Just upgraded mechanical brakes to full hydraulics on my new giant defy. Is changing the rotors good or bad idea?
The rotors are only a chunk of aluminium. The power comes from the pistons and the pads. Heat build up is another matter.
I changed the trp Spyres on my Defy for shimano hydros and left the trp rotors on. No problems. I can't imagine there's anywhere in the UK with a long enough Road descent with enough braking for heat build up to be an issue. I'm darn sarf though so could be wrong
I changed mine from 160mm TRP to 140mm Shimano Freeza on my Defy - prettier aren't they 😆
Dirty rider
How do you determine the rotor size? I thought I would have to stay at what bike came with.
[i]How do you determine the rotor size? I thought I would have to stay at what bike came with.[/i]
You can use bigger rotors with adapters for the mounts
How do you determine the rotor size? I thought I would have to stay at what bike came with.
the defys all use the same frame (apart from the ones with the ISP)
the TRP brakes come with +20mm post mount adapters, the frame takes 140mm rotors stock (as seen on some of the other models) i went down to 140mm when i changed wheels as i didnt see the need for 160mm ones
Thanks dirtyrider I mite do the same. I think 160 mite be a bit too much.
They really aren't too much. But if you want to save a few grams and have a nicer looking rotor crack on
Not if you're 100kg !
the top spec defys come with 140mm rotors, i guess it was cheaper to spec 160mm on the lower end models
So if I take off the spacers I can have 140's ?
Yes
160 won't be too much. You just adjust how much you yank* on the lever. *More like gentle feathering 😉
Can't say I've checked but isn't it more likely to do with frame size? Mine is an XL. Can't see how a bigger rotor with an extra adaptor is going to work out cheaper
The adaptor is already on the caliper. You just take it off which brings it in 20mm
Dirty rider
What do I need to do to be able to have centrelock discs. You can't get 6 bolt on a 140mm.
ice tech rotors are just a steel-aluminium-steel sandwich to provide greater cooling when being used heavily (eg decending the Alps on a heavy full susser).
On a road bike, unless you are a big lad doing lots of downhill braking, I would have thought they were a waste of money.
Size, pad material and brake design will have more effect.
Centrelock disks need a centrelock hub so I would forget it. You can get 6 bolt adapters for centrelock hubs but not the other way round.
As for rotor size your frame and fork will have a size limit due to the forces.
Bigger rotors will also help with heat dissipation (as more area) as well as better braking.
I replaced the worm out TRP rotors on my CX bike a couple of weeks ago, I nearly went for the Icetech rotor but in the end went for the normal Shimano 6 bolt RT76's and saved myself 8 quid an end.
I'm using RS685 hydraulics and I haven't noticed any difference in the braking.
centrelock discs. You can't get 6 bolt on a 140mm.
Bought centre lock wheels
FWIW I have the 140's as standard on mine (Advanced Pro 2) and they are plenty powerful. 75kg rider. I have 160's on my Croix De Fer and they feel just the same, although that is a heavier bike and sometimes loaded up for touring.
Sure you can't get 6 bolt 140's?
Google is indeed your friend...
Got a 6 bolt 140 on the back of my cotic x
Rocketdog send me a link please?
ice tech rotors are just a steel-aluminium-steel sandwich to provide greater cooling when being used heavily (eg decending the Alps on a heavy full susser).On a road bike, unless you are a big lad doing lots of downhill braking, I would have thought they were a waste of money.
The difference between [i]"decending the Alps on a heavy full susser"[/i] and a road bike, is the FS bikes loses a lot of energy to the ground/shock. On the road you have none of that, so the brakes do a lot more work. Also the speeds are generally higher, even on a DH track most people probably average 20mph though anything technical (where you'd need to be braking), on a road bike any chimp can hit 40mph downhill without breaking a sweat.
Not saying you need 203mm rotors, but bigger rotors, or rotors with more cooling capacity do have their place on the road. Similarly I'd not run ice-tech rotors on the commute or cross bike, the braking surface is way too thin to be durable in crappy conditions.
I can't imagine there's anywhere in the UK with a long enough Road descent with enough braking for heat build up to be an issue. I'm darn sarf though so could be wrong
I know of several descents on Exmoor and the Quantocks steep enough to turn my rotors blue. 😕
Derbyshire, North Yorkshire, The Peak District, Lake District and so on. Plenty of places where you can get some serious descending in.
