11: Ride Testing

This is the part we've all be waiting for... riding the Slacker.

Working in a small brand in the bike industry isn’t all glitz and glamour (thankfully), but riding prototypes and progressing projects like the Slacker make all the hard work worthwhile. Testing and developing products is probably the best part of the job.

Ride Testing

Ride testing is a pretty self-explanatory part of the development, it’s the stage we move to after receiving and building prototype frames. The aim of rider testing is to evaluate the on-trail feel/performance of the bike as well as assess longevity and features of the design in the real world.

At Airdrop we have a slightly different take on the development of products. As bike riders first and foremost with a comprehensive understanding of rider biomechanics and inputs we look at everything from the rider's point of view. For us we are developing a bike to feel and ride in a certain way, that's the end goal. There's no disconnect between engineers, product managers and pro riders. And certainly none of the often-criticised 'marketing department input'. We handle it all ourselves - it's just us from start to finish. With that in mind we conduct the majority of rider testing ourselves. We do seek some feedback from a small pool of other trusted riders but the vast majority is all us. It's much easier to evaluate and understand feedback this way, and it allows us to stay focussed on what we want. There's no design-by-committee to deal with and certainly no design-by-internet. Of course we're aware of industry trends but we try to make up our own minds about these things and avoid the temptation to chase sales by jumping on the latest and greatest idea.

Big Plans

We had big plans for testing the Slacker; holidays booked to Whistler, a loose plan for an Alps trip (or trips), a summer of uplifts, a few races and days at the local. Lots of time sitting on chairlifts or huddled into the back of land rovers and hurtling down big hills. But that wasn’t to be.

The 'rona sort of turned plans on their head. Travel either wasn’t allowed or didn’t seem responsible, races were cancelled and uplifts were a write-off for much of the year. That being said though we still got plenty of riding done. Uplifts in Wales and Scotland provided the bulk with some local sessions thrown in for good measure. Days hitting big jumps and bigger holes at Revs, weekends bouncing of lumps of granite at Fort William, evenings sessioning Wharncliffe... it’s ended up being a good test for the Slacker.

Pre-Ride Jitters

That first ride is something I’m always nervous about. You have to remember that to come this far a first prototype represents hundreds of hours of work, having lived and breathed the project for months, sweating all the details, deliberating geo numbers, rehearsing kinematic scenarios, exactly how the bike should perform is by this point crystal clear. However, drawings and data can only tell you so much. The proof of the pudding, as they say, is in the eating.

It goes without saying that developing any new bike is a massive undertaking but for all of us here the Slacker feels more than that. Downhill is something incredibly close to our hearts - it’s the epitome of why we ride bikes. The Slacker project is a real labour-of-love born out of our collective passion for downhill, it's not just another bike in the range.

By this point that first ride can only be likened to meeting a childhood hero. You’ve spent hours imagining what it would be like, you’ve built up a perfect picture, rehearsed it time and time again. But now its here, clammy hands, a lump in your throat. Will it let me down? Did I cock up? What if it's shit? You can't put it off any longer, helmet fastened, goggles on, feet on the pedals, off the brakes, three pedal strokes and...

James' First Ride

For me my first ride was on home soil... Wharncliffe! They are trails I'm super familiar with, I spend most of my life in those woods after all. Home trails made sense for me, something familiar where I could focus on the bike and less on the trails, brain out and go. Conditions were pretty perfect, velcro-like dirt and a mild day made for some big grins.

The big suspension combined with grippy DH tyres and silent ride made it feel as if time had slowed

The first ride on the Slacker for me was my first time back on a DH bike in 6 months or so, if you don’t ride DH bikes often they can feel a little alien to begin with, the grippy tyres and plusher suspension give less feedback and can feel a little numb out of the gate. so I made a conscious effort to ease into it, no first run heroics. That quickly went out the window though three turns in and I'd left the trail bike in the dust. The big suspension combined with grippy DH tyres and silent ride made it feel as if had time had slowed, what had felt like light speed was now a Sunday stroll. A few more back to back runs on the same track, some suspension tweaks and confidence was growing. Dial up the body English a few clicks to deal with the extra input required on a DH bike and we were really cooking.

