Bent hope mono trials disc

[pav]

I just got my new Czar 2007 long, on the first ride the fucking front skewer snaps off the cunt.

I was doing a twisted stoppie down a small hill when it happened so the brake locked up and the wheel kept moving sideways. It fucked up my rotor hardcore.

I have bent it back enough to make it spin fine and stuff like that, its not perfect, but its easily usable.

My problem: When I bent it back, would the shit on my gloves, like sweat or little bit of oil or whatever have contaminated the rotor? It felt poo once it was straight but then I splashed metho all over it and rode down hills and stuff and its better like that now, but when I do a front wheel gap or somethign and pull it hard, as the disc rotates to lock up, the lever just keeps coming to the bar and I have to pull it in really close?

Is this just because of the way the rotor is bent or what? Its a real shit because once I stop and let go of the lever, it goes back to normal? It always used to have a little bit of pump, but never this much?

Will it go away when the disc is clean again or something?

I know nothing about discs and have heard that these hope trials ones are very tepremental, so I want to make sure its good all the time so i dont have to worry about it fucking up.

Thanks


Pav

[Xoo]

Sounds like it's performing just like my mono front. They don't 'lock up tight' right away, like hydraulic rim brakes. I can put my thumb between the hope lever and my bars when it is locked up and my thumb doesn't rub lever or bar. If your rotor is no longer bent I can't see why it would have any effect except the likelyhood the rotor would bend in the same place again later.

Any evidence of fluid loss from caliper or lever??

[SLB]

I bent mine real bad a few months ago. Not even Joel Davis's nuggetness could fix it. I got it spinning but yeah same thing... it wasn't locking up like it used to. I ended up having to buy a new rotor, but in the process learnt how to bleed the brakes. Isopropyl Alcohol would be a better bet to clean to rotor. If the pads are contaminated I've had luck BBQing them and spraying with water. And the pistons might require silicone spray to free them up. They don't seem to be a 'love em and leave em' brake but I've persisted with mine and it's working well.

Ps. keen to see pics of the new rig

[thetart20]

My problem: When I bent it back, would the shit on my gloves, like sweat or little bit of oil or whatever have contaminated the rotor?
Unfortunately so - the only way to get it back to full performance now is new rotor and pads. New rotor will make a bigger difference than new pads if you only want to change one item though.

[AndyT]

I just landed a large drop gap to dirt tranny, going very very fast, and apparently there was a foot tall rock hard metal sprinkler pipe sticking out of the ground. Right into my pedal/crank, my top tube left an awesome black mark on my taint.


So at least your taint isn't black.

[CriPPle]

You'll probably find that the rotor is not as good as it was, even though it looks straight.

What I found with mine was that after a harsh bend, I got it more or less straight again, but there was a nasty sharp bend in it which was too fine to get out. Result is that at that point on the rotor, the contact point occurs earlier and the lever doesn't come in as far. Think of it like the rotor being effectively 'thicker' because of the bend. It would have feld really bad after bending it back because the pads have to re-bed back in.

You might have the opposite, one part of the rotor which is now 'thinner' which makes the lever come to the bar. I believe the effect is worse with hope trials because the pistons are bigger and you get less pad movement to result in more pressure, but that reduced pad movement accenuates any rotor inconsistencies.

Then again, if it's contaminated enough the pads can soften easy and that will bring your lever to the bar also. If you get a high-pitched squeal under braking instead of the standard low-pitch whistle/crackle (or silence), then you're contaminated.

Not sure about a cure, unfortunately. If you do replace the rotor, I found my rotors were really soft out of the box which made them easier to bend, they would probably be both stronger against damage and stiffer feeling if you quelched them early on, while they're still nice and straight.

Let me know how it goes, so I know what to do with mine :P

[pav]

Hey guys,

Thanks for all the replies, I think your're all right with the bent rotor thing. I took the beast for a ride today and as I slowly stop the lever pumps at me when I go over the part I 'straightened'. I also worked out that at the bent part, it goes across to other part of the caliper and when it does this, the left piston has to go in really far and then it pulls in further, but when the rotor is back in the middle it works like normal.

As for contamination, I dont think thats a problem. It still had loads of power in it once I cleaned it all up, just feels a little funny.

Thanks guys, I just spent all my money on the frame, but as soon as I can, I'll be getting a new rotor!


Also, as for pics, I will get them up as soon as I can, my girlfriend has to come around with her camera so we can take some photos, because my stupid camera doesnt connect to the computer. Unless anyone has a wii and I can send you photos on that.

[loffa]

I also worked out that at the bent part, it goes across to other part of the caliper and when it does this, the left piston has to go in really far and then it pulls in further, but when the rotor is back in the middle it works like normal.


You've got that right. It's because of the hopes automatic pad wear adjustment thing. Because your rotor is bent it will force the piston further inside the caliper than it should be, so the first time you pull the lever the pads are too far from the rotor. And on the next pull they have adjusted themselves again to the correct distance. That's why you get terrible lever pump from it.

I had the same problem with my rear mono trials, the rotor had a small but sharp dent in it so that every time it passed the pads it pushed the pads further apart and the lever felt shit. I ended up getting a new rotor (Avid Cleansweep) which got rid of it AND at the same time gave me much better power than the original one ever did. :dunno:

[pav]

Ah the problems of disc.

I miss my magura :'(

[stocktrials]

i bent mine to some degree. got it back to sort of what it should be and its pretty good now. about 90% back to normal, I'd say.

but still makes that Hope high pitched scream that they all do.

[CriPPle]

Custom rotors ftw... I hope. One day.

[goose]

If you have access, try a delta aztec rotor. They're thicker, so stronger, but for some reason I feel like my brake is grippier now that I'm using the delta aztec rotor. It was also a pretty cheap compared to the hayes or avid replacements at my lbs.