I just got a new set of 2007 Hope Mono Mini with 2-piece rotor. I centered the rotor on the front wheel but it is still rubbing a little. When I rotate the wheel it seems that it is centered. Is it normal that a 2-piece rotor can rub a little (more like a ping sound) when the wheel is rotated fast? I came across an article in MTB Action mag about the Hope M4 and the mag said that a rubbing of the 2-piece rotor can be expected during the first few rides. Is this true? Please help. Thanks.
I forgot to add also that the front lever was accidentally pressed without the rotor in between the pads. I just pried the pads with a screw driver so the pads will retract. Is this ok? Also do you need to bleed the brakes if you shorten the lines? Is the hose shortening the same approach as the previous Monos (i.e. you can reuse the olive after shortening the hose)? Thanks.
Get a set of feeler gauges from the auto parts store. Take out your brake pads and measure the rotor to the caliper. The gap should be .8mm on both sides. If its centered and its still rubbing then you know its the rotor.
2. Yes its ok to push the pistons back with a screw driver. I'd use a tire lever so I don't mar the pistons.
If you open the system, you'll be extremely lucky if you don't have to bleed. Fluid out means air in, generally.
Take a look at this post for a guide to setting your caliper(s) up. It sounds to me as though you may have a slightly warped rotor or a lazy piston. Floating or not, rotors shouldn't be touching the pads until you pull the lever.
I'll check if my rotor is just bent or warped. If it is can I just straighten it like a regular rotor? I'm worried that I might damage the spider. Thanks.
Yes, it's pretty much the same truing a 2-piece as it is to sort a normal rotor, although I find that I generally have to apply less pressure to bring it back to true. Just keep your 'alterations' small and gradual and you'll be fine; I'd imagine it would take a fair amount of ham-fist to damage the carrier or rivets.
are you absolutely sure the rub you are hearing are due to the pads on the rotor ? hope brakes totally SUCK in regards to their crappy research/qc/etc. employed with their 2-piece rotors on many, many fork/hub combos.
I have had many hope brakes, all but one having the issue of rotor(s) rubbing on either the caliper adapter and/or the friggin post mount tab (same sound pretty much as rotors intermittently rubbing on pads).
This goes for both older and newer Hopes running a postmount fork. In fact, just had to file down the adapters a bit more on the newest set of brakes in order to have the stupid azz so called "floating" thingies not hit the adapters (same went for my 2006 brakes i just sold). Then, cuz the adapters are retarded, had to file the inside of the caliper slot in order for them to move over enough to center over the friggin rotor (on 3 sets had to do this).
while i do like the M4s on one of my bikes i will no longer use hope brakes
i hear yuh...if the floating rotor is rubbing, even slightly on the post mount and/or caliper adapter, it will make that same pinging sound and if enough time passes, you will even see rub on the inside carrier of the rotor depending on where it is rubbing
I think I can live with the pinging as long as it goes away after a while. Initially it was really rubbing. I just got confused on the article in MBAction when they reviewed the M4 with floating rotor. They said that the rubbing is normal initially because it is a floating rotor. I will still have to shorten the line so I will see if the pinging sound goes away after I break it in. This is one beautiful brake by the way. The machining is first rate.
With respect, MBAction is wrong. The braking surface of the 2-piece is identical to the braking surface on the standard rotor, it's only the central mounting area which differs. When Hopes, or any brakes for that matter, are set up correctly, the rotor should run straight through the center of the gap between the pads - no rubbing, scratching, zinging, pinging or whatever. I don't suppose that MBAction took it upon themselves to explain their pearl of wisdom, did they?
Truing the rotors just takes a few minutes and is well worth the time. If the rotor is catching the pads when the lever is not applied then you may develop uneven pad wear, which in turn will result in squeals, squeeks and/or vibrations under braking. Sort it out from the off and you'll be able to enjoy your brakes at their best.
