Tech Tuesday - Rotor Straightening

Sep 27, 2011

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The argument against using tools: There are a few different companies out there who manufacture tools made specifically to straighten rotors, simply pinching the rotor and acting as a lever to allow you to bend it easier. Some are designed to be used two or three at a time, with one or two holding a section of the rotor in place while the remaining tool acts as the lever. There is even a feeler gauge that allows you to see exactly how far the rotor is out, but nothing works as good as using your bare hands.

There are a few issues with using metal levers (this includes crescent wrenches as well) to straighten rotors, but the first is how easy it is to actually bend the rotor while using these tools. That isn't a good thing? Nope, especially for the home mechanic who might not be doing this repair that often. The extra leverage allows you to very easily bend the rotor too far, making the problem worse than it was when you started the repair. While it would be easy to blame the mechanic and not the tool, some bent rotors only require the slightest amount of force to straighten and some require much more, but a rotor tool can make it difficult to feel the amount of force that you are applying. Using your hands will give you a much better feel for what you are doing, allowing you to make smaller adjustments at each go.

Rotor straightening tools are often quite skinny as well, and applying pressuring to a very focused point on the rotor may do more harm than good. It is often much more effective to use your thumbs to spread the force out as you work the rotor back to straight. The worst case scenario is when so much force is applied by using a rotor straightening tool that it actually kinks the rotor where the tool makes contact, instantly turning it into scrap metal.

But aren't your hands dirty? When was the last time that you cleaned your rotor straightening tools? Your hands have oil on them right now, even if you've just woken up and haven't touched anything yet, which is why you'll want to clean them before doing this job. Getting that oil or grime from your hands onto the rotor will only be detrimental to the performance, so if you are going to try and straighten your bent brake rotor by using your hands you'll want to make sure that they are clean. Very clean. Wash them thoroughly, being sure to rinse off any and all soap that you've used, and then dry them with a towel that you know is clean. Alternately, you can just throw on a new pair of nitrile gloves and be done with it.

Some helpful pointers:
• Much like truing a wheel, this is one of those repair jobs that will only get worse if you try and rush it. Take your time, find the exact place where it needs to be straightened and make very small adjustments at each go. You want to avoid bending the rotor too far or doing it in the wrong place, both of which can cause the rotor to have a wave bend where it is out of true to both the left and right. That's when things can start to get tricky...
• While a small to medium gentle bend in a rotor can usually be trued out with great results, sharper kinks are likely going to be a death blow. Having said that, it certainly doesn't hurt to try and straighten anything.
• The rotor may be out of true in multiple spots, but only work on one at a time to keep things simple.
• The edges of a rotor are usually quite sharp. Be careful not to cut yourself!

What's needed:
• Your clean hands (nitrile gloves help)
• A clean rag
• A sharpie
• Brake clean

Step 1. You first need to identify the exact spot where the rotor is out of true. It is easiest to let the rotor tell you where it's rubbing the brake pads - instead of trying to peer down at the gap between the pads and rotor, listen to the sound it makes when it rubs. You may have to listen carefully, but slowly rotating the rotor through the caliper will tell you exactly where contact is being made.

Step 2. Use a black marker to indicate the exact position and how long the bend is. Only mark the very top edge of the rotor, not the braking surface. This will make keeping track of your progress much easier, especially if there are multiple locations on the rotor that are out of true. If there are multiple places that need attention, concentrate on one at a time.

Step 3. If you need to true the rotor by pushing it in towards the bike, wrap your fingers around the spokes and gently push with your thumbs. Go easy, you'll find that not much force is needed to make substantial changes. If the affected area is long, spread your thumbs far enough apart to straighten it. Apply pressure and then turn the rotor through the caliper to see how effective you've been. Repeat as needed.

Step 4. If the rotor needs to be pulled out away from the bike place one hand at the top of the tire to hold the bike in place and use two or three fingers to gently pull at the rotor. Again, start with only a small amount of force, working your way up to applying only as much pressure as needed.

Step 5. Even though you washed your hands prior to touching the rotor you should still give it a good spray with a brake cleaner to rinse off any oils. Let it air dry.

Have you tried to straighten a rotor this way? Maybe you have a technique you want to share? Tell us about it below.

