Cheers guys - this certainly seems to have stirred some lively debate
Very opinionated chappie isn't he? He doesn't seem to take into account the usage of different bikes and just goes for a generic this is how it should be approach.
Gravel bikes like my Kona are very much influenced by Mountain Bikes in it's approach to sizing, so 460mm wide bars (Centre to Centre), 70mm stem and 170mm cranks. Now off-road the influence those wide bars and short stem can really be felt, the bike can handle some really impressively rough trails. The other benefit on road is the comfort this affords, I have never ridden a more comfy bike and in the summer I rode 440 km across Slovenia loaded up and didn't suffer a single bit of bike fit related discomfort.
So forgive me if I take some of his protestations about bar width with a pinch of salt, it really is up to the individual rider and the usage to which the bike will be put. Narrow bars will suit some riders and their intended use, but equally, wide bars have their place to and can contribute to an impressively comfy all day touring bike.
Indeed, although in his defence I suspect the vast majority of work he sees comes from road cyclists which defines a fairly narrow range of expectation re. fit - speed is the no.1 consideration so fit is a case of maximising aero properties and power output while retaining a tolerable level of comfort. Obviously road bikes tend to have more aggressive geometry than others which generally makes fit more critical.
Conversely with gravel speeds are lower and terrain more variable, so some compromises relative to the ideas of road cycling are to be expected.
Bike fit, eh? Considering they tend to contradict each other in detail, which system do you choose? How do we know that is the optimum, and not one of the differing systems? I have experience of them and remain unconvinced of any significant benefit.
I guess that's the big question. While (as per my response above) there's going to be some subjectivity depending on rider preference and application, I think some things (such as saddle height) are much less subjective.. of course you still have to choose who to believe
Crank length will not scale with height. Even people of the same height can have very different leg dimensions. Even with same leg dimensions riders will have different preferences or indeed not really care whether it’s 170mm or 175mm.
All things being equal though, for a simplified (and flawed) bike-fit model that only references height; crank size should scale - no? I'm well familiar with the variation in fit for a given height (I have long legs, relatively speaking) however I'd expect if the relevant factors to crank length (as defined in
@MichaelW2's post) to scale with height, within a range for any given height.
On this note I see some manufacturers are now quoting inside leg on fitment too; which I guess is a step in the right direction, although off-the-shelf bike sizing is only going to take into account the mean body proportions for whatever height is being targeted.
Interesting while looking at Boardman's latest I compared the men's and women's versions of the Adv. 8.9, and was somewhat surprised and disappointed to see that the geometry of both frames is exactly the same; rather than my expectation that the women's frames would have a shorter reach..
"Bike fitter bitches about other bike fitters shocker" should be the headline. His theory on why people end up on frames that are too big for them is ludicrous. Probably less than 1% of bikes are sold by people who were also selling them in the mid 80s.
Maybe, although I found his point quite salient as someone who's always been told by shops that I need a bigger size than I find comfortable; I think because they're basing their assessment purely on my height..
