Author Topic: Wheel Offset  (Read 4915 times)

Offline peteb

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Wheel Offset
« on: 07.06. 2008 10:06 »
Hi,

I have a 1953 Plunger Frame Golden Flash which I purchased some weeks ago and have been very slowly getting running and roadworthy again.  I did post a question some time back about the carb which I received a lot of help with which was much appreciated

On checking the wheel alignment I have found that the rear wheel is too far over to the right athough the sprocket appears to be in alignment with the drive sprocket.  This misalignment is significant with the rear being at least an inch out of alignment with the front and this can be seen visually in the wheel position in the frame.  Now I know that the previous owner had the wheels rebuilt and all I can think off is that the offset was measured from the wrong side.

So my question is does anyone know what the offset of the rear wheel is and where is it measured from.

Pete

Offline joecr

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Re: Wheel Offset
« Reply #1 on: 07.06. 2008 10:58 »
Hi Pete,

I've just had a quick look at my Golden Flash plunger and the offset on mine is appox 45 mm from the back of the brake drum to the cantre of the wheel rim. I measured it by holding a long steel rule on the back of the brake drum and measuring to the middle of one of the spoke nipples. Not precision engineering but should give you something to work from.
My wheels have recently been rebuild by a local wheelbuilder and he has a very good reputation for a first class job, so should be pretty close.
Hope this is of some help.
Joe.

Online Brian

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Re: Wheel Offset
« Reply #2 on: 07.06. 2008 11:46 »
I have just built the wheels for my A7 plunger and the rear rim should be central to the plungers. The easiest way to check is to use a ruler and measure from the side of the rim to the centre of the plunger columns, it should be the same on both sides. By doing this you will be able to work out how far yours will need shifting. If he has built the wheel so the rim is central to the hub it will be wrong. The QD wheel has shorter spokes on the spline side so you may not be able to move the rim over far enough. What I do is lace the front wheel so it is central between the forks and then use a straight edge to the rear rim as I true it, that way both rims are in line. You may have to rebuild the rear wheel unfortunately. A good wheel builder that has been doing wheels for some time may know the correct offset and be able to sort it for you. I also have a 53' plunger model and they are terrific bikes so good luck with it.    Brian.

Offline dpaddock

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Re: Wheel Offset
« Reply #3 on: 07.06. 2008 16:32 »
Spoking info by the late and great John Gardner of the GSOC (UK) for the plunger and S/A frame rear wheel:

     WM2-19 steel rim; 10 BWG spoke lengths - left, 7-27/32", right, 7-29/32"; rim edge offset 19/32" to edge of hub center.
David
'57 Spitfire


Offline peteb

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Re: Wheel Offset
« Reply #4 on: 08.06. 2008 19:45 »
Thanks for your information guys.

The measured rim offset is 1/4" which is 11/32" short of what it should be.  This measurement is confirmed when I measure the position of the wheel in the frame.

Will be looking for a wheel builder this week.

Again - Many Thanks

Pete

Online RichardL

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Re: Wheel Offset
« Reply #5 on: 09.06. 2008 05:03 »
Pete,

Wouldn't Central Wheel be a likely builder for your wheel, particularly if you are anywhere near Birmingham? My being in the U.S. pretty much ruled out my using them, but, from their website and reputation, I think that's where I would have gone or sent my wheels to had I been in the UK. Others here, I'm sure, will either bless them or curse them from their actual experiences.

Richard

P.S. You didn't happen to play drums in Liverpool once upon a time did you? 
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Offline a10gf

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Re: Wheel Offset
« Reply #6 on: 09.06. 2008 10:22 »
Quote
P.S. You didn't happen to play drums in Liverpool once upon a time did you?
that would be very special !

A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

Offline peteb

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Re: Wheel Offset
« Reply #7 on: 09.06. 2008 17:43 »
Richard

Thanks for you comments about Central Wheels.  They are one of the options I will consider although in general I like to support local businesses wherever possible.  However I can't think of any wheel builders down here in the sunny southwest so will probably have to go further afield this time.

As to the drum playing - I wish, boy do I wish.

