Friday, March 4, 2011

The point of diminishing return?

A recent ride on the Specialized FSR 130mm/5" travel bike brought something into clarity for me.  I have been a bit of a skeptic regarding the movement towards bigger and bigger travel 29ers.  My long standing motto has been that "29ers do more with less".  That is immediately apparent in the first few rides on a hardtail 29er or even a rigid bike.  In fact, the 29er, IMO, has completely saved that type of scooter from near obscurity as purely a XC race thing or a casual putt-a-rounder, WallyMart bike.  The custom steel frame builder that does MTBs should thanks the gods of big wheels daily for breathing life into their business in a big way.

I had forever signed off on anything that was not FS in 26" wheels.  It just sucked to ride it off road.  Now, I love my steel SS hardtail and I even enjoy geared hardtails again.  Who would have thunk it?

And that magic that the big wheels bring to the trails also makes a lesser travel FS enough for most of the folks out there, truth be told.  3-4" sure feels generous when you are gittin' it down a fast, bumpy trail.  But, is that still as true when the travel gets to 5"?  6"? More?  Does the big wheel begin to lose some of its advantages, not that it stops rolling as well or loses its ability to corner faster or stability goes away, but rather are there other factors that begin to encroach into the 29ers advantages that take some of the shine off of the apple?

A recent ride on a 5" travel 29er brought that to mind.  Now this bike is not billed as an AM or DH bike, but rather a XC/Trail bike for rougher trails.  The downhill I was on was a 3 mile path of mostly sandstone and dirt with lots of ruts and odd angles worn into the rock over the ages.  Is is a complete hammer fest on anything without suspension and the ledgy and edgy surface make it a challenge to ride a clean line at speed.  I had two true AM 26" bikes ahead of me.  They were both sporting big forks in the 6" range with 36mm stanchions, 20mm thru-axles, stout tires, maybe a coil rear shock, and head tube angles at around 65* to 67* I suspect. 

I figured it would be possible to stay with them on the FSR, being that I was only giving up an inch of travel and I had the Big Wheel Mojo going for me.  After all, I regularly keep up and haunt 4-5" travel 26ers on smoother singletrack when I am on my hardtails, and even on the SS for that matter.

I got dropped.  See ya.  Well, actually, I was keeping them in sight but losing ground until I took a shot of mud in the eye and had to stop to deal with that....can't ride like Popeye all squinty and all.

So what happened?  A few things come to mind:

  • Rider issues?  They were simply better than me and I was lacking the skittles to keep up.  That could be, but that was the only place all day that happened, so although they certainly were very good riders, so am I.  Still, there is this factor to consider.
  • Bringing a knife to a gunfight.  130mm of travel and a 69*-70ish* HT angle do not an AM bike make, no matter what size your wheels are.  The 26" bikes were built for this type of riding.  Burly singlecrown forks,  stout tires, lighter (or as light) but stiffer wheels, HT angles that get you feeling better about high speed chunk...etc.
Were the bigger wheels helping?  I am sure they were to some degree, but it was not enough to close that gap when the trail REALLY demanded the whole package the other bikes had.  It was not the ace up my sleeve that it is on smoother trails.  Huh.

In fact, there were times when things got really intense that I felt that the big wheels were working against me as much as they may have been helping.  That trail required rapid corrections on (and sometimes IN) very rutted, bomb-cratered rocky surfaces.  In this case, how much was I giving up to the naturally more agile and easier to pick up and turn 26" wheel of the AM bikes?  Maybe not as much as I think, but I bet there was something going on there that I never even feel on a smoother trail.

So, what would happen if I get on a 29er that really was built to be a big wheeled version of the bikes that ran away from me on the devil's highway that day?  There are not too many of them right now...maybe 2 I can think of.  And there is really only one tire to choose from, so if I had one of those bikes, maybe I would have dogged them all the way down.  I sure could have used a slacker HT angle and a beefier fork.  I was using all the travel I had and I could feel the fork 'twanging' as I stuffed it into ruts in the corners.  But I would not have gained any agility, and more likely I would lose some.  As well, the bikes those guys were on were nearly as light as mine was.  A true AM fork and Dissents on wide Sun MTX rims or Gordos or whatever, plus the beef in the frame would be a heavy bike.  What would it take to toss that around at speed?  Would I be able to run through stuff that they have to tip-toe around with those tiny wheels as thus negate the increased mass there?  Maybe.

Like this Lenz Lunchbox?

I know that this guy thinks so and he is certainly in a position to know.  He is one of the main players pushing for and riding on this kind of bike done up in big wheels.

So, what is the point here?  Not too sure, but I think there is a place where the 29" wheel really, really is better, and that is where it allows a rider on a simpler, lighter bike to ride with more confidence and carry speed like a mad man on the average trail, whatever that may be.  I think that the advantage may begin to narrow a bit as the intensity of the trail demands a bigger, tougher, stiffer, slacker, hammer.

One thing for sure though, we have not seen the limits of where 29ers are going in this direction.  If the weight can be held to a reasonable place and the components like forks and tires  become readily available, then I just may get a chance to prove myself wrong and I am always ready to give that a try.

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