Disc Road Bikes, Sram Vs Shimano

crossed

I'm looking for a disc road bike that's going to be used for general road riding and a trip to The Alps next year. I'm currently leaning towards a Roubaix as I've had one in the past and quite liked it.

The two models I'm looking at are the SL4 Comp Disc and the SL4 Elite Disc.
The Elite has Sram Rival 22 with hydraulic discs and the Comp has Ultra with Shimano 785 brakes.

Has anyone had any experience of both Sram and Shimano hydraulic brakes?
If so, which do you prefer and why?

ugo.santalucia

Are the Shimano hydraulics branded for road or cyclocross? It is a subtle but important difference when you are coming down the Glandon... I thought about hydraulics myself, but I am yet to be convinced they are safe for alpine descending

crossed

Why the concern about safety with discs?

ugo.santalucia

Crossed wrote:

Why the concern about safety with discs?

It's not discs, I've been on road discs for 5 years. My concern is hydraulics. They need to be designed and tested for road use. Cyclocross is not demanding on the brakes and the fluid will never get a chance to overheat. I am sure Shimano have thought about these things, but the way they are marketed is key. Wouldn't want to buy hydraulics designed for cyclocross

meanredspider

Yes - why the concern? I descended Alpe D'Huez with TRP HyRd on the front doing most of the braking. I'm 85kg, it was 33C and, given there was lots of slow traffic on the hill at the time, I was braking far more than is ideal. The disc ended up blue but there were no braking issues from the heat. I did the same descent 5x in the day in a range of conditions.

ETA - seen your post now. The brakes need to (will) be designed for "foreseeable misuse" which would include long descents

ugo.santalucia

meanredspider wrote:

Yes - why the concern? I descended Alpe D'Huez with TRP HyRd on the front doing most of the braking. I'm 85kg, it was 33C and, given there was lots of slow traffic on the hill at the time, I was braking far more than is ideal. The disc ended up blue but there were no braking issues from the heat. I did the same descent 5x in the day in a range of conditions.

I am sure your first descent was apprehensive too... I am in two minds... I'd love hydraulics and I am waiting to see how they perform. The other barrier is 11 speed... I don't want 11 speed and if they are only going to make 11 speed levers, it's probably a no go for me.
I'd like to try the HyRD too, but the compatibility with Mach 2 Campagnolo Ergos is a bit of a concern for me

meanredspider

ugo.santalucia wrote:

meanredspider wrote:

Yes - why the concern? I descended Alpe D'Huez with TRP HyRd on the front doing most of the braking. I'm 85kg, it was 33C and, given there was lots of slow traffic on the hill at the time, I was braking far more than is ideal. The disc ended up blue but there were no braking issues from the heat. I did the same descent 5x in the day in a range of conditions.

I am sure your first descent was apprehensive too... I

No, it wasn't - for 2 reasons:
1. I was too cold to worry about anything but how cold I was (it was 0C at the top - add 50kmh to that and it's bloody cold) :shock:
2. I race cars for a hobby - that's not something you do if you allow yourself to think about what might go wrong

crossed

ugo.santalucia wrote:

Crossed wrote:

Why the concern about safety with discs?

It's not discs, I've been on road discs for 5 years. My concern is hydraulics. They need to be designed and tested for road use. Cyclocross is not demanding on the brakes and the fluid will never get a chance to overheat. I am sure Shimano have thought about these things, but the way they are marketed is key. Wouldn't want to buy hydraulics designed for cyclocross

Ah right, I see where you're coming from.

I've checked the Sram and Shimano sites and they list the brakes as being for road use and no mention of cyclocross.

Dippydog3

I have, and am very happy with 785 hydraulics on my road bike. And its eleven speed as well.

How Far is too Far

I have a Sram Force Hydros and find them to be brilliant, not been to the Alps with them but I have done most of the big hills in the lakes and the North Pennines and they have never shown any signs of overheating (I am 82kg)

I have used and still do use cable disk's and the Hydro systems are a lot better IMHO. Its my guess most road and all CX bikes will be on them soon enough.

kingstonian

I have the Shimano hydraulics, they are awesome. And yes, they are marketed for the road.

stueys

Rival 22 hyd on my winter bike, love them, peformance is consistently strong irrespective of conditions. Not ridden shim hydro so no baseline to compare across the two.

Re descents I understand the concern re getting the fluid hot but this feels more like a hypothetical theory to me. Pretty much all alpine descents have plenty of sections where you'll be cooling the brakes off (glandon especially) Unless you are someone who is dragging the brakes all the way down, in which case you might need to stop a few times.

Only descent I've really started to think about the heat was hammering down sal calobra which has far more turns than the average alpine descent.

ugo.santalucia

Stueys wrote:

Pretty much all alpine descents have plenty of sections where you'll be cooling the brakes off .

I know a few that don't...
I wrote this piece many years ago... there are stil over 34 tight hairpins in 6-7 miles or so

http://ridewithugo.xtreemhost.com/scalaro.html

meanredspider

Stueys wrote:

Re descents I understand the concern re getting the fluid hot but this feels more like a hypothetical theory to me. Pretty much all alpine descents have plenty of sections where you'll be cooling the brakes off (glandon especially) Unless you are someone who is dragging the brakes all the way down, in which case you might need to stop a few times.

As above, I did the Alpe D'Huez descent 5x during Alpe D'HuZes event (and 1 more time in practice that I'd forgotten about) with a HyRd on the front (BB7 on the rear). The HyRd has to be pretty much worst case as it is self contained for fluid, Alpe D'Huez must be pretty bad with all of its hairpins, and the event itself with lots of other bikes, slow traffic (much slower through the corners than a bike), "theoretical" 45kmh speed limit and warm temps means the brakes were working very hard, and finally, me at 85kg. I think if there were going to be overheating problems, I'd have had them. I also run a 160mm front disc just to complete the info - the largest likely to be fitted to a road bike (some choose 140mm).

