Jon_g2 

I was told higher end rotors dissipate heat better is this true? I guess my real question would be if ultegra is better than 105 which is what I would be upgrading to. If I'm not mistaking there isn't necessarily a "105" or "ultegra" rotor but I do have part numbers written down. I would be going from SLX-RT70 to CL800.

I love to climb because it only means I get to fly downhill on my way back home and if I can get better braking performance I definitely see the value in upgrading to high end rotors. If this is true, would dura ace then be better than ultegra performance wise? All info is highly appreciated.

SpedFast

Some rotor designs are better at dissipating heat than others, but my understanding is the pads have much more to do with stopping power. I -prefer organic as they have less tendency to squeal. With that said, a 180 rotor will probably be better at stopping than a 160. I've only had 160 rotors on my bikes and I found the stopping power enough to lock up the tires. Anything more than that is kinda unnecessary really

Koyote

Have you had problems with braking on descents? If so, please describe them, and people can offer helpful suggestions.

Jon_g2 

My bike can in yesterday with shimano 105 and it's my first bike with disc brakes and I wanted to see what components I can upgrade for better performance. I started doing research and this guy from a bike shop told me he'd upgrade the rotors because ultegra provides better heat dessipation. Now he's not a technician so I didn't know if to believe him lol.

No but seriously, it's not that I didn't believe him, but I'm just getting different people's thoughts in the matter.

Koyote

My thought: you should probably ride the bike before deciding that some component is not good enough for you.

Jon_g2 

Yes you pose a good point. But I don't want to find out on a descend that the cheapest rotors that shimano provides aren't very good at desisipating heat lol

Polaris OBark

It is not uncommon for bike manufacturers to cheap out on rotor quality. I would use IceTech XT/Ultegra finned rotors. I also don't recommend cheaping out on the pads. At the absolute worst, you are spending a few dollars more than you need to.

If the cheap rotors discolor, they are over-heating.

MarcusT

I've had cheap rotors with organic pads and they worked fine, and I've done some super downhills.
The pads wore out quickly is about the only downside.
I say keep what you have for now, wait until they wear out before looking at replacements

Mtracer

I've downgraded rotors becasue while the Ultegra (CL800) are supposed to cool better, and I accept they probably do, I found them hard to true. They use a sandwich of steel and aluminum and my limited experience with them is they changed shaped, warped would be too strong a term, after very mild use and would rub. Never could get them to not rub for any length of time. Went with next step down, all steel rotor, and no more issue with rubbing. Others have definitely NOT had this issue with them, so I'm not saying all of these are bad.

In my case, I don't have any problem that more cooling solves. So, the less expensive rotors work fine for me.

Unless you're really pushing the brakes to their limit, I doubt you'd notice any sort of improvement in braking by upgrading the rotors.

I'm with the others, solve a problem if you have a problem.

rsbob 

If you are worried about heat buildup, you might want to consider finned pads.

Maelochs

Based on reports from friends who either live in the mountains or ride aggressively on mountain bikes or both, pad choice is the number One factor in braking. Grippy pads might not last as long, but they will not fail under load .... Not saying your bike-shop mechanic is out to make a buck, but pads are chap and new rotors at retail price plus installation is probably good for his shop if not so much better for your braking distances.

Also as an early poster mentioned, most brakes will outperform the tires. Modulation and control are key, more than swept area. Bigger brakes won't necessarily stop you faster, but since you will be able to get the same wheel *********** with less pressure (same pressure over greater area) modulation would be easier. But it seems the pros manage with 160 mm rotors when racing down mountainsides so ... who knows?

While I have no data to back up the statement, I strongly doubt that upgrading from 105 to Ultegra would be the difference between life and death ... unless you ride so close to the edge that a mosquito or gnat could knock you over, or a butterfly cause you to crash with its wing-pressure. And if you really push to the absolute limit ... sooner or later, odds are, you will push too far no matter what gear you ride.

My actual answer is, "Sorry, I haven't a clue" but my desperate need for attention made me type all that stuff.

