GS1150 wheel on GS1000

[salty_monk]

Nope... they draw it up in CAD too..

John - my measurement on the bearing +spacer is taken physically in exactly the same way as yours.
My 750 wheel is from an 83 750ES but it has 1000/1100 bearings & spacer in it. I believe I have the original bearings & spacer somewhere but I know for sure already that the spacer I removed was the same length, just a smaller dia.
It will be good to get to the bottom of why yours is coming up different...

I will take some more measurements & pictures etc when I mount it but that's not going to happen for a few weeks for sure.

Dan

[GSexpress]

Simply put, wheel center and hub center are NOT neccessarily the same thing. Some wheels may have the bearings centered side to side in the wheel and some may not. Some wheels may have the hub surfaces centered in the wheel and some may not. Wheel center is determined by the mid point between the 2 tire mount bead edges. That is the only constant to measure from.. Therefore all measurements should be referenced to the wheel center measured off the bead of the rim. Measure bead to bead and devide by 2. Then measure the thickness of the rim edge to the bead. add that to the results of half the bead to bead. You now have a number for the distance from rim edge to wheel center. Now you can measure with a staight edge across the wheel, the distance from wheel edge to the bearing surfaces. These differences from wheel to wheel deducted from the measurement to wheel center will give you your spacing differences. This has to be done for each side.

simple example:
Wheel A:
Bead to bead...................= 400 mm divided by 2 = 200 mm
bead to edge...................= 13 mm plus 200 = 213 mm edge to center

Wheel B:
Bead to bead...................= 425 mm divided by 2 = 212.5 mm
bead to edge...................= 15 mm plus 212.5 = 227.5 mm

Wheel A has a measurement of 50 mm from edge to bearing on the left side.

213 minus 50 = 163 mm

Wheel B has a measurement of 98 mm from edge to left bearing.

227.5 minus 98 = 159.5

163 - 159.5 = 3.5 mm

3.5 mm is the thickness of the spacer you would need to use wheel B with the stock spacers from wheel A FOR THE LEFT SIDE!

You would need to do the same for the right side. The spacers would then need to be put next to the bearing so that the spacing from the swing arm to the brake rotor and chain sprocket are unchanged.

If the math results are negative, such as putting wheel A in place of wheel B with wheel B's stock spacers you would need to remove that much material from the spacers next to the bearing.

It doesn't end there.

If you are swaping wheel B for wheel A with wheel B's stock spacers you need to do the same measurement and then measure the thickness of all the spacers for each side wheel A to wheel B and compare the difference to the difference in edge to bearing difference. B's spacers should add up to the same as A's spacers + the edge to bearing differerence, if not, B's spacers must be adjusted to equal that spacing to keep it centered in the new swingarm.

This is just a generic example but it applys to all such swaps.

It is also possible that you might need to add spacing to one side and reduce spacing on the other side depending on the difference between hub center, bearing center and bearing spacing with the swingarm being used..

[John Kat]

GS, I totally agree with your method and it's exactly what I did.
Here are the numbers:
Please note that for the 1150 wheel the measurements were taken with the sprocket carrier hub in place but the principle is the same.

For the 1150 wheel the B to B distance is 111 mm ( 3.5" wide)
The bead to edge is 53 mm
The bearing recess is 7+46.5 ( the lenght of the sprocket carrier spacer)=53.5 mm
The net LH offset is thus: 111/2+53-53.5=55mm

For the 1000 wheel the numbers are respectively:
B to B:75 mm ( 2.15" wide)
B to E:23 mm
Bearing recess : 10 mm
The net LH offset is thus: 75/2+23-10=50.5 mm

The conclusion is that the 1150 wheel is offset to the right compared to the GS 1000 wheel by : 55-50.5=4.5 mm.

What got me puzzled in this process is that BOTH wheels have the same bearing to bearing distance of 111 mm that induced me to think that one can interchange them without any issue.
But clearly as you point out this is not the case.
I believe the conclusions Salty Monk came to are related to the fact that he is not measuring a GS 1000 wheel but a later GS 750 wheel.

[salty_monk]

John,

My 1978 GS1000 original wheel has the 116mm spacer/bearing combo too. I do not have to change anything when swapping between the two wheels it slots right in. The 750 wheel setup the way I currently have it is identical to an 83 1100 E wheel.

I am a little lost as to why you are coming up with the direct opposite of what I have at this stage & also why your 1000 wheel has a shorter hub centre. There is no way I could get a 111mm spacer in my wheels as the bearings are fully seated with the 116mm.

I would suggest our next move would be to compare sprocket drives & spacers. I can only think that your sprocket drive or drive side spacer is grossly different to mine.

By the way - when I test fitted the 1150 wheel (very roughly) I measured an approx 5mm difference between the Rim & the swingarm edge at the front (I think it was 60mm on the left 65mm on the right but I could be wrong). I realise that this measurement was not accurate (the wheel was not perfectly straight, was not tight & I was juggling the wheel, the rule etc) but the extra distance was on the brake side.

