finned brake rotors

ugo.santalucia
ugo.santalucia Posts: 28,271
edited March 2016 in Road buying advice
Anyone would recommend a finned rotor over a conventional one? Is the extra cooling a tangible quantity or it's just marketing gimmick like many others?

I'm asking as I cooked a rotor coming down Buttertubs in high winds and would be tempted to try something with more cooling power.
More specifically, being on 6 bolts rather than centrelock, anyone with experience as regards the finned Superstar offerings? I'm in two minds about putting my life in the hands of Superhands... I mean Superstar, but if someone real can recommend them, I might even make the leap... after all, how to resist the lure of some colour anodised tat... :oops:
left the forum March 2023
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Comments

  • Ouch- were they still able to stop you though?

    I'd be tempted to take a 'cross bike with disks with me when I go climbing up North again because of the steep, twisty descents I often find myself on (I've had calliper rubber get burnt coming down a particularly treacherous lane in Wales...) but I do wonder how it would cope with the heat.
  • The front rotor was glowing at the bottom and the pads did smell of burnt... they lost power towards the end of the descent, approaching the T junction, but as they cooled they went back to working fine... the rotor turned charred black. It was a very hard day, as anyone who did the Etape du Dales can confirm weather wise, but those days are not uncommon up-norf
    left the forum March 2023
  • paul1000
    paul1000 Posts: 190
    Had the same problem down a long very steep descent in n/wales, lost my brakes for a while, managed to stop and the front was smoking and when cooled they were fine, have seen these finned holders and wondered myself, might be a gimmick but aluminium is a very good conductor of heat so might work, don't know if they would fit trp spyres though.
  • paul1000
    paul1000 Posts: 190
    Sorry, I was looking at the pad holders which superstar sells.
  • meanredspider
    meanredspider Posts: 12,337
    They may make some difference but I'm a little surprised you had it glowing - I didn't manage that down Alpe D'Huez and I was pushing and it was hot (and I suspect I'm weightier than you). Was the rear brake doing its share of the braking? My disc was blue at the end of the day but I don't think I cooked it completely.
    ROAD < Scott Foil HMX Di2, Volagi Liscio Di2, Jamis Renegade Elite Di2, Cube Reaction Race > ROUGH
  • (Very) Marginal gains :roll: ... Surely better to wait until vented discs are available?
  • They may make some difference but I'm a little surprised you had it glowing - I didn't manage that down Alpe D'Huez and I was pushing and it was hot (and I suspect I'm weightier than you). Was the rear brake doing its share of the braking? My disc was blue at the end of the day but I don't think I cooked it completely.

    It was one of those days... with 40 mph side gales I had to brake far more than one normally does... combine that with a steep 2 Km section, that averages 10%, but it's more often 15-20% and you get the picture.
    left the forum March 2023
  • (Very) Marginal gains :roll: ... Surely better to wait until vented discs are available?

    Not thick enough to be vented, at less than 2 mm
    left the forum March 2023
  • meanredspider
    meanredspider Posts: 12,337
    They may make some difference but I'm a little surprised you had it glowing - I didn't manage that down Alpe D'Huez and I was pushing and it was hot (and I suspect I'm weightier than you). Was the rear brake doing its share of the braking? My disc was blue at the end of the day but I don't think I cooked it completely.

    It was one of those days... with 40 mph side gales I had to brake far more than one normally does... combine that with a steep 2 Km section, that averages 10%, but it's more often 15-20% and you get the picture.

    Yup - I can imagine you were braking more than you would normally anticipate. I'm still a bit surprised as much of the Alpe descents had me dragging brakes behind vehicles at times and that's 10k+ at 10% etc etc. Maybe share a bit more of the lighter braking with the rear? I don't know what the Shimano Ice Tech (?) is like...
    ROAD < Scott Foil HMX Di2, Volagi Liscio Di2, Jamis Renegade Elite Di2, Cube Reaction Race > ROUGH
  • They may make some difference but I'm a little surprised you had it glowing - I didn't manage that down Alpe D'Huez and I was pushing and it was hot (and I suspect I'm weightier than you). Was the rear brake doing its share of the braking? My disc was blue at the end of the day but I don't think I cooked it completely.

    It was one of those days... with 40 mph side gales I had to brake far more than one normally does... combine that with a steep 2 Km section, that averages 10%, but it's more often 15-20% and you get the picture.

