# Inslope turns help needed



## auditunerb5 (Dec 29, 2006)

I am not a big fan of out sloped turns. From a flow perspective you typically need to slow for the turn. There also seems to be some erosion issues due to braking. 

Any advice on properly building an inslope turn that keeps that flow and fun but manages drainage and keeps maintainance to a minimum so the land manager is happy.

I imagine grade reversals before the entry and after the exit would be a good start?


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## auditunerb5 (Dec 29, 2006)

No help on this one?

Anyone use a french drain in the berm? Anything innovative or interesting going on with these turns?


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## Fattirewilly (Dec 10, 2001)

auditunerb5 said:


> No help on this one?
> 
> Anyone use a french drain in the berm? Anything innovative or interesting going on with these turns?


I've looked for a link and I'm coming up empty. I'll keep looking or someone will throw up an illustration. This board a little lower on traffic than other parts of MTBR.

I'll say that at the bottom of the turn, the french drain location you'd probably pick, wouldn't need a french drain because the berm would be finished and you'd be back on a benched side slope. You wouldn't build a berm so that it caused a puddle, if you are, there's usually something else wrong in your design.


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## Skookum (Jan 17, 2005)

The problem with your question is it's pretty vague. In that where on a hill slope are you putting in an inslope.  You can do enough grade reversals to make any turn right. The only problem is when you route the turn in a dip. That should be avoided at all costs, unless you are willing to do something like create a french drain kind of thing. But that will fill up with crud. What mt. bikers have done to some of these mistakes on some berms is create what i named a Scupper. What you do is on a berm or an inslope you create a 2 to 3' gap where the water can drain. You knock in a couple posts and behind those you stack up some logs for retention. You want to dig your posts down quite a bit so you are solid. Now you run two stringers and grab some slats boards and bridge the gap.

Mike W who is the project lead at Duthie Hill showed that to me and i explained to him that would be a roofing equivalent to a scupper drain without a pipe or circular hole. The name derived from the drains on boat decks for somewhere the deck water can escape from. He liked the name so he's calling them Scuppers now...

And if you make Switchbacks i say make them all insloped. Each corner is different, but with grade reversals placed where they need to be it's a better system so you don't have wheels actively sluffing off the bottom side of an outsloped corner.


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## slocaus (Jul 21, 2005)

Vague, yes, and posted just before the weekend when trail builders are gone building trails and got impatient on Saturday when trail builders are gone building trails. 

As Skookum states, there are so many variations. This IMBA chapter is about switchbacks, but covers the problem. On shallower slopes, we try to do a grade reversal just before and just after a turn that needs to be in sloped (or will berm from use). Where we are in CA, we have a 3 month rain season and then 9 months of dry, plus sandy soil that moves. Where the down grade into the turn gets beat up from braking, we will lay pavers, and sometimes pavers around a turn to keep it from blowing out, and yet staying flat so it will drain.


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## ebxtreme (Jan 6, 2004)

auditunerb5 said:


> I am not a big fan of out sloped turns. From a flow perspective you typically need to slow for the turn. There also seems to be some erosion issues due to braking.
> 
> Any advice on properly building an inslope turn that keeps that flow and fun but manages drainage and keeps maintainance to a minimum so the land manager is happy.
> 
> I imagine grade reversals before the entry and after the exit would be a good start?


Grade reversals before are critical no doubt. Another immediately after the turn should get "most" of the water off of the trail.

In a pinch.....if your turn/berm is really big/long and is going to sheet a lot of water, you can also place a culvert at the low spot of the turn. Culverts should be the last solution because they're a lot of maintenance and really a band aid for bad design, but sometimes it's necessary. We are close to finishing a new trail that has HUGE 180 berms and we had to put a handful of culverts on it due to the sheer amount of water that will run down those.

Cheers,
EB


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## cmc4130 (Jan 30, 2008)

slocaus said:


> . . . This IMBA chapter is about switchbacks, but covers the problem.


everything seemed good in that switchback guide up until the last picture. are they serious !!?? a tight turn with no berm ? a rider will have to go very slow around that turn or risk going off the side.

it seems like some of the IMBA guides are valuing erosion concerns above rideability and fun. i'm convinced there are creative ways to deal with water erosion AND have cool, effective berms.

compare this picture









to the first picture in IMBA "_Fifteen Tips for Building Excellent Downhill Trails_" :









this is an uphill view of a 180 berm on Winter Park's "boot camp" trail:


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## cmc4130 (Jan 30, 2008)

*
Fifteen Tips for Building Excellent Downhill Trails*

http://www.imba.com/resources/freeriding/fifteen-tips-building-excellent-downhill-trails

_11. Build Insloped Turns (Berms).
Insloped turns, usually called berms by mountain bikers, help riders carry momentum through corners. Berms keep riders on the trail and, perhaps most importantly, they are fun to ride. Berms must be placed in the right spot in the trail corridor and be the correct height, length, and radius. Berms should naturally draw the rider in and should shoot the rider back out of the corner at a greater speed. If a berm doesn't feel right, don't hesitate to change its height, length, or radius so that it does its job. Berms have the potential to trap water, so it is essential to utilize grade reversals to improve drainage before and after the corner.

Berms can be as short as 1 foot and as tall as you want to go. The faster a rider enters the corner, the taller, longer, and wider the berm should be. Berms are often built too far from the turn's apex, which can cause riders to make a tighter turn in order to cut the corner. Move the entire berm toward the apex of the turn if this happens, as the fastest line through a corner should use the berm._


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## TFitz (Jun 21, 2008)

Another consideration is whether or not the trail is multi-use. Some of the berms pictured above aren't very pedestrian- or horse-friendly. Of course, horses aren't very berm-friendly either!


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## Ridnparadise (Dec 14, 2007)

I am no expert on these things, but the OP seemed to be asking about more subtle turns than park-ride berms. I am thinking slocaus is on the mark. 

Just a couple of things.., In amongst sand is ground-up sand. Larger particles (sand) move on top of smaller silt particles (like in an avalanche). If you can trap sand, then under it is silt. 

Might seem counterintuitive, but if your trail is being built, rather than maintained, you may have time to capture silt and solidify it by doing the wrong thing and building up the downslope side (maybe with stones or logs) and then removing them later after the trail base builds. Then when riders roll it in, the "berm" develops out of a collected base, hopefully bedded on rocks (ie the evil of partial benching) and allowing drainage as well as runoff.

Has anyone else tried this? Dig a pit in the outflow of a rock drain or off-slope drain and harvest it for sand (on top) and silt (below). Sustainability


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## cmc4130 (Jan 30, 2008)

Ridnparadise said:


> I am no expert on these things, but the OP seemed to be asking about more subtle turns than park-ride berms. . . . .


i do get what you mean by 'subtle' versus 'park-ride' berms . . . .but i also think it would be cool to see more xc trails designed with some of the mentality that the FR/DH/MTBMX guys have . . . . even where a park doesn't necessarily have a specifically-tailored 'extreme' trail, it's fun when xc trails incorporate berms.

i realize this offends a significant segment of the purist singletrack xc community.... but at the same time i have seen first hand how a lot of riders are really stoked on it. in my city i spent several years with the local xc club doing trail work. there are a lot of spots in one park for example that were screaming out for berms--typically a directly downgradient trail into a tight turn. or a downgradient to tight turn follwed by a climb (basically making people skid to slow down, before the turn, then have to start the climb from a slow speed).

now, my impression is that IMBA type builders would say, well that trail is badly designed in the first place if it needs a berm to work. and i get that. there would definitely be a way to have sweeping turns sidewinding down the side of the gradient so that the problem doesn't happen. BUT, i would say, on the other hand, there is something more fun about a steep section into a berm. the berm allows you to not have to slow down--and who doesn't like to lean into an occasional turn?

i'll go ahead and admit that i'm biased---my background is bmx and skateboarding before i switched to mtb. my main focus is pump tracks and dirt jumps. but i do also ride singlespeed XC.

here's an example of a downgradient trail into a turn. we (the club) built this berm (this pic was from back in 07) and the section is very fun.










here's another example.... although it's probably kinda hard to figure out. the rider comes from the top right direction then makes a left turn into a descent towards the camera. . . . in this pic, we packed clay into what was an off-camber hole, to create a little bank/berm at the top of this down section. it's a lot more fun to lean into a turn-to-drop-left than what was there before.










Here's another example of some berms the club worked on. There was a downhill section into a berm that sent you back up hill. We decide to add a second berm and make an S. Some might say that S berms are only for pump tracks, dual slalom or freeride-ish trails.... but why not XC too?

















Same berm a few years later. Very little, if any, maintenance in the interim:









In this kind of situation, you see the typical standing water problem. Debris of a tiny "natural berm" stops water from flowing off the trail. The mud puddle causes people to widen the trail by riding around it. .. . . . 









My impression of the IMBA guideline is to "de-berm" i.e. slightly outslope or off-camber the turn so that water drains outwards. However, to my mtbmx brain that's a horrible flow-killer and lost opportunity--what I would love to do would be the opposite. Build UP the entire path around that turn and bank it into a berm; let the water drain inwards. Use dirt from inside the turn to build the berm--not a weird hole, just 6-12" down over a large area. Central Texas doesn't rain enough to have long-term issues with "where is the water going to go"--it will sit there for a day or two then soak straight down.

Here's another downgradient trail into a tight turn. Design flaw to begin with? Maybe. But, best solution IMO, is not a total re-route. It's . . . (you guessed it). . . a rad berm ! 

















Now you go downgradient . . .don't have to hit the brakes at all, and get to lean into this:









Lastly . . . we did this left-turn bank/berm back in '06. Similarly, it's at the bottom of a downgradient, where previously people skidded into a turn. Now you just cruise around the turn to the left. 









Some people might say that a flow trail means using sweeping turns so you don't have to do "fixes" like berms.... I would say the opposite. Go ahead and do tight turns and plan for berms and you'll have a very fun trail. I frequently see trail runners running the berms too and getting stoked. And there's no horses in this park, so not an issue.

This one was built before I met up with the club. Downgradient into a tight 180 turn then back up-gradient: 









Here, there was what was in essence a natural tabletop. Up slope to flat to down. Only the "landing" was a tangle of roots rocks and holes. We re-packed clay on top of it for a smooth "landing." Even though people aren't jumping it, having smooth short declines like this lets people "pump" the natural ups and downs. Pump-track-ish . . . but on an xc trail. 









anyway, I love to hear/see what kind of stuff yall have done that is a little outside the box. ..... (or who knows, maybe yall hate these kinds of elements on trails...?) later !


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## auditunerb5 (Dec 29, 2006)

*Follow up and report*

Background: City Park, plan was to reroute a fall line trail with only one side of the hill to work .

Here is what we ended up with:

Three turns (S shape) on a 1000' run with an average grade of 4%

We built a french drain on the down slope side of the turn that drains across the bottom. We wrapped the gravel in a landscape fabric burrito to prevent silt from clogging the drain. Grade reversals above and below each turn.










Top Turn:










Middle Turn:




























Bottom Turn:



















Trail Builder no helmet test run:


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## cmc4130 (Jan 30, 2008)

auditunerb5 said:


> Background: City Park, plan was to reroute a fall line trail with only one side of the hill to work .
> 
> Here is what we ended up with:
> 
> ...


very nice !


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## Ridnparadise (Dec 14, 2007)

What a sexy turn. Love the drainage. I am guessing you don't get 100mm rain events, but even if you do it probably would sheet across the line of the trail and not pool on the berm. Would love to ride it.

cmc (sorry but that's the :smilewinkgrin: Crime and Misconduct Commission here); you are quite right, trail should be made to flow with berms and such. The hard thing is finding places where that works without consequences like ruts, pooling and loss of rider line options. The best place for manufactured berms is older trails that are in need of love. If the berms are a problem too, then the trail needs to be re-routed. 

Everyone loves a great bermed turn, but unless you can create in-built drains and cope with water and rider impact, berms can just waste away. The best thing about berms (my opinion) is that they can offer an amazing and fun line. When they are everywhere though, they are either a quick fix for steep terrain, a mess due to skidding, or buffed like a baby bum and not so much a riding challenge as a routine.

No doubt though they are a trailmaker's ideal.


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## auditunerb5 (Dec 29, 2006)

Ridnparadise said:


> What a sexy turn. Love the drainage. I am guessing you don't get 100mm rain events, but even if you do it probably would sheet across the line of the trail and not pool on the berm. Would love to ride it..


We got 4" over 24 hours a week after this was wrapped up. They drained perfectly :thumbsup:


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## Ridnparadise (Dec 14, 2007)

Is it a 2 way trail or unidirectional?


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## auditunerb5 (Dec 29, 2006)

*2 way*



Ridnparadise said:


> Is it a 2 way trail or unidirectional?


Yes two way but typically bikes are going down and runners up.


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## J. Johnson (Feb 20, 2011)

(I presume you're talking about turns that connect switchbacks, right?)

There will be erosion (and therefore issues) anywhere requiring traction (application of a skidding force), including acceleration as well as deceleration, and also turning. A fully banked turn can help convert skidding into compression, but not recommended for mixed-use trails.

A grade reversal _above_ a turn can (theoretically) help reduce entry speed (and therefore skidding), but it has always seemed to me that a really effective grade reversal is so deep it will invite shortcutting. I have resolved that by making a nearly flat wide radius turn (with a substantial berm between the upper and lower legs), but requires a deeper cut into the backslope. Which the land manager may not like, but short of installing pavement that is the trade-off.


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## auditunerb5 (Dec 29, 2006)

J. Johnson said:


> (I presume you're talking about turns that connect switchbacks, right?)
> 
> There will be erosion (and therefore issues) anywhere requiring traction (application of a skidding force), including acceleration as well as deceleration, and also turning. A fully banked turn can help convert skidding into compression, but not recommended for mixed-use trails.
> 
> A grade reversal _above_ a turn can (theoretically) help reduce entry speed (and therefore skidding), but it has always seemed to me that a really effective grade reversal is so deep it will invite shortcutting. I have resolved that by making a nearly flat wide radius turn (with a substantial berm between the upper and lower legs), but requires a deeper cut into the backslope. Which the land manager may not like, but short of installing pavement that is the trade-off.


JJ

Why are fully banked turns not recommended by you for mix use trails (pedestrian/bike)?

We were concerned about skidding so we tried to manage speed with grade (avg 4-5%), grade reversals on average every 20-30 feet and a few tighter sections. We also created the entrance of each turn up gradient relative to the size of the turn ( bigger turn = longer uphill section before turn entrance)

In theory we wanted to create a trail that feels fast with bermed "climbing turns" but control speed so braking isn't as necessary to prevent erosion issues and pedestrian conflicts. It's a fine line and the results are still to be determined.


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## J. Johnson (Feb 20, 2011)

Fully banked turns serve to change direction without having to reduce speed (i.e., braking), and in principle are identical to a toboggan run. Would you want pedestrians on a toboggan run? Or be such a pedestrian?

Bombing downhill as fast as possible is a hazard to hikers. On a mixed-use trail safety requires reducing speed, not facilitating it. If you want a bomber run, it should be dedicated as such.


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## Ridnparadise (Dec 14, 2007)

J. Johnson said:


> Fully banked turns serve to change direction without having to reduce speed (i.e., braking), and in principle are identical to a toboggan run. Would you want pedestrians on a toboggan run? Or be such a pedestrian?
> 
> Bombing downhill as fast as possible is a hazard to hikers. On a mixed-use trail safety requires reducing speed, not facilitating it. If you want a bomber run, it should be dedicated as such.


This is a fair comment. Berms are not for controlling skidding or speed. They are for fun, flow and where speed can make limited terrain exciting, rather than dull. As a rider, there is nothing I dislike more than combinations of severe reverse grades and berms (speed trap to berm to speed trap). Makes the entire trail an illusion of flow and panders to safety concerns ahead of pleasure.

We are currently having a serious sludge problem with a berm under construction due to 30-40mm falling since we started it yesterday - geez it has to dry up some year soon - but the one thing we know about berms is that they must end before they cross the fall line. Or read another way, the trail must still be going downhill at the end of the berm or water will pool at the base. I only wish the scenario of terrain traps/berms became impossible because of this, but it doesn't. So inslope turns have to be built carefully and with fun in mind, not control. Fun improves safety where an inslope turn is needed.


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## J. Johnson (Feb 20, 2011)

"For fun" is generally why berms (and even trails) are built, but they also impact skidding and speed, and, as I said before, have safety implications. Part of the challenge of building good trail is looking at the whole picture (not just "fun"), and finding solutions that are good across a range of parameters.

Dips and hollows where water can accumulate should be avoided, and I am not aware of any situations where they cannot be avoided. If you are having a problem with that then perhaps it is a consequence of some other aspect of your design. I do wonder about your statement that berms "must end before they cross the fall line" (i.e., not wrap around the turn?). The photo above shows such an instance, and for sure, the drainage can be tricky, but there are ways of handling it. The main concern in such cases is that the drainage not be trapped on the inside of the turn; this can be handled by draining to a hollow _inside_ of the turn. (Or making the turn flatter; that is, less elevation change from top to bottom.)

There is also a matter of soil types. Some soils are not suitable bases for berms (which may be a consideration in routing the trail), and you may be stuck between having failed trail (washout) or a flat turn.


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## cmc4130 (Jan 30, 2008)

Did these recently.





































Austin Ridge Riders - Austin Mountain Biking Club


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## indytrekracer (Feb 13, 2004)

*Not every trail is built for you*



> My impression of the IMBA guideline is to "de-berm" i.e. slightly outslope or off-camber the turn so that water drains outwards. However, to my mtbmx brain that's a horrible flow-killer and lost opportunity--what I would love to do would be the opposite.


As we build more and more trails across the country, it is very important for riders to remember that all trails are not built specifically for them. Mountain bikers are a very passionate, but diverse trail user group.

This seems to led to riders getting all worked up, if the encounter a trail that isn't exactly what they want.

As a trail builder (IMBA or not), is seems every trail we build provides a open season for riders to criticize us. If a flow trail with in sloped turns is built then we are trail sanitizers and if a trail is built with tight turns and out sloped turns then we are not hard core enough.

Trails built with in sloped turns are great, but so is learning to ride more technically challenging trails.

To your question about how to inslope there are many ways to do an in sloped turn and there is no one right way. The best way to learn is to ride trails with good in sloped turns and stop to look at what they did or to go to work days on trails that have the types of turns you are looking for.


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## aero901 (Apr 11, 2012)

Grade reversals close to the entry/exit are a must on sloped terrain.
The "omega" shaped turn is great since it reduces additional digging needed to create reversals. Sometimes it's necessary to dig a shallow ditch between the entry/exit reversal drains to keep water from flowing back into the turn. Especially if the terrain slopes towards the corner. If the dirt from digging a ditch is good it can be reused in the berm or to build up grade reversals.

On flat terrain where water will pool on the inside of the turn, some kind of drainage is necessary or it can turn into a mud pit. Shallow ditches leading to lower ground or a french drain can be used to redirect water. I've built a few small berms in areas where collecting water was unavoidable and have used both techniques successfully. Perforated drain tile, washed gravel, and filter fabric (in fine textured soils) are needed for french drains and can be a lot of work to haul in (ie. avoid unless necessary). For french drains, a shallow sump located a few feet away and lower than the trail is also a good idea (taper the edges to prevent a hole). This will reduce water pooling on the trail if the drain clogs and further diverts water away from the trail to prevent saturation. Dirt dug to form a sump can usually be reused on the berm.


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## Cotharyus (Jun 21, 2012)

Switchblade2 said:


> I think a good question would be: when is a switchback (that takes at least five yards of dirt to build) a better choice than an insloped turn?


The answer is: When it's too steep. What constitutes too steep is going to vary some, but if you're having a hard time standing on the side of the hill, then it's time to start thinking switch-something, whether it's switch-back or switch-berm.


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## bitflogger (Jan 12, 2004)

Our private ski club has become home of the insloped turn in my area. At this point there are some funny personal smiles.

To start a whole bunch of haters have become paid members and Strava shows a whole bunch of trespassers who claim to hate the modern stuff. 

Next, it's all built on a ridge and ski slopes. Just a few seasons are showing we have fun trails that are sustainable compared to all sorts of past efforts to have fun with gravity. In the same area (neighboring property) large insloped turns are a good solution for two-way trail.

The new style of building also shows riders being savvy or daft with regards to riding skills. Some are learning to pump and fly while some just stand there. I confess to not being a natural born athlete and I've even learned to manual some of the rollers.

Like this style or not, we have growing membership, kids lessons programs that are filled, all sorts of new interest in the sport, and far more sustainable trails.

There's a lot more work to do this well than many realize. Some work in our area is done by pros now, or pros and volunteers together. Not all of what looks like flow trail, berms and roller works well. Doing it and maintaining it is a lot more work than many realize.


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## DeftJester (Apr 19, 2014)

cmc4130 said:


> *
> Fifteen Tips for Building Excellent Downhill Trails*
> 
> http://www.imba.com/resources/freeriding/fifteen-tips-building-excellent-downhill-trails
> ...


:thumbsup::thumbsup::thumbsup:


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## cmc4130 (Jan 30, 2008)

Switchblade2 said:


> . . .
> 
> I find that many riders who like riding really fast want berms on the turns. I personally don't believe the berms are necessary for climbing the trail or descending at slower speeds. If faster riders like berms to increase their descending speed I encourage them to build the berms on their own and to do the future maintenance of those berms.


That's true. But, I've also noticed that slow riders tend to ride berms slowly.

Especially where we're talking about a normal park (not lift-access flow trail), I don't think it's the case that "berms cause everyone to ride too fast."

It's a common criticism (from people who don't like berms in the first place), so that's why I'm addressing it.

Long straights actually cause people to "ride too fast."

Photos I took in 2011 in Vail.

switchback: 








relatively tight-radius berm:









Vail, Keystone and Winter Park

Keystone:
I think people really enjoy this type of thing--even in local parks that are not lift-access DH/Flow trails.









This type of big-radius wide-trail berm (at Keystone) does lead to fast speeds, for riders who want to go fast. But, it seems like slow riders tend to go slow, regardless. 









Camp Tamarancho Flow Trail:


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## cmc4130 (Jan 30, 2008)

Switchblade2 said:


> . . . I am a person who believes the users should either be maintaining the trails or they should be donating to a fund that is used to hire trail maintenance individuals like ACE or Singletrack Trails.
> . . .


Can't disagree with that!


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## cmc4130 (Jan 30, 2008)

In my opinion, there are a lot of parallels and interesting cross-influences between surfing, skateboarding, and "flow trail" . . . .


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## bitflogger (Jan 12, 2004)

cmc4130 said:


> In my opinion, there are a lot of parallels and interesting cross-influences between surfing, skateboarding, and "flow trail" . . . .


I get that but have observed riders on a flow trail just standing or sitting pretty much static. That doesn't work for me on a skate or sailboard.

That difference also seems to create riders who are "meh" over flow trail or like it. That and a huge difference in how fast they can go and the levels of thrill. To me it's a does the rider know how to pump or not.

It is very interesting when that knows how to pump or not shows up on a group ride on two trail segments that come to mind. All of a sudden people who can make you struggle and pant on flats or a climb become "get out of my way". I try to teach or encourage pumping because some are racers and to me it seems like they're not realizing how to get almost free speed. My observation is the really good racers do know how to pump.

My biggest concern with help and insloped turns these days are building our trail posses because we've invested so much in modern and improved trails at same time we've grown mileage. Earlier this season I counted 2 hours as two people moved dirt with help of the tractor to only fix two rollers. We've made miles of them in 3 years. Thus, lots of concern.


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## bitflogger (Jan 12, 2004)

Switchblade2 said:


> Sounds like the Soquel Demo trail. Cost a lot to build and takes a lot of time to maintain. Not really my cup of tea, but good to see folks steeping up and keeping those type of trails fun to ride.


It's - flow trail - popular beyond expectations. That hits home in a funny way because my wife who said she was done with the sport is more into it than ever. I hope we can have 10-25% of the donations and support that made it to not have an eroded mess in a few years.


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## Davey Simon (Dec 10, 2012)

Holy necro post batman.

My apologies


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## endo_alley (May 28, 2013)

"*Switchblade2* - I have noted in previous discussions that some trail builders spend a lot of effort building a berm on the outside edge of the turn. I assume that is to allow riders to carry a lot of speed though the turn. For me personally I don't construct berms on insloped turns. I allow the riders to improve the turn by actually riding the turn. What I personally find that over time riders actually improve the character of the turn by compacting the trail tread and creating a small on the lower outside edge of the turn.

Attached is diagram of how one might construct an insloped turn. In steep terrain I personally make the radius of the turn as short as possible so that the turn can be completed as soon as possible by at least 95% or more of the riders. 
Attached Thumbnails"

The inslope berm on a turn directs water to the inside of the turn where the bike will not ride through it. For this to work well, the grade reversals both before and after the turn need a lot of outslope. Maybe even a nick or drain in the grade reversal. That way minimal surface water travels into and around the turn. Avoid creating a puddle at the bottom of the turn. Some of these designs do not consider adequately draining water immediately before, and immediately upon exiting the turn.


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## raisingarizona (Feb 3, 2009)

J. Johnson said:


> Fully banked turns serve to change direction without having to reduce speed (i.e., braking), and in principle are identical to a toboggan run. Would you want pedestrians on a toboggan run? Or be such a pedestrian?
> 
> Bombing downhill as fast as possible is a hazard to hikers. On a mixed-use trail safety requires reducing speed, not facilitating it. If you want a bomber run, it should be dedicated as such.


Berms don't always equate to speed. You can have a tighter in-sloped corner for a abrupt directional change that isn't very fast but creates a better experience for the rider and reduces skidding. If you can throw in a nice grade reversal before the corner and a real good sight line to the exit and beyond that corner from above then you shouldn't have any conflict issues either.


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## cmc4130 (Jan 30, 2008)




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