Sunday, 19 June 2011

Viva la Revolution

"Trees flash past, first left then right, a ribbon of yellow-brown earth stretches out in front of me winding through a tunnel of green and brown. Leaning into the corners the rear snaps round smartly carrying momentum out of the turn, I feel the tyres grip the earth as eyes search out the terrain ahead. A roller with a perfect take off line, time to get some air, power on and launch. Flying!"

If you read this blog regularly or actually know me then you may have noticed I’ve bought a new bike, I think I’ve mentioned it a bit here and there. In the three weeks since it landed all shiny and new in my front room I’ve had it out at the trail centre and thrashing round the Peak. In summary, it’s brilliant, you should buy one!

For those not up to speed I went for a 29er in the guise of a Gary Fisher Cobia (now sold as a Trek). I already own a Fisher, my Hi-Fi full suspension bike which I love; however i've always felt the rear shock sanitises the riding experience somewhat especially on open country trails. I missed the rawness of my old hardtail (another Fisher, the still excellent Tassajara) which gave a much more organic hands on ride, a feeling of being more connected with the corners and drop offs.

I’ve also become psyched about off road cycle touring and have some plans to push out some big biking adventures in the next few years. I wanted a bike that would cover big mileage on rough but not super technical ground and something that could tow one of these. A 29er looked like it would tick all these boxes.

Little and Large, my Cobia and Hi-Fi

I was taking a risk though, changing the size of the wheels could have big effects on the handling of the bike. Yes I rode it at the shop but there is only so much you can tell going up and down a bit of street outside the store; would it really live up to all those promises when the tyres hit real dirt? In the end I committed because it was a Fisher, pretty much the only mainstream manufacturer that has tried to do anything novel with bike design in recent years. If anyone could get it right it would be them and in my past experience of their bikes they have never put a foot wrong.

"The switchbacks look ridiculously steep, cutting one way then the other as they carve their way up the hillside. My back wheel digs in and traction pushes me forward the front riding up easily over obsticles. "This bike climbs like a beast" i'm working hard but actually quite comfortable not busting may balls. Ahead a tight left-hander at least 135 degrees, not much room to swing this big frame round onto it's new heading. If the 29er is going to fail anywhere it may be here. Slow into the corner, roll the bars over and bring her round, wheels track round and were still going. Next!"

All Fisher bikes have two subtle design tweaks, firstly the frame geometry has been altered to put the riders weight further over the back wheel giving better grip and better climbing performance for a small reduction in acceleration. John who borrowed my Hi-Fi recently noticed this on the first big climb of the day “It just keeps on going!” he blurted sounding slightly amazed that cycling uphill could be this easy. Danm! My secrets out, the reason I burn everyone off on the hills is not because I’m super fit but because the geometry does all the work for me. The second tweak is to the arrangement of the front forks, but rather than read about it here is a nice little video guide.

So the Bike; the Cobia at £850 may sit towards the lower end of the 29er price bracket but it has the same frame as the range topping Paragon which retails at almost twice the price (£1,450). With my limited funds it offered a great base on which to build better components when I have the cash. That said the components are not bad with a mix of Shimano and SRAM, through the gears and drive-train.

Gears are SRAM X5 shifters coupled with Shimano Deore front derailure and a SRAM X7 rear. Despite this hodge-podge of bits they work well and fire through the cogs smoothly and quickly. My only minor nag is that the down shifters sit above the up on the same side of the bars which is the complete opposite of the Shimano set up I’m used to on my Hi-Fi, a recipe for confusion till I get used to it.

"Coming down of the bottom of Stanage Causway speed begins to pick up, slowly for the first few seconds then you can almost feel the big wheels get going and the bike leaps away as fast as lightning. The track is wide but littered with countless loose cobbles sized between snooker balls and footballs. Not the easiest terrain to ride but the 29er cuts through smoothly, momentum holding the bike in like, I feel stable, confident to put some power down. 

So what does it feel like to ride? Well the smoothness is obvious straignt away, its really comfortable on moderately rough ground whith much less jarring than I was used too as the wheels role smoothly over obstacles. The reason for this is because the angle of attack is less;  and here comes the science bit. A 26” and 29” wheel meet the same obstacle on the trail, the obstacle is proportionally smaller to the diameter of the 29” wheel than it is to the 26” and so is the displacement necessary to ride it. An extreme example of this is why it's much easier to cycle down a gravel path then skateboard down one, the gravels a a considerable fraction of the wheel size of the board but tiny compared to the wheel size of the bike.

The second big effect of the 29” wheels is that they have a longer contact patch with the ground; this is the bit of tyre that actually does all the work of gripping the surface and stopping you ending up in a big pile on the floor. It’s actually worryingly small for all wheels, scare yourself and work out how big it is for your car which you throw into wet corners at 70mph! The bigger contact patch gives more traction when climbing and better grip in the corners, it is also more likely to “float” over sand, mud, and snow before becoming bogged down. If your interested a more detailed explanation can be found on the Fisher website.

In the bigger wheels the mass is situated further away from the hub this effects performance in two ways. Firstly it needs slightly more energy and time to get them going although I found that in practice this is marginal. The second effect is that once they are going they stay gone!. The bike accelerates downhill very quickly and carries its momentum through rough ground better than any 26” bike I’ve ridden.

The brakes are Promax Hornets, not a model or indeed brand I was familiar with. They are not quite as sharp as the Avids on my Hi-Fi but i'm not sure if that is down to the brakes themselves or the fact that the bigger wheel has much more angular momentum and is therefore harder to stop. The effect on the trail is negligible you can still easily get the back wheel skidding round corners with ease. 

A word about sizing, I’m 6ft and bought the 19” frame which feels right. 29er’s are naturally bigger bikes even on the smaller frames and I think riders under about 5 ft 6” may find the whole set up a bit big.

"Stainburn red decent line: I've never ridden this clean, usually technically stopped by the boulder fields or mentally by the big drop off at half distance. "Your on the wrong bike you know, this is not what you bought the 29er for" I tell my self as I fly through the bermed corners. "Well at least your giving it a proper test, I retort". The boulders go as easily as I can ever remember, next up the drop off, should I stop and inspect? "F**k it just go". Set the line, sit back and roll off the edge. Then it hits, "The decent is on here don't cock it up now that's the hard bits are over". Switchback after switch back and some more small jumps and it's done, a personal demon is slayed; yes I love this bike"

So what are you waiting for? Join the revolution when your barrelling into those corners with a big smile on you face you won’t regret it.

Just for clarity this isn't me.

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