Shimano Ultegra ST-RS685 Hydraulic Disc Brakes set review

Disc road bikes have been doing the rounds for a while now and if you have already converted then you are probably already aware of the many benefits that disc braking brings to the road.

However, if you've always used a cable-pull system or you are still weighing up your options, then one ride with a bike equipped with Shimano's Ultegra ST-RS685 Hydraulic disc set will probably be enough to convert you to fluid stopping power.

Construction

As a dual-control lever (both brake and gear shifting), the Ultegra ST-RS685 lever is compatible with a front double chainring and 11-speed cassette at the rear.

An aluminium bracket is teamed with a Shimano Engineered Composite brake lever and a resin-and-steel shifter lever body giving a (Shimano claimed) weight of 649g for the pair.

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If you're a Shimano fan you'll be pleased to know that the Ultegra ST-RS685 set is, as expected, designed in keeping with the rest of the Ultegra 6800 groupsets, so whether you're digital or not, the hydraulic system will blend seamlessly.

The Ultegra ST-RS685 dual levers have a taller hood profile than standard Ultegra 6800 to accommodate the main piston and the access point for bleeding/topping up the mineral hydraulic fluid, along with gear shifting components.

Compatibility wise, Shimano naturally says that best results come from matching collars and cuffs, i.e Shimano throughout, but it's worth remembering that Shimano 105 is also now 11-speed and is listed as a compatible product, giving you an option to build to your budget.

The brake caliper has been specifically designed to combat any heat build-up in the rotors with cooling fins allowing air to flow directly to the pads, which Shimano says allows for much better braking performance over long descents over a system that doesn't have any.

It's highly likely that the Ultegra ST-RS685 will be your first foray in to the world of hydraulic oil on a bike (unless you dabble in the dark side of mountain biking), but any concerns about maintenance shouldn't put you off before the first pedal revolution.

There are lots of 'how to' guides for servicing hydraulic disc brakes, and with no cable wear or road crud build-up in cable outers, you'll find maintenance will probably be minimal.

With road disc size 'standard' still to be agreed, it's still a toss-up between 140mm and 160mm rotors, or a combination of both, so it's good to know that whichever way you swing, there's no impact on the Ultegra ST-RS685s – they'll work fine with either.

It's worth noting that the braking aspect of the Hydraulic system is BR-RS805, but for ease of reference we've referred to the entire set under the dual-control lever's name of Ultegra ST-RS68.

Ride

With hands either side of the bars, the Ultegra ST-RS685 hood size is noticeable as they stand an inch or so proud of a non-disc Ultegra pair.

That's not to say it's harder to find radial grip, however, as the circumference remains more or less the same, and if anything the extra height helps gain a secure position when riding on the hoods.

As a rider with small hands, I was pleased to see the 10mm of custom adjustment available for the reach and free stroke of the levers, allowing me to gain even more confidence in gaining a secure reach for all the controls of the bike.

The actual braking element of the Ultgra ST-RS685 is exceptional, with the power and modulation achievable when riding in any position on the handlebars allowing me for the first time to descend on the hoods without fearing any lack of braking ability.

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As expected, the shifting aspect is faultless. The distance the lever is needed to be moved between each gear shift, what Shimano refers to as its "ergonomic short shifting" arc, is vivid, constant in force required (which in itself is minimal) and indeed short in distance needed to move.

Both the braking power and minimal leverage effort savings soon add up, leaving me feeling significantly less fatigued (mentally as well as physically, due to not having to worry about being able to reach the controls as well as use them) than a standard rim braking option often does.

The comparison to a cable-pull system is also significantly better as the minimal effort is constant, especially thanks to Shimano cleverly building in an pad-to-rotor clearance auto-adjust to take account of any brake pad wear.

All of this added up to a really confidence-inspiring ride: having more faith in  modulation allowed me to just focus on the job in hand, and I found myself descending faster than I ordinarily would as a consequence. while I wasn't exactly in mountainous terrain, the hills in the Peak District are some of the longest in the UK and there was never a question of heat dissipation or issues with stopping being a problem.

Any concerns about over-braking were alleviated very quickly: due to instantaneous stopping feedback, there is very little chance of pulling the lever harder than you require.

Value

There's no denying that £624.99 is a lot of money to spend on a brake upgrade and it will certainly bump up the price of a disc bike.

But, sticking my neck out, I really think it's worth the investment. Having ridden a Specialized Ruby with both Ultegra ST-RS685 hydraulic and Tektro Spyre dual pivot mechanical discs, it was like chalk and cheese.

The Ultegra ST-RS685 made me a more confident rider as I wasn't having to constantly adjust my hand positions or worry about being able to reach the brakes (or shifters) and that level of enjoyment from riding a bike, for me, is priceless.