Segal brings back the magnesium bike… plus some secret ingredients to make it work

Good lord that's a very green bike but it certainly attracted our attention

by nick_rearden   September 8, 2011  

The super light but potentialy troublesome element magnesium is making a comeback on new welded tubular Segal frames from the Netherlands.

Magnesium has the advantage of being lighter than aluminium in absolute terms but anyone who remembers their GCSE chemistry lessons will know how plain feisty the reactive material is with oxygen. The clever part, according to its boss Mark Wemmenhove is to alloy the pure magnesium with other materials to make it more corrosion resistant and furthermore well-behaved enough to be drawn into the kind of tube diameters that can be welded into a bicycle frame.

Naturally, we asked what Segal was using to improve the performance of magnesium for making bike frames "Ah ha," replied Wennenhove, "I can tell you that the other elements account for 2% of the total mass but what they are is proprietary, it's our secret."

A more conventional colour scheme but the same secret magnesium blend under the paint.

Fair enough, but he did say that improved as the performance is for strength, stiffness and weldability, the Segal magnesium is still subject to corrosion if it's not coated properly. He showed us a white-painted frame akin to a welded GT frame of about two or three years ago, large puddle welds and all which has a certain butch appeal. But the frame that had first arrested our progress down the aisle was what looked like an anodised green model but which actually turned out to be lacquer in an emerald shade that even an loyal Irishman would have found a bit lairy; we loved it.

Weight is a claimed 1,020 grams which is comparable if not a little lighter if we remember rightly to a Cannondale CAAD 10 frame and the price is €1,600 which is pricey by the standards of a good but heavier aluminium Kinesis frame but a bargain against a whole host of frankly rather generic-looking carbon-fibre frames that are hardly any lighter if at all.

The proof of the pudding, of course, will be how the new Segals ride but at this stage we have carried out no testing other than the bikie's cliché lift and appreciative 'Mmm' but you you can be sure we're looking forward to it. In theory at least magnesium is close enough in its metallurgy to aluminium for us to anticipate no particular shocks in that department bearing in mind the benchmarks like that Cannondale CAAD 10 Segal's engineers have to measure against.

Of course, magnesium is not a new material for building bicycle frames. Back in the late 1980s a British engineer, Frank Kirk who worked for Ford in Essex, collaborated with Norsk Hydro which in turn owned an enormous capacity for producing electricity along with access in Norway to the sea-water from which magnesium is produced by electrolysis, on the production of the Kirk Precision frame, a product that caught the imagination of the cycling world at the time.

The problem was that the excitement ran ahead of the actual execution of the innovative flash casting process and the initial production was fraught with difficulties. In short, parts like brake bridges and shifter bosses fell off despite some impressive demonstrations of the inherent strength of the basic frames by driving cars over them. Like many products slightly ahead of their time, the money and patience ran out before the bugs could be ironed out and the world moved on.

What hasn't changed is that copious amounts of electricity production has to be used for something when people aren't brewing tea or running baths and power companies like to find things to do with their excess capacity. In the case of the Dead Sea in Israel, you have both the electricity and the most amenable source of magnesium suspended in solution up to 25% of the water volume, the highest on the planet. That's where Segal source their pure magnesium with the clever alloying production taking place somewhere else that it doesn't want to tell us about. Nothing has been so mysterious since the first Russian Cold War titanium started to be sneaked out from behind the Iron Curtain.

Lately, and before we saw Segal's welded tubular frames, one of our favourite engineers Bill Shook from American Classic has been extolling the lightweight benefits of magnesium in his wheel rims for a couple of years right up until the Eurobike Demo Day where he showed us the latest version of his Mag wheelsets weighing in at an ethereal 1,108 grams per pair.

Segal have no UK distribution or dealers yet but we expect that will change quickly if the buzz created at Eurobike is anything to go by. Watch this space.

15 user comments

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Or.. they could use Ti and Mag weave with carbon strands all set in the usual resin/plastic base. Have seen this talked about in military armour programs on Discovery. Cool

downfader's picture

posted by downfader [204 posts]
8th September 2011 - 9:06


Of course cast Mg alloys have been around for years in the camera bodies I use....

posted by IHphoto [114 posts]
8th September 2011 - 12:31


Can't remember enough from GCSE chemistry to say anything relevant about Mg, but it's a pretty sexy build, especially in white, IMHO.

posted by kace19 [24 posts]
8th September 2011 - 13:55


Halfords brought out a Magnesium framed Carrera back in the early 2000's didn't they, full 105 and a bright green paint job for a thousand quid if I remember correctly. I think it got some quite good reviews as well.

Twitter - @StuKerton

stuke's picture

posted by stuke [356 posts]
8th September 2011 - 14:34


that segal... White frame world champ stripes cool sounding material but is magnesium drool proof?


posted by cool guy 999 [54 posts]
10th September 2011 - 18:00


I have never trusted anything mag.... remember those old toy cars when I was young ... very brittle and somehow not bright, you can't polish it ???? Ok times have moved on ..... a little research and have still yet to be convinced

ashy_2002's picture

posted by ashy_2002 [56 posts]
10th September 2011 - 19:54


stuke wrote:
Halfords brought out a Magnesium framed Carrera back in the early 2000's didn't they, full 105 and a bright green paint job for a thousand quid if I remember correctly. I think it got some quite good reviews as well.