I honestly think you'd need to be abusing the brakes badly to have an issue. In which case, even with rim brakes, you'd be blowing a tyre or destroying a carbon rim. On the same event I was doing I heard a few tyres let go. At least with discs you have the other brake - once you've popped a front tyre with rims I'd imagine it gets exciting

stueys

ugo.santalucia wrote:

Stueys wrote:

Pretty much all alpine descents have plenty of sections where you'll be cooling the brakes off .

I know a few that don't...
I wrote this piece many years ago... there are stil over 34 tight hairpins in 6-7 miles or so

http://ridewithugo.xtreemhost.com/scalaro.html

Thanks for posting that, looks gorgous so one to add to my bucket list....

Yep, guess there will always be an example road hidden somewhere that's twisty, hilly, or conditions where you can't ride as you would like. But shying away from equipment that is perfectly suited for the 99.9991 of the riding you do because of a hill you might encounter once or twice in your lifetime is probably overly cautious.

I get the theoretical risk, I'm just not seeing it as a consideration for the massive majority of the riding that most people do. The key thing is knowing the potential limits so you can ride safely within them. For me discs wouldn't worry me at all in the Alps, carbon clinchers I would think twice about. But having said that I spent a week coming down alp d'huez, glandon, et al with a buddy on a pair of 404 clinchers with no issues.

cycleclinic

The shimano systems are definatley for road use and will not overheat unless you really abuse them. Tour did a daft test with rider and lots of added weight down a hill with lots of braking. Can't find a link now but they managed to get them to overheat but the test was not real world. Real world they would be fine, especially if you use the XTR ice tech rotors, finned pads and 180mm rotor up front for something really steep and twisty.

Silicon nitride disc from kettle cycles are also available and these would never overheat. There are engineering solutions to these problems and all the parts are on the shelf so to speak in variou places.

ugo.santalucia

thecycleclinic wrote:

The shimano systems are definatley for road use and will not overheat unless you really abuse them. Tour did a daft test with rider and lots of added weight down a hill with lots of braking. Can't find a link now but they managed to get them to overheat but the test was not real world. Real world they would be fine, especially if you use the XTR ice tech rotors, finned pads and 180mm rotor up front for something really steep and twisty.

Silicon nitride disc from kettle cycles are also available and these would never overheat. There are engineering solutions to these problems and all the parts are on the shelf so to speak in variou places.

Malcolm... any reason not to upsize my front rotor from 160 to 180? My fork is a rather beefy Planet X XLS with carbon blades and alloy steerer... it weighs 750 grams or so, it's not a flimsy 400 grams job....

bruto0

ugo.santalucia wrote:

The other barrier is 11 speed... I don't want 11 speed and if they are only going to make 11 speed levers, it's probably a no go for me.

from what I heard, SRAM 11 speed levers work just fine with 10 speed RD/cassette
so if you're buying them, you can recoup some of the cost by replacing the chain, RD and cassette - 10 speed versions ought to be a bit cheaper

holiver

The SRAM levers are uglier in my opinion. That may or may not be important to you.

ugo.santalucia

holiver wrote:

The SRAM levers are uglier in my opinion. That may or may not be important to you.

Double tap has always been a bit confusing to be honest... but most importantly they are traditionally prone to fall apart

robbo2011

ugo.santalucia wrote:

Stueys wrote:

Pretty much all alpine descents have plenty of sections where you'll be cooling the brakes off .

I know a few that don't...
I wrote this piece many years ago... there are stil over 34 tight hairpins in 6-7 miles or so

http://ridewithugo.xtreemhost.com/scalaro.html

12 Km at 9.5% average. Now that is a proper climb. must get down there sometime.

ugo.santalucia

robbo2011 wrote:

ugo.santalucia wrote:

Stueys wrote:

Pretty much all alpine descents have plenty of sections where you'll be cooling the brakes off .

I know a few that don't...
I wrote this piece many years ago... there are stil over 34 tight hairpins in 6-7 miles or so

http://ridewithugo.xtreemhost.com/scalaro.html

12 Km at 9.5% average. Now that is a proper climb. must get down there sometime.

Problem is it goes nowhere and you have to go down the same way, which is less fun... the climb itself is hard as a nail, but very beautiful and rewarding

cycleclinic

Ugo only upsize the rotor if you really want a bigger heat sink. Shimano claim with there MTB systems that the ice tech kit allows riders to drop one rotor size i.e 180mm to 160mm 203mm to 180mm. Your forks will be fine I take it it's the new genesis one, it a beefy thing.

The only time I would be tempted to put 180mm rotors on would be that horrible 400m drop I did in Italy on a mountain road shaded by trees, uneven road surface, -10% to -20% gradient, lots of sharp harpins and I did not dare let my speed creep much over 20 mph as the shade/light was limiting what I could see. My caliper brakes did not feel right after that and rims were too hot too touch.

SRAM double tap shifters do fall apart. The only warranties I get are for these. Good thing fisher's have replaced shifters that were 4 years old with no orginal proof of purchase.

Oh if you get youself down to calibria you can do this, the average gradient is not as steep but with 5km at 11% and with long sections 13%-17% peaking at 22% it is not easy. Take the wiggly road out of osomarso, this goes somewhere Momarmo. Oh and it pretty up at the top. Take a bike with a lower gear though 41:27T was not nice to turn. I was not expecting it to be so steep.