    Yup - I can imagine you were braking more than you would normally anticipate. I'm still a bit surprised as much of the Alpe descents had me dragging brakes behind vehicles at times and that's 10k+ at 10% etc etc. Maybe share a bit more of the lighter braking with the rear? I don't know what the Shimano Ice Tech (?) is like...

    it's only 8% average... 12.5 Km at 8% or so.
    I find northern descents far more technical than the Alpine and Pyreneean ones... worse weather, worse surface, narrow roads, bigger gradients
    left the forum March 2023
  • Ber Nard
    Ber Nard Posts: 827
    (Very) Marginal gains :roll: ... Surely better to wait until vented discs are available?

    Not thick enough to be vented, at less than 2 mm


    Hope have done it but they have to be used with specific calipers due to the additional width.
  • meanredspider
    meanredspider Posts: 12,337
    They may make some difference but I'm a little surprised you had it glowing - I didn't manage that down Alpe D'Huez and I was pushing and it was hot (and I suspect I'm weightier than you). Was the rear brake doing its share of the braking? My disc was blue at the end of the day but I don't think I cooked it completely.

    It was one of those days... with 40 mph side gales I had to brake far more than one normally does... combine that with a steep 2 Km section, that averages 10%, but it's more often 15-20% and you get the picture.

    Yup - I can imagine you were braking more than you would normally anticipate. I'm still a bit surprised as much of the Alpe descents had me dragging brakes behind vehicles at times and that's 10k+ at 10% etc etc. Maybe share a bit more of the lighter braking with the rear? I don't know what the Shimano Ice Tech (?) is like...

    it's only 8% average... 12.5 Km at 8% or so.
    I find northern descents far more technical than the Alpine and Pyreneean ones... worse weather, worse surface, narrow roads, bigger gradients

    Well, that's why I said 10k at 10% - much of the ramps are around 10% - it's the 21 hairpins that are flatter - but they're the bits that you are slow anyway. And, given that cooling (if I remember my O-level physics right) is dT to the power of 5, ambient temp makes a big difference. Northern descents tend to be a lot straighter (at least the Highland ones are - they don't come much more Northern) and tend not to bother with hairpins. But I've never had issues at any point with brake heat (despite hitting 59mph before now). Good luck with sorting it.
    ROAD < Scott Foil HMX Di2, Volagi Liscio Di2, Jamis Renegade Elite Di2, Cube Reaction Race > ROUGH
  • mamil314
    mamil314 Posts: 1,103
    Last i checked, Shimano Ice-Tek RT99 'Freeza' seemed to be 'best' widely available consumer grade disk.
  • Last i checked, Shimano Ice-Tek RT99 'Freeza' seemed to be 'best' widely available consumer grade disk.

    That's centrelock only though
  • mamil314
    mamil314 Posts: 1,103
    True. On the other hand, that guy could, probably, swap a hub quicker than i could a freehub.
  • Interesting. Are mountain bike discs/pads any better at losing heat than road ones? My touring bike has Avid Elixirs with a 160mm rotor. I've ridden down there and down a lot of the other steep descents in the Dales with four panniers full of camping gear with no issues. Would have thought there was a lot more potential energy in my setup to get rid of, but I wasn't injecting any more into the system by peddling! Guess it is about as aero as a brick as well so lots of energy lost to air resistance, so less need to use the brakes?
  • Jagwire makes a finned rotor virtually identical to the Shimano one, but 6 bolts compatible... 54 Euro in Germany, anyone can find it in the UK?
    left the forum March 2023
  • mamba80
    mamba80 Posts: 5,032
    Try different pad compounds? and/or a bigger rotor.
  • mamba80 wrote:
    Try different pad compounds? and/or a bigger rotor.
    I've tried a bigger rotor, but it seems to put a lot of strain on the fork, which being a carbon with alloy inserts, is not the strongest attachment out there.

    Pads are all the same, meaning there are three compounds and none of them has all advantages... eg sintered take more heat, but they also conduct more heat towards the hydraulic.

    The reality is that there is a lot of choice of "brands" but they all sell the same thing
    left the forum March 2023
  • mamba80
    mamba80 Posts: 5,032
    You could try a dot5.1 brake fluid, with a sintered pad.

    with Shimano, the finned ice tech pad ?

    tbh i did think all these problems didnt exist with disk brakes?
    having toured extensively on a 1950's charlton, fully laden in the Pyrenees, with those little fibrax red brake blocks, deliberately travelling on back roads and having no really problems, i m glad i wasnt on disc's lol!
  • fenix
    fenix Posts: 5,437
    This thread isn't encouraging me to go to discs. I've done Buttertubs and the Alps and had zero problems braking with normal rim brakes.
  • Fenix wrote:
    This thread isn't encouraging me to go to discs. I've done Buttertubs and the Alps and had zero problems braking with normal rim brakes.

