Author Topic: 7" brake on C11?  (Read 1068 times)

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Offline Paule

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7" brake on C11?
« on: November 25, 2015, 06:31:39 PM »
Hi, any experience around here about fitting A/B/M Group front wheel with 7" inch brake to C11 with tele forks? I have such a wheel amongst my spares. Genuine C11 axle is 4 1/4" long, the axle off wheel with 7" brake is 5" long. Front brakes have been widely discussed, i am aware. Up to now, my front brake has not turned out very satisfactory. Going downhill here in Switzerland, i experienced a lot of fading when brake got hot.  :o
Thanks for your thoughts, Paul

Offline chaterlea25

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Re: 7" brake on C11?
« Reply #1 on: November 25, 2015, 09:57:54 PM »
Hi, Paule
Are the fork legs the same distance apart on the models with 5 and  7inch brakes?
I  thought they were? Its quite a long time since I swopped around bits on these  ::)
Does your 7" hub does it have a hollow sleeve through the hub with nuts either side?
Later ones have a top hat piece in the middle that the stepped spindle clamps by threading into the righthand fork leg (lefthannd thread)
I have a 7in hub on my Ariel HT (non standard)
When I got the hub it had the hollow sleeve with nuts, I removed the sleeve and fitted the top hat sleeve and used a stepped spindle
I machined the drum true and then oversize linings to size, It works really well,  8)

Hopefully tomorrow I will go and poke around a shed at my childhood home where there are a couple of C's owned by my brother, I will try and make sense of the differences

HTH
John


Offline Paule

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Re: 7" brake on C11?
« Reply #2 on: November 26, 2015, 10:55:41 AM »
Hi John,
Fork leg distance, on my C11 fork i have measured 113 mm. No idea how much it is on 7 inch brake forks. It must be more, i would estimate about 131 mm.
My 7" hub has hollow sleeve as you have described, 127 mm long. My C11 fork has a slightly stepped spindle, nearby the end with lefthand thread. By tightening the LH nut on spindle, the wheel is being pulled to the right hand side of fork where the brake is, afterwards LH end of the spindle is attached by the pinch bolt.
If i manage to get the length of 7" brake hollow sleeve (127 mm) down to about 111 or 112 mm, it should work. Next issue is getting the wheel rim in the right position to line up with rear wheel.
Paul

Offline Paule

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Re: 7" brake on C11?
« Reply #3 on: November 26, 2015, 11:08:56 AM »
The two hubs i have on hand. Cheers, Paul

Online timsdad

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Re: 7" brake on C11?
« Reply #4 on: November 26, 2015, 01:13:28 PM »
The easier way may be to fit a pair of A or B series yokes. The bottom yoke may need the C stem fitting if it's not practical to swop the bearing cones or fit different size balls.

Ray
Just a motorcyclist.

Offline chaterlea25

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Re: 7" brake on C11?
« Reply #5 on: November 26, 2015, 05:56:02 PM »
HI Paule,
Ok, now I see what you have,
The 7in C12 wheel (that looks full width but is not!) uses the top hat sleeve and stepped spindle
Pic below.
This setup is narrower because it loses the outer nuts either side of hub
So all you need is the C12 top hat sleeve and stepped spindle to replace what is there now
remove the sleeve in the LH leg
You may have to re centre the rim though????
That is how I fitted the 7in. hub to my Ariel, I can go and try to measure the hub width later

A & B yokes have a larger and longer steering stem >:(

I went and poked around in the shed today but the two C11's there have the 5in. brake and small spindle :( so that doesnt help

HTH
John

Offline Paule

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Re: 7" brake on C11?
« Reply #6 on: November 26, 2015, 08:55:08 PM »
Ray, sounds interesting, using other yokes. John says, that steering stems are different, so possibly won't fit.
John, 'top hat sleeve', is that part no. 67-5565 ?? I haven't totally understood the modification up to now... In the drawing of the C12 hub, the bearings are being held in place by two locking rings 67-5561 and 67-5562. I'm afraid, my hub (type 3, picture above) won't have these threads in there? How is that part no. 67-5565 held in place? Is it being pulled against the brake plate with a nut?
Many questions  :-[  and many thanks for your support!
Paul

Offline chaterlea25

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Re: 7" brake on C11?
« Reply #7 on: November 26, 2015, 10:05:15 PM »
Hi Paule,
THe top hat piece is fitted between the bearings with the shoulder inside the brake side bearing
and the small diamater through the bearing towards the right hand side (brake)
It is held in place by the shoulder of the spindle once threaded into the RH fork leg
The large diamater of the spindle fits directly into the LH bearing
the sleeve makes up the difference between bearing inside dia. and smaller spindle diamater

A lipped spacer is needed if you want to retain the felt seal and tin cover on the LHS
A sealed bearing would be another solution

I went and measured as best I could the hub in my Ariel (BSA forks)
Hub width app 105mm
distance between fork legsat spindle, (B31 type) app 130mm
B31 type fork leg centres app 175mm
distance from LH leg to hub app 25mm

The same system with stepped spindle is used on the 8in. and 190mm brakes used on
A10's, M21's, Goldies, A65's and a lot of the unit singles

HTH
John


Online timsdad

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Re: 7" brake on C11?
« Reply #8 on: November 27, 2015, 06:58:31 AM »
I did mention that the steering stem or bearings would need playing with, Paul. Sleeving up to bigger bearing cups is simple but the other way less so.

