Defining geometry - How do we design our frames?

A: Well, what we certainly don’t do is cut and paste other brands’ geometries and use them on our own bikes.

On the contrary, we relentlessly prototype frames with geos derived mostly from hare-brained notions hatched during late night bike geek sessions, and we real world test them. We are on a never-ending path to geometry enlightenment and we would rather put our own ideas to the test than simply rely on other people’s findings.

Whether small tweaks to geometry or more conceptual left field changes, they all end up in the same place: on a prototype frame, being ridden by various losers who have somehow over the years become our test pilots.

Our last R&D session was back-to-back testing of two similar Vendettas. It’s no secret that we think the current Vendetta sits pretty much right in the sweet spot of hardtail geometry. With the Vendetta and the Vendetta LS covering the needs of a rider who wants to go slack and the rider who prefers to keep it more restrained, respectively.

The question we wanted to answer through this test session using two new prototypes was simply: slacker, or shorter?

May we introduce prototype 1, THE SLACKER

This Vendetta is both longer and slacker than our current medium model.

It has a 62.5° head angle – that’s two degrees slacker than the current LS model – and an extra 10mm of effective top tube, making it 630mm. Reach is 451mm.

The seat tube has been pushed forward by half a degree to 74.5º.

The rest of the geometry is the same as a Vendetta LS.

And now meet Prototype 2, THE STEEPER

This Vendetta is a little shorter, lower and steeper than our current medium LS and X2 models.

We lowered the bottom bracket by 8mm and significantly shortened the chainstays to 418mm. This limited the tyre’s maximum width to 27.5x2.6.

A 65° head angle combines with a very steep 75.5° seat angle. Reach is roughly 444mm.

The rest of the geometry is more or less the same as a Vendetta LS or Vendetta X2 – aside from small variables such as front-centre.

What is the purpose of this testing?

The main reason for this test session was to define how slack is too slack for a Vendetta. Our pre-testing question was could we go even slacker with future production models, and will the bike still be trail friendly or just become a downhill sled?

We decided to shorten the chainstays to test effective tyre clearances and also discover if the bike can corner any quick whilst keeping stability. There are various, contrasting, schools of thought on chainstay length related to cornering speed and handling, so we wanted to test the water for ourselves.

The bottom bracket drop test was purely to revalidate the Vendetta’s current -30mm drop. We wanted to check that we were in the best place on the crossroads of height vs. practicality: if we were to go any lower, in our theory, we’d be sacrificing rideability with excessive pedal-ground strikes, and the lower centre of gravity would therefore be more a nuisance than a benefit.

Like we said, ideas need to be tested. So that’s what we did.

What happened and where?

October 2017 we took the two frames to our favourite hardtail testing ground in Punta Ala Trail Center, Italy. The trails there are perfect for hardtails: they cover every type of terrain, from highly technical to flowy, and with relatively low altitude (max elevation is some 900m) there is plenty of scope to thrash up and down hills. Some of the trails in the lower coastal range, in my opinion, are simply heaven for hardtail riders.

So what did we learn in Punta Ala?

Last year for 10 days we relentlessly sessioned trails such as Guardian, Trail 1+3, Torretta and the aptly named Test on the current Vendetta LS, which has a 64.5 HA and a relatively long top tube at 620mm.

Taking these familiar trails on again, this time on the subtly differing Vendettas, was going to be fun.

It soon became apparent that the longer and slacker Proto 1 was a downhill missile; it was quite frightening just how much faster and stable the 62.5 head angle made the bike. The ability to plough through technical rock sections with ease was great, whereas not surprisingly the steeper Proto 2 became more delicate to handle at high speed, with line choice and planning of exit strategies essential.

However, once on the Torretta trail we hit the flow sections. With the many bermed corners of this epic trail, Proto 2 started to come into its own: it literally danced its way around the tight berms. Meanwhile, the much longer wheelbase of Proto 1 suddenly seemed a burden in comparison: it really had to be manhandled and wrestled through the turns.

In terms of climbing, it was a similar story. The longer, slacker Proto 1 was a little vague on the steep stuff, especially on corners and around roots, whereas the steeper head angle on Proto 2 felt more planted.

Back in the land of bacon and blondes

The trails around our base in Copenhagen (minus any elevation) are quite similar to most UK forest trails: roots, flow, rocks and mud. We add to this with a few trails we’ve specifically made for testing our bikes with our own bare hands.

On these shorter, tighter trails there’s so little elevation that the longer Proto 1 rarely had a chance to shine like it did in Punta Ala, and we found ourselves gravitating to what became know as the ‘fun’ bike, or ‘the Steeper’, purely because it had more pop, encouraging trail lunacy and stupidity.

This short exercise in testing proved what we already know: the current Vendetta and Vendetta LS are in fact sitting in the hardtail sweet spot for most riders.

The two prototypes are forays into custom geometry, touching on terrain-specific geometry that’s great for riders who want a hardtail that delivers something tailored for either the way they ride or the trails they ride.

Footnote on BB height

We have been firm believers in the -30 bottom bracket drop on our 27.5 Vendettas, beliefs based on our experiences over the years with crank bash vs. handling. Previous prototype Vendettas have run -20, which was too high, and -50, which we repeatedly rammed into anything from roots to rocks.

So we’re actually surprised at the -38 bb drop on Proto 2. It’s grown on us. We’ve had less trail-crank collisions than we thought and the lower BB potentially helped us rail those never-ending berms on the likes of Torretta, Tre Dita and Gagliardo in Punta Ala.