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117 Comments

Score Time

+ 35

iamamodel (Sep 27, 2011 at 1:04)

My tip would be to take the chain off and then you can hear exactly where and how hard it is scraping - and of course when you've done a perfect job (no noise).

This only applies for when it is the rotor on the REAR wheel Smile

norco-ryda (Sep 27, 2011 at 5:49)

good advice!

+ 21

bigdan30 (Sep 27, 2011 at 8:07)

To figure out where the bend on smaller tweaks I use a dry erase marker and draw a single line on the actual braking surface. spin the wheel once or twice, and then the parts that hit the pads are rubbed away, so you can see exactly where and how much needs to be bent and in which direction. Obviously don't go nuts colouring the whole surface, and wash with alcohol immediately apres le repair. works great for the finicky fixes.

Caiokv (Sep 27, 2011 at 9:12)

Hahahah Just imagined a Nyan Cat Running trough the rotor lol

But it is a quite good idea to mark the rotor!

georgy291 (Sep 28, 2011 at 2:26)

then your wheel is prob on wrong

[Reply]

thetake401 (Sep 27, 2011 at 0:54)

what i tend to do is take the rotor off, lay it on a completely flat level surface, and from there, i can tell which sections are out of true because they're not lying flat.

oldfaith (Sep 27, 2011 at 1:12)

I do the same and take to it with a rubber mallet, but on trail I use my fingers, I'm just happy he uses brake clean, I have been using it since I started riding discs and I was always concerned that perhaps mtb pads deteriorate from this as I never saw anyone else use it. great to know!

- 12

pinityoufairy (Sep 27, 2011 at 1:53) (Below Threshold) show comment

this is such a cop out from tech tuesday but actually quite useful and I'm always a fan of cavalier repairs

LemonadeMoney (Sep 27, 2011 at 2:28)

Shouldn't you be applying the brake cleaner to a clean cloth, and then the cloth to the rotor, to avoid spraying other parts? Also worth pointing out you need to wipe clean the rotor to remove the brake cleaner residue?

Views (Sep 27, 2011 at 2:33)

indeed makes sense, brake cleaner is highly corrosive and kills the grease on all parts

+ 62

meathooker (Sep 27, 2011 at 5:25)

What I do is this:

-1 remove bent rotor
-2 set aside
-3 install new, unbent rotor
-4 hang old rotor on garage wall for decoration

tomy177 (Sep 27, 2011 at 5:35)

i just use 99% iso as it is easier to come by and evaporates nicely

oldfaith (Sep 27, 2011 at 6:25)

so is it okay on organic brake pads? because to be honest I use an auto grade product and douse my caliper while the rotor spins, grey crud comes out and I wipe my rotor with a cloth. My pads wear fast but then I feel that's more to do with my riding and as I generally ride alone I have no one to compare ware rates with. I noticed in the picture above Mike uses a special sram product, does anyone here disagree with an automotive product?

carpy95 (Sep 27, 2011 at 7:52)

Nah I don't disagree with an automotive product as long as it is the right product for the job.

DARKSTAR63 (Sep 27, 2011 at 8:36)

It really depends. I work in a automotive repair shop and we have brake cleaner here that melts plastic. You CAN buy less harsh versions of this stuff that will be safe on bikes. But they are not all created equal. Hell, if you have your brake rotor off the bike you can use the agressive product all you like. It wont hurt metal. But as a rule of thumb I do not use automotive products on my bike. Isopropyl Alcohol is all you need to properly clean a brake rotor.
Also, oldfaith, I would not douse the whole caliper like that, especially with brake clean. You risk the cleaner getting into the piston/caliper interface (bore) .......I just dont think its a good idea. Also, it will soak into the pads and the stuff you are using could have ingredients that wont evaporate out.

oldfaith (Sep 27, 2011 at 23:41)

Thanks!

mikeinjasper (Sep 29, 2011 at 7:54)

Meat hooker! I laughed out loud when I read your comment, that's EXACTLY what I do LOL.

