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J.Laverack J.ACK 1 review

3 Mar 2016

The J.Laverack J.ACK 1 has an impressive titanium frame, complemented by components from Brooks and Hunt for a classy finish.

Cyclist Rating: 
Ace wheels and a killer frame - a pleasure to ride
Hefty in the hills

Young British company J.Laverack, based in Rutland, England has set out to create a four-season titanium bike that’s built to go anywhere and do anything. But it has decided to do things a little differently. Opting to equip its entry-level build with components from mega-classy UK companies such as Brooks and Hunt already makes the J.ACK 1 a real eye-catcher. And if you’re a big fan of well-made kit, you should be in for a real treat. All of J.Laverack’s bikes are built to order, but will this one add up to more than the sum of its parts?


The J.ACK’s frame, like every other bike here, is made from aerospace-standard 3AL 2.5V titanium – which contains 3% aluminium and 2.5% vanadium, but the top tube flattens in the middle for more comfortable shouldering. Cabling is internally routed, with the exception of the front brake cable, which is fixed to the outside of a handsome Whisky fork. Cabling access points are beautifully engineered, but our bike was set up with some cable slack at the front end which slightly ruined the forward view. The first 50 frames feature a bead-blasted frame number on the wide down tube (see below), and there’s a date of manufacture neatly blasted on to the back of the seat tube. Classy stuff. The seatstays and chainstays arch towards the rear axle, providing ample clearance for the 28c tyres with mudguards (with room for 32c without), and mounts for mudguards and rack are also provided. Those curvy stays also iron out imperfections in the road. Di2 porting is also built into the frame. Steering geometry is much more aggressive than the spec sheet suggests, with our measurements providing a borderline-racy 73° head angle. A super-stable 991mm wheelbase helps to temper any nervy steering, though. The J.ACK frameset is also available separately, with prices starting from £1,500.


The J.ACK has a full complement of Shimano 105 equipment, including shifters, 50/34 chainset, front and rear derailleurs and 11-32 cassette. Unlike the Evoke, there are cable-actuated Shimano disc brakes. This cyclocross-bred CX77 system uses a dual-pad system. Each brake is independently adjustable making fine-tuning easier.

Finishing kit

Ultra-dependable PRO LT alloy is used for the 42cm compact handlebars, stem and seatpost. There’s also premium suede-effect Fizik bar tape, and topping off the 31.6mm seatpost is a sumptuous Brooks C15 saddle.


The J.ACK uses Hunt’s tubeless-compatible 4 Season wheelset, with tubeless 28c Hutchinson Sector tyres. They will accommodate 23-45c CX rubber, thanks to 
a 17mm rim bed. They’re peppy enough for climbing too.

First impression

Don’t be fooled by the bike’s all-up weight of 9.28kg; the J.ACK proves from the off what a hitter it can be, leaping out of the turns with a willingness for speed and a hunger for higher gears. Comfort levels are high and we ended our first hour on the bike without a single ache or hint of fatigue. We also spent a good half an hour poring over the detail in the frame – there’s no doubt this is the real looker of the bunch. If you buy one, you’d be well advised to buy a spare frameset just to mount on your living room wall.

On the road

For a bike that’s designed to tackle the worst of the UK’s roads, and even rip up bridleways, the J.ACK’s frame surpassed our expectations, providing a ride that’s far more direct than some titanium builds can be. But don’t think that it lacks any comfort; there’s plenty of compliance from the rear end, it’s just that this is combined with a thirst for a good hammering. A Hope PF46 pressfit bottom bracket supplies an efficient transfer of power, while the tapered head tube, attack-mode head angle and aggressive stem set-up lends a directness to front-end feel, spurring us on to our first local climb. No, this bike can’t touch the Kinesis for climbing ability, but it does give away more than a kilo to it.

Specify the J.ACK with Dura-Ace and you’d have a bike that rivals the very best titanium bikes around. That said, it will eagerly punch its way up a short climb, and has more than enough gears to grind out a longer ascent. Stopping power was there when we needed it, and brushing a few km/h off into corners was easily done, even when cranked over. Special mention goes to the Brooks C15 saddle; it looks like it’s going to destroy your backside, but it’s far more comfortable that we expected.


The 130mm tapered head tube and low set-up are the start of a love affair with cornering, and matters are only improved when you’re rolling on 28c tyres. The Hutchinson Sectors almost give the impression of riding an off-road fat bike, such is the way in which they smooth out the road below you – we spent most of our time running them at around 85psi. Their wide contact patch boosts confidence, especially on grimy back roads, although we did experience some slip from the rear tyre when climbing out of the saddle. This we put down to the tyres being freshly fitted. Hunt’s 4 Season wheels only enhance the comfort of the ride; they’re a worthy addition to any bike. 


Geometry chart
Claimed Measured
Top Tube (TT) 539mm 539mm
Seat Tube (ST) 520mm 520mm
Down Tube (DT) N/A 630mm
Fork Length (FL) N/A 400mm
Head Tube (HT) 130mm 129mm
Head Angle (HA) 71 73
Seat Angle (SA) 73 71.8
Wheelbase (WB) 993mm 991mm
BB drop (BB) N/A 67mm



3AL 2.5V titanium frame, Whisky No7 carbon fork


Shimano 105


Shimano CX77 cable discs 


Shimano 105, 50/34


Shimano, 11-32


PRO LT, alloy


PRO LT, alloy


PRO LT, alloy, 31.6mm


Hunt 4 Season


Brooks Cambium C15

Weight 9.28kg

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