I can't remember whether it's the B or the C frame that has the biggest inner dimensions of the cups and suspect it's the heavyweight. However, it may not be because one has more bearing balls. Any other minor problems are easily overcome.


We had a couple of extractors, that Richie made, for the frame cups. I kept hold of these for some time and posted them out to several members to use, who all sent them back except the last one. I have no idea where they are now. I thought this would happen eventually so I made a couple for myself and therefore have no need of Richie's fine tools. I never bothered about the fiver postage but asked folk to send a donation to Pete's Beer and Fag Fund to help with the site expenses.

I suggest, if it's a present member who's got possession of these two extractors, that they post them to someone Down South who's more in the epicentre of things or at least let us know where they are.

Ray
Just a motorcyclist.

Offline Paule

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Re: 7" brake on C11?
« Reply #9 on: November 27, 2015, 11:06:10 PM »
Ray, you're right, i shouldn't abandon this idea to quickly! Have just written to a guy, who is selling a pair of A10 yokes.

http://www.ebay.co.uk/itm/BSA-A10-650cc-Plunger-etc-Front-Fork-Yokes-/391326728965?hash=item5b1ce40305:g:O7MAAOSwv-NWUhTU

Sent him questions about the dimensions and part numbers. Maybe it's easier than i thought. Will keep you posted  when i get his answer. Is diameter of the stanchions normally the same on A, B / C models?

John, thank you, you are very helpful! Now understood how it comes together...  So the width of C11G / C12 wheel (105mm) will fit between C11 fork legs (113mm). This way is certainly the most simple, if having this hub & spindle on hand. Somebody got this hub, as shown in John's attachment?

Paul

PS: Dismantling headstock bearing cups was easy... When i took the bike apart for the frist time, i found out that some cups of 'bicycle pedal crank bearing'  :-\ perfectly fit to C11 headstock cones!  :)

Offline chaterlea25

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Re: 7" brake on C11?
« Reply #10 on: November 28, 2015, 07:51:02 PM »
Hi Paule,
I can measure some B type yokes if you want ?
I have a spare set here, I had got them all sorted and painted when I found a set of Gold star type ones that I will fit instead of the B31 type to my GS replica build
But I'm pretty sure that fitting them to a C would be a nightmare  :(

Thinking back I may have modified the sleeve from the B type 7in. hub to use the stepped spindle??
I can make a drawing of this part if it would help,
The one I have to hand maybe a bit long as its from an 8in hub that has an alloy brake plate

HTH
John



Offline Paule

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Re: 7" brake on C11?
« Reply #11 on: November 29, 2015, 12:01:17 PM »
Hi John, thanks for your offer. Haven't got any reply from ebay seller. Could you please make following measurements:
- part no. of bottom and top yoke?
- Ø of steering stem, where lower bearing cone sits?
- Ø of steering stem above?
- length of steering stem from bottom of lower cone to top?
- length of thread at the top of steering stem?
- distance of fork stanchions, centre to centre?
- Ø of stanchions?
Many thanks,
Paul

Offline chaterlea25

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Re: 7" brake on C11?
« Reply #12 on: November 29, 2015, 04:20:01 PM »
Hi Paule,
OK here goes!!

- part no. of bottom and top yoke?
There are several variants of these
I think all have the same basic dimensions, Theres a casting number underneath the steering lock B33 one I have 42-5035(not 100% sure on this
Early GS pt no.66-5088 top, 66-5089 btm from parts book.. my A10 book seems AWOL at the moment  ???


- Ø of steering stem, where lower bearing cone sits? 30.2mm , 1.1875in.

- Ø of steering stem above? 28.57mm, 1.125in.

bearing cup O/D 53.975mm, 2.125in


- length of steering stem from bottom of lower cone to top? 193mm app

- length of thread at the top of steering stem? 1.125in, 28.5mm app

- distance of fork stanchions, centre to centre? 6.75in. 172mm

- Ø of stanchions? 1.375in same as C

The A/B frame headstock is 6.1875in, 157mm app in height


Another problem would occur if fitting the wider yokes, the headlamp brackets will be in a different position. A/B brackets are in the centre of the shrouds

HTH
John


Offline Paule

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Re: 7" brake on C11?
« Reply #13 on: November 29, 2015, 04:53:06 PM »
Hi John, thousand thanks! Now got loads of brain food  :)
Headlamp can possibly be mounted between two short tubular spacers to keep the old brackets. Will keep you posted, certainly!

This is such a great place for discussing our C models and more!!

Cheers,
Paul

Offline chaterlea25

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Re: 7" brake on C11?
« Reply #14 on: November 29, 2015, 05:07:09 PM »
Hi Paule,
Heres a link to an A65 stepped spindle, It will be a little longer overally than the "C" one but can be shortened easily
http://www.ebay.com/itm/1964-BSA-A65-A65L-Lightning-Rocket-650-A65LB-A65D-650cc-992-front-axle-/231762015937

Hurry theres only 6 hours to go !!

John