Wednesday, April 27, 2011

Mad Fiber tubular road wheelset review

Mad Fiber's first wheels aren't the stiffest on the market, the lightest or the most aerodynamic. They are, however, a capable set of exotic all-rounders with a durable and sensible carbon fibre design. And they're priced well below comparable offerings from the likes of Lightweight, ADA, Mavic and Reynolds.

Our review samples performed impressively until toward the end of our two-and-half-month test period, when we discovered that a faulty front hub adjuster had caused the bearings to wear out prematurely. Fixing that problem would seem to be a simple matter of changing hub internals — which they have since done — so we look forward to seeing the Mad Fiber concept evolve.

Ride testing: Impressive despite problematic hub

The US-made Mad Fiber wheels are extremely light (1,075g/pr) and provide the sort of cloud-like ride that’s not normally associated with such rim depths (60mm front and 66mm rear). They're also manageable in heavy crosswinds – another scenario where deeper rims, over 30mm or so, tend to become more trouble than they’re worth. Lateral stiffness is adequate rather than outstanding, though.

The set pairs a 60mm front rim depth with a 66mm rear rim depth: the set pairs a 60mm front rim depth with a 66mm rear rim depth

The set pairs a 60mm-deep front rim with a 66mm rear

Over dirt, the Mad Fibers continued to impress. Shod with 21mm tubulars pumped up to 100psi, they rode with the comfort of a supple 25mm tire yet provided ample snap when needed. Durability of the carbon components was tested by bouncing them over dirt and smacking into potholes on some less than silky asphalt, and we had no issues. Mad Fiber don’t impose a rider weight limit and the wheels meet DIN and CEN standards.

While it doesn’t seem to affect performance, the wheels produce a loud 'whack' when you really hit something, take rough corners at speed or put a lot of torque through the pedals. This seems to be due to the non-drive spokes unloading and then snapping back. Bigger guys who rode Spinergy’s Rev Xs back in the day will remember the sound.

The only scenario where the Mad Fiber wheels failed to inspire confidence was on high-speed, technical mountain descents. They're so light that they're subject to tire or valve stem imbalance and can even be affected by how evenly glue is spread on the rim. We found they started to oscillate at 35-40mph. While we weren’t downright scared, this made us back off, while on our (heavier) Shimano's WH-7850-C24-TL control set we'd normally continue past 45mph. Below these speeds, they were fine.

The valve hole gives insight to the very compact carbon construction: the valve hole gives insight to the very compact carbon construction

The valve hole gives insight to the very compact carbon construction

Mad Fiber provide a large computer magnet to help balance the wheels and counteract this speed wobble. We found we had to run the magnet on the front wheel even when using a rear mounted speed and cadence sensor. This isn't a problem that's unique to these wheels, though – we've had oscillation on just about every wheelset we've ridden under 1,000g. Deeper-section wheels seem to be particularly prone.

On the plus side, the carbon brake track and proprietary Mad Fiber cork pads provide excellent braking, and the rims run slightly cooler than other carbon tubulars we’ve used, which will help keep the tires on during long descents (standard tubular glue loses roughly half of its strength at 70C).

The Mad Fiber branded skewers lack stiffness when compared to conventional, albeit heavier, Campagnolo or Shimano models. Our main issue with the wheels, however, was the faulty front hub adjuster on our test set. The adjustment mechanism, which is made by White Industries and operates via a tiny set screw, wouldn’t stay tight. This wasn't helped by the way the the flange on Mad Fiber’s proprietary all-carbon hub overhangs the adjustment screw.

The offending set screw on the front hub: the offending set screw on the front hub

The offending set screw on the front hub

We only became aware of the problem when the front bearings wore out, at which stage applying even moderate pressure to the front quick-release skewer caused the wheel to drag excessively. We didn't have any problems with the rear hub, but this too features a very small set screw, accessed via a hole drilled in the hub body. This presents two concerns: the limited adjustment offered by the drilled hole and fear of a fate similar to the front hub.

We contacted Mad Fiber in regards to the issue and returned our test wheels for evaluation. We've just received the set back, which they've fixed with a new end cap that offers both easier access to the hex set screw and a new axle end cap with a greater tolerance that Mad Fiber say should prevent the problem from rearing its head again. By our eye, the new cap seems to push the hex head outboard roughly 1- to 2mm. We've yet to have a chance to test the wheel with the new parts, but the bearings appear to be properly adjusted and feel silky smooth.

Mad fiber's modified end caps, which the manufacturer switched to in march:

Mad Fiber's modified end caps, which the manufacturer switched to in March

A notable first attempt

While we did have issues with Mad Fiber’s debut wheels, they seem to have gotten the tough stuff right – the design, where they've expertly capitalized on carbon fibre's strengths as a material. Fixing the problem with the front hub was as simple as changing its internals rather than a wholesale redesign.

We look forward to the addition of more models to the Mad Fiber range – we’d recommend a ‘sprint’ wheel, a deeper, more aerodynamic model and maybe a wide-rimmed classics or cyclo-cross wheel, possibly with a shallower rim profile.

Source: Road Bikes & Gear

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