponge, if it’s taken out put it back! As for putting it in, it’s a”tongue wagger” and this thread could go on and on. The only reasons I can see for installation is to provide a marginally bigger thrust bearing area for the inner part of the ball race or to move the brake side of the hub closer towards the right fork leg.
I did think it was to act as a grease retainer for the bearing but what about the one on the opposite side. Hmm over to others to think about.
B175, on the road. Honda XBR 500, and ....... Suzuki Burgman 200 scoot! Nicknamed "The hair dryer" - by me I hasten to add; & great storage under the seat when you get to your destination.
April 10, 2020
The dimensions of the shim are as near as damn it the same as the shoulder on the brake side of the spindle so probably not intended to increase the bearing thrust area?
Yup I agree that using the shim to adjust the lateral location of the wheel (i.e centralise it) would work. But to centralise the wheel this way would mean having to remove at least one of the bearings to fit a shim, if one was needed, when the wheel was being fitted to a bike. Did they really do this at the factory? I envisage a guy on the assembly line grabbing a pre-assembled wheel, slotting it in, and fitting the clamps. If this was the case then all assembled wheels would need to have the same offset.
Looking at a Triumph factory video from this era hubs were built up with bearings and spindles before the rims were laced. It is likely that BSA did it the same way. I would have thought that, if a shim was fitted, it would have to be done when the hub was assembled prior to the rim and spokes being fitted.
There must be loads of folks on this forum who have changed wheel bearings on the models mentioned in post 5. It would be of interest if they could report whether they had a shim/s fitted or not.
I know this subject not a big deal and that the inclusion or omission of this shim will not cause any safety issues. I am just curious as to the engineering reasons for it being there.
Cheers
Alan
1939 Ariel VH, 1942 Ariel WNG, 1951 Triumph 6T Thunderbird, 1970 BSA Bantam B175, 1980 Honda CB250N, 1986 Yamaha SRX600
April 10, 2020
Thought about the situation a different way…
The position of the wheel spindle laterally, between the fork legs, is fixed as it is located by the fork end cap bolts which locate into the semi-circular grooves in the spindles. The shim therefore has no effect on the spindles location relative to the forks.
Therefore, all the shim does is move the hub, and the assembled brake plate, 0.9mm closer to the right side fork leg.
The only items that are effected by the lateral position of the hub are:
1. The lateral position of the slot on the brake plate anchor arm, where it fits onto the rectangular stub welded to the fork leg. This stub has a shoulder and therefore the anchor arm cannot go any further than this shoulder without putting a side force on the arm/brake plate.
2. The half nut that secures the brake plate to the spindle. This nut sits very close to the inside of the fork leg but it should not be hard up against the fork as this could effect the correct location of the end cap bolts in the grooves in the wheel spindle.
3. The centering of the wheel rim between the fork legs.
So……
We know that the wheel rim should be located centrally between the fork legs.
Many/most Brit spoked wheels are designed so that the centre of the wheel rim sits centrally between the (centre-line of) the spoke flanges. From a design/engineering point of view this makes good sense.
This means that, with the wheel fitted, the spoke flanges should also be located centrally between the fork legs.
I measured my hub up, without the shim, and it was out of centre by about 1mm. Fitting the shim brought the spoke flanges centrally between the fork legs.
To get the rim centered the offset from the brake drum lip to rim needed to be 16mm (not the 15mm as before the shim was fitted) which makes sense as I’d moved the hub over 1mm.
I found the brake anchor arm aligned spot on with the shoulder on the stub but was not pushed up hard against it.
There was about 1mm gap between the brake plate nut and the fork leg.
In conclusion: the presence of this one shim makes little difference to the setup / alignment of the wheel. Clearly BSA thought it necessary to include it “as required” as it says in the parts book.
I really don’t think BSA measured every single Bantam up to a tolerance of 1mm to see if a shim was needed or not and they would not have been building wheels with different ‘offsets’ to suit a shimmed or not shimmed hub. My view is that they had different manufacturers making the hubs (not unusual for them to have more than one supplier for certain parts) and one make needed the shim.
