pumping Track 原型書(二)

主題: pumping Track 原型書(二) 周四 7月 02, 2009 10:05 pm

六.Choosing a location
You don’t need a lot of space. You can make a sweet track with as little as 20x30 feet of ground.
You can rock hard with 50x50. Odd shapes work fine. Go crazy!
The ideal site is very slightly sloped so rain drains away. If you live in a housing development,
your back yard is probably just right. Bone flat is OK.A steeper slope can be worked with.
Make sure you have permission! If it’s your back yard, sweet. If it’s someone else’s property,
promise something cool in return — like all the hot chicks who will hang out watching the pump
masters. Yeah, baby!

Read your HOA covenants. Few will say exactly,“no pump tracks,” but your neighbors can make trouble.
My old neighbors hated the fact I was having fun in the neighborhood, and so they complained to our
homeowners association.I received a letter:

“Dear Mr. McCormack,
We’ve received numerous complaints about the condition of your back yard.
You cannont rip up your lawn and build a bike track. That violates our covenants. …”
Of course, the covenants failed to say “no pump tracks.” I carefully read the covenants and crafted my response:
Let me assure you that I too am committed to maintaining the appearance and value of properties in this neighborhood.
To re-quote Section 10 of the covenants:

“… After a residence has been constructed on any lot, the remaining unpaved portion of the lot shall promptly be planted
to [sic] grass or other vegetation or covered with decorative materials, and maintained in that condition,
so as to prevent the blowing of dust and dirt from the exposed soil.”

I am in the process of xeriscaping my back yard to create a useful,attractive space that uses minimal water and chemicals.
At this time the cold weather and frozen ground prohibit further landscaping work.
When the weather warms and the ground softens, I will finish the project in accordance with the covenants.
Until that time, I will make sure any exposed dirt is sufficiently packed and/or moistened to prevent blowing dust.
I appreciate everyone’s concern for our fine neighborhood. If you Petr Hanak in Winter Park,
CO. He got permission from this landowner.need anything, please don’t hesitate to ask.
Sincerely,Lee McCormack Ha! Take that.I covered the infields with flagstone, and everything was cool.

七.Two key ideas
Smoothness. Think of a sine wave. Your pump track should have continuous curves, with smooth ups, downs,
lefts and rights. There should be no flat ground, no abrupt edges.
The whole track is a sculpture: a study in constancy and flow.
Do it right the first time: This cannot be overemphasized. The more work you put into each roller and berm,
the better it’ll ride and the longer it’ll last. Don’t rush the project.
Build each component perfectly before you move on. Pile. Pack. Water. Repeat.

八.Grading and drainage
You need to move water off the track without creating so steep a slope the track becomes hard to ride.
An overall grade of 2-3 percent is ideal. This diagram is based on a 2 percent grade.
In housing, the standard grade is 2% away from the house. A usable area can be up to about 5%.
(Source: David Ignatew, landscape architect)
Here’s an example:
The top of the track is the highest point.
The middle of the track (going lengthwise)is slightly higher than the sides.
Water sheets from the top to the bottom and from the mid line to the outside.
To keep water from pooling in the inside berms, drains carry water below .
the track to the outside. Very shallow culverts (just a few inches deep,with soft edges)
will water along the surface without creating a hazard.

九.Do it French style
If you have a flat yard, and especially if you use your own dirt, water will want to collect in the low spots.
Dig deep ditches on the insides of berms and on the sides of the troughs. Fill the ditches with gravel.
Set a grate on top, and seal the gravel with Quickcrete. Make sure the infield and the track drain toward your French drains. Sweet!

十.Watering
Your pump track will need water. You’ll use a lot of water in the building phase,
and the track will need regular watering to set up a hard surface and to keep dust down.I suggest:
A hose – Essential while you’re building, and acceptable for maintenance.
Sprinklers – Excellent for maintenance. You can set a timer so the track gets 15 minutes of water at 5 a.m. Sweet!
Pump tracks need water the way plants do. In the beginning, water your track every time you ride.
Get it wet, let it dry most of the way, then ride!Over time the riding surface will pack as hard as rock.

十一.You’ll need these tools
Earth-moving equipment – To place the dirt in rough piles. Or see below.
Round-bladed shovel – Spend at least $50 on a good one. You and this shovel will become best friends. Or worst enemies.
Tamper, sod roller, ATV, feet, etc. – To compact the dirt.
Tape measure – If you’re the kind of person who washes his hands a lot. Measure twice, dig once!
Giant compass – A stake and rope to mark turns, if you’re as compulsive as I am!
Water – The key to a durable, fast track.
Patience – This is a major project! No matter what, building a track is a very physical endeavor.
By the time you build the track, you’ll be strong enough to ride it.

十二.Let’s talk dirt
OK, are you going to use your own dirt (let’s call it endemic so we seem smart),
or are you gonna import dirt? Each has its advantages:
Endemic dirt
- Cheap
- Easy to reverse
Imported dirt
- Maintain current grade
- Choose great soil
- Less work than digging up your yard
If you use your own dirt
Take out every rock, root and shell casing. Remove sod, or at least break it up until it mixes into the dirt.
Any chunk will cause a cave-in later on.You want perfect homogeneity, just like in American society.
If you buy dirt
Bring in some good topsoil. It’s easy to work with, sets up a great riding surface and drains well.
Topsoil or “loam” is a combination of sand, silt,clay and organic matter.
Most loam has a pretty even mix of these materials. Clay loam has a higher proportion of clay,
and it tends to pack best (and make the best tracks). SO: When you order dirt,
ask for clay loam or topsoil with some clay mixed in.
How much dirt will you need?
You’ll order soil by the cubic yard. To estimate the amount, try this:
Length x Width x Average height / 27 = Cubic yards
Multiply cubic yards by 1.3 to account for soil compaction.
To get the average height, figure half the height of your rollers and berms.
For example:
150ft x 4ft x 1ft / 27 = 22 cubic yards
22 x 1.3 = 29 cubic yards
Get more than you think you’ll need. You’ll find a use for it.

十三.Laying out your track
Post this on your refrigerator: Measure twice, dig once.
I cannot overstress the importance of planning your track. If you just start digging you WILL dig yourself into a corner,
and you’ll end up making compromises — or starting over. No fun!
You can be as creative as you like. But you’ll save serious hassle if you follow these guidelines:
No flat spots: Every square inch should tilt up, down or sideways. You can’t pump flat ground; keep it moving!
Make the berms tall and steep: You can generate close to three Gs, and to rail that hard you need a 70-degree bank.
Make the rollers low and smooth: Many builders go too tall and steep, which is very difficult to pump quickly.
Keep your rollers down to about 16 inches tall, with gradual faces.
Make it versatile: Sets of rollers can be pumped, manualed or jumped in myriad combinations. Gap jumps are cool I guess,
but that’s a different deal.
Consider drainage: So many sweet tracks become swimming pools in winter.
If you have a slope, use shallow ditches and pipes to route water off the track.
If you’re working on flat ground, dig holes in your low spots and fill them with gravel. French drain style.
Start simple: Build an outside loop first. Get that dialed, then add crossovers to multiply the options.
If you start a feature, finish it. Devote enough time each day to complete one berm, set of rollers,
etc. If you leave a feature undone, the dirt gets dry and crappy.
Do it right the first time: This cannot be overemphasized. The more work you put into each roller and berm,
the better it’ll ride and the longer it’ll last. Don’t rush the project.
Build each component perfectly before you move on. Pile. Pack. Water. Repeat.
Get ready to work: The pump track in my yard took 50 man-hours of hard labor. It was definitely worth it.
Don’t begin the Greatest Pump Track on Earth only to lose focus and end up with crap. This happens all the time.