cyberhawk Plus (Oct 3, 2011 at 2:57)

okay,, i have been doing this the same way as they said.. sometimes with hard bends.. i took a bacho to fix it..i ride trials with a rear mono trial brake.. my discs get nackered from time to time,.. i would be poor if i had to buy a new rotor each time,..
the brake cleaner is not so good for your brakes.. it DOES leave a residu..(some brands more than others..i found one good brand we have @ work.. it is normally the cheap house brand) i believe in alcohol too which is said above aswell..
since i do not get to high speeds i really feel the deteriorating braking power of using brake cleaner,. (note alcohol does make the brake fade too, but it lasts only a very short time ! ) if you do use brake cleaner.. i found out paper towels work great.. and they are disposable,,.
NOW CHECK THIS >>>
what i have seen some time ago ..baffled me !
my mate took 2 hammers,,. found the bend in the rotor and using the WOODEN end of one hammer against the disc and hitting the hammer part with the other.. on the lower part of the arms of the disc.. IF i am correct ! if the bend is inwards (to the wheel) hit the out side and vice versa,, he tapped his disc straight in no time,. i practiced it at home with a soon to be replaced hope trial disc.. which i ended up using for 4 months longer or something..cause i got it straight !
it works great.. start with small taps.. dont try to bend the disc arm ! just frighten it and it will return to its original form !
with bend rotor surfaces this does not work.. than use the method as noted somehwere here to.. take rotor off the wheel.. lay it on a flat (glas table !) surface to check the bends..and mark them,, take it OFF the glas table, and whack it straight on a flat piece of wood with a rubber or metal hammer.. note the hammer surface must be clean and smooth !
use a wooden surface so the impact of the hammer can go somewhere,.

[Reply]

erlkonig (Sep 27, 2011 at 9:04)

In twenty years of being a bike mechanic, I've trued all kinds of things by hand - chainrings, wheels, rotors, even frames. When something's bent bad enough to need straightening, there's no harm in giving it a go. The important thing is to be honest with the customer, and realistic about the chances of the part staying straight and not breaking. At home there's much less to worry about, because the amount the shop's going to charge you to straighten a rotor will be very close to the price of a new one, unless they do a half-arsed job, which of course you can do yourself. Useless tips:
1 - A clean paper towel obviates the need for cleaning the rotor afterwards
2 - Rotors can have some really strange complex bends. Circular items exhibit more stiffness in the direction of the bend, so learn to feel for that resistance with your fingertips.
3 - Know when to give up. Especially in the shop, I hate to see mechanics spending two hours trying to save a fairly cheap part.
4 - Rotors aren't necessarily straight even right out of the box, so you might end up straightening it even if you buy a new one.

[Reply]

bongboy (Sep 27, 2011 at 8:51)

Park actually makes a pretty dang good rotor truing fork that works quite well and I use it quite often at my bike shop.

[Reply]

bubbaleech (Sep 26, 2011 at 22:15)

Very good tech tuesday, something most home mechanics should know how to do.

[Reply]

hance (Sep 27, 2011 at 3:06)

This was how I've been doing this for years. When I was just researching for some tips in straightening rotors a few years ago, all I could find is how they suggest to use adjustable wrench in bending the rotors. Still, I opted to use just my hands so as not to mar nor overbend the rotors. Glad to know I am not the only one who believes so.
Big Grin

[Reply]

ArmyFork Plus (Sep 28, 2011 at 11:58)

I like the tips presented but I have to tell everyone to avoid using brake clean, especially automotive brake clean in an enclosed environment. Brake clean is a very toxic substance and is supposed to be used ONLY with full skin protection and supplied air, if you are going to use it please use it outside or find an alternative. I find most citrus degreasers easily clean rotors without the toxic side affects of many brake cleaners, and there are other such products available. We all bike, we all care about our health, so please make sure you read the warning labels on such products before you use them.

[Reply]

jcinkits (Sep 28, 2011 at 22:11)

all i can say is : if it works using tools - it works ! and if it works using your hands [ or a combination of ] then, it works ! However, i agree that if you are looking to keep the rotor, it may be better to repair it with the 'right' tools and, an emergency repair if it works by using yer bloody teeth or a sledge hammer , then...well, you get my drift :-)

So, assuming everyone is straight up, tools work, and no tools work - moving on......

