The performance-cycling world is obsessed with aero efficiency these days – and for very good reasons – but we all still love a lightweight road bike, and they don’t come much lighter than the Scott Addict RC SUB5 that has been put together by Dangerholm. As the name implies, it hits the scales at under 5kg – and that’s for a fully rideable disc brake bike with a 2×12 electronic drivetrain and 29mm tyres.
You’ve probably heard of Dangerholm before; we’ve frequently covered his work on road.cc in the past. If not, he’s a Swedish custom bike builder called Gustav Gullholm, and he’s built all kinds of exotic bikes over recent years.
The Scott Addict RC is already a light bike. The Addict RC Pro we reviewed here on road.cc last year came in at 6.58kg, for example, and the lightest Ultimate model has a claimed weight of just 5.9kg (both of those weights are without pedals).
The Scott Addict RC SUB5 by Dangerholm, though, is just 4.99kg. That weight includes everything: pedals, bottle cages, rim tape, handlebar tape, the lot. At 170mm, the cranks are short but not ridiculously short, and this is a 2x setup so you need to factor the weight of a front derailleur into the mix. He could have gone for rim brakes and ridiculously skinny tyres, but no, it’s a (highly tuned) SRAM Red E1 disc brake system and 29mm tyres.
In other words, Dangerholm hasn’t bent the rules too far here by producing a bike that, realistically, not many people would like to ride. This isn’t a hill-climbing bike that’s focused on shedding the grams with little or no consideration given to anything else, although Dangerholm has certainly worked very hard to get that weight down, and there are rider weight limits that we’ll come to later.
“Never before could you build a really lightweight bike with such performance and ride quality as you can today,” says Dangerholm. “This project is an example and testament to that statement. A proof of concept – that it’s now possible to go below the 5kg limit, all while having a truly great riding bike with all the modern performance you expect. Ready for everyday use, no shortcuts and no compromises.
“And that is where the real challenge lies. Cost aside, it’s relatively easy to reach that weight goal today, but when you’re not willing to compromise on overall performance with, for example, a 1x drivetrain setup, it becomes a bit trickier.”
Dangerholm wanted to achieve a 5kg bike with these “must-have features”:
- 2×12 electronic drivetrain with “a reasonable gearing”
- Minimum 28mm wide tyres
- Modern wide rims for overall handling and performance
- Proper and powerful brakes that allow for good descending
- One-piece aero cockpit to go with the sleek frame set design
- Real bar tape
The total weight was to include pedals, bottle cages and a computer mount. Although some of the components have rider weight limits, the idea was to keep them as high as possible.
Dangerholm calls the Scott Addict RC SUB5 “perhaps the best performing and most ‘normal’ super lightweight road bike ever”. He’s built it to his own preferred spec, so that’s not entirely surprising.
At the heart of things, the standard Scott Addict RC frameset (HMX-SL version, size L) is 630.9g (including hardware), and the fork is 282.4g (there’s a full list of component weights down below).
The Syncros thru axles were swapped for 24.7g titanium alternatives from RideNow. You’ve really got to focus on the details if you’re trying to build a sub-5kg road bike.
The 350mm seatpost and Nexum Drag aero handlebar combo are from Spain’s Darimo, while the saddle is a Gelu K3. Guess its weight. I’ll tell you: 39.2g. And it’s priced at €529.
The saddle has a maximum rider weight limit of 80kg, although if you’re heavier than that, the reinforced version that’ll take riders up to 100kg only adds an extra 10g.
“Carbon saddles often get a lot of scepticism online, but with the right shape they can actually offer very good comfort,” says Dangerholm. “The carbon surface reduces chafing as the bibs can slide more on the saddle, and in this case the wings of the saddle are super flexible.”
Brakes? They’re SRAM Red E1, although they’ve been tuned with titanium clamps from TiMaster. The brake hose nuts, brake pad pins and even the calliper bleed port screws have been swapped for titanium options too, and the brake pads were changed, and the brake rotors are Carbon-Ti X-Rotor CarbonSteel 3 with carbon fibre inner bodies.
“There are several even lighter brake rotor options on the market, but since performance and reliability are such big goals on this project, it was an easy choice to consider these extra grams well spent and go with Carbon-Ti,” says Dangerholm. “And weighing just 146.5g for the pair, they’re still very lightweight.”
The GrigioCarbonio Road T1000 crankset (170mm) weighs 256.3kg, while the Carbon-Ti X-CarbonRing X-AXS chainrings (50T and 37T) feature carbon fibre bodies to keep the weight low, and aluminium teeth.
The pedals are Wahoo Speedplay Nano, featuring titanium axles and further ti tuning to push the weight down to 150.6g. These have a maximum rider weight recommendation of 82kg.
“If required to push the limit up to 90kg, my choice would be the Time XPRO 12 SL [pedals] which would add 25g to the bike,” says Dangerholm. “Dual-sided power meter pedals would add 95.9g.”
On to the wheels…
“It wouldn’t be a true climber without some really lightweight wheels, and at 866.7g these don’t disappoint,” says Dangerholm. “They have been custom-built by the German web shop and wheel building experts R2BIKE using carbon spokes and NonPlus Components Primaro Fusion hubs in a limited white Cerakote finish.”
The rims are Light Bicycle Airia 32 Disc. They’re 32mm deep, hooked, and weigh 275g each.
“Today it’s possible to push wheels below the 800g mark, but once again the main goal with this project is to try and find the perfect balance between low weight and performance, handling and ride quality,” says Dangerholm. “These wheels ticked all the boxes while still being light enough to help bring the total weight down below that 5kg limit.”
Price? Well, let’s not get vulgar and start talking about money.
