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Existentialism-- Just a bloody good excuse to go riding...

Wednesday, September 8, 2010

EG - A new setup

Dropped the idea of a full DH bike, just can't justify one with the lack of suitable riding terrain.

90% of the time a 6 x 6 setup is overkill for most of the riding around here. But an inch more upfront and a slightly slacker HA would definitely be good for the DH trips in Indonesia and Malaysia. Problem is the change to the bar height position might be too much after plugging a 180mm fork in. Chances are I'm unlikely to keep swapping forks back and forth too. So a compromise has to be made.

One change always lead to another. In a bid to minimize bar height changes with a longer fork and  better leverage with a longer flat bar, I got a 760mm Nukeproof flat bar. This together with the latest swap outs on the EG, a 165mm XT crank and a Blackspire Chain Guide for other reasons.

 Fixed up new crank, swapped back into 2 ring mode with old MRP bashguard

New chain guide in place.....

Time to set out with the bar....but first, just to make make sure differences in ride is not due to shorter cranks, new bar is not fixed on until a lap or two is done with the old barand stem.

Verifying old setup measurements at trailhead.
Bar height spot on with previous night measurement @ 41.25"

Have to admit its pretty weird the way I measure the reach on my bikes. For mtb I take it from a virtual point that is usually halfway at the stem which is dependent the sweep and rotation of the bar....something I term as "Effective Stem Length"... .

The reach is from this point to where it dissects the seat if another virtual line is extended upwards and parallel to the center of the seatpost.

Of course when sitting, it would be a bit further back but these points are easier to fix and measure.

Hence anytime I get a 24" +/- 0.25" for this reach measurement, its 99% sure I pretty much don't need to change a stem or adjust the saddle anymore.

With a flat bar, the initial bar height was a whooping 1.5" lower even with most of the steerer under stem stacked with spacers (~34mm).

Placed both bar/stem combo to compare the actual differences in height and length.

One last pic of old setup to benchmark against future changes
Changed up and tweaked, bar rotated up and outwards after 2 days of testing. Final bar height rests @ 40.75", still 0.75" lower than before and strikes a fine balance between climbing up and bombing down.

Pros and Cons of shorter crank arms
Broke my own rules of bike testing by having multiple component changes at once instead of one at a time. To eliminate shorter cranks from the cockpit changes, bike was ridden with  both new and old bar/stem combos. Basically the 165mm crank is a positive change after fearing for the worst.

With the kind of weight on the EG, it makes more sense to spin on the way up than than mashing on the pedals where a shorter crank would be an advantage. It also allows a wider range of gears in the rear to be used. As it spins faster on the down or straights it means having to change up to 1-2 heavier gear on the rear as compared with using the previous 175mm crank arms. Things might change if the other ongoing project for this bike--dieting of the EG gets underway.

Not enough airtime to tell if shorter cranks make for easier launching and better fine adjustments in mid air.

A key thing to the change was to see if it helps to eliminate pedal strikes. With the thin Point-One pedals, already strikes were very much reduced. With the 165mm I went over the usual spots where the pedal has a 50/50 chance of hitting. Seems to work as under full 160mm travel in front, out of ~15 test spots only once was the pedal clipped on the outer edge.

Front travel was then intentionally lowered to 130mm at some sections which reduces the bb height and the strikes on the pedals were also noticeably reduced compared with previous rides.

Downside of shorter cranks? Having to adjust to quicker shifting when coming out of a descend that rolls back into another steep climb. As mentioned it allows the use of harder gearing, this also means if the gearing ratio is not enough, there is a tendency to over spin and actually losing the initial momentum in a climb. Small adaptation that should be dialled in with another couple of rides.

Other related changes-- a slight raise in the seatpost. No issue as the full  5 adjustable inches is hardly ever needed

Comparison of bar/stem combos.
The swap to a flat bar was originally for accomodating a longer travel fork up front. However there was a positive secondary effect from testing out the change. Climbing.

