Hill climb racing is all about your power-to-weight ratio and while aero considerations come in to play on longer or faster courses, there are still potentially significant gains to be made by dropping weight from your bike.
Similarly, as hill climbs in the UK are governed by the CTT and not the UCI, the 6.8kg minimum weight doesn't apply here. You can run pretty much any bike you like, so long as it's not a recumbent and it has two brakes (or one brake if it's a fixed gear).
This makes the UK's hill climb scene a hotbed for wild lightweight tech and mad eyebrow-raising modifications, and is part of the reason why we love it so much.
Potential performance gains aside, dropping grams from your bike is also a lot of fun, and ogling the resulting builds is even more fun (and less harmful to your bank account than doing it yourself).
We were at the National Hill Climb Championships at the weekend to scope out the sauciest lightweight tech on show, and the nine bikes we picked certainly don't disappoint.
Held in Streatley near Reading, this year's nationals course ran over 0.8 kilometres with an average gradient of 13 per cent, peppered with a maximum, gut-wrenching section of 25.9 per cent.
The event's enormous 479-strong start list was also notable for the size of the women's field. A record 140 female riders lined up for this year's nationals, thanks in large to efforts of riders such as Laurie Pestana, whose campaigning saw sponsors fund the places of around 90 female riders.
Click through the nine galleries below to check out every juicy detail and be sure to let us know which is your favourite in the comments.
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Andrew Feather's 5.4kg Cannondale SuperSix
Andrew Feather (HuntBikeWheels.com) has had a perfect hill climb season, winning every single race he entered.
He also took his second win at the nationals following his 2018 victory, with a time of 2:04.86. For this year's event, he rode the same 2019 Cannondale SuperSix EVO he has raced on for the past two seasons.
Bithja Jones' 5.6kg Tifosi Mons
Bithja Jones (Pankhurst Cycles) took the win in the women's event with a time of 2:47.94 on her Tifosi Mons.
Bithja has had an equally impressive season, taking wins at Berkhamsted CC, Newbury Velo and Blazing Saddles' promotions this season.
Her 5.6kg bike is notable for its use of (in the context of hill climbing) deep Fulcrum Racing Speed wheels
Tom Bell's 5.5kg Rose X-Lite Team
Tom Bell (High North Performance) – also a friend of BikeRadar and semi-regular contributor – took second in the men's event with a time of 2:05.93.
He rode a Rose X-Lite Team that, notably, was fitted with a pair of Shimano XTR SPD mountain bike pedals. Click through the gallery above to find out why!
Hamish McDougall's 5.3kg Dolan Seta
Hamish McDougall (Team Lifting Gear Products/Cycles In Motion) possesses two notable things – one of the best/angriest pain faces of any hill climber we have come across and this wonderfully uncompromising fixed gear hill climb bike.
Built around a Dolan Seta track frame, Hamish ran a 39×19t gear on the day for the 13 per cent average gradient climb, which included pitches up to 25 per cent. Perhaps that explains the pain face.
Mary Wilkinson's 7kg Vertex SLR
Mary Wilkinson (Yorkshire Road Club) came second in the women's event aboard this ~7kg Vertex SLR.
As well as running an interesting mix of 10-speed era Shimano Dura-Ace and Ultegra components, Mary also opted for a grippier rear tyre, which was a wise choice because riders in the latter half of the event suffered from heavy rain showers.
Josh Coyne's 5.5kg Cube Litening
Josh Coyne's (Bpm Coaching) 5.5kg Cube Litening is one of our favourite bikes from the day.
The super-clean build features all sorts of interesting tech, with the Profile Svet TT bull horn bars being a particular highlight.
Marcus Cram's sub-5kg Sarto Asola
Marcus Cram's (Blaydon CC) sub-5kg custom Sarto Asola is one of the lightest bikes we saw on the day. Based around a 700g frame that was custom built in Italy and assembled by Backyard Bikeshop in Newcastle, the complete bike weighs under 5kg.
The ludicrously lovely boutique build and unpainted finish also goes some way to bringing the weight down.
Bexy Dew's Colnago V2R
Bexy Dew (Army Cycling) placed fifth in the women's event aboard this beautiful Colnago V2R.
Though we didn't catch a weight for the bike, it really doesn't matter – we're happy just ogling that classic Campagnolo SuperRecord EPS groupset and those tan wall tyres.
Nicola Soden's Parlee
Nicola Soden's (Datalynx-Parenesis Cycling) Parlee features some of the wildest modifications we spotted on the day.
Going as far as chopping the rear brake lever in half and removing the brake pad retaining bolts, this handsome pared-back bike is about as hill-climb specific as they come.