We actually don’t know the full cost, but yeah, a lot. You’re looking at over €1,250 for the hubs alone. What’s the saying? If you have to ask, you probably can’t afford it. The focus of this bike was hitting that sub-5kg weight, not any particular budget.
Specs and weights
- Frame: SCOTT Addict RC HMX-SL L/56cm – 630.9g
- Fork: SCOTT Addict RC HMX-SL – 282.4g
- Thru axles: RideNow Titanium – 24.7g
- Headset: Syncros – 48.3g
- Spacers/cover: Syncros and Darimo – 22.5g
- Topcap: Darimo with Extralite screw – 3.0g
- Expander: Extralite UltraStar 4 (tuned) – 4.4g
- Handlbear combo: Darimo Nexum Drag 100x360mm -6 degrees – 212.4g
- Bar tape: Ciclovation KOM with Extralite HyperPlug HD – 16.8g
- Brakes: SRAM Red AXS (tuned with TiMaster clamps etc) – 632.9g
- Rotors: Carbon-Ti X-Rotor SteelCarbon 3 160+140mm – 146.5g
- Adapters: Bike Ahead Composites The Fixer + Carbon-Ti steel shim – 39.3g
- Hardware: METI titanium calliper screws – 10.9
- Rear derailleur: SRAM Red AXS (tuned with Extralite and TiMaster) – 276.7g
- Front derailleur: SRAM Red AXS – 171.6g
- Chain: SRAM Red – 231.0g
- Cassette: SRAM Red 10-30T – 194.9g
- Chainrings: Carbon-Ti X-CarboRing X-AXS 37-50T – 139.8g
- Chainring bolts: Carbon-Ti X-Fix Road – 8.7g
- Cranks: GrigioCarbonio Road T1000 170mm – 256.3g
- BB: Extralite Hyper BB Ceramic (incl. brake hose guide) – 38.9g
- Pedals: Wahoo Speedplay Nano (tuned) – 150.6g
- Wheels: NonPlus Primaro Fusion hubs, Light Bicycle Airia 32 rims, custom built by R2BIKE – 866.7g
- Tyres: Schwalbe Aerothan 29mm – 342.5g
- Tubes: Tubolito S-Tubo-Road – 41.0g
- Rim tape: Orange Seal – 4.9g
- Seat post: Darimo – 117.7g
- Saddle: Gelu K3 – 39.2g
- Bottle cages: CarbonWorks incl. bolts – 19.4g
- Computer mount: Alpitude incl. bolts – 16.5g
Total: 4,991.4g
15 thoughts on ““The lightest rideable modern road bike ever”: check out Dangerholm’s sub-5kg Scott Addict RC”
“The pedals are Wahoo Speedplay Nano, featuring titanium axles and further ti tuning to push the weight down to 150.6g. These have a maximum rider weight recommendation of 82kg.”
How can a pedal have a weight limit? you don’t rest weight on your pedals but apply force through them. Probably far exceeding a gravitational weight of 80kg AMSL.
One could assume a top pro athlete could weigh well under 80kg and apply far more force than someone who is over 80kg but nowhere near as strong.
My thoughts exactly
I wouldn’t be surprised if the highest forces a pedal receives occurs when going over a sharp bump or pothole, in which case it is quite normal for a rider to take their weight off the saddle and effectively stand on the pedals. I imagine the force generated by such a sudden jolt will far exceed the pedaling force applied by even a very strong sprinter.
There’s also the slightly more prosaic answer that whatever standard tests pedals are required to pass presumably use a reference weight, and the pedals presumably fail when weights above 82kg are used. As with all weight limits in cycling, it’s not absolute – the pedals aren’t going to fail the moment someone weighing 83kg gets on the bike, and someone weighing 81kg is probably going to find themselves needing to replace their pedals sooner rather than later.
Nope – it’s when going past a Telegraph ‘reporter’ and accelerating up to 52mph.
In that scenario, the weight would be equally spread to your 83kg is divided by 2 = 41.5kg per pedal. I sprinter can put far more through each pedal individually as you drive downwards will most you weight through 1 leg/foot
Isn’t it that pro athletes can apply more force without flying off the bike in the opposite direction because they are secretly much denser than normal humans? Or do they have access to pro saddle glue?
Bit rude, there are some quite bright ones if you look hard enough.
Not sure there’s much secret about it – it’s well known that muscle is much denser than fat.
And is it true that Lance Armstrong was actually 3ft tall, weighed 150 kilos (almost all of that in his legs) and he had to use special camera lenses (known as “expanding primary objectives”) to disguise the fact he was using a child-sized bike?
We could all spend a fortune buying light stuff and bolting onto a bike. What’s this chap actually done?
My bike certainly ain’t 5.99kgs BUT I know it’s lighter than a custom steel one ive got AND carbon bikes have a twitchy lightness that even surprises me with ride it with no saddle bad etc, on it 👍
He’s built an incredible bike to show what can be achieved nowadays (and doubtless to have a lot of fun with), which is quite interesting to those who like fast incredibly light bikes such as, for example, a substantial proportion of the readers of a website dedicated to road cycling.
I was in the National Gallery the other day looking at a Michelangelo, any of us could buy a bit of paint and slap it on a canvas, what’s he actually done?
He painted an original picture, you philistine. 🚳
The point <<<>>> Dhill
He’s built a rideable bike that’s very light and probably had a lot of fun doing it.
A couple of years ago, I built a sub-6kg hillclimber bike from parts, although mine is not one that I’d like to do long rides on, with slim, puncture-prone tyres, cutoff bars, 1x 33T chainring and marginal brakes. It’s made for climbing hills. Most of the fun was in researching the parts, sourcing and weighing them, and putting it all together.
This person has managed to beat this by 1kg with a proper drivetrain and tyres, although likely for 10x what I did mine for by the look of it.