Pete

Offline duTch

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Re: Wheel Offset
« Reply #8 on: 09.10. 2012 14:04 »

This is info that I was looking for a year and a half ago, Pete, did you get it sorted? I think I made my offset about 5 or 6 mm to the left of centre, I bought my rims from CWC, but they couldn't give me info; re offset..... *conf*
 Cheers duTch
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline peteb

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Re: Wheel Offset
« Reply #9 on: 09.10. 2012 19:54 »
duTch

From the post by dpaddock above

rim edge offset 19/32" to edge of hub center.

This worked for me.

Hope this helps

Pete

Offline duTch

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Re: Wheel Offset
« Reply #10 on: 10.10. 2012 12:31 »


Thanks Pete,
         I can't work that out, to many 'edges' 19/32" in my lingo is a bit over 15mm a bit under 5/8", from somewhere
 there seems to be differing formulae for this determination, I've read some measure from spline end to rim edge(weird), others rim centre to hub edge, rim cente to hub centre, or hub edge to rim edge.
 Any way I made mine  ~5mm Rim edge to crinkle hub edge -LHS(WM3 rear- 80mm rim /80mm hub)ie; Rim to hub centre LHS=45mm/  or if it were a WM2 would be rim edge on line with crinkle edge on drive side- LHS.
 I'm yet to assess it's functionality, but if I can take a pic will post that
 Brain cells all done cheers, duTch
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline peteb

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Re: Wheel Offset
« Reply #11 on: 15.10. 2012 08:34 »
duTch

Sorry for the delay in replying.  Happy to speak in your lingo, makes more sense to this old(ish) Brit. 

19/32 is 15 mm as near as dammit and this is measured by putting a straight edge across the brake hub and measuring to the rim edge.

Hope this helps - can supply a picture if required.

Cheers

Pete

Offline duTch

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Re: Wheel Offset
« Reply #12 on: 16.10. 2012 11:08 »

 hi Pete,
            I just tried to read what I wrote, If you understand that, we both have the same affliction.. *eek*

 I think to sum it up, I have a WM3, which is 80mm same as the hub centre, I initially made it central, but needed to pull it over to the left ~5mm.
   If it were a WM2, that would make the rim in line with LHS of hub centre, not to say that's 'correct' but is what made mine centre in frame, and that's after having frame pro straightened(Dave Kellet and using drawings from service sheets).
 Other thing to keep in mind is whether or not you have the correct brake drum/chainwheel?
 When I initially threw mine together with what ever I could find to 'fit', sure- 'fitted', but didn't necessarily 'fit' well.
  Case in point, I used a brake drum/chainwheel with replaceable sprocket,  that turned out to be from a A65 QD, didn't know better- no info available then- wrong gearing too, but the bearing housing/+spacer is different and threw the chain alignment/wheel offset out, plus slightly bent frame= Headf#$%^....

 But I think I got it sorted- found a correct chainwheel-(and at the same time discovered one of the books has the brake plate spacer deleted).

  Thing is I contacted SRM, and Gary replied,
Quote
Hello Dutch,
ok rear hub has zero offset , measured from end of hub on the spline side, ( do not measure from end of splines, simply just the end of the crinkly hub bit)
 
Assuming rim is standard WM2 steel rim.
 
Also do not assume wheels are central to forks front and plungers rear, note front wheel is not central in forks on A7/10 and A50/A65 up to 1970 !
 
Regards Gary
,
 
   which didn't make sense to me so I used my own method- hope that's helpful?
 Cheers, duTch
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline Jules

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Re: Wheel Offset
« Reply #13 on: 18.10. 2012 08:34 »
Now you have me confused Dutch  *sad2*. Your inserted note from "Gary" says that the front wheel on my 1956 Swinging Arm is NOT central in forks. Well mine is NOT central in forks but I'm sure when I enquired earlier on the forum the concensus was that IT SHOULD BE CENTRAL in the forks. What is considered correct for my 1956 s/a please? (mine is about 10mm offset to right hand side), cheers

Online bsa-bill

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Re: Wheel Offset
« Reply #14 on: 18.10. 2012 10:52 »
If I can but in and suggest (I don't mind being shown to be wrong - it's how we learn) that it would seem logical to have the front wheel central in the forks, on account of AFAIK the forks will be central to the headstock and frame, then it may be necessary to have an offset on the rear wheel to have it align with the front wheel due to the need to align chain, sprocket or brake on the rear
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco