Climbing Berms

[Ridnparadise]

Am I wrong, or is there a developing trend toward climbing berms over climbing turns? I mean a bermed turn draining on the inside of the riding line, where the rider is easily able to ride the bermed part of trail, rather than taking the shorter, inside line as would once be normal when climbing?

There seem to be some obvious reasons. The average speed of MTB riding is probably increasing due to contoured trail design and better bikes. Charging a climbing berm is probably easier than making a technical, slow, uphill turn. They also make sense on dual-direction trails.

A few examples and would appreciate anyone's thoughts regarding durability, rider satisfaction, alternate thoughts etc...

Yes, this is a downhill berm, but also an uphill one.



A few examples here in both directions.



Perhaps not a typical example, here is a climbing turn that reduces the vertical drop of the turn by harvesting from above and building over a rock bed below (so some water can drain through as well as off if needed), but still is slightly bermed. It is not a downhill bermed turn, as this is a steep and tight corner on a two-way trail and the downhill entry has been designed to encourage speed shedding. Once completed no legs would be seen below the shorts on the guy up top.



A similar turn shortly after construction. It looks better now. Again there is a substantial base of stone all across to the natural slope. Bruce is riding a typical line uphill.



So I ask you; where once there was evil, can one now expect pleasure?

[HypNoTic]

The very nature of a perfect Omega turn usually imply a small berm, because of your momentum, even uphill.

Yes, climbing can be fun. I still prefer downhill!

[ray.vermette]

The area looks very dry & sandy. If that's the case, inside turns (berms) make a lot of sense. Riders can take the corners with little to no braking, and as they bank through the corners, they help compress the soil. On a flat or off-camber turn, they would be braking more before the turn, and angled tires on flat turns would create a shearing force that would loosen the trail surface over time; not good if you have sandy soil.

Also, berms are just plain fun to ride.

[Ridnparadise]

Top 2 picsare in Jindabyne - less than 300mm anual rainfall and degraded granite base - much sturdier than it looks. The bottom 2 are Gold Coast - we have had 1440mm of rain this year, but only 30mm in 2 falls in the last 5 months. It will dump very soon - probably tonight by the radar.

[Oppy]

Bermed turns all the way man. I also like to have the upper quarter of the turn a smaller radius than the lower quarter. There are lots of examples out at Gap Creek if your interested or Saturday 8th December we are working on one at Daisyhill if you want to come up and see how it works. Drop me an email if you want to catch up.

Ciao Oppy

[cmc4130]

This may be slightly different than what you're talking about, but I have worked on several berms where the trail was originally cut to be going across gradient into a 90-ish degree turn up-gradient.

Previously, most xc riders would ride relatively slowly into the somewhat tight 90-degree turn, then have to do a lot of gear shifting and spinning to make it up the gradient.

I, coming from a DJ/bmx/SS-xc background, thought this could be greatly improved by putting in a berm which would allow you to use momentum from the flat straight to be carried through a berm and up the gradient.

The key is that you do not want a large radius berm. Those are better for the downhill direction. If it's a one way trail, and you want people to be able to use the berm to turn and go up hill, then you want a smaller radius turn. You can also design it using a wave-style design with a roller out so that you're using the berm as a type of step up....

I will try to find some good pics.

It's probably hard to tell from this angle, but the area the rider is entering from is lower than the exit area. So it is a berm into an up-gradient direction. (WCPT Austin):

[ebxtreme]

The grades in the pics are really mellow and can easily accommodate a climbing berm. We're currently re-routing a multi use trail that is on an extremely steep grade and, as a result, are using a climbing turn there (with the help of deadman cribbing). It just depends on where you're building.

[OscarW]

Climbing berms are what we started using in our MTB park, as we get a lot of tropical rainstorms that otherwise would just wash out all the fill we use.
We are going to have to pave some of them to prevent erosion as well. We just redid a trail that was destroyed by TS Isaac (18" of rain) which took out a section of trail. During the rebuild last weekend, we decided to try to berm the entry to prevent peeps from spinning their tires and wear out the straight climb after the berm. Time will tell how well it works.
So far the riders that can do this trail are happy with this improvement.
Obviously we don't have the elevations some of you guys have, but the principle remains the same in preventing erosion and speeding things along..

[emptybe_er]

...add a little bit of cement to the mix?

[Ridnparadise]

When I started this thread, I was not thinking of your basic omega turn, nor even a 180 degree turn. The last few posts are what I am getting at: the broader application of climbing berms - where do they work and why. Thanks for the input.

Here's another example of a climbing turn not quite on topic. I am posting it as a counterpoint and because we are building it currently. It will have a climbing berm bit near the highest point, a rocky line bit in the lower third, alternate lines and it links 3 natural platforms. It retains the platforms and that is why it cannot be a simple climbing berm. In fact it will have a few apices as well as the alternate dirt and rock lines and 4 drains. The shape will discourage speed into the corner from above, as it starts uphill between 2 trees. The dead trunk with the ribbon above the rocks will be cut to ground level and be part of the rock garden.

In this spot we could have made a climbing berm, but we didn't, because - just because.

Before







After - well, not really after, it's not finished yet







So there's an example of why not to use a climbing berm.

[Ridnparadise]

Bermed turns all the way man. I also like to have the upper quarter of the turn a smaller radius than the lower quarter. There are lots of examples out at Gap Creek if your interested or Saturday 8th December we are working on one at Daisyhill if you want to come up and see how it works. Drop me an email if you want to catch up.

Ciao Oppy

Thanks Oppy. Would love to come up, but we have such a lot going on here at the moment, I just don't have time to get away. QPWS have given us a list of tasks to get all the Nerang trails legalised. We are still working with limited volunteers and to be honest, some of us cannot leave in case the lust for distance overwhelms common sense among the remaining workerrs.

[OscarW]

...add a little bit of cement to the mix?

All the damage we had, was on the trails that were just filled up with regular dirt and not with what we use now, which is double crushed coral rock aggregate per FDOT standard. One of our guys has a contact at the quarry for the good stuff. We pay $400 per load (22-24 tons) which makes it pricey but we feel worth it. Once set up this stuff almost turns to concrete.
The way it comes to us is slightly moist which is perfect for shaping and tamping down. We bought a Plate-tamper and that has been a great asset in pounding the fill into place. Some of the riders think we are building roads now..
Our goal is not to have to come back to repair the same stuff ad nauseum. It does wear but some repairs have lasted for over a year and look like they may last a few more.

To pay for all this we have 3-4 fundraiser races per year and the local LBS are huge contributors. The more peeps ride, the more bikes they sell and service, so it is a win-win situation for all.