As first rides go this was a good one. The bike was easy to ride from the off, huge amounts of grip but never felt cumbersome. The 470mm reach for me at 6' 2" felt right from the off, the right amount of space to move in without feeling disengaged from the ride. The bike's balance felt good front to rear. Turn-in was direct and the handling was quicker than I expected. From a kinematic standpoint progression felt good, I wasn’t wallowing through the mid stroke and off the top small bump performance was ace, I did dial In a little extra low speed compression after a few hefty bottom outs but nothing unexpected at all. The ride was quiet - just the sound of tyres and dirt. For me the big stand out was cornering, once up to speed handling was sharp, direction changes were quick and the bike felt playful, the grip was there to push in the turns but end up off line on a tighter turn radius than expected and the quick handling could get you round anyhow. For me it was a reminder that DH bikes are just better.

Andy's First Ride

My first ride was very soon after we got the Slacker in the building, I had a bunch of mates from Scotland heading down to Revs for the weekend, so I thought I’d get myself booked on the uplift and go ride some DH. It was a freezing, wet Welsh day, not the most ideal conditions for riding a bike I’d never ridden before on trails I’d also never ridden before, but I was with people who knew the trails, so I put my trust in them and in our ability to design a bike that works.

You can enter a corner a wee bit more inside than normal, commit to the turn and the slacker will just rail it

First lap was down the Freeride line, a relatively mellow trail for Revs with some decent jumps and some good turns to square off, perfect for a warmup lap! First straight was just getting used to the soft, grippy tyres, the soft suspension and the feeling of less feedback from the trail when compared to a trail bike. One of the very first things I noticed was how silent the Slacker was, just the sound of tires on dirt and the suspension working. A quiet bike really gives confidence to push harder and get off the brakes a bit. A few turns in and it was all go. It’s as if your sense of speed changes when you’re on a DH bike, what is hectic, rough and fast on your trail bike feels like a gentle ride down the cycle path on a DH bike, you can just go much faster, hit things harder without really noticing just how much faster you are going.

A few setup changes and runs later and I was gaining confidence. The Slacker was fairly easy to get used to, the 470mm reach, while a bit longer than my previous DH bike gave me enough room to move in without feeling too long or cumbersome to move around.

After the inevitable session on Vision line - which the Slacker handled gracefully - it was time to get stuck into some proper DH tracks. I few back-to-back runs down the same trail so I could think less on the trail and more on what the bike was doing. The trail I chose for this was Far Side, it has a pretty good mix of flat out, rough sections mixed in with some tight, awkward turns and some jumps for my own entertainment. On the fast, straight stuff the Slacker was well balanced, stable, it didn’t feel like a runaway freight train nor did it feel so twitchy that roots or rocks were going to pitch if off line. At high speed, direction changes were quick, and the Slacker still felt playful. On the tighter, steeper turns the bike handled much better than its weight would suggest, easy to manoeuvre, turning in was quick and direct. You could just lean into the turn and the grip was there to commit.

The thing I took away from my first ride on the Slacker was its cornering ability; you can enter a corner a wee bit more inside than normal, commit to the turn and the slacker will just rail it, providing you’ve got enough air in your rear tyre to stop it from rolling off the rim! I went away hoping for many more days of riding DH on the Slacker. For me, nothing beats a DH bike on the right trails. Long live the DH bike!

What Did We Learn?

After a good few months of riding it's time to evaluate that feedback and work it in to the next generation of prototypes. As far as testing has gone things went pretty smoothly, once you get past the whole global pandemic thing. As a proof of concept we are super happy with this first version and at least from a performance point-of-view it's pretty close to where we want to be. Maybe even better than expectations. Remember - when we started this project we didn't know if we'd even get this far, so to arrive at a point where we've got a bike that's pretty dialled to ride is a big milestone.

Geometry: Sizing

For the first-generation prototypes we decided to explore the limitations of just two frame sizes, mainly to try to keep a lid on production costs. Our thinking behind this was maybe be a little idealistic but the logic still stands: the smaller the production start-up cost the more likely it would be we could get the Slacker in to production. Remember, the Slacker Project is a big move for us. Unfortunately, two sizes didn’t quite hit the mark even with the reach adjust headset.