Whats worse is a lot of them are relatively tight, twisty and steep with quite often poor surfaces. So lot of changes in speed. Some of the ones i've done are basically 4 or 5 minutes of repeated acceleration to 50 or 60 kph then braking to 20 or 30. Can get rims too hot to touch with no issues at all.
I'd prefer 100+kph down an alp than some of the descents in the UK.
I've passed 60mph (100kph) here quite a few times. 😉
[url= https://www.strava.com/segments/1225403 ]Crowcombe Combe.[/url]
Anyone with links for 140mm rotors?
Anyone with links for 140mm rotors?
You can't get Ice Tech Freeza rotors in 140mm 6 bolt.
ghostlymachine - MemberWhats worse is a lot of them are relatively tight, twisty and steep with quite often poor surfaces. So lot of changes in speed. Some of the ones i've done are basically 4 or 5 minutes of repeated acceleration to 50 or 60 kph then braking to 20 or 30. Can get rims too hot to touch with no issues at all.
As I understand it, this is the sort of braking you want. High speed with a occasional strong braking effort, rather than continuous dragging of the brakes, which doesn't allow the brakes any chance to cool down in between efforts.
jacob46 - MemberDirty rider
What do I need to do to be able to have centrelock discs. You can't get 6 bolt on a 140mm.
Plenty of 140mm rotors available with 6 bolts....
6 bolt not Centre locking
I ain't changing wheels as well.
Thanks.
Have you clicked on any of those links stumpy01 posted? People try to help......
jacob46 - Member6 bolt not Centre locking
I ain't changing wheels as well.
Did you look at any of those links? They are all 6 bolt. 😆
davosaurusrex - MemberPeople try to help......
Oooooh, you wonder why you bother sometimes, don't you!? 🙄 😀
Oooooh, you wonder why you bother sometimes, don't you!?
Got form for it, do you have a head office he can complain to? Await the "no one answers my questions about 140mm rotors thred". 😉
http://singletrackworld.com/forum/topic/pinnacle-arkose-4-front-hub-bearings-help-please
It's not occasional, it's repeated, hard on the brakes, off for 30 seconds, hard on the brakes and so on. It's not as bad as dragging them (is anything?), but the long open descents in the Alps and the Pyrennes might give you minutes between applications, plus it's quite often just to feather off a bit of speed. Not dumping half of it.As I understand it, this is the sort of braking you want. High speed with a occasional strong braking effort, rather than continuous dragging of the brakes, which doesn't allow the brakes any chance to cool down in between efforts.
I'm surprised they aren't looking at bigger discs on road bikes to give a bigger heatsink TBH.
I'm surprised they aren't looking at bigger discs on road bikes to give a bigger heatsink TBH.
That's what the ice-tech/freeza rotors give you, the disk is extended inwards from the aluminium core (aluminium conducts much better than steel) to the cooling fins which give you the area (and turbulent air) which is what gives you the heat transfer.
My Ice tech ones on the MTB do stay noticeably cooler than the equivalent solid rotors.
To be fair to the OP the title does say Shimano Ice Tech 6 bolt, which I've not been able to find in 140mm flavour.
[quote="thisisnotaspoon"]That's what the ice-tech/freeza rotors give youAh, gotcha. Will go and have a look at that then.
OTOH, if you get them hot enough, the aluminium melts and dribbles out the bottom. Probably fine unless you're a dragger, but lots of people are.
Looks shiny, use the aluminium core to conduct heat away from the braking suface, then instead of cooking the aluminium core, radiate it away from the fins.
Think i've seen some images of melted icetech cored rotors somewhere.
Think i've seen some images of melted icetech cored rotors somewhere.
Yea, a few people have problems.
Catch 22, do you become a better rider, brake less and not need better rotors, or do you buy better rotors and run the risk of melting them. My hunch would be that if you can melt ice tech rotors, you'd have fading or boiling issues with normal ones anyway.
Similarly I'd not run ice-tech rotors on the commute or cross bike, the braking surface is way too thin to be durable in crappy conditions.
bollocks, why are they specced on mtbs then?
My mtb gets a clean when it's dirty, my commuter. Um. It gets a clean occasionally.
I'm surprised they aren't looking at bigger discs on road bikes to give a bigger heatsink TBH.
I think it's safe to say airflow would be usually much greater due to faster forward and rotational speed..?
Edit : ignore me, I didn't realise that the Freeza rotors are CL only. How annoying.
Similarly I'd not run ice-tech rotors on the commute or cross bike, the braking surface is way too thin to be durable in crappy conditions.
bollocks, why are they specced on mtbs then?
