G2 brake drum diameters

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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Kiwiengineer
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Joined: Fri Oct 15, 2021 1:20 pm
Location: New Zealand NEW ZEALAND

G2 brake drum diameters

Post by Kiwiengineer »

Hi dose any one k ow what the standard brake drum diameter is for g2’s and also what the maximum diameter is?
Roderick
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Re: G2 brake drum diameters

Post by Roderick »

The internal diameter of an unworn Lightweight brake drum front or rear, is 130mm measured with a vernier caliper. I measured up 3 drums that I have had ion store but not used for over 50 years so they are almost certainly as they left the factory.

There is no max. diameter. If they are very oval & have to be skimmed to remove the ovality, the rule is to remove the absolute, absolute minimum of metal.

Rod
Kiwiengineer
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Joined: Fri Oct 15, 2021 1:20 pm
Location: New Zealand NEW ZEALAND

Re: G2 brake drum diameters

Post by Kiwiengineer »

Ok I thought they were 6” or 152.4mm
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Duncan
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Re: G2 brake drum diameters

Post by Duncan »

Kiwiengineer wrote: Tue Nov 09, 2021 7:38 am Ok I thought they were 6” or 152.4mm
I believe that you are correct, they should be 6"?
Roderick
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Joined: Mon Jan 01, 1990 12:00 am
Location: WEST YORKSHIRE UK

Re: G2 brake drum diameters

Post by Roderick »

Yes, they are 6" diameter. I was unfamiliar with the venier caliper I used to measure the drum. It was scaled for outside measurements. Apologies.
Rod I
Kiwiengineer
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Re: G2 brake drum diameters

Post by Kiwiengineer »

Easy mistake our big ones at work you have to add 20mm on when measuring internally
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