Frame Identification

[RichardS]

Hi Richard,
I've taken readings off a 1965 G15 frame which should be identical as fas as these dimensions are concerned.
A = 470 mm
B = 487 mm

- Knut

You're a gentleman sir, thank you.

[RichardS]

I'm curious about your comment "heavy Norton parts", I've not weighed them (and don't intend to) but I doubt there's much between them. I view the larger diameter stanchions on the Roadholders as desirable being significantly stiffer, but you re right the straight pull spokes are perhaps a slight redeeming feature of the AMC, and the Teledraulics do have rebound springs absent in the Roadholders.
As I said, the Teledraulics I have are in a bad state and grinding and hard-chroming needs pretty deep pockets whereas I have near new stanchions for the Roadholders. I'd like to do some scrambles again, but likely it will spend more time on the road than the dirt so the stopping power is attractive

The headstock will need to be swapped - I have a Norton set and a couple of adaptors to match them up to the frame/'bearings' is no big deal. I vaguely mooted the idea of boring the frame to take taper rollers rather than the ghastly AMC ball things, but I doubt it's worth the effort. I'm not going to be hammering it that hard and setting it up in the mill is a lot of fiddling without jigs.

[RichardS]

I haddn't thought about converting to a hydraulic front brake, I did it to the rear of a NorVin and it worked well - worth thinking about.....

[mdt-son]

Weight of some fork components:

Teledraulic stanchions: 1806 g each
Roadholder stanchhions: 1947 g each (Matchless type)
Teledraulic dampers: ----
Roadholder dampers and springs: 1226 g incl. nut
Teledraulic springs: ----
Teledraulic sliders: 1958 g (slider, bushes, damper and spring)
Roadholder sliders: 725 g on average less bushes
Teledraulic triple tree: 3356 g less rotation limiting pins, bearing seats and stem nuts
Roadholder triple tree: 2010 + 1080 g less bearing seats and stem nuts

(To be completed)

Weight of a complete long Roadholder as fitted to the G15CS is 30 lb (13.6 kg).
Weight of a complete Teledraulic as fitted to the G80CS is 27.4 lb (12.4 kg).

[RichardS]

Weight of some fork components:

Teledraulic stanchions: 1806 g each
Roadholder stanchhions: 1947 g each (Matchless type)
Teledraulic dampers: ----
Roadholder dampers and springs: 1226 g incl. nut
Teledraulic springs: ----
Teledraulic sliders: 1958 g (slider, bushes, damper and spring)
Roadholder sliders: 725 g on average less bushes
Teledraulic triple tree: 3356 g less rotation limiting pins, bearing seats and stem nuts
Roadholder triple tree: 2010 + 1080 g less bearing seats and stem nuts

(To be completed)

Good grief Knut, I didn't mean my slightly throw-away comment to be some sort of challenge. The measured weights are interesting, but really, it's not my decision criteria.
We then have hub weights to include and potentially the bending stiffness of the fork legs which interests me almost as much as masses.
33mm dia Roadholders vs 1-1/4" Teledraulics could be significant as stiffness is related to diameter ^4, but I have not measured the stanchion ID's to know the whole story - and I'm not challenging you to do so.

I do accept that Teledraulics are pretty good forks for the period, 'though I have my reservations about 7" AJS front brakes.
I loved my G12CSR greatly, but broke two cranks and a con-rod and the front brake was woefully inadequate. It was followed by a 500 Dommie and a 650SS both with Norton 8" front stoppers which were adequate and lastly a NorVin with initially a 8" Norton 2LS front brake that faded badly before I added an early Commando Lockheed disc to the wideline Roadholders. That sorted the matter and I routinely put a stripe of shredded Pirelli Phantom up the centre of the headlamp. All that was 40 years ago in the happy, mis-spent day of youth.

Now, I'm going to decide based on parts I have in the shed and frankly, what I 'like' and what amuses me as a project. This is never going to be a rivet counter's project, not least because some one before me vandalised the frame in ways that render it irretrievably non-oringinal. And despite my desire in years past, at 63 years now, I'm not going to be giving the bike a serious beating round any scrambles track.

[mdt-son]

I know, Richard, I just got the urge to find out for myself. Sorry for hijacking your thread. You are right on account of total weight. Teledraulic forks are hampered by those heavy yokes, especially the top yoke.

As I have new Teledraulic and Roadholder stanchions on the bench, I may calculate second area moments in a jiffy.

AMC's 7" front brakes are inadequate, and one may wonder how the factory got away with it. Today there are several workarounds which I have pointed at. Fitment of Norton's 8" front hub means putting a lot of weight on a dual purpose bike supposed to be light.

I agree that for a mostly road going bike, fork bending stiffness is paramount, especially if you consider adding a disc brake.
For a scrambles bike, it's all about weight, as demonstrated by the G85CS, for which AMC reverted to 1-1/8" stanchions.

- Knut