Dan

[GSexpress]

GS, I totally agree with your method and it's exactly what I did.
Here are the numbers:
Please note that for the 1150 wheel the measurements were taken with the sprocket carrier hub in place but the principle is the same.

For the 1150 wheel the B to B distance is 111 mm ( 3.5" wide)
The bead to edge is 53 mm
The bearing recess is 7+46.5 ( the lenght of the sprocket carrier spacer)=53.5 mm
The net LH offset is thus: 111/2+53-53.5=55mm

For the 1000 wheel the numbers are respectively:
B to B:75 mm ( 2.15" wide)
B to E:23 mm
Bearing recess : 10 mm
The net LH offset is thus: 75/2+23-10=50.5 mm

The conclusion is that the 1150 wheel is offset to the right compared to the GS 1000 wheel by : 55-50.5=4.5 mm.

What got me puzzled in this process is that BOTH wheels have the same bearing to bearing distance of 111 mm that induced me to think that one can interchange them without any issue.
But clearly as you point out this is not the case.
I believe the conclusions Salty Monk came to are related to the fact that he is not measuring a GS 1000 wheel but a later GS 750 wheel.

I think your measurements are off my friend.

You've got a B to E of 53mm on the 1150 wheel and 23mm on the 1000 wheel. They should be the same on both and less than 23mm. I was trying to give a formula that would work for any wheel some have different Bead to Edge thicknesses from one side to the other, our GS's don't, so you could measure edge to edge on the GS wheel and devide by 2 to get wheel center. Also not removing the sproket carrier and spacer leaves room for inacuracy's. The spacer itself could be different from bike to bike and lube could take up space between the bearing and the spacer. Plus you don't include any measurement for it on the 1000 wheel.

The fact that you get a different Bearing to bearing spacing from SM is not unusual. There can be many reasons for this; pocket depth, bearing thickness differences, (slight differences between factory suppliers, and aftermarcket replacements) wear and bearing seating. That's why the bearing to bearing dimention is not used in determining spacing differences, And why your spacing may be different than SM's spacing. Everyone doing a wheel swap should do the math themselves. It is the bearing spacing and offset differences from wheel to wheel that keep it from being a straight swap in the first place. Even replacing a like wheel can present problems sometimes.

[tatu]

John,

My 1978 GS1000 original wheel has the 116mm spacer/bearing combo too. I do not have to change anything when swapping between the two wheels it slots right in. The 750 wheel setup the way I currently have it is identical to an 83 1100 E wheel.

I am a little lost as to why you are coming up with the direct opposite of what I have at this stage & also why your 1000 wheel has a shorter hub centre. There is no way I could get a 111mm spacer in my wheels as the bearings are fully seated with the 116mm.

I would suggest our next move would be to compare sprocket drives & spacers. I can only think that your sprocket drive or drive side spacer is grossly different to mine.

By the way - when I test fitted the 1150 wheel (very roughly) I measured an approx 5mm difference between the Rim & the swingarm edge at the front (I think it was 60mm on the left 65mm on the right but I could be wrong). I realise that this measurement was not accurate (the wheel was not perfectly straight, was not tight & I was juggling the wheel, the rule etc) but the extra distance was on the brake side.

Dan

This where I got to today too. All the previous pages making sense but trying to make it fit what I have (I'm going the other way) was making my head spin.
I need to move the wheel 2.25mm to the left but keep the drive line the same, ie narrow the chain/tyre gap.
I was about to skim a spare sprocket carrier and take the same off the carrier spacer. But having second thoughts I'll use the offset sprocket I have.
I will not have to kink the torque arm and the standard chain guard will fit perfectly.

[GSexpress]

John,

My 1978 GS1000 original wheel has the 116mm spacer/bearing combo too. I do not have to change anything when swapping between the two wheels it slots right in. The 750 wheel setup the way I currently have it is identical to an 83 1100 E wheel.

I am a little lost as to why you are coming up with the direct opposite of what I have at this stage & also why your 1000 wheel has a shorter hub centre. There is no way I could get a 111mm spacer in my wheels as the bearings are fully seated with the 116mm.

I would suggest our next move would be to compare sprocket drives & spacers. I can only think that your sprocket drive or drive side spacer is grossly different to mine.

By the way - when I test fitted the 1150 wheel (very roughly) I measured an approx 5mm difference between the Rim & the swingarm edge at the front (I think it was 60mm on the left 65mm on the right but I could be wrong). I realise that this measurement was not accurate (the wheel was not perfectly straight, was not tight & I was juggling the wheel, the rule etc) but the extra distance was on the brake side.

Dan

The swing arm is not neccessarily an acurate point to measure to. They are not neccessarily the same distance from bike center to one side or the other. Swing arms may be biased to one side or the other to allow for chain or brake offsets. The only thing you can count on is that the factory centered the wheel That is why wheel center is the only constant to measure from.

[John Kat]

You've got a B to E of 53mm on the 1150 wheel and 23mm on the 1000 wheel. They should be the same on both and less than 23mm.

