BERD POLYLIGHT FIBER SPOKES REVIEW
PRICEY BUT PERFORM NICELY
Review by Robert Johnston
The general concept of bicycle wheel construction hasn’t changed too much in my lifetime: an alloy or carbon fiber rim is usually joined to an aluminum alloy hub by steel spokes. There’s been a few all-carbon offerings, and the occasional aluminum spoke along the way, but otherwise the differences have been minor. As materials continue to develop and companies look into ways to implement them, from time to time we get an idea totally out of the ordinary. Since the job of the spoke is simply to provide a tensile force that pulls the rim towards the hub, there’s a variety of non-metallic materials that could be used, but often there’s the issue of abrasion and impact damage to consider from incidents like stray sticks or a broken derailleur, which can render certain materials unsuitable for the task. Plastic fibers such as the UHMWPE used by Berd for their PolyLight spokes are one of the suitable materials, at least according to Berd. Robert tried to create the “ultimate All Mountain wheelset” by modifying his Light Bicycle AM930S and Industry 9 Hydra wheelset to use the Berd fiber spokes instead of the Sapim CX Ray steel spokes fitted, which shaved a considerable amount of weight in the process and promised to improve the damping properties of the wheel according to their blurb. Read on to learn why the build process was so arduous, and why it may have been worth it in the end.
The Berd PolyLight spokes are made from Ultra High Molecular Weight Polyethylene (UHMWPE) fibers, an advanced polymer with the highest impact strength of any current thermoplastic and abrasion resistance up to 15 times better than carbon steel. This is the same material that was made popular by brand Dyneema and has found itself into anything from ballistic vests to the ropes on cranes. It should qualify for use on a bicycle wheel then, you’d imagine. An additional benefit is a claimed 200% improvement in vibration damping compared with steel spokes, which should yield a more comfortable ride.
In fiber form, UHMWPE can exhibit strength-to-weight ratios 8 times that of high-strength steels – part of the reason why Berd’s PolyLight spokes can save over 40% in weight compared with a premium steel equivalent. For reference, 64 of Berd’s PolyLight spokes in a 260mm equivalent length weigh in at a claimed 156g, whereas Sapim claims their CX-Ray bladed spokes to weigh 272g for the same length. Length calculation for the PolyLight spokes is slightly different to a standard steel spoke, so Berd’s spoke calculator must be used to determine accurate lengths required. There is a comprehensive 178mm – 315mm length range that should fit just about every wheelset on the market. Berd offers the PolyLight spokes in black or white as standard, and also offers a custom spoke color kit to add a choice of 7 colored inks to your white Berd spokes when the wheel is built.
Berd Polylight spokes don’t require special hubs or rims, thanks to their integral eyelet at the hub end, and 14 gauge (2.0mm) stainless steel threaded connection for the rim end which mounts to the rim with a standard nipple. This steel section has a flat section built in to allow the spoke to be held with a special tool, preventing wind-up of the spokes when tensioning.
The PolyLight spokes will fit a standard J-Bend or straight pull hub, but the hub usually requires modification using Berd’s Builder’s kit that is sold separately at a cost of $92.99 if the customer wishes to build the wheel themselves. This kit should allow for many wheels to be built with Berd spokes, offsetting the initial cost. This initial cost is $8 per spoke, or $512 for a pair of 32 spoke wheels.
If you don’t want to go through the process to build the wheels with Berd spokes yourself (as I’ll explain in The Dirt section), you can ship your wheels to Berd and have their skilled technicians do it for you for $752 all-in. If you don’t have rims and hubs you’d like to use, there is also a range of prebuilt carbon-rimmed wheels available with the PolyLight spokes on Berd’s site from $1,995 to $2,195. It’s certainly not cheap to equip your bike with the Berd PolyLight spokes, but for those looking for the ultimate performance it may just be worth it. Read on to find out why.
THE BUILD PROCESS
As part of the review, I was keen to build up the test wheelset with the Berd PolyLight spokes myself so that I could report back on how easy it was; share some tips and tricks if I found any; and get a proper feel for the build quality of the product. The process went smoothly, and I ended up with the wheelset running straight and true ready to hit the trails, but it was far from easy, and rather time consuming. To want to build a Berd-equipped wheelset yourself, you’ve really got to want to save those few bucks and have plenty of time to spare. It’s much more involved than simply lacing up a metallic spoke, partly due to the different needs of the spokes where they sit in the hub, and partly due to the extended bed-in period that the fiber spokes demand.
First things first, most hubs on the market have relatively sharp edges where the spoke holes are drilled. This isn’t an issue for a metallic spoke, however it could cause a plastic fiber to abrade over time and ultimately cause your spokes to fail, so you have to use the Berd hub preparation kit to smooth out the holes prior to lacing. There’s something seriously terrifying about taking their drill bit to your expensive hubs to ream material away, but once you’ve done a couple you begin to realize it’s a fairly straightforward and low risk operation. Following both sides of the spoke holes on both hubs of the wheelset, you then use a rubber polishing bit to remove any burrs remaining, and your hub is ready to be laced.
