Planet X Uncle John review

Value to get you 'cross

Our rating 
4.5 out of 5 star rating 4.5
GBP £860.00 RRP | USD $1,411.94

Our review

The deal clincher here is the price. The Uncle John makes your budget go a very long way without inflicting the drawbacks of other cheap bikes
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Planet X let you spec the Uncle John (and indeed any of their bikes) in any way you like. We requested parts that we could build into a reasonably light, but still resilient, cyclo-cross bike that wouldn’t be out of place on the race course but had all the characteristics needed to make trail time an enjoyable affair. And the package price is simply fantastic.


Ride & handling: Confidence-inspiring ride and spot-on handling makes for great fun on descents

The Uncle John has something that made us clamour to get out on it again and again. It was a hoot to take down trails we’d usually want a mountain bike with several inches of travel on, and part of that is down to the relatively tall, broad and open front-end setup.

With the bars high and wide, you have plenty of space to manoeuvre the front end of the bike beneath you as trail obstacles approach and the Uncle John allows you to assume a proper attack position, whether you’re on the hoods or in the drops. It’s confidence-inspiring and makes for great fun on both slow and fast descents.

On tamer trails it bowled along happily enough and with rack and pannier mounts would easily translate to being a winter road trainer as well as being light enough to step up to the start line, though it lacks a flattened top tube to ease carrying.

A standard 32-spoke construction makes tweaks easy to fix: a standard 32-spoke construction makes tweaks easy to fix
Seb Rogers

Chassis: Quality frame and carbon fork that belie their price

The Uncle John ’cross frame is £175 on its own and with a carbon fork up front it’s still well under what we’d consider to be the budget barrier. It’s anything but budget in terms of quality, though.

The frame has round seatstays and a rounded top tube, flattened chainstays and down tube, and triple-butted tube profiles for a flattering ride and light weight. The high-gloss red warpaint looks delicious, but chipped easily, despite being so thick that we had to scrape the dropouts to get the wheel in.

Rack, mudguard eyes and two sets of bottle bosses are all present and correct. Rear stays are kinked to increase mud and tyre room and there’s no brace between the chainstays to inhibit clearance. The headset is a traditional external affair, adding a couple of centimetres to the otherwise minimal 110mm head tube.

The rear brake’s built-in cable-stop bridges the seatstays well away from any mud clearance problems, rather than being seat-clamp mounted. But this means if you’re planning to use the Uncle John’s disc mount later you’ll be left with a redundant lump of metal sticking out of the back of your frame.

FSA’s carbon k-force compact crank is a significant investment, and the 34-tooth inner ring is a boon on steep climbs: fsa’s carbon k-force compact crank is a significant investment, and the 34-tooth inner ring is a boon on steep climbs
Seb Rogers

Equipment: Stunningly good value-for-money build kit, although A57 wheels aren’t the toughest

Shimano Dura-Ace shifters were supplied on our test version as the requested Ultegra weren’t available. They performed smoothly, but might ordinarily be considered inappropriate on a ’cross bike, which will suffer tougher love.

FSA’s carbon K-Force compact crankset is a significant investment on its own, and the 34-tooth inner ring is a boon on steep climbs as well as when winching your way through deep mud pits, where the Continental Cyclocross Race tyres gripped surprisingly well.

Shimano LX cantilevers are low profile, but will get covered in mud and there’s an assertive feel of brakes with more leverage. If we were speccing a more expensive build we’d probably plump for discs just because we can, as ’cross frames with  disc tabs are few and far between, particularly at this bargain price.

The slender Planet X perch was universally loved. With plenty of room to move back and forth as the terrain varies, and a slim profile that allows you to get right off the back without fear of disaster, it’s very comfortable as well as being a good looker.

The A57 wheelset is the lightest on test and we did manage to damage the rear rim, though it withstood plenty of other hits. Standard 32-spoke construction means tweaks are easy to fix, though setting up wide brake blocks on such a narrow braking surface is a faff.


We requested wide bars on the Uncle John and true to form it arrived with a pair of 44cm Planet X Strada shallow drops, which give as much useful room along the tops as possible.

Planet-X uncle john: planet-x uncle john
Seb Rogers

Product Specifications


Name Uncle John (10)
Brand Planet-X

Available Sizes 51 54 57 59
Rear Hub Planet-X A57
Top Tube (cm) 52.2
Standover Height (cm) 79
Seat Tube (cm) 51
Chainstays (cm) 44
Bottom Bracket Height (cm) 26.5
Weight (kg) 9.46
Stem Planet-X Superlight Team 3D Forged 4-bolt 31.8 110mm
Shifters Shimano Dura Ace 7800
Seatpost On-One Twelfty Sport layback
Seat Angle 74
Rims Planet-X A57
Rear Wheel Weight 1020
Rear Tyre Size 700x35C
Rear Derailleur Shimano Ultegra 10 speed
Bottom Bracket FSA MegaExo
Headset Type FSA Orbit X-CX
Head Angle 71
Handlebar Planet-X Strada 31.8 shallow drop 42cm
Front Wheel Weight 860
Front Hub Planet-X A57
Front Derailleur Shimano Ultegra 10 speed
Frame Weight 1820
Frame Material Triple butted aluminium
Fork Weight 930
Fork Carbon blades, alloy steerer
Cranks FSA K-Force Carbon Compact 50/34
Cassette Shimano 105 12-25
Brakes Shimano LX cantilevers
Wheelbase (cm) 101.3