I noticed that on Lone wolf’s website his B175 front wheel spindle assembly photo did not show a shim so as I suspected it was not a blanket fitment.
Cheers
Alan
1939 Ariel VH, 1942 Ariel WNG, 1951 Triumph 6T Thunderbird, 1970 BSA Bantam B175, 1980 Honda CB250N, 1986 Yamaha SRX600
June 13, 2015
January 24, 2012
Alan.Moore said
I noticed that on Lone wolf’s website his B175 front wheel spindle assembly photo did not show a shim so as I suspected it was not a blanket fitment.
Cheers
Alan
Wotcha.
Don’t take anything regarding that B 175 as being correct.
It had been put together over the years by a various number of blind monkeys ( or so it would appear ) who delighted in wielding big hammers.
^..^
April 10, 2020
Lone Wolf said
Wotcha.
Don’t take anything regarding that B 175 as being correct.
It had been put together over the years by a various number of blind monkeys ( or so it would appear ) who delighted in wielding big hammers.
Ah fair point…I assumed that as you thought the bearings looked like the originals the front wheel may have not been apart.
Nice rebuild by the way.
I’m going to use your wiring diagrams and how the original switches can be wired up to make a new loom to for a simple 12 volt system with a 12v reg/rect (same as the one Rex sells).
Cheers
Alan
1939 Ariel VH, 1942 Ariel WNG, 1951 Triumph 6T Thunderbird, 1970 BSA Bantam B175, 1980 Honda CB250N, 1986 Yamaha SRX600
February 7, 2013
Hi All
Without digressing as to what made me look at my B175 front hub I think I have come up with a more likely reason as to why the shim was fitted. Alan’s sketch of the front hub doesen’t show that the brake plate has a lip round the outside to, I think, keep grit, muck, and water from getting in. If during manufacture of the brake plate the depth of the lip could vary, the shim would move the plate away from the brake drum so it wouldn’t rub.
It was awhile ago when I rebuilt my front wheel so I cannot verify whether there is a shim there or not. Certainally what came out, went back.
Digressing – it was when I took my scoot for an MOT – no spitting please!
B175, on the road. Honda XBR 500, and ....... Suzuki Burgman 200 scoot! Nicknamed "The hair dryer" - by me I hasten to add; & great storage under the seat when you get to your destination.
April 10, 2020
not henpecked:
I think the location of the brake plate, relative to the hub/brake drum casting, is governed by the location of the bearing as the brake plates central projection is held tight against the bearing by the spindle nut. This bearing sits hard up against a machined shoulder in the hub and is held there by the LH thread locking ring. The shim fits on the other side of the bearing (not the brake drum side) and does not alter the location of the brake plate relative to the hub.
As for your Scoot….I’ve just got a 110cc Honda Vision from my Dad who at 87 yrs of age has decided to give up riding. Bit smaller then your Burgman but with a topbox and under seat storage loads of storage space for a bit of shopping……. and I don’t have to worry that some tea-leaf is going to pinch one of my classics while I’m in in town shopping.
Cheers
Alan
1939 Ariel VH, 1942 Ariel WNG, 1951 Triumph 6T Thunderbird, 1970 BSA Bantam B175, 1980 Honda CB250N, 1986 Yamaha SRX600
Most Users Ever Online: 223
Currently Online:
22 Guest(s)
Currently Browsing this Page:
1 Guest(s)
Top Posters:
cocorico: 4722
Cornish Rooster: 2892
Blue Heeler: 2393
bart: 2364
sunny: 2330
Sprung Chicken: 2085
David Dale: 2001
Stoo63: 1762
Piquet: 1749
mike p5xbx: 1743
Newest Members:
MartW
Forum Stats:
Groups: 9
Forums: 50
Topics: 11657
Posts: 101390
Member Stats:
Guest Posters: 1393
Members: 4250
Moderators: 4
Admins: 2
Administrators: Bantam-Super, Jimi
Moderators: pete (Secretary and Essex and London Rep), DrT, Johnny D, Gina Hinde