Jon_g2 

All really, really great answers which is why I come here to ask for help. I think the general consensus is to go with better pads instead of upgrading rotors then which is what I will do. I am aware that organic pads wear out faster but do brake better which is probably what I'm gonna go with. If I'm not mistaking I read that organic pads don't like to get wet much buy I don't do much riding in wet weather. My local shop doesn't carry swisstop so I'll look only as they seem to be the best there is unless you guys recommend others.

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PeteHski

IME standard 105 pads (organic) do not require an upgrade unless you live in the mountains with big days of high speed descending, in which case switching to sintered pads is a good option.

From what you have posted so far I would bet the standard 105 discs and pads will serve you fine. They are good brakes out of the box.

wolfchild

You just got a new bike which you haven't even ridden and you don't know how it handles and you already want to upgrade components ?...Makes no sense at all.

Herzlos

There are a lot of bikes with cheaper rotors than 105 so I wouldn't worry about it especially if they are your first set of discs.

Above that level a lot of it's about weight saving, so more expensive manufacturing, and a bit of heat dissipation. Unless you're braking hard for a long time on a steep descent on a hot day you'll probably be fine - certainly better than rim brakes.

That said, rotors aren't very expensive so there's no harm in upgrading.

Jughed

For reference I’m 185#’s

I have 105 discs on my road bike and the bottom spec SRAM on my CX bike. The SRAM stuff is flimsy in comparison to the 105.

I ride some mountains with both setups. I’m a timid descender and I use the brakes a bunch.

I do a sketchy gravel climb on the CX bike, 1.5 miles, 15-20%+ grade… Im on the cheap brakes hard the entire way down. Smoking hot rotors, you can smell the pads… no failures.

The 105’s are even better, never an issue. I have 10k miles on the pads and rotors… granted I don’t climb very often, but they are holding up just fine.

Maelochs

My crazy friends who go downhill fast recommend Hardheaded Ram disc pads in DH blue, or I think the tandem set in gold or yellow, maybe? But these were mentioned in a thread about insane downhills with the absolute need for reliable braking, in one case on an MTB and in the other, on a loaded touring bike.

I have never used them or even researched them but you might want to .

Koyote

Your stock brake pads are organic.

Just ride your bike.

Chuck M 

Some guy as in customer or some guy as in employee? Because the employee has a job to sell you things whether you need it or not. Another customer may be trying to sound like a walking encyclopedia of bicycle knowledge.

Just take Koyote’s advice and ride the bike and see for yourself how they work.

DorkDisk

For improved braking, I find going up a rotor size to be easiest and most noticable upgrade.

Jon_g2 

Lol you took the time to write a comment that doesn't help anyone. Thanks.

Koyote

He makes a lot of sense, actually.

Iride01 

If there was a big enough overheating issue with rotors that come on anything less than the top tier bikes overheating, then I think we'd have many more people posting about their issues with rotors overheating and probably quite a few class action lawsuits on all the brands of bicycles being sold along with the makers of those brake components.

People go down long mountain roads everyday. You aren't the only one that likes to go down them fast.

If you are using your brakes a lot while going down those long mountain roads, then you are doing it wrong.

PeteHski

+1
You are looking to upgrade something that probably doesn't need upgrading. Ride the new bike and see if you have any braking issues that require an upgrade. I doubt you will as stock 105 brakes are pretty solid. If you find that you are cooking the rotors and the pads are fading badly on your descents, that's the time to start looking at upgrade options. At least wear them out first!

cyccommute 

Frankly, if your brakes are fading on descents, it’s best to review the way the brakes are used! I live in mountains and do lots of steep downhills that are very often long as well. And I don’t hold back on speed. In 40 years of riding in Colorado (mostly), I’ve never experienced brake fade on any bike from cantilever equipped mountain bikes purpose used to heavily loaded road touring bikes to mountain bikes pulling trailers with camping gear to mountain bikes with bikepacking loads to tandems. In fact the tandem was pulling a trailer and used cantilever brakes.

Braking is more involved than clamping on the brakes at the top of a hill and keeping them clamped on until you hit the bottom. Pulse brake to give the brakes time to cool.