Review: DT Swiss 240 EXP hubs

DT Swiss, the Swiss watch maker for bike hubs, announced they are retiring their venerable ratchet system in 2019 with the updated 180 top-of-the-line hub, and replacing it with a new "Ratchet EXP" system. This new technology has since trickled down to the 240 as of April 2020. Their patenteted ratchet system used to consist of 2 axially moving ratchet rings, which have teeth on the faces that engage as the rings are pressed together, and release when rotated in the non-driving direction. This is commonly referred to as a Hirth coupling and a common solution in the mechanical power transmission industry for applications where smart electrical controls are not desirable and / or reversing the rotation direction is very bad for the equipment, such as inching drives in mill applications.

The new Ratchet EXP, currently used in the 180 and 240 premium hubs, does away with the second movable ratchet ring, and integrates it into the hub body. This allows DT to use a larger drive side bearing and a wider bearing span than the previous generation. The moving ratchet ring remains on the freehub body, so the system is similar to the Mavic ID360 system. Less moving parts, bigger bearings and a wider bearing span, all good things, right? Maybe not... Read on!

 

Front hub

The new 240 front hub is very similar to the old one with slighly different machining to save a few grams, and non-removable decals available in red and black only. Available in both "Classic" J-bend and Straightpull configurations, 6-bolt and Centerlock brake disc attachments, 100mm and 110mm "Boost" widths and almost all possible shaft options, there are 18 different options for the front hub alone! A non-disc hub is also available if you're still rocking rim brakes, but this is only available for a 5mm QR axle. Yes, rim brakes are a dying breed, good riddance! There's even a beefed-up E-bike version, but I would not be surprised if it turned out to be a re-branded 350 hub. Spoke hole counts are limited to 24 for the road, and 28 or 32 for the MTB hubs.

The configurator on DT Swiss's website allows you to easily choose the correct model. I went with a Classic 15x110mm Boost hub, Centerlock brake disc attachment and 28 holes. After having numerous wheels built by my go-to guy, Titaniumthumbs, I knew J-bend was the way to go for ease of spoke replacements. DT claim this hub weighs 119g and I weighed mine at 122 grams.

I have a set of old 240S hubs and pretty much the only difference between the new and the old is that the end caps are easier to remove on the new one thanks to a small machined flange at the end. Bearings are protected by a contactless labyrinth seal on the end cap, and DT have chosen to keep using standard bearing sizes and not go with special sizes. Nice! Machining quality is top notch and even with the standard, non-ceramic bearings the hub spins freely for days. What more can you ask for? 5/5 for the front hub!

Rear hub

So the front hub is perfect, but the rear is where things start to get interesting! First, the 240 is no longer available with an 18-tooth ratchet, which is only a good thing as the 20-degree POE is just ridiculous and makes you feel like your bike is broken. The new EXPs ship with a 36-tooth ratchet and can be upgraded to 54-tooth with the measily sum of around 80EUR + the same for the special tool required to remove the hub side ratchet. This is still cheap when compared to the reason why I didn't keep my i9 Hydra as my go-to hub: The i9 Microspline freehub costs 250EUR! That's only 40EUR less than the complete DT 240 rear hub! This combined with the Hydra's tendency to chew through bearings every 1600km and I just couldn't justify keeping the super fast engagement.

The machining on the new 240 hub shell is mostly the same as the old model. DT advertise the weight as 219 grams for a 12x148 Boost Classic hub with the Microspline freehub. I measured mine at 226 grams, which is around 60 grams less than my previous i9 Hydra.

The new ratchet system, however, proved problematic right from the start. During my first ride I already experienced several concerning crunching noises from the hub. I put this down to the rather coupious amount of grease from the factory and the cold -2 - 0 Celsius weather. Cleaning the hub and experimenting with both DumondeTech grease and oil helped with the crunching, but produced another problem: The hub would disengage completely! I have had to limp home to change bikes once and have taken the hub apart in the forest once to fix this issue. Luckily the freehub just pulls off the hub body, so even removing and re-installing it on the trail is possible. However, THIS SHOULD NOT BE NECESSARY! I have since cleaned the freehub again and inspected it carefully, and it appears the new straight spring in the EXP ratchet may be the issue. It will occasionally bind, sticking the moving ratchet to the freehub body's splines.

I have since replaced the spring to make sure it's not twisted and applied only a small amount of DT's OE grease and so far this seems to have solved the issue. My dealer, Bike24, promptly replaced both the spring and the moving ratchet under warranty.

Freehub sound

Every hub review needs a sound clip, so here's a comparison of the freehub sound with DumondeTech oil and DT's proprietary "Special grease".

 

Conclusion

Buying into to DT Swiss you'd expect 150% quality and perfect function, however, sadly in the case of the Ratchet EXP this is not the case. As the problems were already evident from the factory, I can't say this new system is better than the old ratchet system. Rather on the contrary! I would prefer the old system, but sadly it's no longer available for the 240 series hubs. The front hub is perfect, but the crunching and disengaging problems, which in my sample were likely due to a defective spring, are still concerning.

Value for money: Front hub 5/5, rear hub 4/5

Finish: Front hub 5/5, rear hub 5/5

Fit: Front hub 5/5, rear hub 5/5

Function: Front hub 5/5, rear hub X/5 (due to the spring issue I experienced)