RE: [CR]Simplex chainguard?

(Example: Events:Cirque du Cyclisme:2004)

From: "Mark Bulgier" <mark@bulgier.net>
To: classicrendezvous@bikelist.org
Subject: RE: [CR]Simplex chainguard?
Date: Wed, 19 Mar 2003 23:40:07 -0800


Warren Young asked about:
>
> > An NOS alloy shorty chainguard with typical L JUY, Simplex,
> > BTE, SGDG on it. Only one mounting tab at the seat tube
> > position. [snip]
> > The frame makers would have to make the appropriate braze-on
> > for the tab, yes? Anyone seen one?

Matthew Gorski replied:
> These were made for quite a few years and are more plentiful
> than you may think....I have a few. I believe they spanned the
> 50's/60's/70's almost unchanged and were shown in the catalogs
> as well.

I have two NIP examples as well, so I didn't balk at installing one on Laurie's "too ugly to get stolen" grocery shopping bike, a 1970 Raleigh Super Course.

I just snapped a few ugly snapshots to show them to you, installed and apart: http://bulgier.net/pics/bike/Simplex/Chainguard1.jpg http://bulgier.net/pics/bike/Simplex/Chainguard2.jpg http://bulgier.net/pics/bike/Simplex/Chainguard3.jpg http://bulgier.net/pics/bike/Simplex/Chainguard4.jpg http://bulgier.net/pics/bike/Simplex/Chainguard5.jpg

#1 is a "portrait" of the whole assembly #2 and 3 are closeups of the downtube clamp #4 is a shot of the catalog page with the exploded diagram #5 is a shot of the bag of parts, showing the special bolt that attaches the thing to the front derailleur.

Note, you have to drill your own hole in the chainguard for the downtube strut to bolt to - the location of this hole will vary from one frame to the next, even varying a bit depending on chainring size. You assemble it on the bike, then figure out where to drill the hole.

It sounds from your description like you may be missing the downtube clamp and strut, but that won't be hard to make out of parts out of your average bike junk box. No braze-on required, though the catalog does show an optional braze-on to replace the downtube clamp.

Do you have the bolt that attaches it to the Simplex pushrod front derailleur? If not, you could mimic this with a longer bolt that has threads all the way up; cut off the head and thread a nut about 1/3 of the way down to match the one in photo #5. This advice may be hard to pull off though, because the pushrod derailleur takes an odd thread - 5 x 0.75 I think (where the normal 5mm bolt has a 0.8mm pitch). It's a tad finer than the normal 5mm thread, enough off that you can't force it. So getting a long bolt to make this out of may be difficult; I don't know a source offhand. Also most bolts that long don't have threads all the way to the head - they usually have an unthreaded section, which won't work in this application.

Another somewhat cobby fix would be to take two Simplex bolts and weld or braze the heads together so that threads point out in both directions. This would definitely work but the requirement of welding/brazing makes it impractical for most folks.

Or you could just buy one that's complete! I think I got mine from John Barron or maybe Bicycle Classics but that was a long time ago.

Good luck!

Mark Bulgier
Seattle, Wa
USA