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TECH NEWS
Just in: Genesis Datum 30 arrives for review
This is the brand new Genesis Datum 30, a large-tyre disc-equipped carbon road bike. The British company has taken the popular Equilibrium as the starting point with the geometry and designed a carbon fibre frame and fork able to accommodate 32mm tyres with mudguards, and given it a thru-axle up front and short chainstays out back.
The British company has carved a nice little niche over the years, with well designed steel, titanium and aluminium bikes that cater for British cyclists and British roads. It’s not been afraid of adopting new standards either, with disc brakes now common across the range, tyres increasing in width and a venture into carbon fibre with its race-orientated Zero.
- Buyer’s guide to gravel and adventure bikes plus 11 of the best
The Datum though is a something very new and different. Firstly, let’s get one thing out of the way, it isn’t a gravel bike. Well, you could ride it on gravel roads (if you lived in the States) but Genesis is keen to point out that the Datum is designed simply to be a fast road bike with the benefits that the bigger tyres provides (comfort, smoothness, traction) with the occasional ability to tackle a towpath or bridleway. Roadplus then....
“It’s our new large-tyred road disc bike that’ll comfortably sit mile-after-mile on tarmac, but, should the tarmac come to an end, won’t mean turning back or the premature end of the ride,” says brand manager Albert Steward. “Not necessarily about out-and-out overall speed, but more fun, adventure, exploration and pneumatically-suspended comfort.”
“In reality the Datum is really just a bike for riding around and enjoying yourself, across a variety of terrain, both paved and unpaved, albeit fast or somewhat more leisurely. It could be a gravel bike to some, in the same way it could be a fast, comfy road bike to others,” he adds.
The new Datum isn’t available until October, but we managed to twist Genesis brand manager Albert Steward’s arm into letting us have one sooner. The bike here is the range-topping Datum 30, costing £3,199.99 with a Shimano Ultegra Di2 drivetrain and hydraulic disc brakes. The range also includes two other models, a £1,799 Datum 10 with Shimano Tiagra and TRP HyRd brakes, and the £2,099 Datum 20 with Shimano 105 in the middle.
The bike we’ve got isn’t quite production specification though. It has a regular drop handlebar rather than the flared drops that production bikes will have, and it’s wearing the wrong tyres - production bikes will have a Strada Bianca 33mm clincher tyre.
Genesis has done a nice job on the frame. It’s a good looking bike. To keep the chainstays short (420mm) yet provide space for big tyres and mudguards, Genesis has curved the seat tube, providing more clearance. That’s something you usually only seen on aero and time trial bikes and is done for aerodynamic reasons.
The seat tube accepts a 27.2mm and along with the skinny seatstays, should provide a decent amount of deflection to provide a smooth ride. Elsewhere, the frame is oversized to ensure the necessary stiffness, with chunky chainstays, a huge down tube and tapered head tube.
The geometry details include a 72 degree head angle, which along with a 50mm offset fork provides a 59mm trail, which Genesis reckons provides agility without sacrificing stability and maintains a healthy toe-clearance. The size medium we have here has a 561mm top tube, 1,017mm wheelbase, and a 385mm reach and 585mm stack.
Up front, the new fork has a 397mm axle-crown measurement, typical of cyclocross bikes. It features a squared-off crown to maximise tyre clearance and a bolt-thru axle. The rear axle is a regular 135mm quick release.
There are flat mounts for the disc brakes and all the wires and hoses are internally routed. You get three bottle cage mounts, one on the down tube, making it ideal for any bikepacking adventures. While there is a full complement of mudguard mounts, there are no rack mounts. Genesis reckon customers are more likely to fit bikepacking bags to the top tube and seatpost than conventional racks and panniers.
Common across the range are compact 50/30t chainsets and wide-range 11-32t cassettes, so you can scale any hill or lug a laden bike over inhospitable terrain. The bikes will come with the company’s new RandoX handlebar. It’s a compact drop bar with flared drops, like those on the GT Grade.
On the scales, the bike here weighs 8.91kg (19.64lb), which makes it one of the lighter disc-equipped road bikes we’ve had through the office.
Endurance road bikes have been very popular in the past couple years, with carbon fibre frames, disc brakes and space for up to 28mm tyres. You could look as the Datum as being the evolution of the endurance road bike for those that crave the ability to fit even wider tyres than 28mm, and I know there are plenty of cyclists that want wider tyres.
We haven’t tested many bikes that offer a carbon fibre frame with such large tyre clearance, most endurance road bikes stop at 28mm, such as the Cannondale Synapse or Giant Defy. Of those bikes with similar tyre clearance, there is the Bowmans Pilgrim (which is currently being tested) provides an aluminium frame, carbon fork and clearance for up to 33mm tyres.
There is the GT Grade of course too, another bike inspired by the gravel riding scene. It is available in carbon fibre or aluminium, at a range of price points, and has space for up to 35mm tyres.
