Dutch/German company Isaac have a reputation for producing very light and stiff race-ready machines with prices to match. But this year they’ve entered into the highly competitive sub-£2,000 arena.
The Kaon retains the qualities of Isaac’s dearer models. It’s light – 8.4kg (18.5lb) when equipped with Shimano 105 and R500 wheels. And thanks to some of the deepest chainstays and one of the largest bottom bracket shells we’ve seen, joined to the front with a massive triangular down tube, it’s seriously taut under pedalling. Parallel 73-degree angles and a short wheelbase (99.5cm on our 58cm bike) ensure that the Kaon has a nice snappy feel to its handling.
The front end has what is fast becoming the standard of a 1 1/8in to 1 1/4in tapered head tube, joining the frame to a fork that’s slender compared with the oversized down tube and bottom bracket shell. The top tube and seatstays are slender as well, providing a little flex to help with comfort.
Over coarse Tarmac you can feel the back end working, knocking the edge off sharp impacts well, with the slender fork doing much the same up front. The Kaon isn’t what we’d call comfort orientated, though – it’s still a rock solid race machine through and through.
On roads with plenty of gravel, high-frequency vibrations do get through to the bar. It’s not enough to rattle your fillings but over long rides it can get a little wearing. Thicker bar tape or a quality carbon bar would cure it if it got too much.
It’s a similar story through the saddle – the frame is designed to take a 31.6mm seatpost, using oversized tubing to add stiffness without extra weight, but a basic aluminium post of this diameter is never going to offer the amount of flex – and therefore comfort – that you’d want for longer rides.
You can improve the situation with a carbon post. We used a Storck Comfort 260, a carbon post that’s designed to flex, which took the sting away perfectly. It’s an upgrade we’d recommend for anyone with a bike fitted with an oversized post.
The way the Isaac handles shows its pedigree, sharp to change direction and accelerate – especially when you consider the hefty R500 wheelset (albeit with good Schwalbe Durano tyres). In fact, we only really noticed the extra mass of the wheels on the climbs. Because the Kaon frame is light it feels as though you’re dragging the rear wheel on ascents rather than it propelling you.
But although climbing was steady rather than sprightly, it was never a chore thanks to the 50/34 compact chainset and 12-28 cassette out back. It’s really the ideal spread for pretty much all riding conditions. Only the super-strong rider or confident fast descender will miss the bigger lower gears.
With better wheels and a couple of upgrades down the line, the Kaon would be a fine serious race bike. Changing from the aluminium seatpost to a lighter carbon one would cure most of its niggles and turn it into a very decent proposition for distance rides. For Isaac’s first foray into more ‘affordable’ territory it’s a good machine, which we think deserves those few improvements.
The Kaon has the increasingly common 1 1/8 to 1 1/4in head tube