Yeah Kona did one too, a really nice looking white magnesium road bike must be about 10 years ago, pretty light and stiff as… as I remember it was their range-topper then it sort of disappeared

Tony Farrelly's picture

posted by Tony Farrelly [4202 posts]
10th September 2011 - 23:32


ashy_2002 wrote:
I have never trusted anything mag.... remember those old toy cars when I was young ... very brittle and somehow not bright, you can't polish it ???? Ok times have moved on ..... a little research and have still yet to be convinced
God yes, those cars! Must say I expressed some of those reservations to Segal Man at the show and I would have hardly expected him to say, "Oh yeah, you're right," but he did sound pretty plausible on this mysterious 2% that the pure magnesium is alloyed with to make it more amenable for bicycle frame production. Not least because bike frames are by no means the most stressful, corrosive and mission critical applications that occur in the Great Pantheon of Engineering Challenges; helicopter parts were mentioned, for example. As ever, the proof of the pudding will be in the eating.

posted by nick_rearden [864 posts]
11th September 2011 - 22:17


The mystery is solved by Segal's own published data. According to a spec sheet, the alloying metals actually total 3% by weight, not the 2% mentioned by Mark Wemmenhove. They are 2% zinc and 1% manganese. Metallurgists believe that these additions give it "good formability, good damping capacity and medium strength" during processing.

posted by Max Glaskin [8 posts]
28th September 2011 - 10:09


Nice Max! I was having an interesting chat after this at Eurobike with the chaps from Reynolds tubes about the Ultimate Tensile Strength (UTS) of the various steel alloys used to make their tubes. One of these fine days it would be interesting to make a chart of the comparative UTS of the various materials used to make bike frames including this magnesium alloy but I guess the problem in the end would be that such a chart would offer no help with how the material is then subsequently used to make a frame. Diameters, wall thicknesses, whether it's bonded, brazed or welded and then whether you paint it green or not all go into the mix...

posted by nick_rearden [864 posts]
28th September 2011 - 12:09


Some such charts do exist, Nick, and I've been wading through a plethora of them during the last two weeks as research for my cycling science book. Those nice people at Reynolds have helped me, too. When looking for info about magnesium bikes I came across your Segal post and thanks to what I'd learned in the past fortnight, could interpret their codes. My hope is to pull together all relevant materials information in a way that means something to the cyclist who has an interest in science - or even for the scientist who has an interest in cycling. By the way, apart from Segal and Paketa (US), does anyone know of other magnesium frame bikes currently available?

posted by Max Glaskin [8 posts]
28th September 2011 - 12:18


Well, apart from those names mentioned above that are no longer in production, no, Max, not to our knowledge but that doesn't mean something isn't going on somewhere. Let's see if anything comes back, and please keep us posted. Meanwhile, the Segal folks aren't exhibiting at the Cycle Show in Birmingham this weekend but they said they might be there visiting so there might be news on UK distribution and we might see you, Max?

posted by nick_rearden [864 posts]
28th September 2011 - 12:46


It would be good to meet again but I'm doubtful about shlepping up to the NEC, particularly when the weather is so amazing. Mind you, if someone at the show is exhibiting a bike made out of aerogel and honey, I'd be tempted. I hope yu have a groovy time and look forward t catching up again soon.

posted by Max Glaskin [8 posts]
28th September 2011 - 12:54


I know some of the guys at Segal (in Israel they do the same job for Campag as technical reps / service & warranty as I do in the UK) - the technologies & techniques that they are using have a wide application in magnesium fabrication, and they have used related materials and technology over there in the automotive and aerospace industries - so they understand how to use magnesium & it's alloys pretty thoroughly in all sorts of challenging environments.

Unlike some of the other companies that have introduced slightly left-field materials into cycling, they are not having to solve problems "on-the-hoof" in the way that Kirk were 'way back when - I was involved peripherally on that project as mechanic for Steve Poulter who rode for them & saw first-hand some of the issues referred to.

It'll be interesting to ride a bike & see how their material's properties in terms of UTS, elongation and ductility characteristics translate into ride quality - I don't think it's just or logical to simply look at the base metal's characteristics or just compare it to the MaZac that toy cars and the like used to be made of - on that basis, we'd be saying that you can't build a rigid welded frame in aluminium or that carbon is a bad choice of material for structural parts of anything because you can't mould diamonds ...

This week I have mostly been riding a Mondiale in Deda V107 with Campagnolo Super Record 11 ...

posted by velotech_cycling [78 posts]
5th October 2011 - 16:06


velotech_cycling wrote:
...I don't think it's just or logical to simply look at the base metal's characteristics...


A good point, well made. Certainly why I won't be compiling any UTS comparison charts in a hurry. The danger is always that the second you do someone will point at a value in isolation and say, "Look, material x is rubbish because of..." or "My frame is best because of factor y." You're rarely comparing apples with apples and to be honest we as commentators and reviewers would do well sometimes to write less about what the material is and more on what it delivers.

posted by nick_rearden [864 posts]
5th October 2011 - 17:54