How to convert your trail bike into a DH friendly sled

The scenario: you love ripping it up on trails, and enjoy hammering on your trail bike for hours on end. However, after watching some bike videos, a seed is planted, and the desire to step up your technical game and ride more challenging terrain has formed. Maybe you’re ready to attempt that jump or log drop you have gone around the last dozen times you rode your local loop, so you’ve begun reading up on the whole freeride thing and scan YouTube for tutorials on acquiring new bike skills.

If you’re ready to take the next step, make it a lot easier on yourself and do it right. A riding position optimized for climbing doesn’t lend itself for jumping or technical handling. By utilizing the correct equipment and and an optimized set up, you can minimize injury and maximize your learning curve. When we originally posted this article we took a Specialized Enduro SL, a bike solidly planted in the all mountain category, and maximized its potential for use in a bike park. Here it is again, with a few additional examples of trail and all mountain bikes, converted and ready for some freeride action.

It’s all about the set up

The first and most important step in beginning your freeriding education starts here, with the proper set up of your ride. In an ideal situation, you could go out and purchase a brand new 7 inch travel freeride bike that is designed for this application. A few popular examples of freeride bikes include the Specialized SX trail popularized by freeride hero Darren “the Claw” Berrecloth, or the Trek Scratch, the bike ridden in videos by super-shredder Cam McCaul. If you have the budget to build up an Intense Slopestyle, or an Uzzi, even better.  Downhill bikes are often the bike of choice these days with trails and features aimed at high speed riding.

However, a full blown purposed built bike for gravity and freeriding applications is hard to justify for most of us. Fortunately you can still get in the game by converting your existing bike into a ride that is ready to handle the learning curve of downhill or freeride mountain biking.

Let’s assume your bike is equipped with a minimum of 5 inches of travel and falls under the all mountain or trail bike category. New bikes for the most part fall into this category; a true cross country specific bikes isn’t built for constant abuse, and while these spec changes on your bike will make it much more suitable for ski area/ black diamond trail riding, this type of riding will dramatically reduce the useful life of a XC specific bike. The geometry and construction of this style of frame will also limit its potential.

That said, if it is what you have, you’ll want to inspect it for damage and cracks regularly.  Our goal is to get you up to speed with a minimal amount of downtime, IE, hospital visits.

For this example, we’re going to assume you have a bike comparable to our test sled, a Specialized Enduro Sl. When this article was initially written, it was the latest and greatest, but at the time came with a longish 70mm stem. If you’re buying a new bike with 6″ of travel front and rear you’re probably set, aside from adding a dropper post.

If you purchased a bike on the used market, you’ll likely want to swap some components out.

Case Study: 2008 Specialized Enduro SL

Most all mountain bikes are already set up somewhat downhill friendly. This model has an 8″ rotor in the front for additional stopping power, and a 7″ rotor in the rear. The stem however, is a compromise between downhill and xc with its 80mm length- perfect for all mountain riding, but for DH/FR standards, it is a bit long, and isn’t optimized for technical handling. This bike is equipped with one of the best trail bike upgrades available, a gravity dropper adjustable height seat post. However, for bigger stunts, you will want the capability of slamming the seat down all the way. Looking at the wheels, they are relatively light, and while they have decent air volume, the tires are light weight for its class: Kenda Nevegal 2.35, front and rear. These treads are great for trails and all around, but they are known to pinch flat under aggressive moves.

This bike is already part way there, and would be suitable for most conditions- a great compromise between lightweight and downhill performance. We’re going to take it a step further though, and set it up for black diamond ski-area riding or serious freeride trails; the type of riding you’ll find at resorts like Whistler, Northstar, or Mammoth Mountain. Gravity assisted all the way, where adding weight to a bike like this will actually help build your confidence.

Cockpit/ riding position

Let’s look at the riding position first. If you were to generalize the bar to saddle relationship, you would find that your average XC bike has a bar height that is lower than the saddle. On a typical all mountain/ long travel trail bike, the relative height of the handlebar to the seat tends to be a lot closer on average. However, when you look at a downhill, freeride, or dirt jump bike, you’ll find the bar is considerably higher than the seat height. On most dirt jump bikes the seat is slammed down as low as it can possibly go- this ensures that contact with the saddle will not be a factor, and frees up space for the rider to maneuver.

All mountain and long travel trail bikes are typically sent out with a 70-90mm length stem, (*at 5’10, I ride a medium everything, and will be using a medium frame in our example- smaller or longer bikes will scale accordingly) This is a suitable length for a typical trail setup, but a less than ideal riding position when you are 6 feet above the ground on an elevated ladder. We want to be more upright, in a “ready” position at all times in this situation.

