Angerbird – Custom Build Deluxe
Reading time: 11–12 minutes
You know the situation: There are plenty of solid bikes with decent specs. With a tiny investment, you can make it fit your needs by swapping handlebar, saddle and pedals. This could be it and make you a happy fella. Or you could think about every tiny part and build a bike, which is truly yours. We from
TESTPILOT would like to take you on the journey, on the deep dive on bikes and components. Helping you understand how you also can improve your riding experience. Keep in mind – even slight chances can make a major difference. In this particular Custom-Firebird a lot of blood and sweat went into. Every part had been chosen for its particular function. Even the frame itself got a custom geometry and a unique paint job. We hope you enjoy Jens’ custom Angerbird project.
Do I want to ride an Enduro or a Trailbike? – Why not both?
The Pivot Firebird gets delivered with a regular 170 mm in the front and 165 mm in the back. It sits bold in the enduro category and is used in the enduro world series. In the portfolio of Pivot, under the Firebird, you will find the Switchblade with 160 mm / 142 mm. It bridges the gap between the trail and enduro category. While the Firebird made my home trails too easy on some days, the Switchblade felt a tad underbiked for my needs. I was looking for a bike which provided a more direct handling.
I weight about 200 lbs and have a reputation of rather taking a direct line than avoiding rocks. Corners I also ride rather committed.
With my weight of about 200 lbs and my riding style, it seems like an enduro bike might be the better fit. But as said – I was looking for a responsive bike; Therefore I decided to go with the Firebird. To make this still work for my needs, I shortened the travel in the front and the rear and adjusted the geometry.
The Frame – Make it fit to your body and the intended use
The foundation was built by the Pivot Firebird. I'm 191 cm tall, so the XL frame size works wonderfully when the trails are open and fast. When things get tight and twisty, it can become a handful. This has less to do with the reach alone than with the wheelbase. 1266 mm on the Large and 1299 mm on the X-Large doesn't sound like a massive increase; it's a 33 mm difference to be precise. But there are a few more parameters to consider.
If you compare XL and L in detail, the following numbers will stand out. The reach increases by 32 mm (493 vs. 515 mm) and the stack is 9 mm higher on the XL. These 9 mm make the bike feel even bigger. Like a pair of jeans, where the smaller size just pinches, and the larger size sits too baggy, it can be the same with bikes. So I aimed to move a large frame a little towards the X-Large. More on this later.
To slacken the head angle a little bit more for my taste, I use a Burgtec offset bushing in the shock. This reduces the installation length of the shock by 1.5 mm, which has an effect of approx. -1 degree. A bike that is lower at the bottom bracket with an offset bushing also tilts backwards. The slacker head angle is one result, but also a slightly shorter reach. I wanted a playful large and not an X-large plow truck. So I lengthened the reach to get in between and compensate for the loss of reach due to the offset bushing.
The reachset from Works Components generates an additional +5 mm of reach and also compensates for the shorter fork height I installed on the front. Compared to the zero-stack headset, the reachset sits externally and adds an extra 10 mm in height. The standard fork for the Firebird is a Fox 38 with 170 mm of travel, with an axle-to-crown height of 583.7 mm. The Lyrik, in contrast, comes in 12.7 mm shorter, at 571 mm. This means I only lose 2.7 mm in total, which doesn’t have a significant impact.
In the end, the head angle is exactly 64 degrees, though with 1 cm less suspension travel, making it 0.6° slacker than the regular 64.6°. The reachset from Works Components allowed me to extend the reach on the Large to 498 mm by an additional 5 mm. Personally, I find the seat angle on the Firebird steep enough with the standard geometry, so the slight rearward tilt doesn’t bother me.
Travel and Shock
The core idea was to build a bike that wouldn’t completely flatten moderate trails, making them feel dull. I wanted a shorter travel bike that wouldn’t squat too much under impulses from the top — like when pushing the bike through rollers and turns. Within the metric standard for shocks, introduced in 2016, there’s the option to achieve less stroke length with the same eye-to-eye measurement. Less stroke, depending on the leverage ratio, results therefore in less travel.
