bendo
Viscount
Posts: 538
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Post by bendo on Aug 3, 2016 22:23:10 GMT
Been looking for a nice Tange fork for a while and finally found a NOS one for 27". Decided to swap over the forks on my Victor which still had its original chromoly forks with the braze-on head light boss on the right blade.
Some interesting discoveries. My excellent lbs did the work since i don't have the right tools. The steerer would need cutting too. What they found was the thread of the steerer did not match any other threads they had. Meaning the Tange fork couldn't use the original headset. Could it be a French thread? But the original headset is 22.2 dia not 22 so that didn't make sense. Still a mystery. If anyone has wisdom in this I'd be interested to know
So i went with a new headset. Tange cartridge bearings. Good thing about the NOS fork is it had enough steerer for the very high stack height. Tell you what, the bike tracks so straight now! I've never had a Viscount that rode so straight no hands. Never realised that so much of that was duevto the type and age of the headset. I suppose that's why the French call them 'jeu de direction'.
The only downside is that the new forks have slightly less rake. Maybe 5-7mm at most. But that's enough to mean i now have toe overlap. If it ain't broke don't fix it! Pics soon. b
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Post by 54roadie on Aug 23, 2016 10:14:26 GMT
How did you install a new headset if the thread matched nothing else on hand? Run a tap over the fork? Go threadless? I'm very curious.
Thanks in advance, Frank
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Post by eaglerock on Feb 13, 2018 8:17:52 GMT
Frank, I believe you're missing the key issue. The new Tange threaded headset matches the new-ish Tange threaded fork; it just doesn't match the threading on the old Viscount headset. Once the Viscount headset cups are removed from the head tube, you install the new headset and off you go.
The unanswered question is: Did the old Viscount headset (and old Viscount fork) use the same standard 1"x24 threading as the current production items? Certainly Lambert used a lot of oddball in-house parts, with sizes and threadings unusual in the rest of the bike industry of the time. The fork swap package from Yamaha included a threaded Tange fork and a replacement Tange headset. Either Yamaha didn't trust the Lambert/Viscount headsets any more than they trusted the forks, or they knew that the old headsets wouldn't work with a standard threaded steerer.
And Lambert/Viscount might have used unpredictable mixes of metric and Imperial threads; I recently discovered that the stem bolts on my early Lambert alloy stem (on a 72/73 Professional Grand Prix) use a 7/16" hex bolt and a 1/2" bar clamp nut, while the seatpost clamp bolts are M5. Huh? That seems like a very strange choice. Maybe those parts were just what was available at the moment of assembly.
I suspect that the old threading actually was a normal BSC threading. If Lambert inherited tools from Viking, the tools would have been designed for that thread. Any tools purchased from outside vendors would also have had that thread, or Lambert would have had to have special dies fabricated - an expensive proposition. In bendo's case, my guess is that the locknut on the headset may have had the threading messed up either by 40+ years of use, or by a sloppy installation that only revealed itself once the headset was disassembled. Since both the original headset threads and the original fork steerer were steel, it's perfectly possible to cross-thread the two pieces at assembly and damage the threads if you're not careful. The tightened elements are likely to stay together, especially since there's not much reason to fiddle with a sealed bearing headset once you've got it working.
Has anyone checked a clean Lambert/Viscount locknut/top cup on a regular fork, to see if it threads on cleanly? I'm just about to do a fork replacement myself; I'd go check threadings now, if I didn't have a stem frozen in the steerer. Once I've had my shop do the surgery, I'll check the Lambert threaded components against the replacement forks and follow up.
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Post by 54roadie on Feb 13, 2018 22:53:06 GMT
Now that's yet another tale for the Viscount history. Every Viscount I've ever owned, think that's 6 by now, came with a standard thread Tange headset. I've never had a problem swapping one out for something else.
Thank you!
Frank
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Post by blackwizard on Feb 14, 2018 6:06:12 GMT
I’m building up my Lambert GP now and had to fabricate a stem bolt last night as the head on the old one was rounded out on the hex and had to be removed with a torx. Found the actual head is smaller than anything I could buy (good old Lambert eh) so got one slightly bigger from a bike jumble, turned the head down by about 1.5mm then tapped out the original wedge to suit the courser larger thread on the new stem. Sounds a pain but was actually quite a quick straight forwards process once I got into it.
The fact is when working with any old bike like this which is certainly an odd ball when it comes to components you have to be prepared to use your brain and work or engineer around problems. The same has to be said about the B.B. bearings, what a job removing and replacing those but it is do able, I made a wood jig using old laminate shelving to support the B.B. and bearing whilst using some persuasive force and a blooming big lump hammer, crude but worked,
So far I’m sticking with the old “Death Fork” but did plan on making up a spare set that don’t actually risk me loosing my teeth through chewing tarmac so it’s interesting to read this thread - what I expected to be a straightforward swap may not now be so, guess that’s part o having a Lambert 😜
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robt
Viscount
Posts: 558
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Post by robt on Feb 15, 2018 12:25:27 GMT
On checking the graunching b/b on my Victor, I went to remove the crank bolts to get a closer look at the bearings. I tried a 13mm socket - too small; 14mm- too big. The same happened with 1/2" and 9/16" sockets. I ended up ordering a 17/32" socket (equivalent to 13.5mm), which fits perfectly. According to t'internet, 17/32" is a bolt size that was favoured by the Aerospace industry (and, as I found, by Lambert/Viscount).
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Post by eaglerock on Feb 16, 2018 12:15:07 GMT
Perhaps it would be useful to set up a spreadsheet for fastener measurements, to collect the odd mix of Imperial and metric bits so people don't round off their bolt ends.
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Post by blackwizard on Feb 16, 2018 13:58:04 GMT
Found exactly the same on my Lambert........fortunately I had a set of Imperial sockets courtesy of my father who found them on special offer in I think Lidel a few months ago......
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