The first thing we’re doing with this bike is putting a 50mm stem on it. (we’re seeing 30mm and 40mm stems being used these days as well, but on frames designed for them) If you’re riding jumps and pure technical riding, the focus is on handling. Shortening the stem to a DH/DJ length puts your weight back, and while the top tube of the bike is still longer than a true DH or slope style ride, it will more closely emulate the riding position. We’ve also removed the Specialized suspension and gone with a Fox Talus 36, which is much more jump friendly. We’ve removed the all mountain enduro bar which at 26″ wide was a bit narrow, and installed a wider, 28″ uncut Specialized Demo DH handlebar. *(editors note: these days bars in the 760mm-785mm/ 29″-30″ are becoming more common) The additional width of the downhill handlebars will make the bike considerably easier to handle in the loose rocky sections you may encounter on the mountain, and offers additional  leverage needed to control the bike in the gnar.

The next step is to pull off the clip-in pedals and add flat pedals. A lot of trail riders learned to ride with clip-in pedals, but in order to learn proper riding technique and minimize the risk of crashing and injury, flat pedals are necessary. Yes, you will see pro BMX racers and downhill racers racing clipped in, but I guaranty that when they are off the track and riding for fun, the majority of them ride with flats. You will not see any high level riders riding skinnies, or dirt jumping clipped in regularly either. If you don’t take the time to learn the basic skills correctly, you run the risk of hurting yourself and hampering your own personal progression. It can have a steep learning curve, so invest in some sticky rubber soled shoes like the models from 5.10, and you’ll be amazed. The bonus here is that after you’ve gotten dialed on platform pedals, running your clip-ins will feel like you’re cheating.

Tire/ Wheel selection

After the pedals, we pulled the wheels and added DH wheels and tires. The wider rims and dual ply tires add weight to the bike, causing it to deflect less on rock gardens— adding a lot more control and stability. If the concept of hitting jumps is new for you, the additional rotating weight from heavy tires can be amazing. Though heavy wheels are a bummer pedaling up hills, they offer a serious amount of stability on challenging terrain. As we were setting this bike up for Northstar at Tahoe, a ski area bikepark known for big rocks and loose dirt, we went with a 2.7 in the front, as because it was the biggest the fork could handle. The bonus here is that big tires, with their additional air volume, almost feel like an inch of travel has been added to the bike. The main thing though, is the feeling of control and the hook up you’ll have in the loose rocky stuff.

When you’re learning your way through a jump line like Live wire, or A-Line, having heavier, slower rotating tires will boost your confidence. Our last step was to remove the Gravity Dropper seat post and lightweight saddle. In its place we installed a SDG iBeam post and dirt jump saddle. The iBeam system is great because it takes the broken seat rail out of the equation; it’s light, durable, and easy to set up. The main thing though is that we can now slam the seat down all the way- you’re riding downhill, and the time spent in the saddle, if you are riding with proper technique, will be considerably less. The lower your seat height is while jumping or approaching drops, the better.

We would also recommend some form of chain guide as well. If you have a limited budget, swapping the big ring with a bash guard is a good start. Running a dual ring or single ring with a chain guide is even better.

Case Study #2: 2009 Fisher Roscoe 140mm trail bike

Here is another example of a bike we optimized for DH or more aggressive riding. With this case, we wanted to retain the all mountain and trail riding capability, (and relatively light weight) while making it handle more like a freeride bike.

Here is our trail bike- a Fisher Roscoe One, fresh off the show room floor. In stock form, it comes configured with clip in pedals, and a longer stem. In this case, we did the bare minimum in modifications to get it ready for freeride use. The bars, stem, and pedals were changed out. Keeping the stock tires and wheels ended up leaving us with a bike that felt suitable for gated gravity racing. With a chain guide, it would have worked well for racing dual slalom, or even some mountain cross courses.

With the wider bars and short stem the Fisher became a very fun bike to ride. Fortunately most of today’s bikes don’t come spec’d with ridiculously long stems. Experimenting with wider bars and a shorter stem goes a long ways to increasing the fun factor of any bike.

 

Case Study #3: Trek Remedy

Our preferred stem length ranges from 40mm to 70mm depending on the reach of the bike and intended applications, but the main thing to remember is that when changing up your cockpit controls, you want to view the bar and stem as a whole. Adding a shorter stem means also selecting a wider bar.