WHEEL TECHNOLOGY

The wheels that come on many new tandems will last for only a year or two. And when you need to replace them with a capable pair of wheels, be prepared to shell out $300–$900. Because wheels are the most important (and expensive) item on any new bicycle, and wheels work twice as hard when used on a tandem, every Santana includes a strong pair of wheels that combine innovative design elements, tandem-specific materials, and high-quality workmanship.

TWO CRITICAL DESIGN ELEMENTS

The wheels on every Santana feature symmetric “dishless” design and widely-spaced hub flanges. Dishless wheels, a design pioneered by Santana back in the ’70s, allow spokes on both sides of a tandem’s rear wheel to carry the same load. Wide flange separation, a related characteristic, improves the spoke bracing angle to provide additional lateral strength while preventing “dynamic transfer”—momentary spoke-tension overloads that eventually will cause a rim to fatigue, crack and fail.

These two critical wheel strength considerations—wide flange separation and dishless symmetry—explain why Santana rejected the mid-’90s frame width compromise attempted by a few competitors who needed “just enough” space to equip their tandems with drum brakes and 8 cogs. Because 145mm—halfway between pre-existing single bike and tandem standards of 130mm and 160mm—was never wide enough to allow adequate spoke bracing and a dishless design, builders offering this cramped alternative can provide just one or the other. Meanwhile, Santana’s 160mm tandem standard will accommodate a wide array of advancements, including stronger and lighter wheels, additional gears and powerful disc brakes.

UNDERSTANDING WHEEL STRENGTH

While most people mistakenly count spokes, a wheel’s strength is actually determined by its geometry—best shown through a comparison of three rear wheels.

A traditional wheel is crippled by narrow right-side spoke bracing angles. Extra spokes are needed to oppose the stress allowed by a barely-adequate 17mm of lateral offset.

With Shimano’s innovative cross-over lacing, the right lateral spoke offset increases from 17 to 27mm. This seemingly small change allows spoke count to be halved—16 spokes can safely and reliably replace 32.

By increasing the right lateral offset to 43mm, Santana’s 160mm frame spacing permits an optimized version of cross-over lacing. Significantly, the right and left bracing angles are balanced—allowing spokes on both sides of the wheel to shoulder an equal share of the load. Thanks to the subtle optimizations allowed by 160mm spacing, Shimano’s tandem wheel empowers 16 spokes to do the work of 40.

TANDEM SPECIFIC HUBS

Because single-bike hubs and freewheels were never designed to withstand a tandem’s doubled torque, the rear hub on every Santana features stronger internals, disc brake capability, symmetric “dishless” design, widely-spaced flanges, 160mm spacing, and clearance for 11 cogs. The Hadley Racing hubs used on our Hadley/Velocity and Spinergy wheels are handmade just down the street from our own factory. For decades Hadley has been the most trusted name for downhill mountain bike hubs due to their precision and incredible durability that stands up to the harshest offroad abuse. Their tandem hubs use an extra thick axle to support even a loaded touring team.

ULTRA-STRONG RIMS

To combat stresses resulting from doubled rider weight and a tandem’s higher tire pressures, Santana uses the finest rims available. The special tandem rims co-developed by Santana are a bit wider than a normal road rim and substantially deeper than a typical mountain bike rim. These cutting-edge rims also have reinforced spoke seating areas (to prevent spoke pull-through), and machined sidewalls (for smooth and stable braking). Surprisingly, these uniquely proportioned rims weigh no more than the weaker rims found on other tandems.

WHEELSMITH™ SPOKES

Santana tandem wheels are built with Wheelsmith stainless steel spokes. Rear 700c wheels get Wheelsmith’s DH-13 butted spokes. These thicker-at-the-bend spokes are 34% stronger, yet just 2% heavier.

WORLD’S BEST WHEEL WARRANTY

Other tandem wheels are guaranteed only against original defects. Santana’s Wheelsmith wheels, built with higher-grade materials and to more-exacting standards, require no preventative maintenance and are guaranteed for a full two years—the longest and best wheel warranty in the bicycle industry—a valuable difference that can provide a free rebuild in the event of fatigued spokes or a cracked rim.