This is attributed to a combination of both the lower bar height from the ground and the characteristics of a long flat bar.

Long flat bar is nothing new as my initial experience with them was when singlespeeding with a Nitto Torsion and Salsa Cromoto (666 and 685mm with 11-15 degree backsweep). Of course none of those are as ridiculously long as today's standard of 760 to Blackspire's latest offering of a whooping 800mm.

However I believe there is a relationship between bar length and travel. The longer length favored today has a lot to do with longer travels up front which raises the front height of a bike and needs a longer bar to keep it weighted down with less force, hence more agility to steer the front. From another point, whenever I tried to put a longer bar (say a 720mm) on a 100mm travel bike, it just doesn't seem right both in the handling and looks of it.

Back then I have already realized the ergonomic differences of relatively longer flat bar with more sweep but before these long flat bars made popular by the current trend in DH riding, there was just nothing out there to make a change to. So like most people I was stuck with the usual riser bars until now...

I have kept my ideal "reach" distance constant  in both setup at 24" +/- 0.25. However with the lower front and 4 cm additional in bar length, the front loading is noticeable. Things felt more "xc" with the accompanying numbness of xc riding in the saddle area and a tad uncomfortable when pressed against the nose. A slight tilt down of the saddle is needed. Slight departure from my usual saddle position.

But overall the change has helped made climbing much more positive. Nothing beats the 2  test section at Bukit Timah. First the oxymoron uphill rock garden. With the old riser bar+50mm stem, it was a 70/30 make-or-break at 160mm front travel. Wet and slippery days will usually fare worse when the rear starts to slip and the front hit the unavoidable foot high rock that is lodged smack in the middle of the line. Second is the usual short but steep 45 degrees concrete climb that gets everyone swearing under their breath.

On the new bar combo with the 65mm stem it was quicker to steer and the front felt lighter. Just a slight tad more twitchy but manageable. Unweighting the front to pull up over obstacles was easier despite the lower front end. Really strange as the opposite was expected with a flat bar at a lower height from the ground. Still can't really figure out where I got all the leverage from. The longer bar alone doesn't seem quite enough to explain it.

The overall climbing feel can be compared to a bike with lesser travel. While not as nimble as a 100mm XC bike but maybe more like a good geometry bike spotting 120-130mm front travel.

New Setup
760mm Nukeproof with 9 degree backsweep and Sunline 65mm AM stem

Old setup
720mm Funn Fatboy 9 x 5.5 degree back and upsweeps, 30mm rise with Titec El Norte 50mm stem

What usually works for the ups will work against the downs and vice versa. This is where (I think) the characteristics of flat bar with more sweep makes for a difference compared to traditional flat and riser bars.

Though the backsweep is 9 degrees but on a flat bar it somehow translates to more, putting the hands in a more neutral position than a 9 degree backsweep riser.

The rise in a bar has a psychological impact for me, giving more confidence when the bike is pointed down. Not sure why. With the flat bar, I have to fight this missing "factor". As the bar was a little lower than before and wider now, it could also have accounted for the fact that on the faster and rougher descents, it gave rise to a more heart dropping feel as the travel gets used towards the max.

Consequently it led to shifting the weight a little more rearward than usual. However once the adaptations were made, all the descents had a more fluid flow when turning. Together with the front being lighter to steer (despite a longer stem) flicking around the bends while descending was surprisingly easier. Before, I often had to use more lateral motions (body English) together with turning the front to swing the bike and get out of the tighter corners. Now the turns are approached with the outer leg pressed in to get a better grip earlier as there is no need to swing the body as much.

From pure numbers, I have gained a buffer of ~38mm to cater for an additional 20mm increase in front travel. Plenty enough in that aspect but need to watch for lever position hitting top tube as there is lesser clearance when the bar is turned.

Only thing to be wary of was the tight spots between trees while meandering with a longer bar.

However things will probably change again when a 180mm fork replaces the current 36 TALAS with a ~0.5 degree slackening in the HA. Guess more tweaks by then.

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