Wheel offset

Information relating to the Matchless G5 or AJS Model 8 350cc Lightweight
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jajo57
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Wheel offset

Post by jajo57 »

I have the rims, I have the hubs and I have the spokes for my G5, I now need to get them assembled, can someone please tell me what the offset should be and are they the same for front and rear. I looked in the Technical Advice area but could find nothing to help me there but, maybe I missed it.

Thanks in advance.

Richard
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Les Howard
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Re: Wheel offset

Post by Les Howard »

Hi...If you don't receive any figures here is a way to measure it.

For the front wheel: Fit the wheel hub assembly with spacers if required and tighten as if fitting a complete wheel. Cut a 2" strip of cardboard that fit exactly between the forks measure the distance . Say you are fitting a WM2 rim with 69mm width. Mark the centre of the cardbord and measure 69/2 from this centre mark each side of it. The two marks will represent the rim edges ...(they should be equi-distant from the ends of the strip). This will be where you want the rim to sit. Hold the cardboard between the forks and flush with the hub. Now using a chosen reference on the hub measure where in relation one of the rim marks is. This will be the offset you require when building the rim. Usually the face of the brake drum is used by the wheel builder, so if you have used say the spoke flange to measure from the cardboard, when you remove the hub assembly you will simply re position the cardboard strip where it tallied up before and then re measure and adjust your offset measurement to correspond to the brake drum face...This will be the rim offset to the brake drum face.

For the rear wheel, this is not so easy as often swing arms are not always equal distance from the bikes centre line, although some are!.
So, as before fit the rear wheel hub axle assembly pushing it all the way forward in the slots and make sure hub is directly facing forwards and not skewed to the side. Tape a bar or piece of wood across the frame directly above the rear hub. I would then use a laser line and shine this down the bikes top frame tube or use a straight edge then mark the wood cross piece's centre. Make sure the bike is level and drop a pumb line down from this centre mark to the hub and mark with a felt tip pen this position on the hub...Remove wheel assembly.The mark will represent the centre of the bike on the rear hub position. Then using the cardboard measure use previously you can line up the centre of the 69mm cardboard marks to find whre the edge of the new rim should be. Use a convenient flat edge of the hub and measure to the cardboard mark on any side you choose. Note the distance ...This will be the rear wheels offset for your wheel builder...ATb....Les
Last edited by Les Howard on Mon Aug 11, 2014 12:35 pm, edited 1 time in total.
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iansoady
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Re: Wheel offset

Post by iansoady »

Or a quicker way would be to ring Central Wheel at Coleshill who have all the figures (or at least have had for everything I've needed).
Ian
1931 Sunbeam Model 10
1999 Honda SLR650
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jajo57
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Re: Wheel offset

Post by jajo57 »

Thanks Ian. Did exactly what you suggested and they came up with the information.

Richard
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Les Howard
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Re: Wheel offset

Post by Les Howard »

Sorry I wasted your time trying to be helpful then. Another one on my List.
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Ozmadman
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Re: Wheel offset

Post by Ozmadman »

Les P H wrote:Sorry I wasted your time trying to be helpful then. Another one on my List.
It's never a waste of time when something like this is posted on the forum in my opinion as it will help others if they can be bothered to search when their similar problem arises. What is frustrating, and I have been there myself, is posting a lengthy response to help someone who gives no response, thanks or acknowledgement for your efforts, this isn't to get some kind of praise or adulation but should be a matter of courtesy toward the person who has made the effort to help. I once did similar and then posted two further comments to the person asking how they were getting on and still no response, this was a guest and does nothing to the support the argument of allowing full access to the forum for non members. So, thanks for the post, I may need it one day!!

Paul
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
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Les Howard
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Re: Wheel offset

Post by Les Howard »

Dear Paul (Ozmadman) Thank you VERY much for your post here and your support. My faith is restored that politeness is still considered by others to be worthwhile, and as we know ...costs nothing!

Anyway...just phoned Central Wheels and was told the bleedin obvious: Firstly it is NOT USUAL practice to give out these offset measurements as they are not keen to hold up their wheel builders to get the info......and they would certainly not give out info to someone who has NOT bought the rims spokes etc, from them, which, of course, is totally understandable and fair....You can imagine the conversation. "Oh Hi Central Wheels, I have just bought my new chrome rims on Ebay...I don't know my wheel offsets...can you tell me."? Hmmmm....someone must have got very lucky...Les
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Ozmadman
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Re: Wheel offset

Post by Ozmadman »

Les P H wrote:it is NOT USUAL practice to give out these offset measurements as they are not keen to hold up their wheel builders to get the info......and they would certainly not give out info to someone who has NOT bought the rims spokes etc, from them, which, of course, is totally understandable and fair.Les
On that basis I have copied your info into a notepad file and saved it so I can find it easily when the time comes. I have Yamaha rear wheel that will probably need re-chroming at some point and I would like to have a go at re-spoking it myself

Paul
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
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robcurrie
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Re: Wheel offset

Post by robcurrie »

Les, this sort of information could be made "permanent" by putting it in the Tech Articles section on the Club site. It will also make it easier to find again for all club members. At the moment there are no tech articles on rims, so it will be a new sub section. Other helpful info on wheel building and alignment could also be added there.
ATB

Rob C
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dave16mct
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Re: Wheel offset

Post by dave16mct »

Yes I thought it was a great bit of technical info and just the sort of thing we need to know. I'm also going to have a go at my own wheels. I have a good truing jig and I'm going to make the 'Taverner' jig to help me get started. So thanks Les for the info! :beer:
Cheers Dave.
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