Time is better known for pedals and high-end carbon bike frames than wheels. But the 2010 Time catalogue includes not just bikes and pedals, but also stems, bars, shoes, saddles, gloves, shoe covers, and now, wheels.
Like many companies these days, Time is branching out into high performance, prebuilt wheels, with two models: the Hi-Tense and Equal. I’ve been riding the $1500 Hi-Tense, and found it to be a perfectly good, all-purpose wheelset. While the Hi-Tense wheels don’t outperform in any one particular department, they handle everyday, all-conditions riding very well.
The primary engineering principles applied to the Time Hi-Tense wheels are (as you might guess) high spoke tension, and reduced spoke bracing angle on the non-drive side of the rear hub.
Usually, the drive and non-drive spoke bracing angles in a rear wheel are unequal, and this inequality requires different spoke tension on either side of the wheel. Due to cogset width, the hub’s drive side flange is closer to the center of the hub, which reduces the angle of the spokes bracing the rim. Drive side spokes, viewed from behind the wheel, trace a path to the rim that’s more vertical (less angled to the outside). Therefore they have to be tighter both to support the rim and provide lateral truing force.
Non-drive spokes have a higher angle out to their hub flange, which is farther outboard of the hub centerline, and thus require less tension to create equal pulling force against the drive side spokes. The net result is unequal tension on either side of the wheel, and a wheel that’s typically not as strong or stable as one with equal spoke bracing angle and tension on each side.
Well-built, traditional wheels actually work just fine, but in the quest for lighter, stiffer, stronger wheels, companies have come up with various methods for equalizing rear spoke tension. For example, rims can be drilled asymmetrically, so that drive side spokes can enter the rim farther toward the non-drive side, increasing their bracing angle. And SRAM’s new road wheels have a tall, drive side hub flange that places the spoke anchor point as far outboard as possible, again increasing the bracing angle.
All this is to help illustrate what Time is doing with the Hi-Tense wheels. Their approach is to move the non-drive hub flange inboard, toward the hub centerline, and thereby create a more equal bracing angle with the drive side spokes. (Actually, the Hi-Tense non-drive spoke anchor points at the hub are not in a flange per se, but rather thread directly in to the carbon/aluminum hub shell).
The reduced bracing angle requires very high spoke tension in order for the wheel to be adequately stiff and strong. In turn, very high spoke tension is best achieved with straight-pull spokes, because traditional J-bend spoke heads are typically not as strong and have more stress risers than straight-pull spokes.
The concept of inboard non-drive spoke placement, combined with high-tension, straight-pull spokes, was patented by wheel innovator Guy Frullani. Time has licensed and modified his design, and the Hi-Tense wheel is the result.
Time’s execution of the Frullani concept is quite nice. The hub shells are RTM (Resin Transfer Molding) carbon fiber, with aluminum interior spoke and bearing seats. The front hub axle is carbon fiber, and the rear hub axle is aluminum. The cassette body has 42 teeth with three pawls for fast, 8.5-degree engagement. In order to provide optimum support and stiffness for the more narrowly placed spokes, the oversized hub bearings are placed as far outboard in the hub shell as possible (“Wide Track” bearings).
Drive side spokes have a head and anchor in a tall, machined hub flange. Non-drive and front hub spokes thread directly into the hub shells. The spokes are threaded where they meet the rim and anchored with hidden nipples. Access to the nipples is through the tire bed, and they require a 3mm Allen wrench for truing. The spokes are bladed Sapim (20 front, 24 rear). The rims are shallow section aluminum (23mm deep in the front, and 25mm rear).
Time ships the wheels with a tool for bearing access and adjustment, as well as padded wheel bags, quick release skewers, and rim tape. My wheels weighed 640 grams for the front, 910 for the rear, and the QR skewers are 145 grams.
Time’s goal with high spoke tension was a responsive, stiff wheelset, and for the most part, they’ve achieved the goal. I found the Hi-Tense wheels tracked perfectly and exhibited no instability, flex, or wind-up that might be associated with inadequately tensioned, narrow flanged wheels. The overall sensation is stiffness, solidity and stability.
I managed about 30-35 hours of riding time over the course of two months. As in most of my tests, I rode some dirt road climbs and descents, in addition to standard lunch rides and a couple of four-hour weekend excursions. I don’t beat the tar out of bike parts, but for normal usage, the Hi-Tense wheels proved durable. They never required truing, and the silky bearings remained smooth, never loosening or developing play. The rapid freehub engagement is nice.
I ride with 25c tires, which do more to smooth out a rough road than any wheel ever will. But if I had to guess, the narrow spoke placement and high tension of the Hi-Tense wheels don’t do much in the way of vibration damping.
On a rainy ride, the rim’s nicely machined brake tracks shed aluminum shavings, more so than I typically see. While braking in all conditions was smooth and predictable, the rim material might be a little too soft and easily worn for those that often ride in adverse conditions.
For $1500, the Hi-Tense wheels are not particularly light, at 1550 grams per pair. They’re not ultra-light, snappy climbing wheels, and they are not ultra-fast, aerodynamic wheels for ripping the flats. They’re good, all-around wheels. In my experience, they’re solid, durable, stiff, and reliable — but I’ve ridden wheels fitting that description that cost half as much.
So in the spectrum of sweet road wheels, these are very nice. But in the price vs. weight vs. performance matrix, they need to lighten up before their solid stiffness translates to the snappy responsiveness that gets me to pay top dollar. [slideshow id=4]