What Are They Doing Different?!

It's the elimination of use of lime.

The silty soil used for building tracks is stored in large piles and can result in a high moisture content and with tracks being built a few days prior to practice and race day it never gets  chance to dry out and firm up.    

"Wet soil treated with lime or quicklime, is a very effective method for drying. The lime reacts with moisture in the soil to generate heat, drive off water vapor, and bind some of the water in the chemical reaction. This reaction occurs very quickly, in a matter of 1 to 3 hours to allow for compaction to proceed"

Edit - I had to Google that, yes, it appears it does have trace Asbestos.....only if it came from the Libby Mine in Montana.

Thanks for asking that question...I'm a little wiser this morning after all the reading I've done to check on that.

Here's what I have found.

A reader recently asked me whether it was true that vermiculite contains asbestos and therefore should be avoided. It just goes to show that horticultural myths have an extended life, as this one was debunked ages ago and I thought it was long dead.

First, an explanation.

Vermiculite is a naturally occurring mineral composed of shiny flakes resembling mica. When heated to outrageously hot temperatures, about 1000°C, it puffs up like popcorn, giving a light-weight expanded rock useful not only in horticulture and also in insulation and fireproofing.

Vermiculite itself is not a health hazard. It’s an inert mineral widely employed in gardening circles, practically omnipresent in packaged growing mixes, and accepted in organic gardening.

So far, so good.

But vermiculite wasn’t always quite so innocuous. Back in the mid-twentieth century, much of the vermiculite produced in North America was taken from the Libby Mine in Montana. Sold under the trade name Zonolite, this vermiculite was contaminated with asbestos fibers, as the two are naturally copresent in the same rock formation, although this went unrecognized for some 60 years. From about 1920 to 1990, Zonolite was widely used in the construction industry throughout North America, notably as attic insulation. It was also employed, to a lesser extent, in horticulture.

By the way, Zonolite never was sold in Europe or other continents: it was strictly a North American commodity.

Following the discovery of the presence of asbestos fibers in the vermiculite it produced, the Libby Mine closed in 1990 (in fact, little Zonolite was distributed after 1980). To date, no other vermiculite mines have been found to contain asbestos and periodic tests are done to make sure it stays that way.

As a result, you can safely use any growing mix presently sold that contains vermiculite and be sure it is asbestos-free. That is, unless you have bags of potting soil dating back to before 1990 and which come from Libby, Montana… and that strikes me as being unlikely.

If you have ridden a track with 2-3 sections with ruts, sure you will be able to do them holding the bike tighter, just to overcome situations when tires grab anything in the ruts warning to ripp bars out of your hands.

It will take so much energy and focus you won't ride as aggressive the rest of the track.

You need more energy going in, you have less going out compared to a smooth track where you can charge everywhere and not having to hold on to the bars as much.

It's not the bikes or lack of packing, it's simply wet dirt. Very wet winter in most places.

In my opinion and my experience Vermiculite would have the opposite effect of what you guys are thinking.  Yes, it is an absorbent.  But in potting soil where it is mostly used, it is not used to absorb water and moisture out of pots and trays.  That would not be beneficial.  It is used to keep the potting soil from compacting and wick off moisture to keep pots and trays from generating fungus and mold.  So it keeps the soil aerated and fluffy. This allows each cell of a growing tray to have even absorption of water and keep the tops from getting hard and crusty blocking off airflow to the roots of the plant.  This aeration does not allow the perfect environment for mold and fungus to produce.  Opposite result of what you would want on a mx track that you was wanting to compact.  

Somewhat comparable is super absorbent polymer (SAP).  This white powder absorbs water 500 to 1 by weight and can even dry out wet sand. 1 pound can dry out up to 500 pounds of sand.  (Lime is 1 to 1) Sounds good, but the real world effect is opposite.  One of the common uses for SAP will describe this.  It is used in coal industry for coal processing.  In particular on the wet tailings conveyor.  Wet coal sticks to a conveyor belt and you have to use wipers ect. to keep the belt clean.  This also creates a pile of coal that periodically needs cleaned up and wet coal is a nightmare for transportation.  One of the solutions to prevent this is to feed (sprinkle) SAP onto the wet coal that is ridding the conveyor.  By the time it is mixed in with the coal (from the bounce of the conveyor) and goes off the end of the conveyor it is the constancy of light fluffy cake batter.  NOT dried out bricks like you would imagine.  The effect is the opposite.  

Turning soil into cake batter is not the answer for an mx track.  In my opinion, the reason lime works on an mx track is because it turns the soil into something that is more of a texture of a clay based soil which will compact really well.  I also the believe the reason there was a problem at the one race was because of ignorance.  Some dipshit had the idea of more lime the better and created a toxic high acidic environment.    

I'm sorry but the simplicity and wit of this comment really made my day.

Killed it.

Dartfish + heavier bikes + traction control = ruts