The new (not yet available) Cannondale Slate occupies similar space to the Datum, but it combines an aluminium frame with a 30mm travel suspension fork, but with space for massive 42mm tyres.
The range hasn't been added to the www.genesisbikes.co.uk website yet, but there is some interesting information on the design of the Datum in this blog.
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.
Latest Comments
- Hirsute 1 hour 23 min ago
Radar tells me their closing speed, if they are slowing and how far away. Then I decide to say a prayer. The change of light pattern is incidental.
- lonpfrb 1 hour 43 min ago
Quite so, which is why our village 20mph zone covers the whole residential extent. Of course, enforcement is another thing..
- lonpfrb 2 hours 9 min ago
No, that's very doubtful while proper testing would be fully destructive.
- TheBillder 2 hours 55 min ago
In that £1000 exactly scenario, beginners should probably be made aware that pedals will be extra.
- don simon fbpe 3 hours 23 min ago
What's wrong with dropping down on to the Millenium Bridge, or the swing bridge, then the brief, but satisfying climb back up the hill? #training....
- chrisonabike 4 hours 4 min ago
The relatives might of course disagree, but in general I'd countenance a relatively light sentence* if only we could fix it so that those who...
- ktache 4 hours 43 min ago
Id forgotten that I got a second hand set of project two's for my getting to work bike over twenty years back.
- Veganpotter 5 hours 40 min ago
My bet is that all these tires popping off are from people with bad pressure gauges or they're simply just putting too much air in on purpose. ...
- chrisonabike 6 hours 56 min ago
David9694 - you were right! These new autonomous vehicles really are conspiring to run out of control!...
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40 comments
Vittoria will not be making tubeless tyres for road use in the near future, not fit for purpose apparently.
Nice bike though
This is one of the nicest looking bikes I've seen for this year so far...and it'd suit the crappy chip seal I have to ride on in this part of NZ very well indeed. Bike builders - more beautiful paintwork and large tyre options, please!
Probably a hidden mudguard eye on the leg rather than the drop out. Lots of brands do this on disc brake road bikes and some even do it on some of their lower end rim braked bike. Gives the aesthetic of a "full on" racer when guards aren't fitted. Trek do it for one. And as said the sample here is pre-production.
So no mudguard eyelet on the front fork ? How's that gel with the "full complement of mudguard mounts" ?
The mudguard mount is on the inside of the fork leg about half way up, it's not at the dropout like it conventionally us
"Compact 50/30t? Is that something new?
replyquote
posted by bendertherobot"
caught my eye - personally I'd like something like a 48/30t but suspect the gap would be still be too large, presumably a typo as suspect you are hinting at
Could have done with one of these today, when I hit a stretch of road repaired with loose stones on my ride in France. I'm intrigued.
have a Mason definition currently running 30mm Strada Bianca
at 80psi ... they're lovely every where so far
Why don't designers put the caliper on the front of the fork? Then there would be no need for new axle standards at all. The reaction to braking force would drive the axle upwards into the dropout, rather than down and out. Through axles are a solution to a problem of their own making.
Rim brake designers knew this!
Cotic put the disc caliper on the front of their roadrat fork, but changed it back in the latest version, maybe cause a front mount looked odd.
How are thru axles a solution to a problem of their own making? They are helping to solve an issue caused by braking forces and they help to stiffen up the fork, neither of which are caused by the thru axle.
The simplest solution to avoid disc brakes pulling the wheel out is to have the dropouts tilted forward, as giant have done on their defy range.
Rim brakes were placed on the front of the fork cause it's a pain to put them on the back cause the down tube is in the way. The braking forces from a rim brake pull the hub back, so won't pop the wheel out of vertical dropouts. Oh, and take a look at a load of the aero bike around these days .... Calliper on back of fork.
@joules1975
Conti GP4000II in 28mm on my Defy Advanced Pro's disc rims measured to a massive 31.2mm width when measured with Park digital calipers
Hardly any room between the tire top and fork crown, but plenty of clearance in the rear. Very good tire, especially at 80psi on rough roads
I've since moved to Vittoria OC Pave in 27mm which come up a smidgen over 27mm on the same rim; have to run harder at 90psi but finding it a very interesting tire in that very quick rolling, but also very grippy and so far good durability a few weeks in
So the only advantage this has over my Defy Advanced 2 is slightly better brakes?
For £700!?!?!
Thanks for that Joules. Why don't Madison buy them in and send them to the bike assembly factories?
And, crucially, why do their bikes get so heavily discounted after 6 months. This datum will no doubt turn up somewhere at 30% off. Surely that seller won't be making a loss?
Just think of the extra shipping charges if the stuff has to get to Madison and then get shipped back to Far East for bike assembly. Also, stuff for bikes is sold by shimano specifically for bikes (OEM), unboxed, without instructions etc, while aftermarket stuff comes with all that. The pricing structure and sales agreements from shimano will be totally different, and I suspect shimano don't like the two getting mixed (even though we all know it happens - most the cheap stuff from CRC etc is OEM). Slightly different but think of those labels on cans/crisps from multipacks that say 'not to be sold seperately' - similar kind of thing.