[Reply]

modern-day-viking (Oct 2, 2011 at 13:06)

So first problem you are touching the rotor with your hands which have different oils on it and letting that rotor pass through the caliper so now you run the risk of fowling your brake pads and on an xo brake those run around 30 dollars canadian. Secondly you run the risk of cutting your hand. I would suggest purchasing a park tool DT-2 sprayed with some rubbing alcohol. Admittedly using the tool takes some skill but thats what practice is for. You solution has too many opportunities of running other things and causing more problems.

[Reply]

carpy95 (Sep 26, 2011 at 20:46)

This is a very useful tip because rotors go out of "true" (bend) easily, but if you are looking for perfection, your LBS will (should) have a rotor gauge which will give extremely exact numbers for them to tweak it.

mikelevy Mod Plus (Sep 26, 2011 at 20:54)

Exactly. A proper shop with have the tools to get it bang on, but this is really for the home mechanic who might be a bit hesitant to start bending away. Nothing to be scared of!

carpy95 (Sep 26, 2011 at 20:56)

Yeah, especially because if you make a mistake, you can correct it by simply bending it back, you won't screw it up for good.

joseph13 Plus (Sep 27, 2011 at 0:43)

Funny you put this article up because not to long ago I was out riding with some friends and I crashed and ended up tacoing a 6" rotor in the back of my bike (don't ask how it's beyond me haha) so I decide to take my rotor off so that I can keep riding just with my front and I look over and my buddy is trying to be a hero and bend the rotor back haha it was almost bent at a 90° angle... Just goes to show that some people lack the common sense that these articles instill onto others! Great article!

[Reply]

disturbed0rider (Sep 27, 2011 at 12:55)

Automotive Disc brake cleaners normally contain rust inhibitors. These do not affect the braking force on cars and trucks etc as the heat generated is much higher so they burn off any residue, but can greatly reduce the effectiveness of Disc Brakes on a bicycle.

[Reply]

carbonlite (Sep 27, 2011 at 21:30)

I just want to clarify for everyone he is NOT putting lube on the rotor a the end there. I can't tell you how many people came into the shop I worked at this summer with squeaky brakes that stopped working after they lubed their rotor...

[Reply]

b1rdie (Sep 28, 2011 at 12:29)

I think a tool is only as good as the hands that drive it, so if you are to use a tool the first time to try to true a rotor, it would be better to use the tool on an already useless rotor to get the feeling of the amount of strengh needed to be applied. There are for sure bends that can not be corrected just by hand, but I agree that Mike's right on suggesting the use of hands for the diy job.

[Reply]

mtb24pride (Sep 27, 2011 at 5:16)

My rotor is untrue and its really annoying because i have to set up my brake really loose (pads for from rotor) to stop it from braking without me doing anything. I tried to bend it back, but no matter how many times and how hard i pull, it just gets back to its bent position. You seem to be using a skinny rotor, mine is a thick Hope floating disc rotor... Any tips ?
Thanks

citizenlee (Sep 27, 2011 at 5:31)

This only works if your rotor is slightly out of true... if it's really warped then you just have to admit defeat and get a new one.

I found Hope floating rotors especially hard to bend back, which is annoying as they're twice the price.

See here for a cheaper alternative: http://superstar.tibolts.co.uk/product_info.php?products_id=455

mtb24pride (Sep 27, 2011 at 5:34)

Mine isnt very bent, just slightly but it still touches the pad if i try to set my brake up properly, the rotor doesnt need replacement, but its really stiff so dont manage to bend it back out. Should i try to get extra leverage ?

stewartluxton (Sep 27, 2011 at 7:39)

maybe you can find someone who does forged iron stuff (fences, gates, bars etc) ask them to heat it and correct the warp for you.

mtb24pride (Sep 27, 2011 at 7:58)

Ha non merci. I dont have any friends who can do that and if i go to some stranger they will either refuse or ask for me to pay a little something, i'll keep trying maybe perseverance will pay off

doug13 (Sep 27, 2011 at 12:41)

Bin the floating rotor, you will be forever trying to get it straight, and when you do it will get knocked out again, they are more hassle than they are worth. remember they arn't attached the the centre (hense floating) so is very tricky to get any leverage. You are trying to get a thin ring of metal flat, not easy.

