Time was you could take off the inside chain ring and the ‘bar tape as far as the brake levers and call it a time trial bike. Then along came the ‘low profile’ bikes – ‘velos plongeant’ the French called them, with their dropping top tubes and inverted bars.
But now, if your time trial bike doesn’t look like it came from Star Wars then you just won’t cut it.
Carbon is the universal choice of frame materiel now, and allows for much more exotic tube profiles than steel or aluminium ever did – providing it fits within the UCI 3:1 aspect ratio ruling.
On the subject of the UCI, they’ve dreamed up a nice earner in the shape of the little homologation stickers – a snip to get your frame approved at Swiss Francs 5,000.
Dirk – our spanner man from the six days – was telling me that on the eve of the team time trial he was having a bit of bother with the UCI technical staff regarding the slots in the down tube of the Topsport Mercator Merckx frames.
The UCI man was saying that he didn’t think he could let the bikes be ridden.
Then Dirk pointed to the ‘UCI approved’ sticker on the top tube . . .
On the subject of slots in tubes, it’s a recent trend, but the idea has been around a long time. Condor Cycles of London built a pursuit bike for Aussie six day star Graeme Gilmore way back in the 70’s which had tear drop slots in the front forks – the principle being that air passes through the tube rather than around.
Aerodynamics in bike design are the current ‘buzz’ – the UCI minimum weight limit of 6.8 kilograms put an end to the relentless quest for lightness; so another path has to be chosen.
One would think that frames would end up all looking the same – a wind tunnel is a wind tunnel.
But not a bit of it – take fork design, aside from the slots issue, Felt began a new trend last year when they eschewed the notion that front forks should sit as close as possible to profile of the front wheel.
After testing in the Mercedes wind tunnel (we’re told), they went down the route that rather than try to keep the air out of the space between the wheel and the fork blade, it was better to let it flow through – we first saw it on Roger Kluge’s bike at the Six Days of Berlin.
Team GB have picked up on the concept – if you check out the fork crowns on the GB team pursuit bikes from the Olympics, you’ll see that they’ve taken it to extremes.
Kris wonders if there’s another aspect – if the down tubes are perfect airfoils, then perhaps the air flow over the tube generates lift? If that’s the case then the bike would effectively be lighter and the drag on the tyres reduced.
As far as head tubes go, the Look inspired ‘external steerer’ is de rigueur with Ahead now looking ‘old hat.’
Scott’s front end is perhaps the most futuristic, but Trek’s Speed Concept still has a very slippery look all round.
BMC have the tightest solution to the front wheel/down tube interface. Even if it isn’t aero, it looks like it is – and this shot shows the integral front brake, too.
Meanwhile, Willier have gone down a different route with the forks blades running all the way up to meet the tri bars. It’s different . . .
One thing we’re not quite sure on is the the use of ‘gripper strip’ to handlebars, rather than tape, we believed that this had been outlawed by the UCI – but over at Sky they still have the ‘sandpaper look’ on the bars and tri bars.
The introduction of electric gears means a whole new range of headaches for mechanics, but there are solutions on hand.
You can now change gear with the push of a button at the same time as you brake; or use the bar end buttons on your tri-bars whilst in the crouch.
Where to put the battery is the question – the original position just below the bottle cage is out of fashion.
On the new Treks they’re under the bottom bracket; Sky’s Pinarellos have them stashed in the massive chain stays; Matt Goss’s Scott has the battery in the down tube whilst some team mates have it under the saddles on their TT bikes – the Argos mechanics simply stick it behind the seat pillar.
And whilst we’re talking about seats, we also thought that the UCI had rendered ‘gripper’ strip to saddles illegal?
But all of the stub nosed TT saddle we saw still had measures to hold the rider in place as he levers that 55 x 11.
And a bottle cage behind the saddle is ok – as long as it forms part of the structure.
Brakes used to be a simple affair back when I was a lad; you could go for Universals – or Campag if you were flush – both were side pulls which stopped you.
Or you could buy Mafac centre pulls which, when applied in the wet, did nothing – Weinmanns? Let’s not talk about those – but the side pull 500 was really light for your TT bike.
But it’s not so simple now; there’s a big debate about position and technology – Scott stand by the good old in front of the fork crown solution and say that in wind tunnel tests, that’s what’s best.
But the likes of Giant prefer to tuck the brake behind the crown with ever more convoluted cable routing. Whilst BMC, Ridley, Merckx and Trek have all gone down the ‘integral’ approach – we first spotted it on Bjorne Leukeman’s Vacansoleil Ridley in last year’s Tour.
And Le Gorille – as the French describe Andre Greipel – was riding them in this year’s Tour. However, the word is that they’re too tricky for ‘weekend spanner men’ – because they’re part of the fork a stripped thread would mean complete fork replacement.
Garmin have added a new twist with hydraulic Maguras, front and back.
The back one is mounted below the bracket – a location loathed by mechanics – and is covered by a small plastic cowl. Again, we thought that UCI rules forbade any ‘fairings’ – but possibly the argument is that the cowl is to keep muck off the calliper?
Scott mount the rear brake at the bracket, but above it, clearance on the crank is minimal but at least it’s more accessible than under the shell.
One thing which most manufacturers do seem to agree on is that the best aero effect is achieved if you bring the seat stays lower on the seat tube than the traditional position at the seat cluster.
However, some keep them tight on the wheel whilst Felt give the air plenty of room to pass through.
Rear discs are a must, but even there the technology is evolving – HED’s thinking is that the rim should be wider than the tubular to smooth the air flow over the rubber – a trend we first noticed last winter.
Deep section rims on the front depend on conditions, the windier it is, the shallower the rim; if you don’t want the bike all over the place.
But if you don’t have the legs – they all feel like a farm gate, no matter how aero.