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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
Once STI/Ergopowers were introduced, bar shape had to evolve to something more like these Deda Piega bars from the 90s:
BUT the drops were still fitted level. That's why the 'ramps' are 'ramped'.
Hmmm. Must go and check my handlebar setup now.
Just yesterday, I was watching a video about hand positions and the alignment of your wrists when on the hoods: https://www.youtube.com/watch?v=O9jq4WBrKOY
I was talking to the poster above who was complaining about the spacer above the stem, so you can wind your neck back in and figure out how to follow threads without needing to quote the post directly before
Fair shout. As you were.
Presumably they will want to be able to sell the bike to someone, or just the frame. Slamming the stem and cutting the tube short is fine on your bike if that fits you, but they’d just be limiting their chances of a sale here
I imagine they never considered any of that. Get on the blower mate.
Freds are a right sensitive bunch, it seems
Well, now I'm confused.
@Nick T - that picture is roughly how I have my bars setup and it feels right for me. What's the issues with that kind of setup?
@Don Simon - I agree in principle, but that bike doesn't have a front brake and we all know where that can lead.
Oops!
Alright settle down
All's fine here, Fred.
Do it as wrong as this if:
a) you don't give a shit about rules.
b) it encourages you to get out of your car and on to a bike.
And here’s an example of how to get it wrong. That’s how bike fitters set up their customers bikes now though, because all their customers are Freds
4bd18944-25cb-4091-b2c1-2e9f417212fd.jpeg
Bullshit. I had a professional bike set up and before the appointment my bars/hoods looked similar to the fugly bike the article is about. After all measurements etc were done my bars looked very similar to your pic. There just ISN'T one set up that suits everyone, this is why the things are adjstable in the first place. Your bike bike needs to fit and be comfortable before worrying about how it looks compared to some mythical rule.
Alu Recon cassettes are like biscuits, you only need give them a hard stare and the teeth snap, 'race day' cassette that has a high % of not lasting a hard stage race, durability my arse.
Stronglight and SRAM make lighter 50T rings than the Carbon-ti, I had a check of my records and 84g was the lightest 52T ring I used (Stronglight), 29g for a 33T Stronglight, Fibrelyte combo (50/34) are supposedly 77g a pair however.
I was going to buy some Corima 24mm tubs and build them onto my FRM carbon axled hubs, with DT aerolites they were going to be 880-890g for a 24/20 wheelset that wouldn't be anywhere near as flaky as that in the build. Certainly wouldn't want to ride 'prototype' rims with ti spokes unless I was under 65kg and just out for a genetle pootle on smooth roads!
These builds are utterly pointless, certainly isn't practical nor durable in any real way, wall art if you like ugly.
I had the Ashima rotors on a couple of MTBs and they were fine.
Maybe not the same kind of speeds as on an open road descent but unless you seriously drag the brakes I reckon it would be pretty hard to boil brakes even with the lack of material on these rotors.
I've still got them but been too lazy to fit them to my current MTB.
This is wrong...
It looks like Fairwheel Bikes do not know what they are doing.
I had these rotors on road bike and they just heated up and faded
24 titanium spokes + disk brakes will feel flimsy and wobbly under heavy breaking.
Good luck on long, steep descents!
That looks really nice. I thought 8kg was light weight. Congratulations.
Why save all that weight and fit it with a compact crank?
But the weight of the those extra 8 teeth if you go standard...
A bike you could race on? Not until they scrap the 6.8kg weight restriction, unless you are not in a UCI governed event. The only thing it's good for is hill climb events (in which case you don't need discs, inner ring, front brake, drops etc.).
I don't understand the obsession with building these things. The only benefit of a lightweight build is if you are racing the rest is just showing off how much excess money you have. Of course it's always satisfying to drop people on superlights
You can definitely get lighter frames than that. Trek's top end Emonda is 665g for the disc brake version - forks add another 350g.
It isn't - itr's very stretcy and makes it very difficult to build a wheel to a decent tension. Proper pain in the arse. I'd much rather have a wheelset a few grams heavier built with normal triple butted spokes and brass nipples. Alloy ones being another example of the "more trouble than it's worth" school.
A sub 821gram wheelset is mightly impressive!
If anything the frame is the porky part @ 854grams...
Agreed, surely there's at least 100g to be saved there if not quite a bit more.
it's kind of a fun project, but will never be the right kind of bike for me even if I had the spare cash
They've just started selling Factor which is probably why the choice was made
Really bored of the obsession with weight saving. I'd prefer if the bike industry concentrated on reliability instead.
Give me a 8.5 kilo bike with components that last 20,000 miles and I'd be much happier.
If you look carefully, you can see that the body of the ring is carbon but there appears to be a metal outer ring that has the teeth machined into it.
Carbon chain rings just seem wrong to me in terms of durability
Don't like this bike. I think it looks like a dog dinner (although that's just personal taste...) especially the weird positioning of the bars. Looks like it was to get the hoods level because they fastened them on too high.
Wheels could be far lighter, the rims are quite heavy - even aluminium Mavic OpenPro's are only 430g and they have a brake track. Plus that many spokes seems over kill for a lightweight road bike. My road bike only has 16F/21R and I'm yet to break one and I'm an 82Kg track rider, so no lightweight. Also, while I appreciate they may want the spacers, they could atleast trim the steerer to get rid of the one on top.
Those rims are 440g for the pair not each and the stem has to have a spacer on top before tightening down for warranty
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