We've been very happy with the larger size, as a park bike we feel the 470mm (465/470/475mm) reach with the three position reach adjust works well for riders 5'11" to 6'3" and right now have no desire to explore a longer size. We actually feel as soon as the wheelbase is pushed past 1270mm and up towards 1300mm you lose that park bike feel we are pursuing. This probably means riders 6'4" and above would find the fit on the small side but by offering a bike in a size to suit these riders it wouldn’t be in keeping with our desired performance criteria. By default, bigger bikes don’t handle the same and we would argue a larger bike is not a park bike, as in our mind a park bike is defined by its sharper handling and lively ride.

On the other hand the smaller size missed mark, the 440mm (435/440/445mm) reach didn’t work so well for riders 5'9" to 5'11", the feedback being they would prefer something a little longer. It also didn’t quite work out as genuine 'small' with riders 5'3" to 5'4" finding it little long combined with the DH standard 50mm stem. With the average male being 5'10" and almost 70% of the male population being between 5'7" and 6'1" it really doesn’t make sense to not have a frame that works for Mr Average. We are also conscious we want this frame to work for women and juniors alike (we don't design our bikes to be gender specific). And with the average woman being 5'5" and 70% of females falling between 5'2" and 5'7" clearly the sizing needs to be modified.

All this points to a need for more sizes and a wider reach range. Most likely 3 different sizes catering for heights from 5'3" to 6'4". Theoretically three sizes across that height range combined with the reach adjust headset would mean we are able to quite tightly bunch reach numbers giving riders a genuine chance to upsize or downsize dependant on preference, with nine different reach dimensions achievable across the range.

Geometry: Performance & Handling

We like to define certain aspects of the geometry as performance or handling. For sure the sizing and kinematics of the bike have a bearing on performance but when breaking down separate aspects of the design it's easiest to encapsulate geo numbers such as head angle, rear centre length and BB drop as handling geo.

In terms of performance geometry we're very happy with where we are right now. There was a question mark over the BB drop... would it be it too low? Testing proved that we made the right calls and the benefits appear to outweigh the negatives. Certainly, the rider's low centre of gravity between the axles aids in giving a stable centred feel in the bike and must contribute to cornering performance.

With regard to head angle we did play with offset bushes and angle adjust cups to test a few different scenarios but concluded 63° was the right number. 62.5° felt vague at slower speeds and the increased front-centre length was noticeable and detracted from the snappier handling we like. We did also try 63.5° and although we did prefer this to 62.5° we felt 63° offered a good balance between stability and agility. At 63° paired with a short-offset fork and the 435mm chain stay the bike felt balanced and poised. There are certainly situations where the slacker or steeper angles excelled but we felt 63° offered the best of both worlds.

Kinematics

We have a fair bit of experience with Horst-link 4 bar layouts and felt pretty confident in the key kinematic characteristics we had decided on. You can’t really argue with the data, those are facts. So really rider testing in terms of kinematics is just validation of our working assumptions.

There is another layer to it though and that’s how our chosen kinematic interacts with the geo on trail; what we tend to call dynamic geometry. With the correct suspension setup how would this effect dynamic geo and chassis shape? Kinematics and geo working in harmony should allow the rider to get the most out the suspension without having to make any performance compromises to adjust chassis shape.

On trail everything was pretty much as expected. We settled on a 400lb spring and damper adjustments were noticeable throughout the range of adjustments, our damper settings were fairly central with a MM tune shock, so no crazy tunes required. Off the top performance was good and followed with adequate mid and bottom out stroke without any unnecessary harshness. Support throughout the stroke allowed the rider to reap the rewards of his inputs and contributed to a playful, poppy feeling. Under braking, suspension performance remained active and consistent and didn’t require and excessive adjustment from the rider. Pedal kickback wasn’t noticeable at any point. The main takeaway from a Kinematic standpoint was that there was in fact very little to say, which in itself is a job well done (it's nice when that happens). The suspension works predictably and effectively allowing the rider to focus on the trail alone, there are no quirks to the performance requiring us to compensate with over-springing or excessive damping.

Weight

We had already identified the weight to be an issue prior to building the prototypes and were curious if this would manifest itself on trail. The additional weight didn’t feel like it was an issue when riding and didn’t detract from the playful nature of the ride. It will be interesting to see if there is any noticeable difference on trail once the Slacker has been on a diet and if that has a positive or negative effect on the ride.