Firebird: 165mm travel
Leverage ratio of the standard shock: 205 x 65 || So out of 165mm travel tamed via 65mm stroke on the shock, you get a leverage ratio of 2,53846.
A 2,5mm spacer on the shock shortens the stroke to 62,5.
62,5 x 2,53846 = 158,65 mm
A custom-tuned RockShox Super Deluxe Coil was chosen to keep the rear suspension under control. Internally, it was adjusted for my weight and the riding style described.
Although the Super Deluxe features a hydraulic, adjustable bottom-out control, a slightly longer bottom-out bumper was installed on the piston rod to make the transition to the end of the travel even smoother.
Coil! But please make it adjustable
Air shocks have made significant advancements recently. The ability to fine-tune with minimal changes to PSI or by using a different volume spacers are a couple of their main benefits, making it tough to justify opting for a coil shock. So, why consider one at all?
Opting for a coil shock does mean sacrificing the fine-tuning capability through air pressure adjustments. Whether riding with or without a backpack or wanting to tweak the bike for different trails, an air shock offers much more flexibility. However, you won’t get by without a shock pump if you go this route.
I appreciate the consistent performance and feel of a coil shock, especially during hard impacts on the suspension when full travel is used.
I appreciate the consistent performance and feel of a coil shock, especially during hard impacts on the suspension when full travel is used. The more consistent rebound forces are, the easier it gets for me to handle them. I also ride with flat pedals, so maintaining continuous contact with the pedal is essential — something I can only achieve with a well-tuned and predictable rear suspension. This is especially important when riding a bike with shorter travel in rough terrain.
As mentioned above, choosing the right spring rate for a coil shock can be tricky, not just due to variations like riding with or without a backpack. An adjustable coil spring can fine-tune the suspension for different loads with ease, delivering either more grip or more pop — making it adaptable from loamy trails to jump trails with just a quick turn of a plastic spacer.
Sprindex is a very clever product that allows tool-free adjustments to a shock, not only for specific trail conditions, but also for finding the perfect spring rate in fine increments. On very steep trails, you can soften the spring by 50 lbs to sit deeper in the travel, which helps slacken the head angle and build confidence. While you can’t adjust it directly from the handlebars mid-ride, it only takes a few seconds during a quick break on alpine trails.
For maximum pop on jump trails, I quickly dial up the spring to 550 lbs, giving more support in big berms and greater resistance during takeoff compression.
The fork – less travel for a more direct handling
As a full on enduro bike, the Firebird typically comes equipped with a 170 mm fork, with the option to go up to 180 mm. Contrary to this philosophy, I went in the opposite direction with the "Angerbird," as mentioned above. Up front, I’m using a Lyrik Ultimate RC2 Charger 3 with 160 mm of travel.
"Stiffness" is a tricky term when describing bikes. More stiffness doesn't always equal better performance.
"Stiffness" is a tricky term when describing bikes. More stiffness doesn't always equal better performance.The concept behind the Angerbird is a bike with relatively short travel, and still, it should be able to handle aggressive riding similar to a full enduro by modern standards. The stiffness of the Lyrik is slightly higher than that of a Fox 36, making it a good match for the intended build. The Charger 3 has recently been updated to version 3.1, but even the 3.0 version is barely distinguishable from a stock Fox fork in terms of performance. Whether RockShox or Fox, both brands produce high-quality products that deliver strong performance on the trail.
From a consumer’s perspective, this is a great development. Not only is there a wider selection, but the competition between these brands hopefully drives prices down, which benefits riders eventually in the long run.
The Cockpit – Bar, Stem, Grips
At this point, we won’t delve into the details of the dependencies between foot and hand position. We should cover that in a dedicated article. To keep this short, I look for a specific ratio of reach and stack on my bikes. But it’s not just about the frame; I also consider pedal position, stem length, handlebar width, and bar roll. You can make a shorter bike feel "larger" with a slightly higher front end, while a longer bike can often be ridden with a slightly lower front end.