For what reason? You seem to be negating your own logic whereby the rim is not necessarily located in the same position with respect to the hub on different wheels?
I fail to understand what's wrong as I did exactly what you are proposing?
The fact that I left the Sprocket carrier on the 1150 wheel might add a little error but doesn't detract from the logic you exposed.
Last, don't forget that the wheel bearings rest against a shoulder in the wheel and there is no way that the the same wheel in production would go from 111 mm to 116 mm.
I propose you measure your own wheels to determine if and how they differ from mine.

[John Kat]

John,

My 1978 GS1000 original wheel has the 116mm spacer/bearing combo too. I do not have to change anything when swapping between the two wheels it slots right in. The 750 wheel setup the way I currently have it is identical to an 83 1100 E wheel.

I am a little lost as to why you are coming up with the direct opposite of what I have at this stage & also why your 1000 wheel has a shorter hub centre. There is no way I could get a 111mm spacer in my wheels as the bearings are fully seated with the 116mm.

I would suggest our next move would be to compare sprocket drives & spacers. I can only think that your sprocket drive or drive side spacer is grossly different to mine.

By the way - when I test fitted the 1150 wheel (very roughly) I measured an approx 5mm difference between the Rim & the swingarm edge at the front (I think it was 60mm on the left 65mm on the right but I could be wrong). I realise that this measurement was not accurate (the wheel was not perfectly straight, was not tight & I was juggling the wheel, the rule etc) but the extra distance was on the brake side.

Dan

Dan, I'll answer tomorrow in order to think it through further

[salty_monk]

Dan, I'll answer tomorrow in order to think it through further

Ok. I am very intrigued now. I can say that I will be very surprised if what I've measured doesn't work for me as I have both wheels on hand.
The fact that it tallies up to what GS Express posted is nice too.

GS Express - I know that measuring to swingarm is not an accurate science, especially the way I did it!
I was really just trying to get an idea. It does seem to tie in nicely to what I measured in the wheels (i.e. that I need an extra 5mm in there somewhere & it needs to be on both sides not just 1 side). That was before this thread started! I just mentioned it now as it seemed relevant

[John Kat]

John,
I would suggest our next move would be to compare sprocket drives & spacers. I can only think that your sprocket drive or drive side spacer is grossly different to mine.
Dan

Dan, here are the measurements that I did with a GS 750 wire wheel hub.
As I mentionned earlier this hub is almost identical to my GS 1000 EC and GS 1100 SD Kat hubs with 50 mm offset and 111 mm bearing to bearing.
The picture is upside down but starting from the drive side you have:
chain adjuster: 3mm, LH spacer: 28 mm, sprocket carrier spacer: 47.5 mm, wheel hub B to B: 111mm, hub to caliper spacer: 23.5 mm, caliper bracket: 24 mm, RH spacer 12 mm, chain adjuster: 3 mm.
The total between swingarm is thus 252 mm.
The open swingarm is 260 mm allowing a "pinch" of 8 mm.

[John Kat]

I thought about this offset issue a little more today and I found a quick and (potentially) dirty way to find out if your "new" wheel is offset or not
It must be done with the wheel tight but not necessarily in it's swingarm.
You take your micrometer and you measure the distance from the outside of the chain sprocket to the seam of the rear wheel.
If the distance is the same for your two wheels there is no offset.
If there is a difference, obviously there is an offset that is equal to the difference between your two measurements.
Before anyone starts yelling, make sure you are using the same sprocket hub carrier for both measurements.
I did not because I know there are the same on both bikes I measured but I also paid attention to an eventual difference in width of the sprocket itself.
Now the data: The black 2.5" wheel is on my 1100 Kat : 93 mm
The gold 3" wheel is on my GS 1000 ST: 97.5 mm
So clearly if my original wheel was centered, I need to move my new "gold" wheel to the left by 97.5-93= 4.5 mm.
And that's exactly what I did by shortening the LH spacer by 4 mm!
No rocket science here

[salty_monk]

John,

Our open swingarm measures the same at 260mm. Id be surprised if my "pinch" is 8mm but I guess we'll find out!

I don't know if I have a spacer set off the bike, I did have but not 100% it's complete, will check. Its another GS1000 spacer set. What is your spacer set from?

I have a spare sprocket drive and sprocket so I can do your other measurement.

Dan

[John Kat]

The spacer set is from a GS 1000.
Any luck with the simplified "sprocket" offset measurement?
I measured the "sprocket" offset on another GS 1000 equipped with the std 2.5" wheel and it's still 93 mm...

[salty_monk]

Not yet John, still early here, you're 9hrs ahead of me

By the way - thinking about this, are we 100% that the seam is central/in the same spot on the wheels in relation to the rim? It would seem to make sense that it is central but tool offset in the casting might be different wheel to wheel...

If I have to I will pull my rear 78 1000 wheel & spacer set to measure. By the way, what sprockets are you using? 630? 9mm thickness?

Where are you in France? I lived just outside Hyeres in the South for a few months.

Dan