mtb24pride (Sep 27, 2011 at 12:46)

Yeah but i cant afford a new one... And the red looks good with my bike haha
thanks for the advice though

wilkey (Sep 27, 2011 at 17:49)

hmmm...

wilkey (Sep 27, 2011 at 17:50)

if worse comes to worse use two rotor truing tools, to lever against each other, and give er' hell

bigtard (Sep 28, 2011 at 0:45)

you could just get a GOOD bike mechanic to fix it?

mtb24pride (Sep 28, 2011 at 0:53)

Im pretty sure you could consider me as a quite good bike mechanic, i always get to what i want, but the rotor is just reaply stiff and wont bend. Besides this doesnt require much skill, just control the strength with wich you pull/push the rotor. A GOOD bike mechanic couldnt do much more, the only advantage he would have is tools but i dont think they would be very useful, pull with your hand or with a tool, the rotor just doesnt wanna bend back in shape

freeride5 (Sep 28, 2011 at 13:26)

bend it back at the spokes of the rotor and it will will go if its being stiff like that but use the adjustable wrench trick or the parktool

mtb24pride (Sep 28, 2011 at 16:52)

Will try.
Thanks !

doug13 (Sep 29, 2011 at 2:00)

make sure you have centred the caliper properly first, on hopes you need to set the rotor in the centre of the caliper not the centre of the pads. Just not on the bent bit! You should have centre markings on the caliper to help, the pads then will centre themselves after a few brakes, then check and adjust the rotor again. Good luck. If you get nowhere then take it to a good mechanic and tell him you'll buy him a beer if he can get it running true. Smile

oh and don't try and bend the centre of the rotor! Just the braking surface, I'm guessing freeride5 didn't pick up on the fact that you have a floating rotor.

mtb24pride (Sep 29, 2011 at 2:37)

Thats what i thought too with the brakimg surface, because im pretty sure the center of the rotor is nice and straight, its just the floating bit thats bent, but i thought i might give it a try because it didnt seem to work when bending braking surface.
My caliper and pads are well centred, i dont have a hope brake btw i run a mechanic avid BB7, i just have the hope rotor. Apart from being bent the rotor is quite damaged anyways so i might change it anyways, but cant afford it yet so i'll just try and get mine straight, myself ! If i do it myself i'll have learnt it and it will be free, i work on my bike alot and am pretty good mechanic and i keep learning on my own, i dont like having to go to someone who can do it for me

[Reply]

OakTwnRippr (Sep 27, 2011 at 10:00)

Ooooops......just used a crescent wrench and it worked but came out a little squirrely. wish this article came out before i tried to repair - United Airlines bent the crap out my new spendy shimano ice-tech rotor. [ Air Canada didn't on the way up to Whistler ].
Shimano mechanic at last weekends Tara Llanes Classic said same thing - "use your hands first". Shoulda woulda coulda. Got it close enough, but from here i'll be taking Mt-Bike-E's advice - Vice and 2 pcs of Oak. .....And perhaps fewer beers.

potatoracing2 (Sep 27, 2011 at 17:48)

They also break guitars. expensive taylor guitars

potatoracing2 (Sep 27, 2011 at 18:02)

http://www.youtube.com/watch?v=5YGc4zOqozo

OakTwnRippr (Sep 29, 2011 at 23:24)

Funny UA guitar vid.
Just tried straightening the botched rotor again. This time by hand as shown here. Sweetness, success. Thanks Mike Levy @PB!

[Reply]

boxxer27 (Sep 27, 2011 at 20:24)

I like seeing the back of a new carbon Trek Session....does this mean a full review soon??? Also great article, I hate the sound of breaks rubbing. Goes to show that if needed you could true a rotor on the trails.

[Reply]

HenryR (Sep 29, 2011 at 10:01)

pretty good article, truing rotors is definitely part of the mountain biking game for me. just FYI the mysterious and dangerous oils on your hands (sarcastic) are not going to hurt your brakes

[Reply]

TouchMeslowly (Sep 27, 2011 at 19:22)

yah you go ahead and use your fingers to bend the rotor, im going to use my parktools rotor straightener

[Reply]

jjc2222 (Sep 27, 2011 at 11:45)

I simply use the tool that parktools designed for this..
But then again im running floating know so havent used it on own disks...