There is a relationship between a rider's height, the proportions of torso, leg, and arm length, and how one interacts with the handlebars to navigate turns or lift the front wheel off the ground. The closer you get to an ideal value and ratio between the bike and your body, the more efficiently, and intuitively, you can maneuver the bike.
Say goodbye to the spacer stack for good was the motto, and thus a 50 mm rise handlebar became the baseline for the Angerbird. Grips are a complex topic on their own; it's not just about finding a set with the right diameter. Cushioning is also an important aspect that will be discussed in more detail on this page. The ODI Rogue grips provide me with plenty of both.
Drivetrain, Crank and Chainring
One could always opt for the latest trend and choose a wireless drivetrain. Alternatively, one might argue that you need top-tier performance from a cable-actuated drivetrain. However, it’s important not to overlook how much functionality and durability have been passed down to more affordable group sets in recent years.
For shifting gears, an XT derailleur is sufficient for me. It operates smoothly and precisely, handles the occasional rock strike without losing functionality, has an adjustable clutch, and can be replaced affordably if it ever won't survive a rock strike.
For the shifter, it's important to me to be able to shift multiple gears at once more easily, which is possible in the Shimano lineup starting from the XT level. Since I prefer the ergonomics of the XTR trigger, I was willing to spend a bit more on that. The clamp version allows me to position my brake levers and shifter more freely compared to I-Spec.
A 157 Super Boost rear end means the chainring offset should be at 0 mm. The OneUp system allows for a clean look, and when it’s time to change the chainring, I don’t have to remove the crankset. I prefer not to use carbon for the latter. Just like pedals, which eventually show wear, cranks often take hits from rocks or get scuffed while pedaling.
Aluminum gives me a better sense of durability here, and the weight disadvantage over carbon? For real? While carbon cranks could offer a slightly lighter option. At 170 mm, the crank length is slightly short for my height and leg length, but it does provide me with more ground clearance.
Chainguide – Reduced to the Max
Chain guides used to be not only significantly bulkier, but also heavy and challenging to adjust. I wanted something more elegant that still provides enough security for the chain and protection against potential strikes. I chose the 77designz Freesolo. Additionally, I trimmed the excess material from the guide rail because there are currently no plans to install a larger chainring on the Angerbird.
Pedals – Needs to fit the foot, but also the trail
There is a wide range of options for flat pedals available on the market. Especially for people with larger feet, there are now significantly more choices. With a shoe size of 44 and my preference for the bulky FiveTen Impacts, I found a good match in one of these larger models, which fit me perfectly. However, on some trails, my feet can feel a bit cramped. The outer edges of the pedals often bear the brunt of this, getting scuffed up, and in the worst-case scenario, a hard hit can bend the axle or crank, or even lead to a crash.
To gain more ground clearance and reduce rock contact, I prefer pedals with a slightly narrower profile. My shoes extend about 1 cm beyond the edge, but with the stiff Impacts, this isn’t a problem.
Wheelset – No lag and the sound is something
I’m mostly a fan of a directly engaging hub. When I'm motivated on the trail, I enjoy accelerating out of corners by getting on the pedals early. When the input is translated directly, it makes for an even more fun ride. You can’t get much more direct than the 0.52° engagement of the i9 Hydra in Superboost. At the rear, it’s paired with an older EG.30 Newmen rim, which provides plenty of (aluminum) material to handle some abuse.
Many lighter wheelsets use straight pull spokes, but my focus is on products that offer long durability. I prefer longer intervals between service stops and ease of maintenance. J-bend spokes and 36 spokes make it easier for me to re-truing the rear wheel, even if they are a bit heavier.
Hub sound is essential for some riders. The Hydra is definitely on the louder side. Sometimes I love it, and other times I wish for some quiet. With the Hydra, though, it’s unlikely to be quiet!
