PeteHski

From those pics it looks like the rotor got contaminated with something which then burnt on. You can see traces of it near the hub where the word “lock” is stamped on the rotor.

Nah, on second thoughts it really looks like it over-heated massively.

spclark 

Yes, try to avoid fingerprinting / contaminating the surface of your discs with anything whatsoever. The idea is the brake pads should have a clean disc to do their work with; anything in between will impede their performance potential.

Discs can be cleaned with denatured alcohol or acetone but be careful to keep solvents AWAY from the pads.

I don't see anything wrong (from what you've shown us) but your LBS crew's opinions are worth more than my $0.02.

That coloration is commonplace with heat applied to stainless, but if the discs don't show any warping or unusual wear I think you'll be fine riding on them. Maybe adjust your braking habits a bit so they're not ON 110% for prolonged periods?

I use my rear at partial pressure when the fronts are 100%; you want to have a. balance of braking power between both ends 'cause those're the only points your tires have contact with the ground.

Fronts do a LOT more work than back, but both be employed at the same time just not to the same degree or your rear will lock up and that's A Bad Thing.

PeteHski

Yours looks like the one below.

https://www.******.com/r/bikewrench/...ced_smoke_too/

spclark 

That link goes nowhere. Why the •••••• ?

Mtracer

I can't understand what misalignment you are thinking of beyond some brake pad rub. If pads rub a little, then sure you don't want that. Though if it were rubbing so bad it was overheating, I think you'd find the bike really hard to move. So unless your putting out 1,000 W and moving like 4 MPH, I don't see how brake rub would be overheating anything.

I just don't think there's any reason to not ride the bike. I don't think you're going to hurt anything or make anything worse. I'm assuming there's no obvious bad noises etc.

Maybe the rotors were overheated by someone else on a test ride (seems unlikely). But as I said earlier, my bet is on something else left on the rotors that turned weird colors, maybe not even due to high heat. If the brakes work, ride the bike until you can get it looked at by the shop.

As for touching the rotors with your hands. You don't want to do that. Any oils have the potential to contaminate the pads and greatly reduce braking or if nothing else, the brakes will squeal like crazy. It's not big deal to clean the rotors. Just put some alcohol or similar on a clean rag and wipe both sides of the rotor.

LarrySellerz

Ive essentially been doing hill repeats, because the corner store is at the bottom of the hill which is 1.8 miles and 415 feet, with some very steep sections

PeteHski

This forum appears to auto blank links to another well known forum beginning with r and ending in t.

genejockey 

That is correct.

eduskator

I heard OP has Velcro on his arse to avoid this.

indyfabz

Yeah. There is that, but I didn't want to like go there.

mstateglfr 

With 80% of Larry's threads having been about how he caused random problems due to his bike(s) being old/in poor condition, I would have figured a brand new high level bike would equate to significantly fewer Larry issues threads.
Yet here we are- 4 pages in.

njkayaker

It’s fairly obvious that the problems are due to Larry being Larry.

tomato coupe

Yep, what's the common denominator?

aliasfox

I'm sure if you take the bike to Redwood City, they'll be able to diagnose and help you with the issue. I'm surprised the bike uses Wilier branded rotors, and not a Shimano floating type (I see Shimano cranks on your bike, I assume the rest is Shimano, as well). I've never purchased from them, but the couple of times I've stopped in, they seem nice. It looks like there might've been some residue on the rotors that heated up when you used the brakes - looks like a frying pan that's been left on the heat too long.

Riding in the same neck of the woods as you, I don't know if I've ever ridden the brakes going down any of the roads coming off of Cañada Rd. I've gone down Page Mill a handful of times in the past couple of months, and I've slammed on my brakes going into those -15% switchbacks - but I definitely don't have the brakes on for miles - kind of ruins the fun. I'll double check, but I don't think I've seen that kind of discoloration on my rotors (and at 195lbs, I'm not exactly featherweight).

If that were on my bike, I'd consider switching to Shimano IceTech rotors and metallic pads to mitigate heat going forward.

SoSmellyAir

A while ago, before buying spare brake pads for my gravel bike, I did some research into resin vs. metallic brake pads and learned that some cheaper rotors (e.g., Shimano RT56) were only compatible with resin pads because they have not undergone heat treatment. If these cheaper rotors are used with metallic pads they overheat and warp. While this may or may not be the cause in the OP's case, the purplish bluish hue near the braking surface of the rotor is the classic sign of overheating.

LarrySellerz

I live on silverhill road. It is, to my knowledge, the steepest hill in Redwood City. If you’re climbing farm hill to Canada college, it’s to the left of the last bump and steeper but shorter.

Btw I think I figured out part of the issue. Im constantly on my phone, watching YouTube videos and stuff, it’s a personal problem as well as generational thing. I descend my hill, then farm hill to Alameda, with my right hand occupied with my phone. The front brake has to do all the work, and im not engaged enough to ride it fast so yeah I’m dragging that front brake a lot. I do this like 2 or 3 times a day. This probably explains to rotor color happening so quickly.

my hill is the hella steep silverhill, and then down to the main road there are 3 steep bumps with flattish between. I could limit my braking, but you can easily hit 50+mph even 60 on this route and I don’t like going fast down hills.

my bikes also making a messed up noise that I think is unrelated to this and I’m taking it to the shop asap. Unfortunately it rained a bit so the bike has aged like x10 of what it normally would . Keep it outside at work because im moving between buildings all the time. Try to keep it dry but when it’s wet it is wet

LarrySellerz

Is the rotor wearing away from this? If I weighed the rotor after scrubbing the purple stuff off, would it be much less?

I need stuff repeated multiple times sometimes.

Is that blueish hue also on the braking surface itself but getting constantly rubbed off?

It is easily removable with elbow grease and solvents or is the new color of the metal.

genejockey 

Much that had been obscure is now clear.

PeteHski

No

PeteHski

I just checked the front rotor on the bike that I took to the Alps and regularly ride down 20%+ local hills. Thousands of miles and there is a very slight hint of discolouring in the same area as yours. But nowhere near as obvious. I weigh around 80 kg and brake “normally”. These brakes had the hardest time in the Alps as I was riding in a large group on unfamiliar descents and was dragging the brakes almost constantly for tens of km at a time with no recovery cooling. I wore out the pads in less than a week, but otherwise no issues.

mstateglfr 

You ride down a steep twisty road while watching youtube with your phone in your right hand?
That isnt a generational issue, its simply a you issue. Dont push that onto an entire generation.

aliasfox

I haven't yet gotten a cycling computer (maybe soon), so my phone is in a stem mount. I rarely look at it when I'm moving, and then it's just to check directions or the time. If I'm checking/responding to texts, it's at a light or pulled over.

I'm 38, so solidly millennial - let's just call this a personal thing. I've ridden with many others between 30-40 who are able to stay off their phones, as well.

If we can't stay off of our phones while on a two-wheeled vehicle, where our contact patches are about 2 square inches total, and the only crash protection comes from an inch or so of styrofoam, then how do we expect drivers protected behind two tons of steel to pay attention?

I understand some of the liberties we take as cyclists (especially when there isn't any traffic), but first and foremost we should be paying attention to our surroundings. I say this after a couple of close calls last night threading through rush hour traffic - luckily, the drivers were paying attention, as was I.

eduskator

Larry is a bada*s, period.

Still can't get over that saddle angle... I even dreamt of it last night. The guy must have serious arm strength, especially if he's holding his phone with one hand.

njkayaker

Your rotor problems are likely soon to be superseded by smacking into a car. So, stop worrying about the rotor.

njkayaker

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