Open Min.D California review

The Open Min.D California is Open’s lightest and most expensive bike to date, a highly refined version of Open’s Min.D road bike, a bike that marries 32mm tyre clearance and disc brakes to geometry designed for real-world riders.

To that end, the Min.D California gets a revised carbon layup that helps shed weight to just 775g, 75g lighter than the regular Min.D, while promising better compliance and greater stiffness. The Min.D California is also, you guessed it, made in California, in the same place Cervelo used to make its California project R-series bikes.

Open Min.D California frameset

That makes sense, since ex-Cervelo founder Gerard Vroomen is the man behind Open, and here is a bike that shows this old hand still has cutting edge ideas.

‘Every gram of carbon saved represents at least one headache in developing this frame,’ says Vroomen of the Open Min.D California. So how many paracetamols is that in total?

The huge reduction in weight does come with the tradeoff of an organ-reducing price: £7,500 for the frameset, up from £3,199 for the standard Min.D.

But that’s fine, because this bike comes from the same facility that Vroomen used when he and fellow Cervélo founder Phil White produced the ‘world’s lightest’ frames, the R5Ca (2010, 675g) and RCa (2013, 667g).

So at least with the Min.D California you’ll be getting the world’s lightest disc frame then? Nope, that award still sits in the downstairs toilet of Specialized’s S-Works Aethos at 585g (54cm, claimed).

Still, the build here is 6.4kg, and it really does play out. The Min.D California feels incredibly light. But it is also so much more than that.

The California maintains the same geometry as the standard Min.D, which in a size large means 585mm stack and 385mm reach, whereas an Aethos, for example, is 565mm and 395mm.

Riding the Open Min.D California

That almost puts the Min.D California in the endurance bracket, even more so given its 72.5° head tube, and true enough, the position is more upright than a lot of dyed-in-the-wool racers. Initially I didn’t like it, finding myself searching for an aggressive stance I felt should already be there in a bike this highly engineered.

But in a short space of time I adapted to this more upright feeling, and it just clicked – that magic of a bike feeling less like you’re sat on it, more like you’re sat in it. And that level of intuitiveness continued with the handling, which despite the slack head tube is remarkably sharp.

That’s down to two things. Trail is 57mm, which is medium-short, and is created by the clever speccing of a fork with 55mm fork offset (counterintuitively, longer fork offset decreases trail).

Second, 405mm chainstays help keep the wheelbase at 998mm. In another world that could be deemed long and thus stately, but twinned with the front setup it allowed the bike to be whipped in and out of turns like the most aggressive racers (which have around 55mm trail, wheelbase closer to 990mm), yet maintain a solid, stoic passage – this is one stable bike.

Achieving this is no mean feat, because the Min.D is also exceptionally stiff – the people in California have worked some real magic – and together with its lightness there was every chance the result would be skittish. But far from it, and a key element to that, I think, is the integrated seatmast.

Vroomen says this is an area they paid special attention to, with the bike markedly different in layup to the standard Min.D. Now, I’ve not ridden the Min.D (although tech editor Sam did), so I can’t compare, but I can say I could feel the ISM and probably those very skinny, slightly bowed seatstays working away below me, flexing in response to the road, cossetting me while helping the wheels maintain contact with the floor – a crucial component of grip, stability and confidence. Utterly remarkable.

Finally, with this abundant stiffness, low weight and spritely everything, climbing was an unadulterated joy. As joyful as a 1-in-10 can ever be, anyway.

Open Min.D California verdict

This build is nearly £16,000. Can I justify that?

I can tell you the parts are as fancy as things get: the full carbon stem (€359) and bars (€399) from Darimo weigh 70g and 132g respectively; the Schmolke saddle (€500) is 55g. The Princeton wheels (£3,399) are 1,396g; the latest Dura-Ace groupset is probably also quite light and costs £3,539. But beyond that, I am at a loss.

I can’t tell you this bike is worth 16 grand, because while there are customers out there for it in the same way people buy Porsches, there are those who will think this is just exorbitant.

What I can tell you, though, is this bike is beautifully engineered and a true labour of love for its makers – after all, they could have just stopped with the regular Open Min.D.

And if it were mine, I’d want to see fully integrated cables and I don’t care how you do it; I’d go tubeless not clincher and wider – there’s room for 32mm; and I see no reason to save 60g and lose the padding on a saddle.

But beyond that, this bike is all the best things a road bike can currently be, with just a bit of magic sprinkled on top. Phenomenal.

Pick of the kit

Assos Equipe RSR S9 Targa bibshorts, £255, assos.com

Assos has updated its flagship bibs, and I like them. The primary difference between the S9s and other bibshorts is the straps. Instead of stopping at the waist, they attach about a third of the way down the backside.

This means they feel a bit like they’re hoicking themselves up at first, but that soon translates into a feeling like a big hug. It also means the waist has less pressure.

That said, compression is high, which Assos claims ‘leads to less fatigue’ as apparently compressed muscles are better, or something. Either way they fit perfectly.

Open Min.D California alternatives

Open Min.D

At a mere £3,199, the Min.D is available as a regular frameset, identical all save for the layup and the fact it’s made in the Far East. It weighs 870g, but the shared geometry means it should ride exceptionally.

• Read our full Open Min.D review

Open U.P.

Open’s U.P. (£2,599 frameset) set the scene for modern gravel bikes, with wide clearance, light weight (1,040g frame) and direct handling. For an even lighter frame choose the U.P.P.E.R. (180g saved, £3,999).

• Read our full Open U.P. review
• Read our full Open U.P.P.E.R. review 

Open Min.D California spec

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