The Eastern Tandem Rally organization recently wrapped up its season of road tandem rallies with pretty successful MATES and ETR rallies, the rallies themselves the subject of possible future reports. What I wanted to talk about here is the rash of incidents that resulted in three crashes and a near miss. What the incidents have in common is an underpinning of mechanical issues.
In the first, a very experienced team had no sooner set off from the host hotel at MATES when the front tire on their recumbent suffered a blowout at speed on the hill in front of the hotel. In addition to a ghastly amount of road rash incurred by the pair, the stoker landed on her hip and fractured her femur. The captain had just inflated the tire 15 minutes earlier in the parking lot to the correct inflation pressure. The brakes were correctly adjusted and the wheel and tire properly mounted. The tire just let go, there was no warning at all. This is spooky when it happens, but the best reconstruction we have is that while the tread was more than adequate, the tire was perhaps several seasons old, and had been stored off the tandem in an unconditioned garage, and only recently remounted. Turns out extended low heat is really hard on tires, the temperature attained by a summer garage can cook the bonding agents in the plies of a tire. A miniscule failure between parallel threads in a tire ply of the tire quickly puts extreme pressure on bond right next to the failure, and the plies separate like a zipper until the entire tire can’t handle it and fails, all in less than a second. Think of tires like wine – the best place to store tires is cool and dark, because they are sensitive to both heat and light, most probably ultraviolet wavelengths. Like some wines meant to be drunk young, tires can easily be aged too long, so we recommend maintaining only a minimal stock of spare tires – only buy a couple at a time. Another recommendation would be to never mount an old or used tire on a front wheel. Put new tires on the front wheel if possible. A regular puncture flat on a front tire is dangerous enough, since it’s not hard to lose control of a front-flatted tandem before you get it stopped. But an old front tire invites this kind of a blowout, and with front blowouts, especially at speed, it’s a coin toss whether you are going to kiss the pavement.
The second incident, later that same day at MATES, occurred when a team were descending a narrow, curvy back-country lane. The day had had intermittent showers, and the road was wet and potholed. Rounding the corner, the stoker unconsciously unclipped out of the Keo pedal, and her right heel caught between the chainstay and the rear wheel, breaking a spoke, the carbon sole of the shoe, and instantly locking the wheel and the transmission. Although the tire tread shredded, it fortunately didn’t blow and the sled literally skidded to a stop, fortunately upright. In this case the stoker suffered a large cut on her heel that took many stitches to close, miraculously just nicking her Achilles tendon. Subsequent inspection of the pedals revealed that the tension springs on the Keo cleats were set to the minimum. While minimal tension on cleats may be a good idea offroad, allowing you to quickly release, it’s less desirable on road bikes. Road cleats are arguably best tensioned until it becomes difficult to release them, and then eased off from there. This is particularly true for the vast majority of tandem stokers who don’t clip out at a stop sign. They don’t need to release very often, so cleat tension can be left fairly high. It also illustrates the importance of releasing from a cleat with the heel rotating outwards from the frame, rather than inwards towards the transmission. Granted, depending on the shape your ankles are in, releasing outboard may be physically painful or difficult for some. So it becomes a balancing act between that and cleat tension. And if you ever, ever choose to clip out with your heel inboard, don’t do it with the crank extending aft, towards the back of the bike. That’s the position most likely to suck a heel into the wheel.
The third incident again involved an ETR wet morning and a potholed descent. In this case, a team got caught out by downhill braking by a string of tandems ahead on the slick road. Normally overtaking on left, in this case the speed of the descent combined with the sudden realization that, even with the brakes on full, the tandem was running out of road. The overtaking team was forced into the right ditch, with a resulting crash that fractured helmets but [apparently] nothing worse than the stoker’s black eye, facial bruises and assorted road rash. [Subsequent to initial writing, it was reported the stoker had sustained a significant concussion and was out of work, and off the bike for six weeks or more. The bike also required repair. -Ed.] The captain reported that the brakes, a set of high-end side pulls, didn’t suffice to slow the machine. A combination of factors resulted in the poor braking. The rims were wet, which decreased braking effectiveness. And in this case, the person who pulled the tandem out of the ditch after the crash reported the rear brake was found with its quick release lever open. In this position, the brake works, but the amount of available cable travel is significantly less before the brake lever bottoms out against the handlebar. If that happens, no amount of additional pulling generates any more braking.
