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TECH NEWS
Bike Check: Fairwheel Bikes’ 5.1kg Factor O2 disc brake road bike
We’ve reported on some extremely lightweight road bikes over the years, but this 5.1kg (11lb) Factor O2 from US bike shop Fairwheel Bikes is definitely one of the lightest disc-equipped bikes we’ve ever seen.
But it could have been much lighter. With a different crankset, carbon disc rotors and a change of tyres, the weight could have been 4.76kg according to Fairwheel. Erring on the side of caution and durability, the bike shop instead wanted to build a bike that was as light as possible whilst still being robust and race-worthy.
- 6 of the lightest road bikes — bike makers challenge the scales with exotic materials
Fairwheel Bikes is no stranger to building one-off custom road bikes that barely get the scales moving, but this latest project was all about trying to build the lightest disc brake road racer. We think it’s fair to say they certainly achieved that.
“The goal for this isn’t necessarily to have the worlds lightest, but rather something that is very light but still race worthy. Actually, it might be both.”
Obviously, if you’re going to build a lightweight bike you need to start with a light frame. The Factor O2 was chosen in a small 52cm size and it weighed 853.2g on the scales. That’s a good starting point.
The fork with a cut steerer tube added 352.1g, and further weight was saved with a Cane Creek AER headset while Tune Magnesium spacers replaced the stock carbon spacers because they come in at just 8.9g apiece.
SRAM’s eTap HRD wireless groupset was chosen and matched with a THM Clavicula SE 300g crankset with an HSC ceramic bottom bracket, which added just 68.1g. The standard SRAM chainrings were whipped off and replaced with a Carbon-ti 50t big ring and Fibre Lyte 34t inner chainring.
The chain and cassette are far from stock as well. A YBN Titanium chain was chosen for its 215.6g weight while the Recon AL 11-25t cassette with its 150.4g weight saves on the mass - though a SRAM Red 11-25t cassette has a claimed 151g weight so it’s a small saving. But at this level, it’s all about the marginal gains…
The disc brakes came in for some weight saving attention too, though I’m not sure if I’d want to save weight on the brakes personally. Ashima Ai2 rotors weighing just 114.3g and even the rotor bolts, Custom Rainbow Ti, saved weight compared to the stock setup.
You can save a load of weight with the right wheel choice, and here Fairwheel really went to town. Extralight SPD hubs (64.9g front, 145.4g rear) combined with FSE prototype rims (442g/pair) and Pillar Xtra Titanium spokes (150.4 for both wheels) and 17.7g worth of Pillar nipples ensure a very lightweight wheelset. A pair of Vittoria Corsa Speed tyres added 377.2g.
Onto the contact points and a 146.6g Schmolke TLO handlebar combined with an 85.1g THM Tibia stem, Lizard Skins DSP tape, Schmolke 78.3g seatpost and Gelu 46.5g saddle. All very lightweight indeed.
You can view the full list of components and weights here.
What’s the bike like to ride? We’ll never know, partly because it’s an expensive trip to the US to find out but also because at 52cm the bike will never fit anyone on the tech team. It does show how crazy attention to detail, and deep pockets, can really shave away loads of weight.
What do you think? Is it a step too far or should more bike manufacturers be aiming for this sort of weight?
David worked on the road.cc tech team from 2012-2020. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds, and you can now find him over on his own YouTube channel David Arthur - Just Ride Bikes.
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54 comments
Ah didn't realise it was for the pair that's more reasonable! Some top caps (e.g. zipp) now come with a 1-2mm spacer built in for a neat, low finish - that's what they need, not a ~10mm spacer then a downward pointing cap, just looks messy.
Your lucky streak would come to a swift end if you had a 16h front disc brake wheel
Ah yes, forgot it was disc braked, fair enough. I remain unimpressed though :-P
Completely agree- it looks like a severely wounded bull about to start its fateful last stagger towards the matador.
The bar position is just about the only thing they got right, despite the spacers. Hoods should be lower than the tops, that’s the point of them
That's not what The Rules say: http://www.velominati.com/the-rules/#46
Rules are for saddos.
But these are THE RULES
I think you'll find that THE BIGGEST SADDOS follow them.
How about if I only follow the ones that I want? Does that make me a medium saddo? Or a saddo-wannabe?
I neither know nor care. What do the rules say?
They say "Obey The Rules", but if I'm disregarding that particular rule (No. 1), then I don't know which variety of saddo that I am.
Maybe I should just follow some of the rules ironically.
I think you’ll find that this rule applies to the bottom hook of the drops, which should be parallel to the ground. Pointing bars up, with the hoods in comfort mode and the brake levers pointed forwards makes you look like Alan Sugar
As Nick T says, they're talking about the drop part of the bar, not the ramps.
This is what the Velominati mob mean is correct:
Not this:
Yep, first one is definitely right, looks rather nice.
That said, I don't at all care how other people have their bikes setup (providing they are able to use the brakes that is) - I'm just rather particular about mine (that's one of the frustrations of having mild OCD).
Standard bend bars 'should' have the bottom part of the drops parallel to the gound (pic 1 above) not rotated up as in pic 2 but if you value comfort over subjective aesthetics then do what you like.
The picture of the Whyte bike earlier in the thread shows compact bend bars which are generally set up with the tops horizontal and with a horizontal transition into the hoods; the set up shown is pretty close to what is 'correct' for these type of bars.
Standard bend bars were all the rage when stems were quill and saddle to bar drop was small. If you run a slammed stem and standard bend bars then my compliments to your flexibility and your chiropractor.
No, it's not.
I assume if I have to ask how much that build costs, I can't afford it?!
I think the croissant I had for breakfast weighed more than half the drivetrain! Very impressive.
I bet it rides like a dog !
Titanium spokes? I shudder to think how much they must cost.
About 10 years ago they were roughly £2 each.
And broke with alarming regularity!
That's surprising. I'd have guessed that they'd cost a lot more than that.
Also, I'd have thought that titanium would be an almost ideal material for spokes except for it's tendency to bond with other metals (stuck nipples).
I would seriously avoid those particular rotors. There was a story on bike rumors a few years ago about an American guy and his friends doing a long descent down a mountain road and he had these rotors fitted. Because they don't dissipate enough heat, his brakes boiled and he had to throw himself off the bike at around 40 mph onto the verge at the side of the road
.
That's bad braking not bad brakes!
Also those rotors are a bit chubby on the scales! My MTB rotors weigh 76g rear160mm and 96g for the front180mm I have them on all my bikes and even on long descents they work perform significantly better than stock Shimano's, they grab a little more but if you're braking properly this isn't a bad thing.
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