    Buttertubs was with a 40 mph side/tail wind, I think that created the issue... but those conditions are not uncommon
    left the forum March 2023
  • mamba80 wrote:
    You could try a dot5.1 brake fluid, with a sintered pad.

    with Shimano, the finned ice tech pad ?

    None of these solutions is feasible
    left the forum March 2023
  • I've been looking for 6 bolt finned rotors and came across these. http://www.tredz.co.uk/.Jagwire-Elite-C ... _84878.htm
  • meanredspider
    meanredspider Posts: 12,337
    Well, I'm 5 years plus of using disc brakes on road bikes, weighing in from 85-95kg. I'm known as "Bomber" by my Highland cycling buddies because I descend fast. I've done close to 100kmh down from Glenshee. I've descended the Alpe lots of times - the last 3 ramps are at or close to 12%. It was 33C at one point. I've done 15% 1km twisty descents. Never had heat problems. I can't think of testing these brakes more thoroughly.

    Ugo - I can only think you dragged your brakes or they were dragging. They simply didn't have the opportunity to dissipate heat.
    ROAD < Scott Foil HMX Di2, Volagi Liscio Di2, Jamis Renegade Elite Di2, Cube Reaction Race > ROUGH
  • cycleclinic
    cycleclinic Posts: 6,865
    Finned rotors do help. Shimano for example say with finned rotors you can go one rotor size down.

    the best of course are the XTR freeza rotors. Overheating those is hard but you need CL hubs. The XT rotors are the next best.

    Finned pads too. If I had a disc brake bike for anything but commuting then it would have finned rotors 160F/160R and finned pads and ideally CL hubs as I think these transfer heat better. Since however I ride it in suffolk I don't need that.

    And for those that think that disc brakes are a bad idea because of this over heating issue. One long hill decent to many I cooked my rim brake pads. they were not worn but they smelt bad and I needed move my braking points back by the end of the last decent.

    Having used disc brakes on MTB's for year and had some overheating issues early on those issues have been resolved. Now as always roadies have to learn new tricks. The issue of the forks could be a real issue and it is possible that the light weight carbon disc forks may not be the best solution. I know the set I have (ritchey) flex alot when I brake. They have been removed and replaced with a set of Lynsky forks these are heavy but stiffer.

    Had one customer who had his wheel pull over to the left on braking. He thought it was the wheel I built but being a canny chap he swapped wheels with a friend and found the same problem but his friend did not. So it was the fork leg that was flexing.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • Finned rotors do help. Shimano for example say with finned rotors you can go one rotor size down.

    the best of course are the XTR freeza rotors. Overheating those is hard but you need CL hubs. The XT rotors are the next best.

    Finned pads too. If I had a disc brake bike for anything but commuting then it would have finned rotors 160F/160R and finned pads and ideally CL hubs as I think these transfer heat better. Since however I ride it in suffolk I don't need that.

    And for those that think that disc brakes are a bad idea because of this over heating issue. One long hill decent to many I cooked my rim brake pads. they were not worn but they smelt bad and I needed move my braking points back by the end of the last decent.

    Having used disc brakes on MTB's for year and had some overheating issues early on those issues have been resolved. Now as always roadies have to learn new tricks. The issue of the forks could be a real issue and it is possible that the light weight carbon disc forks may not be the best solution. I know the set I have (ritchey) flex alot when I brake. They have been removed and replaced with a set of Lynsky forks these are heavy but stiffer.

    Had one customer who had his wheel pull over to the left on braking. He thought it was the wheel I built but being a canny chap he swapped wheels with a friend and found the same problem but his friend did not. So it was the fork leg that was flexing.

    Shimano seems to have the upper hand, as the fins are actually integrated in the rorot structure, rather than being riveted to it like in the Jagwire case...
    What a better excuse to rebuild the front wheel on a DT 350 hub... it needed a rebuild anyway, after over two years of daily use... :wink:
    left the forum March 2023
  • cycleclinic
    cycleclinic Posts: 6,865
    You know you want too. The best disc systems have always been made by Shimano. tried others work on many more and none measure up.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • ugo.santalucia
    ugo.santalucia Posts: 28,271
    An update: I fitted a front DT 350 hub with CL and a 160 mm Shimano Freeza rotor. Very happy. This morning I went down this, which has a couple of Km at 12-13% average and very twisty. No fading, no squealing, no overheating

    https://www.strava.com/segments/6632912
    left the forum March 2023
  • cycleclinic
    cycleclinic Posts: 6,865
    thumbs up. All I did today was ride in the fens. It was not even that windy.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.