Prob because there's a performance benefit for some at the risk of some reduced lifespan but you'd replace a rotor once the surface has shown noticeable wear compared to the spokes anyway, ice-tech or std rotor. For a cross or commuter bike, why would you need ice-techs in the first place?
I'd just fit a 180 std rotor on the front if durability and heat was a concern, more surface area per wheel rev.
bollocks, why are they specced on mtbs then?
Because (as JamesO says) they're better at what they're designed to do.
But the steel surface is quite a bit thinner than even I'd (as a penny pinching northerner) let a solid rotor wear by.
I've got 2 sets of ice-tech rotors, both bought aftermarket so I knew the limitations (poorer life, chance of melting) and feel they're a good compromise in the hot/dry. Not much use for them in the wet and mud so I stick cheaper rotors on my SS and swap the ice techs for solid rotors in winter.
The difference between "decending the Alps on a heavy full susser" and a road bike, is the FS bikes loses a lot of energy to the ground/shock. On the road you have none of that, so the brakes do a lot more work. Also the speeds are generally higher, even on a DH track most people probably average 20mph though anything technical (where you'd need to be braking), on a road bike any chimp can hit 40mph downhill without breaking a sweat.Not saying you need 203mm rotors, but bigger rotors, or rotors with more cooling capacity do have their place on the road. Similarly I'd not run ice-tech rotors on the commute or cross bike, the braking surface is way too thin to be durable in crappy conditions.
Surely on a road bike if you are braking you are doing it wrong 😉 I am not a road cyclist but do you not also use your body drag by sitting up in a brake dragging situation? I can see why a long drag or brake from high speed would put a lot of cooling requirements into a road bike brake though, I just expected there to be more scope for predicated and managed braking (after all most roadies will be used to rim brakes where abuse is wearing out your expensive wheels) and using your body drag than mountain biking where you might have to brake suddenly and very sharply and staying composed on rough terrain dominates body position etc.
I have turned a brake disc blue on my mtb up on a road section near rivington when a tractor pulled out in front of me with a plough on the back though.
As for the thin metal then surely gritty mtb is the worst place for them but good point about them and that is why I chose not to get them (apart from me not needing them). Larger discs make more sense than fancy dissimilar metal sandwiches which have thin braking surfaces and failure of the disc on a road bike would be very nasty indeed. There might be a very slight increase in weight but i think there are plenty of places to lose weight that make more sense than brakes, especially if you do ride somewhere with big descents. If you ride in Norfolk then stick the smallest brakes you can find on!
[quote="molgrips"]I think it's safe to say airflow would be usually much greater due to faster forward and rotational speed..?Yes, but the energy going in (worst case) is far far greater. You still need to store it all somewhere before you can dump it to atmosphere.
Surely on a road bike if you are braking you are doing it wrong I am not a road cyclist but do you not also use your body drag by sitting up in a brake dragging situation? I can see why a long drag or brake from high speed would put a lot of cooling requirements into a road bike brake though, I just expected there to be more scope for predicated and managed braking (after all most roadies will be used to rim brakes where abuse is wearing out your expensive wheels) and using your body drag than mountain biking where you might have to brake suddenly and very sharply and staying composed on rough terrain dominates body position etc.
Whilst sitting up to slow down is useful in a group, it's not something you'd do to have significant effect on a decent, you still need to brake for corners. And when you do it's a lot more energy than on an MTB.
That and [i]if you are braking you are doing it wrong[/i] is a bit like saying Sam Hill can ride the Fort Bill track in sub 5 minutes with 180mm rotors so why do people ride trail centers ever need 200mm ones? What the Pro's do, and what Joe Blogs does are going to be very different. I suspect that Joe will drag his brakes down decent to keep his speed sensible, Contador won't! In the same way you (comparatively) rarely see pro's melting the repair patches off tubes due to the heat from rim brakes.
Like Disks themselves, ice-tech/freeza is a development, you don't have to use it, but it's probably a marginal gain over conventional disks, which are probably a gain over rim brakes for Joe Blogs.
andyl - Member
I am not a road cyclist but do you not also use your body drag by sitting up in a brake dragging situation?
yes, sitting up into the wind will slow you down a bit, but sit up enough to make the most of it and you can't reach the levers properly - they're down in the drops...
dirtyrider - Member
why are they (ice tech rotors) specced on mtbs then?
the name 'ice tech' is really cool, and we're total mugs for that kind of thing.