Rear wheel offset

[ailgev]

Hi all,

Im after some info on rear wheel offset. Im setting up a wire wheel from the t3 v1000 era into a Lemans MKIV swing arm.

I only had the hub and built the wheel with no offset which resulted in the wheel sitting approximately 15mm to the right of frame centre.

I measured an old wire wheel offset and it looks like it has about 3mm offset from the drive side face of the hub to the side of 2.15 rim.

I am looking at putting a 3 to a 3.5 rim on.

Do I just measure the offset from the centre of the rim to the hub drive side face or similarly minus the 3.5 width from the 2.15 width (and then halve that result) to maintain the correct offset from the side of the rim?

Hope this isn't confusing!!!

Any advice or links to sites appreciated!

[Huzo]

When I didn't the Norge wheels, I made a measurement from the mounting face of the disc to the outer edge of the rim.
After checking that the new spoke rim was EXACTLY the same as the cast one, I set the hub on the centre spindle of the jig with appropriate length spacers, (25mm from memory) and had the aforementioned rim sitting flush on the base of the jig.
This ensured that the offset was identical to the original wheel barrow wheels that came as  standard.
I can (and will) elaborate if you need me to, but it's (as usual), a bit of a saga.

[rodekyll]

But if you've got the proper spokes the offset sets itself.  Lace it up and the hub is in the only place it can be.

[Antietam Classic Cycle]

But if you've got the proper spokes the offset sets itself.  Lace it up and the hub is in the only place it can be.

A "Mk IV" (Le Mans 1000) has cast wheels, so that ain't going to work. 

[Huzo]

The last two posts require some clarification.
Relying on the spoke lengths entirely will lead to tears, because there is obviously a fair amount of thread on each spoke and you (or I), will not know where to take the nipple up to on the threaded section.
However help is fortunately at hand.
Check out the accompanying shots which will explain about 5% of the dramas you will encounter, but if (and only if) you require clarification I'll be back later(you lucky bastards) to explain the intricacies.
Bear in mind, my project is a little different to what you're doing but the guts is the same.
Build a jig from a known wheel and construct yours in that.
I'm off for now with a guy on the best R1150S BMW in Oz so I'll try not to embarrass him or myself by parking too close.

[Huzo]

Oh and BTW.
A bit off topic.


Tell me where you've see a better R1150S with 139,000 on the clock.

[rodekyll]

A "Mk IV" (Le Mans 1000) has cast wheels, so that ain't going to work. 

Sorry, missed the proper reference.  Corrected the post.

[jacksonracingcomau]

Hi all,

Im after some info on rear wheel offset. Im setting up a wire wheel from the t3 v1000 era into a Lemans MKIV swing arm.

I only had the hub and built the wheel with no offset which resulted in the wheel sitting approximately 15mm to the right of frame centre.

I measured an old wire wheel offset and it looks like it has about 3mm offset from the drive side face of the hub to the side of 2.15 rim.

I am looking at putting a 3 to a 3.5 rim on.

Do I just measure the offset from the centre of the rim to the hub drive side face or similarly minus the 3.5 width from the 2.15 width (and then halve that result) to maintain the correct offset from the side of the rim?

Hope this isn't confusing!!!

Any advice or links to sites appreciated!

Yes but

2.15 was laced square  to frame centre ie wheels in line
Factory 3.5 stil laced the wheel same but offset it 5mm to left with spacers to get tyre clearance.
I have offset my 4.25 rim 5mm to left with spokes but my 3� rim is in line

So decision on size of rim important before making decision on where to lace it , more than 130mm section tyre will need a bit of extra offset either in spokes or with spacers.
Using centre line of frame to get start point is good, if < 130 tyre, lace inline
If bigger, actual tyre matters �� not all tyres measure the same as nominal but manufacturers usually have real �hot� sizes in their cattledogs
I recommend the 4.25 rim, 150/70 tyres are vey common, hence always available, good choice of rubber

[Arizona Wayne]

LeMans IV came with either a 120/90 or 130/80 rear tire.   What size tire do you plan on putting on this bike?   I put a 130/90 rear tire on my LeMans IV with no issues.  If you put on a wider rear tire you also have to make sure it's going to clear the right swingarm/shaft which needs an indention big enough for that.   I saw a LeMans I  w/a 150 rear tire on a mag that had the swingarm modified to do it. When you do this you have to make sure the swingarm clears the internal drive shaft. 

[ailgev]

Thanks everyone. Ive figured it out.

I'll be using a 3.5 inch rim with a 130 tyre. I can keep it offset so that it is frame centre line.
41mm from hub flange face to rim centre line and no swing arm clearance issues.

Thanks again for the help.

Paul.

[Rough Edge racing]

 On the land speed racing bikes I build...The front wheel is centered under the steering stem...The rear wheel centered behind the front wheel...otherwise the bike will drift to one side going down the track... I don't know if every street bike is like this but the ones I have checked are...

[Huzo]

On the land speed racing bikes I build...The front wheel is centered under the steering stem...The rear wheel centered behind the front wheel...otherwise the bike will drift to one side going down the track... I don't know if every street bike is like this but the ones I have checked are...

A year or so back there was a thread started by some idiot from Australia that went on for bloody ages !!
It was on this very topic. Have a read, it's called track offset.
I'll bump it for your perusal..