[Reply]

AlexRose (Sep 27, 2011 at 5:23)

How the hell did they get their hands on a Session 9.9 already!? I work at a Trek dealer and we can't even get it yet. lol

potatoracing2 (Sep 27, 2011 at 17:49)

how did they manage to already bend a rotor?!

AlexRose (Sep 27, 2011 at 17:52)

Well Avid rotors are usually never straight in the first place lol

potatoracing2 (Sep 27, 2011 at 17:57)

hahaha good point! thats actually why im looking at this, in regards to my bent G2 Clean Sweep 160mm

bigtard (Sep 28, 2011 at 0:54)

how do you think bud. probably because theyre the media
trek doesnt individually give a shit about every dealer theyve got
they care about media

[Reply]

bmxerjosh1 (Sep 27, 2011 at 11:57)

make a small line a the top edge of the rotor surface with a marker, very small.
go ride a round for a few minutes without using your brake,
MAKE SURE YOU DONT USE YOUR BRAKE!!! Smile

then you put the bike on the stand. where ever there is no line is where you bend it.
if the line is still there ride more.
works for me, makes it easy to find the spot

[Reply]

skusedh (Sep 27, 2011 at 2:40)

Please can we have video tech tuesdays back its so much easier to hear and see someone doing it at the same time and also i miss the cock ups at the end Razz

[Reply]

socalshreder (Sep 27, 2011 at 22:01)

I just did this lol. On a pair of hayes rotros that are like 3 years old. I d still ratger buy new ones though but thats just me. My rotoars were soundidng like wahles moaning lol.

[Reply]

WAKIdesigns (Sep 27, 2011 at 0:47)

Good to know that I was doing it the wrong way... I lost my use-brute-force-on-expensive-stuff virginity while straightening a rotor on a local "DH" race. I was doing it by pushing away the brand new rotor using my foot in SPD shoe, having spokes of my deemax wheel as support...

[Reply]

Mt-Biker-E (Sep 27, 2011 at 6:55)

When my rotors need more than a quick alignment I remove them completely & put them between 2 pieces of smooth oak & press them in a vice. Its quick & easy and they come out true.

bigtard (Sep 28, 2011 at 0:52)

that doesnt work, not that ive tried. i just know it doesnt. the fact that you think it works means you dont know whats going on. if somethings bent, you have to bend it back past straight to counter act the bend. clamping it between anything straight will only bring it straight for as long as you hold it, then it will just flex back to the original amount of bend
think about it

[Reply]

czarny360 (Sep 27, 2011 at 1:28)

Try to fix the Shimano Xt Discs or Hopes like that ;p i got my XT bent a bit and that was a hell of a fight to repair it... but i did it after 6 hrs of fight it was like a new one ^^

masterk (Sep 27, 2011 at 2:18)

hope disc a very easy to bent back in to shape if you got floating disc

mtb24pride (Sep 27, 2011 at 5:18)

Mine wont give up, it will stay bent the other way no matter how hard i pull...

masterk (Sep 27, 2011 at 9:25)

there's your problem your pushing to hard got did it gradauly otherwise it just bend other way like you said if it carrys on just take it to your lbs

mtb24pride (Sep 27, 2011 at 10:17)

No it doesnt bend the way i pull. I have done it gradually, but it just always gets back to its bent form, it doesnt get unbent or bent back the other way

bigtard (Sep 28, 2011 at 0:53)

do it better, youre obviously doing it wrong or it would be working wouldnt it?

mtb24pride (Sep 28, 2011 at 0:55)

How do you wanna pull wrong ? I pull the opposite way of the one in which its bent, when i pull itbends the way i want, but when i let go it just gets back to its bent shape

[Reply]

Mooore (Sep 27, 2011 at 5:13)

I have a red marker. Will that be a suitable substitute for the black one suggested? Only joking, top tip, thanks. I've always used an adjustable but will give the man hands technique a whirl next time. Cheers.

