TRP CX8.4 cyclocross brake

Powerful linear-pull stopping

BikeRadar score 4/5

TRP's new CX8.4 linear-pull cyclo-cross brake builds on the success of the original CX9 model but tone things down just a touch. The lever arms have been shortened by 6mm to help firm up the feel with SRAM and Campagnolo controls while also slightly tempering the original's on-off personality. 

The length change only minimally affects the CX8.4's stopping power, which comes on nearly as strong as before and builds as quickly as ever. Mountain bikers using modern hydraulic disc brakes will invariably find the CX8.4 to be a bit crude but for cyclo-cross riders coming off of nearly any cantilever, the CX8.4 is a revelation in terms of brute force. 

Just a single finger provides more than enough power in nearly any typical 'cross situation, arm pump is but a bad memory at the end of a tough hour, and as an added bonus, fork shudder is eradicated since the direct cable routing foregoes any steerer-mounted stop.

Even with the revised arm length, though, the CX8.4 is a little tricky to modulate – especially on loose ground – and unlike with cantilevers, there's no geometrical way to detune the power. This doesn't create many problems after the initial adaptation period (which can be a little painful if you're coming off of Euro-style wide-profile cantilevers) but graceful control on gravel or slick ground can still be elusive if you tend to be a little ham-fisted with your levers.

Lever feel when using the CX8.4 is indeed more positive than the CX9 when paired with SRAM or Campagnolo levers, though still a little squishier than many 'crossers will be used to. Pad clearance is improved with this combination as well but it's still pretty tight so users will need to keep their wheels in nearly perfect true to avoid rubbing. 

As we noted with the CX9 last year, pad choice has a big effect on the CX8.4's lever feedback, with harder compounds generally lending a more positive feel – and often having the additional bonus of tempering the brakes' occasional grabbiness. We also played around with some older mountain bike thinline cartridge pads (Shimano originally developed the format to tackle this exact problem) and the feel got better yet, though not as much as we'd hoped.

TRP don't restrict the two CX brake models to one lever format or another, so users can feel free to mix and match to achieve the desired effect. Pairing the CX8.4 with Shimano levers would yield the firmest feel while using the CX9 with SRAM or Campagnolo levers would provide the most power but also the most squish and trickiest modulation.

Setup is a breeze, with straightforward single-tool adjustments for pad height, angle and twist, and even spring tension balance from left to right.  TRP have integrated a cable tension adjuster into the new stainless steel noodles so buyers won't have to make their own now, either. If weight is an issue to you, it's worth noting that the CX8.4 is heavier than most high-end cantilever setups.

Pricing has climbed from last year – a complete set is now US$149.99 – though it's still reasonable as compared to many ultralight wide-profile cantilevers, which neither work as well nor are as easy to live with. The pending wave of disc-equipped 'cross bikes will likely make all of this discussion moot in a few years but in the meantime, TRP's linear-pull brakes are still the best option we've come across for 'cross riders seeking big power.

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