Sunday, August 31, 2014

Cornering

Ever wonder why some riders just pull away when it gets twisty, even though others might be a more powerful climbers or faster in a the straights?

In mountain biking, you need sufficient fitness and power to weight of course.  But without bike handling skills, you will be left in the dust.  In this article I will discuss cornering.

There are a couple of camps on cornering.  Cross Country or Down Hill/All mountain .

DH and All Mountain riders, generally run full suspension rigs with more travel, wider tires and bars than those used by the XC crowd.  They will drop the seat post, unlike XC, where the length of the rides and races preclude standing the whole time.  There is debate on whether the energy savings of staying seated is worth more than the aggressive handling that a dropped seat allows.  Dropper seat posts are a burgeoning option to do both.

For all turns above tip over speed 4-5 mph, initiating the turn, with a counter steer, weighting the outside grip, momentarily turning slightly opposite the turn, helps set up turning in the direction you want to go.

XC riders and racer, particularly those with a road back ground, will then steer into the turn and by weighting the inside grip and outside pedal(pedaling forward, not backwards to prevent derailing the chain and crossing gears).  Not long ago more hardtails than full suspension bikes were found at the races.  That ratio has flipped and there are more FS bikes now.

The DH/AM rider will also counter steer and then weight the inside grip, but here is were the dynamics differ.  Ala BikeJames and Better rides, you keep your outside foot back to support the weight of the hip swing to the outside weighting that pedal down, akin to carving a ski turn, with a back pedal action.

Lee McCormack, is similar but you go into the corner with the outside foot forward, allowing you to swing your inside knee towards the inside of the corner, allowing a forward pedal to weight the outside foot.

In his article Seb Kemp states a concern that weighting the inside grip,may push the front tire to far to the outside.

I am in the XC camp.  You can read below to see how that came about.  My style is more of a blend.  I run my saddle a little lower than my road bike height, but still in efficient pedaling range.  I will slide my but off the saddle slightly to the outside.  With the outside foot down, inside leg is up high enough to do this, or even let it move in front of the saddle to get more outside if needed.  I keep my upper body close to the bars to weight the front wheel, to maximize traction, with a slight up words roll to the outside.  Kind of automatic when you push the inside bar down, while staying close to the bars.  But like Seb says don't let the front wheel stray to far outside.  I learned pressure on the inside grip method.  it comes from road biking where the handlebars are much narrower.  So after the counter steer, weight the inside grip to get the lean going in the direction of the turn, then drive the front wheel into the ground with the outside grip.  It kind of feels like flying and the handlebars are your wings.

There are times that keeping your pedals level ground, particularly in rough terrain.  There is one technical section at the Vortex at Santos in Ocala Florida that I go in to the right and snake left and right in not much more than a bike length.  I felt much more stable with the left foot back, because the two right snakes define the feature.

I see a problem with outside pedal back, weight the pedal down is effectively a back pedal.  Even with a chain guide upfront, the chain can cross up in back across the the cogs.  Sometimes just a nasty noise, sometimes the chain skips or jams, twists or breaks.  The hopefully you just stop and not knee the stem or pitch off the bike, ouch.

I was part of a lengthy discussing at Mountain Bike Geezer.

I started to revisit cornering after encountering machine made berms for the first time at  Tannehill Alabama, shortly after embarking on this Quest.

I mean man made berms, not the occasional natural banking off of a the base of a tree or the contour trails that cross washes, kills and runs.  Now, I have been riding for decades on fire roads and deer trails.  Deer don't have much need for berms.  I taught myself how to corner after reading Davis Phiney's book "Training For Cycling", oh so many years ago.  being a sprinter and not a climber, he used cornering skills regain contact with the peloton on the descents.  You can get copies on online cheap.

Berms actually require little technique, at speed.  I had to train myself not to do my usual technique on berms.  You need to keep your weigh more in line with the bike. You and the bike lean in relationship to the horizon but is nearly perpendicular to to the banked surface.   To actually increase your speed, bring your mass to the inside, swing your inside knee in and opening your chest facing it toward the exit of the berm, pushing the bike into the hole that is the apex of the berm and pull the bars back to the chest on exit, pulling a wheelie or almost pulling one.  I am starting to get it, letting off the brakes and using as much speed as possible, seems to be the trick.




Friday, August 22, 2014

Velocity Blunt 35


 Up to now I have not said much about the Blunt 35s.  To be blunt, they have given me pretty much zero reason to worry about them, they simply do a great job of holding the bead of that big tire tubelessly. I am super happy with the Velocity tubeless rim strip and valve!  As a system it is great, give the 3 inch tire a nice profile and is strong and reasonably light, particulary compared to the Surly Rabbit Hole.No apparent damage,even after numerous soft bottom outs, usually running 13.5 psi, Last ride, I must have had a puncture or burp and was down to 9.5 PSI and Blunt still held the Knards bead!
                                                                                   
No sign of stretch, using Stan's sealant on the lighter 120 TPI Kards
Casing

Knob to knob.
After lot's of trail time, the corner and side knobs are showing some wear.  This may account for the hunting on wet rocks on the Lynskey.





Monday, August 11, 2014

Surly 29er+ Velocity Blunt 35 Knard to Follow

After several months of Knard, Knard and nothing but Knard on the front of my either my Lynskey Pro29 SL, fits nicely in the Black sheep fork, for everything short of the Maah Daah Hey after a rain or on my old Ferrous and Switchblade fork combo (plenty of room there).  Except for some railbed riding.

Click here for my First Look at the Knard.
Click here for Follow Up

The Knard Rolls pretty good on the Velocity's Blunt 35. I am running it tubeless, but I was pretty conservative on the pressure and only ran it 17.5, just 1.5 psi lower than my 2.35 Ikon. I dropped another half PSI when I got back near the car at Games Loop/UWF Pensacola Florida.  It was great in the sugar sand of course.  Slid out on some fresh pine needles. Usually I could feel it slide and hook back up though.  I had to keep it weighted, more on top of the front wheel, kinda like riding a hardtail with a big fork up front.

As I slowly lowered the pressure, like half a PSI each ride, I had to ride on top of the front end less.  I worked down to 14 PSI.  That was just starting to feel more shock absorption at 14.  I stayed here a while, as I am concerned about breaking a bead and rolling the Knard off of the Blunt 35.

I settled at 13.5 psi, getting just the occasional bottom out clank.  I weigh around 200 lbs. No scale in the bus so not 100% sure.

Now I always break something at Stokes, Stokes has my number, you could say,  Stokes is pretty much all rock garden, even though rock gardens are usually my forte. My Stan's sealant was getting thin I guess.  I burped or punctured and was able to put the Knard/Blunt 35 up a few times, but ended up putting in a tube.
Back at a compressor, I removed the tube, added some Stan's and  reinflated and it has been good for a couple months now.


Wet rocks seem to be the Knards nemesis.  Particularly on technical rocky climbs, the Knard hunts around a bit, sometimes finding the wrong line, accentuated on a single speed.

Having a 29er+ up front and a weekend on a fat bike, got me jonesin for a 29er+ rear as well.  The Surly Krampus and the Carver Titanium Gnarvester, if you guys are listening :-) Lynskey said they could build me a custom one.  A guy can Dream.

My Lynskey was down for a while, when I got her back together, the bike's handling felt a little slower than I remember with the Knard.  The Ferrous has slightly steeper head angle, and maybe I got used to that.  I gave the 2.35 Ikon another try for comparison and it just worked better with my Lynskey geometry.