VARIATIONS ON AN ALUMINUM THEME
Since we deal in Vintage Bicycles, I thought it might be interesting to see how different manufacturers built vintage aluminum bicycle frame…before TIG Welding. This is by no means an exhaustive or in depth technical discussion of vintage aluminum frames, just a look at how different frame builders built an aluminum frame. Even after the TIG welding became available, Raleigh continued to use the bonded lug method with their Technium series of Aluminum/Steel frames.
Below are three vintage (1980’s) lugged aluminum frames:
We have: a 1984 Alan Record – Italian; a 1986 Vitus 979 – French; and a (probably) 1989 Dura All – Japanese. While there had been aluminum framed bicycles as early as the 1940’s, Alan was the first to produce a ‘modern’ aluminum frame followed closely by Vitus. Both supplied their frames to other bicycle manufacturers, like Peugeot and Gitane and Guerciotti who put their own names on them. The Dura All / Nakagawa / Gan Well / etc. is not so well documented. Some people say that they are very early versions of an SR Aluminum frame, but there is not a lot of information about this frame. It was sold under many different names including Performance Bicycles, which is what I think mine was sold as based on the remnants and shadows of former decals on the anodized tubes.
They are very similar in how they are constructed but the differences are in the lugs.
Unlike Aluminum Frames of today, which used oversize diameter tubing, these frames used straight gauge aluminum of the same diameter as was used on Steel bikes. All three used an epoxy to bond the tubes to the lugs. The difference is that Vitus ONLY used epoxy while Alan used epoxy and the tubes were ‘screwed’ into the lugs, and the Dura All used rivets on the underside of the lugs to further attach the tubes to the lugs.
This video shows the stays being screwed into the seat post clamp and dropouts:
Here are drawings of the Vitus 979 Lugs
Vitus felt that bonding the lugs to the tubes using a male / female joining socket was stronger and more flexible and more durable than the ‘glued and screwed’ method that Alan pioneered.
If we look at the head tube of the three frames we can see the similarities and differences
The Vitus 979 head tube shows the almost smooth flow of the head tube into the top tube and down tube. There’s an obvious joint but the three pieces appear to be the same diameter. The Dura All also has the head tube and top tube/down tube lug in one unit. The way the tubes join the head tube looks more like a traditional steel lug with the top tube and down tube sliding into the head tube. The difference between the Dura All and the Vitus and Alan is the small rivet seen on the bottom of the lug where the down tube enters the lug. The Alan shows another way where there is an actual head tube with a lug at the top for the top tube and a lug at the bottom for the down tube, just like a regular steel lugged frame. Alan frames sometimes develop a crack down the middle of the top tube/head tube lug right above the head badge.
These are the Seat Lugs
They all look very similar, though to my eye the Alan is the most graceful of the three. The Vitus seat lug appears smaller, but looking at the drawings above, you can see that most of the lug is internal. Later models of the 979 would have a ‘grub screw’ on the back of the seat lug to hold the seat post as it was possible to tighten the seat post screw enough to break the ‘ears’. The Alan and Dura All both look like a traditional steel lugged frame.
Again we can see the Vitus tubing and lugs appear to be the same diameter with the joint visible. The Dura All and the Alan both appear more like traditional steel lugged frames with the difference being that the Dura All has rivets on the rear of the bottom bracket and on both sides of the bottom bracket.
A 59cm Vitus frame and fork weighed in at just under 4 lbs and a race 979 weighed 18-19 lbs. A 58cm Alan Record tipped the scales at 4lb 14 oz. I’m not sure how much the Dura-All weighs but those rivets must make it the heaviest. This when the very lightest Raleigh frame made of Reynolds 753 which required such special brazing skills that bicycle manufacturers had to send brazing samples to Reynolds before they would even sell them the tubing, weighed in at a little over 5 lbs.
I must say, though that the weight difference is so small that I can’t feel it. I do think that the Dura-All is the ‘whippiest’ of the three.
I hope this was interesting to you. If there are any errors, please let me know as there is already enough wrong information polluting the interwebs and I don’t want to add to it.