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TECH NEWS
Shimano hydraulic discs trickle down to 105 level
Not content with offering us a brand new Tiagra groupset yesterday, Shimano have followed that up with news that hydraulic braking is moving down to 105 level. There's entirely new callipers based on the Flat Mount standard, a new lever and new rotors. So new everything, really. And a new Ultegra calliper too, to make use of the Flat Mount standard.
The new ST-RS505 shifter (abover) looks a bit different to the current Ultegra-level one, the shape of the hood looks like it's been tweaked and stands a bit further proud of the lever (alloy rather than carbon presumably). The scheduled drop date for these products isn't until October, so what we're seeing here are renders rather than final products. It's an 11-speed shifter to match the rest of the 105 groupset. There's 10mm of reach adjustment so you can tune the levers to your hands.
The callipers (BR-RS505 for 105, BR-RS805 for Ultegra) utilise the Flat Mount standard that Shimano are pushing hard for road bikes. Callipers sit flush with the frame and fork so they're neater and more aerodynamic, and the whole assembly looks a bit more refined. "This new design allows consumers to move away from the mountain bike history and look, which has been used until now, using a method better suited to high performance road bike riding", say Shimano. The new callipers use the same hose routing as the newer Ultegra units, where the hose runs down the inside of the calliper for better heel (and mudguard and rack) clearance.
The new rotor, the SM-RT81, uses an alloy spider and Shimano's ICE technology construction: a layer of aluminium sandwiched between two steel outer layers. Both of these aid heat dissipation from the braking surface, although the new rotor misses out on the cooling fins of the more expensive SM-RT99 rotor that's currently available. So far as we can see from the press release it's only available in a 140mm diameter, but we'll check with Shimano. The new rotor should be available imminently.
There's no word on UK pricing yet, but with a set of the Ultegra-level 685 brakes currently £479.99 at RRP and £100 less than that online, we'd expect the new system to be somewhere around the £349 mark at RRP, for a full set of brakes (without rotors). When we know for sure, you will too.
Dave is a founding father of road.cc, having previously worked on Cycling Plus and What Mountain Bike magazines back in the day. He also writes about e-bikes for our sister publication ebiketips. He's won three mountain bike bog snorkelling World Championships, and races at the back of the third cats.
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16 comments
why hidraulic goes to tiagra and not 105 ther is almost no hubs or wheels with 10 speed hubs
Disc brakes on a road bike?
Whatever will they think of next? 
does the new flat mount work with currently available disc frames?
might be another year or two before the market settles down and some favoured standards begin to emerge. will take a brave soul to buy a disc equipped road bike at the moment IMHO
Why??
Plenty have and plenty more will (including me) the fact there hasn't been a industry std set yet makes no real difference in my eyes because as soon as they do they will find something better and then change the std to that
Road bikes are still evolving and i don't think there will ever be a cross the board standard as manufacturers like to try new things to sell more bikes
Mtb's have been evolving for years now and they are still evolving now
Personally i think you need to pick when you want to build a new bike and go with the standards that are in place at that time
I fear if you wait for a standard you'll be waiting an awfully long time. MTB had settled at a 100mm axle length, but has never agreed a diameter or locking mechanism standard. And just when it seemed like at least the axle length was a constant, along came Boost and added another 10mm to axle lengths.
I've just accepted that there are no permanent standards in the bike industry and depending on how you see it that's either a good thing as the engineers are constantly improving things, or it's a cynical ploy by the cycling industry to make us repeatedly repurchase things we already had.
Re discs, anything you buy now will be fine, flatmount can be fitted to posts with adaptors, newer wheelsets are 15mm, 12mm and 9mm compatible, etc.
Can imagine that a flat mount brake caliper could fit a post mount with an adapter but probably not the other way round.
This is generally good news although I'm not ready to shell out on hydro brakes yet. Is there news on whether shimano will do an updated cable caliper? I have the BR517s and they work well but damn, they ugly.
Has anybody actually tried a real world performance comparison of discs against calipers or integrated calipers? Climbing, descending, rolling terrain, cross-wind.
Road cyclists are a fussy bunch
- tell them they will lose a few seconds over a rolling mile or a few seconds on their favourite climb
- tell them there's only a difference in aero at > 10deg yaw
- tell them their disc hubs are a 100g heavier than caliper equivilants - and the disc itself weighs 100g each
It doesn't stack up so well for the Average Joe.
But hey - his descending might be better because he can do some late braking....
No - and the world press has been remarkably silent on bikes with discs, let alone whether they are any good or not compared to calipers....
Obvious troll is obvious
Is the peculiar aesthetic of the hydro shifter because the brake level reach has been wound in? It looks like there is a lot of space at the top of the lever to the shifter body, and the cut out on the back of the lever doesn't match up with the shape of the shift lever behind.
It's a shame the hubs don't look to be thru axle compatible though...
I think I prefer them to the stovepipe hat look, the extra gubbins has to go somewhere. Is there a render that shows them mounted on a set of handlebars?
Certainly not the best aesthetics. Unless I was really strapped I think I'd be looking to use the currently available Ultegra level units. It'll be a boon for the oem market though.
It would be nice if they did a 10 spd version to mate up with new Tiagra so you could run a hydro hybrid much the same as you can with 105/hydro Ultegra now.
I wonder how long it will be before someone realises there's loads of empty space inside handlebars, stems and frames where you can easily hide brake cylinders?
Haha, good April Fool's joke.
That's ruined the market for bikes with cable discs this summer then.
World's ugliest shifter, bar none