The fourth incident was the most spectacular, and while no injury resulted, it was only by the grace of God and a break in the traffic that tragedy was averted. This ETR rally team was finishing the ride, descending a pretty, classic Eastern ridge: a wooded, moderately steep, twisty hill where the road bends into a blind right that suddenly tees out on the rural, busy Old Mine Road. Again this was a tandem equipped only with rim brakes, in this case a pair of linear pulls on 26” wheels. The captain slammed on the brakes full, and whizzed through the stop sign and clean across Old Mine Road, the uncontrolled main road athwart the bottom of the tee. They were going so fast that they didn’t stop for 50 yards down a farming track that fortuitously opened into the cornfield before them. The Old Mine Road is named for…you guessed it…mines. Mine roads attract dump trucks; lots of them, in fact, were whizzing by that afternoon. Only a matter of luck kept this team from becoming a new hood ornament.
In this case, the tandem wheels had just been rebuilt by the proverbial local bike shop, who simply didn’t know what they were doing. Unfortunately the tandem team didn’t have the mechanical background to catch the bike shop’s errors. The front wheel had been rebuilt with a slightly narrower rim, which in itself was not a problem, but no adjustment had been made to the front linear pull brake. As a result, with the brake on full, the noodle cable housing stop on the right linear brakearm had fetched up against the cable stop on the left brakearm. Essentially, the brake housing was metal-to-metal and no amount of additional muscle was going to apply the slightest more brake force. Back at the ETR ride start, the shade tree mechanics adjusted the spacers under the brake pads to effectively move the brake pads inboard, fixing the problem in five minutes.
The rear wheel had no five-minute fix. A quick look at the new wheel revealed that the bike shop had rebuilt the wheel with a disk brake-only rim mounted on the hub with no threads on the left side, so there was no way – ever – to mount a disk brake on it. For those not familiar with them, disk brake-only rims by design have no braking surface built into the rim, hence there was no place for a rim brake to grab against. They are built this way on purpose, since they are designed for bikes with disk brakes alone. But it’s criminally negligent, in my mind, for a bike shop to lace up a disk brake-only rim on a hub with no disk brake rotor mount. What were they thinking? Needless to say, the linear pull brake gained no purchase on the sides of the rim. Only a few tattered decals, shredded by the rim brakes, gave silent testimony to how scary that ride had been. This bike, with two souls on board, had no working brakes when they needed them. That evening, one of the local teams went home and snagged a loaner wheel with conventional brake surfaces at the rim, adjusted the brakes for measure, and that was that.
The first point I’d make is that mechanical vigilance is needed. Each of us is responsible for the bike and the team riding it, and a quick mechanical check is in order before you launch. Even pilots walk around the plane before takeoff. Alternately, stopping at the top of a major descent to check the brakes isn’t a bad idea. Secondly, tandemists are a widely dispersed community and need to share the word – both our enthusiasm for the sport and the mechanical details. The fine points of mechanical adjustment are not obvious to all. So it never hurts to talk about this, and it is a service to the community to lend a hand to help other teams out mechanically, particularly with the newbies. It is an even greater service to take an extra minute to talk about what you are doing, including why it is important. Teach a person to fish.
The second point I’d make is the case for auxiliary brakes on a tandem, be they drums or disks. Over the last decade we’ve seen a trend by the go-fast crowd abandoning drums and disks in favor of a pair of side pulls, invariably Dura-Ace. These are very good brakes, and have recorded some of the best scores in recently published brake tests. But let’s face it, side pull brakes are designed for skinny Euro racers on half-bikes, not your average club-cut tandem team. And it’s all a matter of the margin. If conditions are sunny and fine, the decent not too steep nor too long, the brakes properly adjusted, the extra weight and velocity of tandems may be handled. But if any little thing is amiss, either mechanical adjustment of the brake, brake shoe selection or brake wear, wet rims, an old tire or rim, a mismatch of tire and rim, excess tire pressure, well, it may all end in tears, as Phil Liggett says. I think the craze for lighter weight is starting to catch up with us as a community, and for safety’s sake, we need to step back from the brink. Our family is on board, guys.
Full disclosure: a) Mishap #2 was ours, personally. b) I have a 28 pound tandem shod only with a pair of linear pull brakes. But I’m well aware of its limitations, and we rarely take it off the flat coastal plain we call home, where the big hill is a Jersey Turnpike overpass. Anywhere it gets even moderately hilly, we strap on the touring bike, a twelve pound heavier machine, set up with dual disks, which have significantly more stopping power (and zero heat build-up in the rims) than our flatland flyer.