September 5, 2011
Correction: we’ve spoken to Giant and need to clarify that this isn’t actually a new ‘standard’. You’ll be able to use everything except a 1.5″ (or 1″…) steerer tube in the Overdrive 2 headtube. It’s also only going to be appearing on seven of Giant’s mountain bike models next year, not 57, as stated below, although that’s what Chipps was told originally.
OK, time to sit down and get the pen and paper out… Giant Bicycles has a new headset standard for you to get your head round.
This is the premise: OK, so with everyone getting wider and wider bars, there’s a lot more sideways force going through your stem and steerer – a 1 1/8th inch steerer that harks back to the days of quill stems. So what Giant proposes is that everyone adopts a new size for stems and steerers. They call it ‘Overdrive 2’
So, what’s Overdrive 2? Well, it uses a ‘normal’ tapered head tube (Giant has been doing tapered since about 2008) – but the fork steerer tapers from 1.5in at the bottom – which is the normal size for tapered steerers these days – to 1.25in at the top. Yes, that’s an inch and a ‘didn’t Gary Fisher do that size, ages ago’ quarter.
Giant’s own testing reckons that it makes the steering stiffness 30% stiffer. Obviously you need a 1.25in stem, but these are already being made by Giant, Ritchey and Truvative.
And how does Giant squeezed that big steerer in? It has developed a new, skinny top bearing with FSA that, presumably is 0.0625in thinner (if our rusty fraction arithmetic is correct). Giant reckons that the new system weighs no more than the current tapered system (that we’ve had for only a couple of years.)
Giant is touting Overdrive 2 as an open standard and expects many other companies to hop aboard next year in having, we’ll call them ‘shallow taper’ (or chunky stemmed) front ends. To show its commitment, Giant will have 57 models next year with Overdrive 2.
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