[Reply]

crmxer (Sep 28, 2011 at 13:09)

When I have a bent rotor, I go to PricePoint.com and order a new one for $12

[Reply]

debonis (Sep 27, 2011 at 13:00)

this is how I've always straightened my rotors...works very well. and saves money on buying new rotors..and buy other bike parts with the saved money

[Reply]

shanertownsend (Sep 27, 2011 at 3:17)

im sorry but surly once the rotor builds heat up again it will return back to the state it was ie back to the memory that it had from being bent so this is just a quick fix not a proper one ?

neimbc (Sep 27, 2011 at 5:22)

No, they are not made from the material which you are implying - that's pretty hi tech stuff. This metal will not retain any such properties. Whether bent or straight, heat applied will not return it to it's prior position. Also, Rubbing Alcohol (isopropyl) is a fantastic brake pad/rotor cleaner. It's probably what 's in the spay can.

Borgschulze (Sep 27, 2011 at 12:58)

If it had memory like that, it would never bend in the first place.

shanertownsend (Sep 28, 2011 at 9:00)

but if it was bent when hot that would make it bent and then to return to the shap eafter

Borgschulze (Sep 28, 2011 at 12:25)

I guess if you're on a really long DH run and you bail.... it would have to get very hot to permanently bend.

[Reply]

psychobiker1 (Sep 27, 2011 at 5:05)

i would encourage folks to check the wheel for true before trying to bend the rotor. the wheel can have an effect...

mtb24pride (Sep 27, 2011 at 5:13)

If your wheel is untrue, it has no effect whatsoever on the rotor.

fatlarry (Sep 27, 2011 at 7:29)

I've seen this mistake before... I think he's talking about a QR wheel that's dislodged slightly. The first thing you notice is the brakes are rubbing, but actually the axle is crooked. Remember, - always start with the basics and work your way to the more complicated.

mtb24pride (Sep 27, 2011 at 7:55)

Oh ok i see what you guys mean now, check that the hub axle is well placed in the frame... That of course will have an effect.
The thing is that the way psychobiker1 said it, it seemed like he was talking about an untrue wheel rim... Which has no link at all with rotor problems.

fatlarry (Sep 27, 2011 at 8:25)

Agree - psychobiker1 either is wrong in his statement or just bad at communicating.

[Reply]

wilson12359 (Sep 27, 2011 at 0:16)

Very helpful tech tuesday as its a job that anyone can do and with the right know how can be done right.
Thanks

[Reply]

Plasticpylo (Sep 27, 2011 at 5:35)

Don't forget that brake cleaners make your stoppers useless for the first few corners.

wilkey (Sep 27, 2011 at 17:59)

if you use iso alcohol you can just light it on fire. looks cool tons of fun and there is nothing on the rotor

[Reply]

Fader18 (Sep 28, 2011 at 18:19)

because its fair and stuff that you have a carbon session to just mess around with, we should all get a turn Smile

[Reply]

northwestdhdad Plus (Sep 27, 2011 at 9:16)

Wish you could favorite articles (like we do for photos/videos) so some day I could use this as a guide.

mattpatt (Sep 28, 2011 at 6:49)

Good idea Mike. Maybe tweet it in the meantime? I do that for stuff I want to "bookmark" and share later... BTW - you could also bookmark it in your browser, but I know, that's sooo 1999. Smile

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jamesdexter (Sep 27, 2011 at 10:58)

I spin the wheel backwards so there is no noise from the hub, unless you run a crankstopper

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automaticLongman Plus (Oct 10, 2011 at 1:59)

Thanks Mike! This is the best way I've ever tried straightening rotors!

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wilkey (Sep 27, 2011 at 18:01)

I am bored. I think I have made 3 comments on this page. and who knows how many likes and dislikes

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Lonerangers (Sep 27, 2011 at 11:16)

thank you, this came just in time the squeaking was driving me crazy!

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Arawn (Sep 28, 2011 at 5:05)

what happened to the tech tuesday vids? aint seen a new one for ages now

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dhabartrider11 (Sep 27, 2011 at 20:22)

I just use shimano rotors, avid rotors suck

bigtard (Sep 28, 2011 at 0:58)

theyre all the same bud. they all come from the factory slightly off, or totally fine, its pretty random. its not like anybodys got some amazing frigging rotor producing technique that makes one brands rotor more awesome than anyone else.
and you should use the rotor that lines up for your pads braking track

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goosecock (Sep 27, 2011 at 0:17)

Please make a video out of it!!!