Having been a genesis dealer a while back, I don't recall Madison dropping prices that soon after launch, in fact they didn't drop them often full stop. I suspect it will be retailers looking at sales figures and deciding to try and get bikes moving that are for whatever reason not otherwise selling. Either that or the fact that genesis bikes availability doesn't tend to be till spring, with end of season sale beginning in August.
Tim France and Neil Phillips are also putting the Datum through it's paces on Transcontinental...
http://cobbles-to-kebabs.co.uk/
I have a Synapse Disc and while it's comfy enough it doesn't feel great out of the saddle.
The stem is slammed so I blame the chainstays. 420mm is not "short". Enigma claim 409mm stays on the Enigma Disc. I'd rather shorter stays and manage chainline with sensible gear choices.
I don't see the point in running tyres wider than 28mm on road, they just make the bike feel sluggish. Each to their own though.
What tyres did you try that were bigger than 28mm though? Most wider tyres out there at the moment are touring or commuter tyres, which are generally heavier and slower rolling due to the construction of the tyre.
I bet if Conti did some GP 4000S in 30mm or 32mm, they would feel just as quick as the current widths once up to speed, and it would only be the acceleration that would be noticeably slower, but not by much.
35mm Schwalbe Kojak, 330g and 200tpi.
Plus Gatorskins, 32mm 325g.
Only question I keep coming back to is - are there any larger volume (non CX!) tubeless tyres available? I thought that beyond 28mm there was nothing. I'm sure they'll follow, but as per usual with the newer end of anything 'niche' (that includes hydro road disc, DI2 when it emerged, etc. etc.), it may be best to wait it out.
Schwalbe G-One 35mm and 40mm tyres on the way http://road.cc/content/news/157273-schwalbe-launches-faster-and-lighter-...
Have you though of fitting motobike tyres or it not top end 4×4's have wheels that also same diameter as bike wheels.
What an odd comment, or maybe you haven't seen a fatbike yet?
I'm taking the piss.
I'm taking the piss.
Now I might be wrong, but as I understand it the tyres you can run tubeless depends more on the pressure you are running than the tyre. Running normal road tyres tubeless is a bad idea cause they have to have pressures of 70+ psi, but once you get down to 50psi, the issues of bead blowing off tend to disappear (my crest rims have max pressures on them - 55psi for 1", 50 psi for 1.5, 40psi for 2", 35psi for 2.4, etc.
So, on that basis, anything 35mm can probably be run tubeless without issues, as long as you stay within the rim manufacturers pressure limits.
DO NOT DO THIS.
Road tubeless are different in three ways: a thicker sidewall, sometimes a butyl liner, and a ***much stronger bead***.
In the course of researching my recent Slime Pro tubeless kit review I spoke with a number of industry folks. They all agreed that riding a clincher as tubeless is a very bad idea, and you won't know it until your tyre rolls off the rim at 60kph into a tight corner with an HGV on the other side of the road.
I implore anyone reading this, or knowing anyone thinking of doing this, or who has done: do not do it.
So how come mountain bikers have been getting away with riding standard clinchers tyres, often on standard rims, in a tubeless set-up for years?
Just look at the Stans system, where you can generally get away with a simple strip of airtight tape on the rim, some sealant, and away you go (even when not using 'tubeless' rims, like the stans or AM classic - although inflating the tyre int he first place is a lot easier on those rims).
I can only put it down to one thing - the pressure. I would never risk running tubeless a standard road clincher at normal road pressues ... REALLY BAD IDEA ... I get that, but I have run 35mm + tyres tubeless for some time now without any issues at all, but I have only ever run them up to 50psi, and often lower - i.e. at or near the max stated pressure that many rim manufacturers like Stans recommend for that kind of width.
The key is the fit of the tyre to the rim, but the ture sidewall construction also plays a part (but it doesn't have to be a tyre that is specifcally tubless UNLESS you are planning on running 'normal' road pressures. Check out this link re converting to tubeless for Cyclo-cross - in my experience the same applies for wide road tyres.
https://www.cxmagazine.com/going-tubeless-cyclocross-tires-racing-recomm...
With any such set-up on the road - cyclo-cross tyres or wide road tyre, you definately can't be as agressive with the cornering, if only because the lower pressure doesn't support you as well as you turn and so the bike can feel a little vague in terms of steering, but for rougher roads/off-road and general comfort, it's brilliant.
If I want a slightly more leisurely ride, in a bit more comfort with the ability to take an offroad/rougher short cut then I take my bike with the wide tyres in a tubeless set-up. If I want to ride a decent road speeds and be able to really attack the corners, I take my main road bike which has GP 4000s with tubes, but even then I'm only running them at 75 psi.
Looks nice; what's the BB? Also keen to read the Bowman review while I wait for Mason's larger-tyred offering.
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