The Berd PolyLight spokes don’t have a J-Bend as supplied, instead using the integral eyelet and either a “rod” or “tangential straight pull insert” to stop the eyelet from pulling through the hub spoke hole. To get these eyelets through each hub spoke hole, you use a wire hook and give the spoke a good tug, then open out the eyelet with an awl to let the rod fit in. You then pull the spoke tight in the direction of tension to compress the eyelet against the rod and fix the spoke into the hub. Once the spokes are all laced into the hub, you lace them up to the rim in the typical manner with the usual spoke cross patterns, with the exception of the need to prevent the spoke from winding up freely with a tool that holds the flat section of the rim connection – similar to a bladed spoke.
Once you have all of the Berd spokes laced to your rim and secured a couple of turns, it’s time to go through the tensioning process. This is where the real time is added to the wheel building operation, as the spokes bed in and stretch considerably as tension is added. You set all of the “high tension side” spokes (brake side up front, drive side in the rear) to the tension of 10 on the Park Tool spoke tension gauge, then bring the wheel into dish and true by tensioning the low tension side accordingly. You then have to repeat this process 3 times with a 24 hour wait in between to account for the spokes bedding in and losing their tension. Once you’re up to these tensions there’s a notable resistance to turning the spokes with the supplied Berd spoke tools, and their sharp edges dig into your fingers, so by the time you’ve done it for the third time in three days your hands will likely know about it. It’s frustrating and time consuming, but if you’re prepared and accept the fact then it’s not difficult nor particularly problematic. That said, if I was shelling out the cash for the spokes, then I’d very likely opt to spend the extra to have the masters at Berd do the handiwork in one of their service centers.
Once I’d earned my Berd experience the hard way, I was very keen to get the wheels out on to the trail to experience the ride. The Light Bicycle AM930S wheelset was already a firm favorite of mine for its quick acceleration and comfortable yet solid ride, so I was excited to find out if I could better it yet again, but apprehensive that the feel would be pushed too far to the flexible end of the spectrum. Much to my relief, the only changes to the ride were positive in nature.
Shaving 120g from the wheelset made a perceivable difference to the snappiness of acceleration, which may have been aided by reduced wind-up of the spokes compared with the outgoing bladed spokes. There were none of the pops or pings that you’d normally get from a newly built wheelset, in fact the initial stand-out was the overall silence of the wheelset, from slightly reduced hub noise to a quieter rumble as you roll through choppy rocks. The wheels felt to calm down the trail all around initially, which had me hopeful for the same experience when the going got extra rough.
Getting on to the descents, these quieter notions continued, with slightly less trail buzz coming through the bars and a notable sting taken off the off-axis impacts as I snaked my way down the root and rock-infested trails of my home testing ground in the Tweed Valley, Scotland. Thankfully this came without the price of reduced precision or confidence in pushing the wheels hard – the Berd spokes feel as if they hold the wheel’s structure well, giving plentiful stiffness for the harder impacts like a squared-off turn or hard off-camber compression.
Through the testing process, especially at the beginning, I was very concerned of the spokes losing their tension and the wheel then losing its structure, so I was sure to check the tension before and after each ride to monitor and adjust it if needed. Much to my surprise, following the initial building ordeal, the wheel stayed arrow-straight and the spokes held their tension amicably. The spoke rods at the hub had me uncomfortable that they’d stand up with their unrefined look, but thankfully they held strong without issue – I began to appreciate their simplicity and effectiveness once I came to terms with their suitability. There was seldom a ride that left the spokes clean at the end, so it was unsurprising that the bright white shine they had initially was stained regardless of my efforts to scrub them. If this isn’t something you dig, you could get the black spokes or use a coloring kit to add color to the white spokes, but I personally dig the stained white spokes to tell the story of the trail time they’ve enjoyed. Otherwise, there’s no sign of fatigue or fraying beyond the untidy edges that existed initially and they’ve shrugged off numerous tangles with the shrubbery and stray sticks without any complaints, so I’d be confident in their ability to survive for the long haul. The concern of breaking one of the spokes when you’re on a riding trip shouldn’t be a reason to shy away from the PolyLight spokes, since you can simply install a metal spoke in their place for a quick fix should the worst happen.
The Berd PolyLight spokes ride better all around, and seem to be plenty durable to shred on without concern. The only places they lose out to a metallic counterpart, in my opinion, are the considerably more involved build process; and that high price tag which will place them firmly out of the reach of most riders. I’m excited to see the prices trickle down over time and to enjoy riding more fiber-spoked wheelsets in the future.
The Wolf’s Last Word
Improved comfort, quicker acceleration and plentiful confidence for harder charging, the Berd PolyLight fiber spokes took my favorite wheelset to date and improved its performance further all-round. They don’t come cheap, and the build process isn’t easy if you decide to do it yourself, but if you can equip your wheels with a set then I think you’ll be very impressed.
Price: $8 per spoke (~$500/wheelset)