"Hubs for life" is how DT Swiss’ 240s were first introduced to me many years ago. Rather than considering them a wear part, needing replacing in a cyclical manner, they were labeled an investment. Sure, the bearings would eventually hit their limits, but put a fresh set in and keep on riding ad infinitum.
At the heart of this mantra sat the Star Ratchet system. Something so beautifully simple that it left you asking why would you do it any other way. Countless other small details, rarely seen by the user, were employed to make the 240 hubs a go-to for anyone after low weight, high performance and outstanding reliability.
I was sold on how my friend described the 240 and have cherished every set I've ever owned, never selling a pair and transferring them from rim to rim, bike to bike.
240 EXP Hub DetailsHub Options:
Classic J-bend (28 & 32 spoke holes) or straight pull (28 only spoke holes)Front Axle System:
15/100mm, 15/110mm, 20/110mm, 20/110mm BO & LeftyRear Axle System:
12/142mm, 12/148mm, 12/150mm & 12/157mm+Freehub System:
SRAM XD, Shimano standard & Micro SplineBrake Mount:
Centerlock & 6-boltWeight:
From 104g front and 199g rearPrice:
From $220.90 (€149.90) front and $433.90 (€293.90) rearMore info: DT Swiss Hubs
But now there's a new 240 EXP hub that uses DT Swiss’ updated Ratchet EXP freehub system, first seen on their 180 EXP hubs, come in a huge variety of sizes, fixtures and freehub versions and were even considered as part of the whole bike system throughout their development.
Just grabbing your bike and going for a ride is a simple pleasure, and one that DT would like to play their part in. Having a bike that rattles around from worn-out bearings or slips when you're really pushing on the pedals isn’t fun. Neither is time spent in the workshop instead of riding.
The new 240 rear hubs see an increased bearing width between the two main hub bearings. The drive side bearing now sits inside the threaded ring of the Ratchet EXP system, increasing axle stiffness by 15% and reducing axle deflection, which should up the bearing life. The 240 EXP uses stainless steel bearings, as opposed to the ceramic bearings in the 180 hubs, and also sees those bearings increase in size.
The design of the Ratchet EXP system is so that the surface area transmitting the load from freehub to hub shell is as big as possible. All teeth on each of the ratchets engage at the same time, and when compared to a standard pawl design the difference in contact area is clearly seen. This increased area spreads the load and so lowers the pressure on the faces leading to reduced wear. DT Swiss also spec 36-tooth ratchets as standard to maintain good reliability for all users. The single spring in the Ratchet EXP system now ensures a faster full engagement between the two ratchets, resulting in less wear between them.
From time to time, especially if you're riding in extreme conditions, a bit of maintenance can go a long way to having a smoother running bike and ensuring a long lifespan of your hubs. The whole Ratchet EXP system can be dismantled for some normal maintenance without any tools and a degree in engineering. There are tool-free end caps with small notches designed into them to make removal by hand hassle-free.
The Ratchet EXP system uses fewer parts compared to its predecessor. So, there are fewer parts to fall on the floor and bounce under the washing machine. The single spring inside the system is now straight too, so no need to make sure it's in the right way round.
DT Swiss also made some small modifications to the flange dimensions so that, dependent on your rim, you can mostly run the same spoke lengths left and right. Their spoke length calculator
is another tool in place to make maintenance or wheel building easier.
Not wanting to restrict any customers from having a new 240 EXP hub, DT Swiss offer it in an eye-watering number of configurations for both road and mountain bikes.
Focussing on the mountain bike options there are classic hub, using J-bend, and straight pull options for the spokes in 28 or 32 spoke counts. Boost, non-boost, Super Boost and DH width options with end caps for through axle and quick release. The end caps from the old 240s will also fit on the new hubs.
There are Centerlock and 6-bolt options for disc mounting. And if you've got a frame with rim brakes then there are even options without disc mounts for you. SRAM XD, standard Shimano and Micro Spline freehub options exist for the freehubs, all interchangeable on the same hub body. All SRAM, Shimano and Campagnolo options are available for the road too.
As standard the 240 EXP comes with a 36-tooth ratchet, but there is an optional upgrade to a 54-tooth for riders who prefer more points of engagement.
What's mightily impressive is how DT Swiss talk about their hub development as part of the complete system of a bike. Many manufacturers focus solely on the product in hand, and can often forget about its role in the greater sum of parts.
The new 240 EXP's low weight might not be as significant when compared to other areas you can save chunks of weight. But grams do add up, and lighter hubs also benefit your un-sprung mass on a suspension bike.
DT's choice to go with a 36-tooth ratchet also tells a lot about their consideration of the hub's role in a whole bike. Once again, the topic of pedal kickback raises its head, something being talked about a lot at the moment. DT recognize that the number of factors involved in this topic is huge, and that ultimately, it's a balancing act of all these factors that they need to do.
Pedal kick as a theory isn't hard to get a hold of, although be warned - it can take a turn for the extra-nerdy very quickly.
When we go through our travel on a suspension bike the distance between the rear axle and bottom bracket increases, and something needs to give in the drivetrain to accommodate for this. If our freehub is engaged, either when we're pedalling or locking the wheel under braking, that increase between the rear axle and BB causes the upper part of the chain to pull on the cranks and we can measure the angle the cranks would move dependent on what gear you’re in, how much travel you use and how much your kinematic design changes that distance between the rear axle and BB.
If you're freewheeling, though, your freehub isn't engaged. That means the chain pull from suspension compression would have to cause the freehub to at least match the angular speed of the hub body before pedal kickback could be considered a problem and bring the points of engagement into the equation. Once the freehub and hub body are spinning at the same speed the number of points of engagement comes into play at how fast that impact at the rear wheel could turn into pedal kickback. A fast-engaging hub could potentially make it possible to feel those pedal kickback issues more often, while a slower engaging hub would feel them less often.
On the other end of the scale is the backlash of the hub versus points of engagement. That faster engagement hub would take less time before your pedal stroke would turn into the bike going forwards while the slower engaging hub would take a little longer.
DT cites a triangle of balance between points of engagement, weight and reliability. More points of engagement, above their 54-tooth option, would require an enlarged construction to have the same reliability, and so upping the weight. More points of engagement would up the chances of pedal kickback to be prevalent in the riding experience too.
According to DT, using 36-teeth strikes just the right balance between all these factors. It picks up well when you start to pedal, doesn't interfere with the rider or suspension as much as a faster engaging hub when you hit a bump, and can be packaged neatly inside a low weight and high reliability system.
All in all, pretty tech minded for just a simple hub.