Brakes – Getting slow fast
Brakes on a bike are a very personal matter. Everyone has their own preferences and will passionately defend their choice. There’s no right or wrong solution as long as you can safely descend steep slopes and come to a stop when necessary.
For me personally, the following points are important:
Braking power
Consistent deceleration even on long descents
Short lever travel
Lever position relatively close to the handlebars
Modulation
Easy to bleed
Long maintenance intervals
There are several brake options on the market that cover many of these points. However, if you have very specific preferences, you might want to go the extra mile and fully customize your brake setup.
The Shimano XTR 2011 lever feels comfortable for my index finger. The wide clamp provides solid support compared to the thinner, revised clamp of the subsequent generation.
Pairing this lever with a Magura MT7 caliper results in an – let's say – interesting lever ratio. Magura itself does not have a Servo-Wave mechanism in its lever unit, and the pad distance to the brake rotor is also shorter. This combination achieves a very short lever travel. It takes a bit of getting used to, but after a while, you wouldn't want it any other way.
The Trickstuff Dächle rotor also provides consistent performance on long descents, featuring a thickness of 2.05 mm, which places it in the same league as a Magura rotor at 2.00 mm. One of the nice features of the Dächle rotor is its proverbial "roof": the beveled outer edges significantly simplify wheel installation. It's a small detail, but it offers an advantage in daily bike handling. The brakes are equipped with Trickstuff 170 mm power pads, which provide an excellent bite.
Sattel – Matchy-Matchy and freedom to move
If you want to move freely on the bike, the saddle shouldn’t be in the way. It needs to be easily adjustable and have no edges where your shorts could catch on.
The SDG Bel Air fits my backside perfectly, offers no catch points for fabric folds, and the fact that it comes in a matching oil-slick look is definitely a bonus.
Dropperpost – freedom to move!
After all these years, it's still amusing how much some bikers rejected dropper posts. "Unnecessary gadget! Quick release!" In the end, this product has transformed mountain biking and has become indispensable. At the same time, dropper posts have become more reliable and offer increasing amounts of travel. The BikeYoke Revive 3.0 has an impressive 213 mm of travel, ensuring me complete freedom of movement.
In the last update of this post, the overall height was reduced. If you have a frame with sufficient insertion depth and a short seat tube, this allows for an even wider range of saddle heights. One highlight for me is the ability to perform a quick bleed. Most dropper posts remain functional for a long time and don’t sag. However, if they do, you typically have to send them in for service. With the BikeYoke you don't need to do it because you can do this trailside.
Tire choice grew – Continental
In collaboration with the Athertons and other World Cup pros, Continental introduced their entirely new Gravity tire lineup in 2022. Out of the five models designed for all conditions, the Kryptotal has quickly become a favorite in the MTB community. I’ve been testing the tire in different casings for some time, and for the Angerbird, I specifically chose the Enduro casing. Following the motto “let’s see how it will hold up...,” I deliberately skipped a DH casing at the rear and opted not to use an insert. In due course, we’ll share detailed experiences here.
Ghetto Tubeless – Oldschool SAfety
This hack seems so old by now that it often confuses those encountering it for the first time. It’s definitely more work than installing a tire insert, but I’m convinced it’s worth the effort. I'll be posting a detailed guide soon.
The short version: A tube is stretched over the rim and then cut lengthwise. The tire is mounted onto the rim while the tube extends between the rim and tire. The result is some sort of tubular tire setup, offering a bit more protection against pinch flats and reduced air loss in corners.
How we will continue?
The idea behind this bike is to have something that feels completely custom-tailored. Here and there, adjustments will be made. Once enough changes have accumulated, we’ll post an update.
Author – Jens Staudt
Height: 191 cm
Weight: 200 lbs (incl ride gear)
Riding style: With his racing background, the lines are planned, even if there is anything bigger in his way. If possible, sections will be jumped over. You should use the entire width of a trail. Others would say - uncompromising.
Motivation: A product should function carefree and for as long as possible. If you have to screw less, you can ride more. He likes to tinker and see how the bike can be optimized.