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Hi I have two swinging arms. One is 1/2" wider in the "jaws" than the other. There is no apparent damage. So what have I got. I guess one is correct A65 and the other isn't. I cant find an answer on any of the parts lists that I have checked. This is harking back to my chain not running true. Its running true now but I'm still not satisfied with my set up.
Conundrum ----again
Mike 8) 8) 8)
If it helps, I would be willing to try to measure the width of the S/A jaws on both an A10 and an A65 for comparison? Not an easy measurement with the wheels in place but I'm sure I could find a way of doing it.
According to the workshop manuals the open end inside measurement of the A65 swinging arm is 7 25/32 inches for all the pre oil in frame models.
I have a NOS swinging arm for my 1970 pre-OIF Firebird project which measures 199mm or 7.835" in old money between the plates. HTH
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Hi. Thanks for your assistance with this. The one on the bike is 8.25". Defo not A65. So Spaceman at some stage an A10 measurement would be handy just to confirm what the "wrong one" might be. I seriously suspect A7/A10..
My problems with the chain line got worse as I went along and got to the point where Its impossible to fit the rear brake rod. I think I was aware that it was a bit more serious, but I guess we've all been there at some stage. "I'll just do this and it will be OK".
So now bite the bullet and strip the rear end off then offer it up, then strip it again and get the arm powdered coated, which is a B----r cos the frame and existing arm are done in gold. Big sigh "Oh deary deary me". Before anyone askes Why gold??? just cos thats what I fancied.
So again for all your help, advice and patience---thank you
The spare one is marginally over 7.75" so at least I know that I have an A65 arm. Thanks Julian and Ian C.
Now all I have to do is rebuild the back end for the third time.
Mike 8) 8) 8)
Within approximately 1/32", my A65 swinging arm spacing is 7 3/4" and my late A10 is 7". I believe both early and late A10 swinging arm spacing is actually 7 1/32". My measurements were with back wheels fitted.
I remember someone asking whether their A65 swinging arm might be off an A10 but there is quite a big dimensional difference between them; namely, 3/4"!
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So thats different altogether as my wrong one is about 8.25". 1/2" different.
Fortunately its no longer terribly important. But I shall now have to find another for the next (Unstarted )project.
Mike 8) 8) 8) 8)
Mike 8) 8) 8) 8)
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Sorry guys if my previous was a bit cryptic when I said the gold finish "is what I fancied" It should have said thats what I fancied to fit in with what I am trying to do. I want something different and as this is really a Bitsa Beesa now is the time to do it. (all genuwine BEESA bits).
Mike 8) 8) 8)
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Found another swinging arm.
Mike 8) 8) 8)
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I changed my swinging arm today just to check it out. Now this has just thrown up another factor. The wrong 'un on the bike is about 1 and 1/4 inches shorter than what I know to be an abso correct 1966 A65 arm.
So brief Q.. What the hell do I have. It fits perfectly to the frame the rear shocks line up perfectly but it is not A50 A65 arm. Theres no sign of it being "butchered" in any way.
So I aint even in a position to guess. Just simply no Isiah. Over to you gentlemen.
Mike 8) 8) 8)
I think that the pre 1966 swinging arm is shorter than the 1966 on item.
The 1966 onwards swinging arm is 15 3/8" long measured from the centre of the pivot to the rear shock lower mounting hole.
As far as I can see, the equivalent length for the pre-1966 standard swinging arm with rod operated brake was 14 1/8" and the equivalent for the earlier standard swinging arm with cable operated brake was 14 3/4".
So, if you have an earlier swinging arm designed for the rod operated brake, it would be 1 1/4" shorter than the later swinging arm.
Maybe it has something to do with the fact that the earlier models had 18" wheels and I think from 64 onwards they had 19" wheels.
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OK I have just mejured it. From SA cntere to Shock centre is 14 1/8", However the jaws are 8 1/4". The width is inexplicable. There is no apparent damage and no sign of anyone altering it. All the welds are good (I know thats nothing to go by) and the angles are good (obviously wrong)
I can only conclude that someone has widened it to take a big fat tyre. I'll have another look tomo and see what clearances are if I wanted to put in something like a 600 x 15 or 16. .
Its no longer important because I have bought another SA. But Im interested just to see.
Mike 8) 8) 8) 8)
Quote from: bikerbob on 27 Sep, 2022, 17:27
Maybe it has something to do with the fact that the earlier models had 18" wheels and I think from 64 onwards they had 19" wheels.
I think that is exactly it but, even in 1965, the A65 T/R still used an 18" rear wheel and the shorter swinging arm. By 1966, all were fitted with a 19" rear wheel and the longer swinging arm.
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Yes I think we have reached the right conclusion on this. I always run with 4.00 x 18. Approx 26" total diameter The peripherr difference between that and (I think) 350 x 19 approx 26" diameter both properly inflated is less than half inch. That of course depends on the tyre tread form. Piddling amount. But I considr the 400 x 18 gives a better ride. However as You guys are now aware I can no longer ride so its purely accademic ----that posh for dont matta much.
Take care and enjoy.
Mike 8) 8) 8) 8)
Hi Mike,
There are 3 different arms:
Best wishes...
I have just been out to the garage and measured the swinging arm on my 1962 A65 from the centre of the bush to the centre of the suspension is 14" the width where the spindle goes through is difficult to get exact with the wheel fitted but I make approx 73/4" certainly not 81/4"
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Thanks again gents. That really tends to confirm my thoughts of an altered SA. Certainly no other reasonable explanation. I am awaiting another which I hope is going to be the 14.125" and 7.75" in the jaws.
The positive aspect is that I know the one I have aint right. I have another in place at the moment but it belongs to another (eventual) bike.
I hope my other one arrives tomo then maybe I can put this one to sleep.
Thanks all for your interest and input.
Mike 8) 8) 8)