GSuperstar (Sep 27, 2011 at 0:27)

I'm not sure how he could get any clearer with a video? He's been pretty precise...

mtb24pride (Sep 27, 2011 at 5:19)

Yeah but tech tuesday videos are so enjoyable and hypnotising !

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Downhill81 (Sep 27, 2011 at 15:55)

Where is the videos

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xipanza (Sep 27, 2011 at 6:34)

I do this!!!

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Icculus19425 (Sep 27, 2011 at 4:01)

Is this Aaron Gwin's WC Session 9.9? I would think he would just get new rotors all the time

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shishka (Sep 27, 2011 at 22:24)

How would you recomend getting feces out of a rotor?

mzeek (Sep 28, 2011 at 22:28)

You are such a moron shishka. Stay gangster ya poser f*g.

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jimbill (Sep 27, 2011 at 8:02)

This is a pretty irresponsible article. Its like writing a paragraph on how to do an appendectomy. If you want it done properly, bring it to a shop that has a bunch of experience in straightening rotors, and get it within tolerance. Or, be prepared to be purchasing a new set of rotors after you've bent the crap out of them. Anything brake related should not be tackled without a bunch of confidence you can do it right.

z-man (Sep 27, 2011 at 8:30)

its just straighting a rotor, its not gonna cause the brakes to fail in a disastrous way. Try it your self, most people know their mechanical abilities, and are prepared to replace parts if the job is not done right. honestly straitening a rotor is easy as pie.

erlkonig (Sep 27, 2011 at 8:37)

Yeah, settle down, captain.

Mt-Biker-E (Sep 27, 2011 at 8:52)

all it takes is a vice & 2 pieces of hard wood that are level. sandwich the rotor & press with the vice. Takes only a few minutes to remove the rotor & replace it. Done quick & simple & takes little if any mechanical skill.

huckk (Sep 27, 2011 at 16:30)

I work in a shop, and i prefer my fingers to a tool any day...

wilkey (Sep 27, 2011 at 18:01)

ha! you have no friends

jcinkits (Sep 27, 2011 at 23:12)

@ jimbill - good thing i don't depend on your advice [ at least in this situation ] or i would still be walking my ride down the mountain : i hit a rock so hard i 90o a rotor [ L shape ] - first i bent it back by hand as far as i could [ about 30o still to go ] then using a multi tool with two of the allen tools out like a V wedge, bent it back some more - then used an adjustable wrench that a trail rider who stopped let me use, [ yeh ! i agree, who the hell carries one of those on a rip - but this guy did ] i got enough of the crimp out that with my weight on the bike while riding, it was able to pass through the calipers without any noticeable hesitation or hold, so i could get down the mountain and later have it replaced - the only thing irresponsible [ in my opinion ] is an 'absolutism' statement about repairs - by the way, i rode it this way for several more rides till i could afford a [ good ] new rotor -

jimbill (Sep 28, 2011 at 0:03)

Sorry for offending, but I as a mechanic, who has straightened plenty of rotors, I take issue with "The argument against using tools". Doing it by hand is not better or easier. Like the saying goes, "A little knowing is a dangerous thing." The right tools in the right hands will get the job done right. Doing an emergency repair is one thing, but "fixing" a rotor for regular use, means getting it within a reasonable tolerance so your pads don't see excessive wear. And a whole paragraph on how to wash your hands...really? Sorry, again. I really do hope this article helps someone.

bigtard (Sep 28, 2011 at 1:02)

doing it by hand is way better. tools bend it back in a way that is very unlikely to be like the way it was bent in the first place. which means youre gonna throw a bunch of uneven kinks in it.
if its too kinked you've gotta put it on a vices anvil and hammer the kinks out of it.
ive never used a tool and a bike has never left my shop with a rotor that wasnt straight as hell

czarny360 (Sep 29, 2011 at 10:18)

i dont pull the rotor... i just hit with a plastic little hammer

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