SHIMANO SWEET-16 WHEELS

Wanting to add a more exciting option to our handbuilt 32 spoke wheels Santana approached Shimano’s engineers to request development assistance on a lightweight set of aerodynamic tandem wheels. The California-built samples we provided had 24 spokes in each wheel. A few months later we were surprised to receive Shimano’s counter-proposal: a pair of wheels with 16 spokes. An enclosed note instructed us to install them on a tandem and, “See if you can break them.”

Believing this would be easy, at first we restricted ourselves to paved roads. But after hundreds of uneventful miles, we took them off-road. Finding a stony stair-step descent that would cave-in a normal wheel, we failed repeated attempts to break a spoke or ding a rim. During a second year of rough treatment, with the wheels still straight and tight, we decided to cheat. But with one spoke removed, the rear wheel stayed amazingly true and continued to support our 420-pound test team! After two full years of abuse, we assured Shimano that their durable design was ready for our customers.

“Not so fast” they replied. “First we must test our wheels against a known standard.”

To meet their second challenge, we air-shipped some of our legendary 160mm dishless tandem wheels to Osaka. In Shimano’s new wheel-testing lab these wheels were mounted in machines for multi-week sessions simulating thousands of miles of out-of-the-saddle sprints and climbs. In grueling head-to-head tests, Santana’s traditional 40-spoke wheels were the first to yield.

Because the test results seemed too good to be true, Shimano agreed to produce these revolutionary tandem wheels after Santana consented to the substitution of a heavier rim. Three seasons and thousands of wheels later Shimano’s now famous Sweet-16 tandem wheels have surpassed all expectations. Except in rare cases when a rear wheel’s spoke tension was ignored, this huge fleet of wheels remains trouble-free.*

More recently Shimano upgraded Santana’s exclusive wheelset. In addition to replacing the heavy disc-brake flange with universal disc/drum threading, Shimano consented to install the lighter rims that passed all earlier tests. These changes reduce the Sweet-16s weight by a third of a pound, making this aero wheelset a lightweight as well.

Now that other tandem builders offer “aero” wheels with 24 spokes, you might assume those extra spokes provide comparable durability. Actually, if you check with other builders you’ll learn their 24-spoke wheels are intended for lightweight teams without packs. The Shimano Sweet-16s are not merely cleaner, faster and better looking, they’re the only aerodynamic tandem wheels with adequate strength for heavy teams and loaded tours. To appreciate how 16 strategically-positioned spokes can outperform 24 (or even 40).

Now available as a no-cost option with our Standard Build Kit or aftermarket for $599.

*Checking spoke tension is fast and easy—no tools or experience needed. Simply “pluck” a few spokes with your bare fingers. Because all 32 spokes are initially tightened to the same specification (and front wheels invariably remain tight), a lower tone from rear spokes indicates a need for subsequent service. Further information is available here.

EMERGENCY RIM INCLUDED

Each year dozens of tours and vacations are cut short because of the tandem’s number one reliability issue—rear wheel failure. While not an everyday occurrence, if you wish to tour or travel to distant races, a busted rear rim is catastrophic enough to warrant consideration. With a single bike it’s relatively simple to reach the nearest bike shop, whip out your credit card, and buy a new rim. Even if they don’t have a suitable rim, they’ll be happy to sell you a pre-built rear wheel. Rims suitable for tandems are stocked by fewer than 5% of all bike shops. Pre-built wheels with a tandem’s 145mm or 160mm spacing are nearly impossible to find, even in a large city. Unless your tandem is equipped with an emergency rescue rim, you can cool your heels for three to four business days while waiting for FedEx to deliver a tandem’s rear rim.

Santana tandems and wheelsets come equipped with a spare rear rescue rim that’s cleverly hidden within the front wheel. Huh? When customers call Santana with an emergency request to FedEx a rear rim we tell to relax, buy or borrow a standard single bike front wheel, and scavenge the needed rear rim from their front wheel. Using this strategy any bike shop can have them back on the road at minimal cost, and within a couple of hours. Much later, after reaching home, Santana owners can rebuild the front wheel using a new rim and their original hub. The single bike front wheel can be returned, sold on craigslist or saved as a souvenir. While our solution seems obvious, you’d be surprised how many tandems come equipped with non-matching rims or a front disc brake. A travel tandem equipped with either of these shortsighted “features” is woefully deficient by design. Think we’re exaggerating? Email us for a list of couples whose vacations or anticipated races (such as Paris Brest Paris) have been saved by our spare rescue rim.