Isaac Hadron GT: a carbon all-road gravel bike from €2,699
Isaac's new all-road bike is the cheapest gravel model the Dutch brand makes, with Shimano GRX 2x12 and room for 50mm tyres. On paper it deserves a British dealer, and it doesn't have one.
Somebody at Isaac has been thinking about bad weather. The Dutch brand's new Hadron GT is a carbon gravel bike with mudguard mounts, a threaded bottom bracket and room for 50mm tyres, which is more or less the list we'd write ourselves for a British winter.
Isaac files it under all-road, meaning a gravel bike that expects to spend a good share of its life on tarmac. It is also the cheapest gravel bike in the range. Prices start at €2,699 with mechanical Shimano GRX and DT Swiss wheels. The Torus, the next model up, costs €700 more with the same groupset and wheels.
The catch is that Isaac has no dealer in the UK and no price in sterling, which we'll come to.
We haven't seen a Hadron GT, never mind ridden one. What follows comes from the press release and from Isaac's own website, which turned out to be the more useful of the two.
Isaac is older than its low profile here suggests. The company says it began in 2001 making carbon forks, with Danish roots and spells in Germany and England. In 2009 the licence to the name passed to Tehava International of Geleen in South Limburg, where the Cauberg is one of Isaac's test roads. Each bike, the company says, is assembled in the Netherlands by one mechanic from start to finish, which is a nice thing to be able to say at this price.
A 45mm tyre, with space for the mud to come along. Photo: Isaac
Tyre clearance, mudguards and mounts
The frame and fork clear a 50mm tyre, by Isaac's measure. The bike arrives on 700 x 45c Goodyear Connectors, so there is a size in hand. We reviewed the Goodyear Connector as a 700 x 40c back in 2018 and found it fast on hardpack and quick to wash out in sand.
Then there are the mudguard mounts, which we'd take over the last 5mm of tyre clearance any day between October and April. Bosses on the top tube, the downtube and the fork legs take care of bags and extra bottles.
The bottom bracket is a threaded T47, so there are no press-fit cups to creak. The seatpost is a plain round 27.2mm, the rear dropout takes a UDH hanger and the hoses disappear into the headset.
It is a good-looking thing too, in a deep metallic green with orange logos and tan-wall tyres. Opal Green is the only colour, and going by the photos we wouldn't ask for another.
Two bolts for a top tube bag, and no cables in sight. Photo: Isaac
Geometry and gearing
The release talks about long days and stable handling, as releases do. This time the geometry chart agrees: a 71° head angle (70° on the XS), 435mm chainstays in every size and, in a size M, 562mm of stack, 379mm of reach and a 1,036mm wheelbase. For scale, the 3T Racemax+ WPNT race bike we covered last week has similar stack and reach in its size M and is 16mm shorter between the wheels. The Isaac should be the calmer of the two.
Both builds are 2x12, which makes sense on a bike meant for road miles as well as gravel. The cheaper bike has mechanical GRX RX610 levers and chainset with RX820 derailleurs, 46/30t chainrings and an 11-36t cassette, so the lowest gear is 30 x 36, comfortably under 1:1. The dearer one has GRX RX825 Di2 electronic shifting and 48/31t rings on the same cassette.
Either way the wheels are DT Swiss G1800s with 160mm rotors, and the bar, stem and seatpost are aluminium, the bar flared by 16°. Isaac doesn't publish a weight for the frame or for either bike, which is the one number we'd still like to see.
Pricing and UK availability
The Hadron GT costs €2,699 with mechanical GRX and €3,499 with Di2, in five sizes from XS to XL. The release says it is available now, and when we looked on 13 November the mechanical bike was in stock in every size and the Di2 bike in none.
British riders have been able to buy an Isaac before: Jungle Products took on UK distribution in 2011. Today Isaac's dealer map shows 103 outlets, most of them in the Netherlands and Belgium, and the only one in Britain or Ireland is in Garristown, County Dublin.
Isaac's webshop does list the UK among the countries it delivers to, and its prices include VAT. The ordering pages don't explain what happens to duty and VAT on a bike sent here, and a bike ordered online can't be returned, because each one is assembled to order. So get the full cost to your door from Isaac in writing before you reach for the tape measure.
We'd like to see one in a British bike shop. There is a lot of sensible bike here for the money.
The full spec and the geometry chart are on Isaac's Hadron GT page.
