Sticking with aluminium

by Simon Hargreaves

CCM's 450 Adventure frame is the first to be held together by glue

Compared to engines, suspension, brake systems and electronics, a bike frame seems relatively simple. It must be rigid enough to hold a swingarm and forks in place, resist the efforts of a rider, an engine, the ground and physics to twist, bend or deflect it, and be durable for the lifetime of the bike. Ideally it's also light, easy to process in production, cosmetically pleasing and cheap.

But as long as the first two requirements are met, different bikes have different priorities and thus there is no single perfect frame design, which is why we get anything from round, oval, square or rectangular tubes, pressed sections, extrusions, cast or forged sections, usually in combination and made from steel or aluminium alloy (although titanium, magnesium, carbon fibre and even fresh air have been used – the German Windhoff in 1927, 1976 Quantal Cosworth Norton and 1992 Britten V1000 were frameless, with the engine connecting headstock and swingarm. And, arguably, Ducati's Panigale, BMW's flat twins and hub-centre bikes like Bimota's Tesi and Yamaha GTS1000 are frameless). With hundreds of frame permutations over the years, it's rare to hear of a new one.

But a Lancashire's CCM is doing something different: the new GP450 Adventure, MCN's group test winner, has a frame held together by glue (although they prefer 'adhesive', and call the process Bond-lite).

Gluing metal-on-metal isn't new. The idea came from WWII, when the De Havilland Hornet had wood and aluminium stuck together in its wings to achieve weight and strength targets. After the war, bonding metals with newly developed adhesives instead of riveting or welding had many advantages: stronger (with no localised weakness), lower weight, lower aerodynamic drag and better sealing (for fuel, air etc). The Apollo rockets and Space Shuttle were held together in part by glue and, back on the ground, in 1996 Lotus built the Elise with aluminium extrusions joined by locating screws and epoxy resin.

CCM's Adventure frame makes use of some of these advantages. It starts life as 13 separate sections of forged 6082 T6 aluminium billet, with CNC machined tapered joint ends and an anodising pretreatment to provide a key for the glue. A pip on the surface of each joint leaves a 0.2mm gap to stop the adhesive being squeezed out of the joint during assembly. A frame jig isn't needed because the joints only fit together one way. Assembly starts at the headstock, with a two-pack adhesive run into the joints from a handheld gun. Sections are bolted into one another one by one, into a complete frame. It takes around an hour, then the adhesive is cured in an oven at 60° for two hours.

CCM say the result is, in terms of strength and stiffness, effectively a one-piece frame with stresses evenly distributed (the locating bolts are left in place because the resin has glued them in – they have no effect on joint strength). And as the entire area of the joint is glued, there are none of the localised weak points associated with welding. And, with years of testing the frame in motocross competition with no breakages, it clearly works.

Of course, the irony of CCM gluing frames together is only fully apparent when you remember where the Lancashire factory is located: Bolton.

Captain Scarlet
Captain Scarlet's picture
Joined: 01/12/2009

Glad to see CCM have come out of the Fog era(did you see what I did there?) and are making fairly fine (if expensive) off-roaders again.

But a claim of the first to be held together by glue? I'm not sure about that? The MZ Skorpion, 20 years ago, had a frame held together by glue - although I'm not sure if the production versions ended up being welded? They even raced (figurative term) those things I believe - a Yam 660 engine as standard and designed by Sewell and Powell or whatever they were called?

GTS1000 - frameless? Not sure why Yamaha made such a huge thing about it having an 'Omega Concept' chassis then?

I got to ride one of those rare beasts, the single sided hub centre-steering front-end took a bit of getting used to with all that weight and lack of feedback (Flitwick Yamaha did alright with it at the TT mind). The Exup motor was nice, quite palatable, unlike the price.

But it most certainly did have a frame, in fact, it was flipping enormously chunky!

I myself have a bike largely held together with rubber bands and cable ties. From a safety perspective, I'm quite pleased that it's not a motorcycle ;-D

shuggiemac's picture
Joined: 23/11/2008

I've been out of circulation for quite a while what with one thing or another but I was never truly gone. Anyway first time back in ages and I see a statement about the first glued frame and I though - aha that's not correct the MZ Skorpion had one so I'll jum back in with both feet. So here I am and what do I see but me ol' mucker Captain Scarlet has beaten me too it, not for the first time either.

I had a test ride on one of the Skorpions way back when and it was actually OK. Trouble was that I was riding a 350LC at the time so getting off that and on to this nearly new bike one of the first things I did was bounce it off the rev limiter.

Anyway it was glued and if memry serves me well the production bike all were too.

As fates would have it after all these years I live about an hors drive from the old MZ site and sad to say there is no sign of them there ever really having been there as you drive through.

Captain Scarlet
Captain Scarlet's picture
Joined: 01/12/2009

Tiz indeed a shame, that MZ has passed on to the great clunkers in the sky. Still, some old by with too much money will probably revise the brand someday, somehow. Although thinking about it, the name probably isn't as provocative as say, Vincent for instance?

The Skorpion was pretty light (not 350 LC light I'm sure) back in the day I think. And (for a single) the 660 Yam was probably the best engine around in that capacity and configuration. It was probably good, but too late for the market to confidently buy into it?

I'm too lazy to re-read the article, but I think the word 'first' may have been removed? ;-D Anyway, good to have you back Shuggs. Wonder where RIC and others have gone to?

Navy Boy
Joined: 12/02/2009

We're here...

An interesting article nonetheless and I like the look of the CCMs. If I was off around the world then I'd be wanting one of those me thinks.

I remember rather liking the Skorpions - Never did ride one though which probably says it all.