I haven't seen the video but I will look into it now. I guess MBAction is incorrect on this one as I just installed the rear and it is centered and not rubbing or pinging. Thanks for all the replies. This is really an excellent forum.
I tried to straighten the rotor last night. After that everything is fine and no rubbing, until I apply the brakes. It starts rubbing again. I'm beginning to give up on this rotor. Another thing I noticed is that one side of the pad is sticking out compared to the other. Although there's enough clearance fr the rotor. I would say the space between the front pad and the rear brake pad is the same. the rear is not rubbing only the front. When I spin the front wheel I can see that the rotor is definitely moving sideways from time to time, hence it is rubbing. I'm thinking of calling Hope USA already to see if they can replace the rotor even though I bought it here at MTBR (brand new by the way). Any idea on how to remedy this? Thanks.
Unless the rotor is actually bent (ie. creased) then it can be trued, it's just a matter of perseverance. Like I said, take it a little at a time and you'll get it in time. There's no guarantee if Hope send another rotor that you won't need to true that, too.
I will try to straighten it again tonight. By the way do you think it is normal to have one pad sitting more inward than the other but I have enough space in between the pads for the rotor to rotate freely? I noticed that one side of the pad is sticking out more than the other. I only have this one small portion of the rotor rubbing the pad on one side only. Thanks.
The position of the pad relative to the caliper is determined by the piston. If one pad appears further out from the caliper than the other, the chances are that one piston is extended further than the other. Did you watch this...
yes I did. Unfortunately most of the video was focused on the guy talking. I also looked at the piece of instruction manual that came with the brakes. I guess one pad sticking more than the other is fine as long as there is enough space for the rotor to rotate freely. I estimate that the space between the pads (front and rear brakes) are about the same. The rear does not rub only the front. I tried to reset the pistons by pushing both pads on the front brake and I got a really wide space in between the pads. I installed the wheel with the rotor centered between the pads. When I pressed the lever the pads contract towards the rotor. When I release the lever, the inboard pad does not retract fully, the outboard pad does. In spite of this, I still have enough space to re-center the rotor but part of the rotor is still rubbing. I think that the amount of force to move the inboard and outboard pads are not equal that's why this is happening. I might try to insert a tire lever in between pads and squeeze the lever. I remember doing this on my old mini before to equalize the force coming on both pads. What do you think? thanks
1. Install the wheel with rotor. Caliper is not installed yet.
2. Remove the pads from the caliper.
3. Center the caliper without the pads using the post-mount bolts.
4. Remove the calieper and install the pads.
5. Re-install the calipers.
Sounds good. I totally forgot that the Mini has to be removed to fit the pads! I'm used to the M4 or M6 where the pads can be fitted from either side of the caliper. So yes, use the PM bolts to get your alignment, then remove the caliper from the frame/fork mounts to refit the pads. You could also ensure that the pistons are both pushed back flush with the caliper before you fit the pads. A plastic tyre lever is the ideal tool for this.
Just one more dummy question. When I tried to push the pistons back all the way out, then I refit the pads and center the rotor, something wrong is happening as soon as I pull the lever. The pistons does not retract equally after making contact with the rotor. The inboard piston/pad only retracts slightly, actually barely removing the contact on the rotor. The outboard piston/pad on the other hand moves farther back, not touching the rotor. Do you think I have a sticky piston or is there anything wrong with my caliper? Thanks.
Don't worry about asking questions; they're not dumb at all. Sometimes on new brakes you'll get one piston seal which holds on a little harder than the other, which will cause the problem you're describing. You should be able to loosen the seal up a little by just working the lazy piston out and in a few times - applying a little DOT fluid or silicone lube to piston as you go can help, too. If you get the pistons/pads properly aligned and free from rubbing then you could just crack on and use the brake; the piston seals will usually equalise after some trail time.
Do what Steve says. Put some DOT around the seal, put your pads back in, install your wheel and rotor, apply pressure on the brake lever to close the pistons then with a rubber glove grab the rotor and push the rotor lightly on both sides of the caliaper to the side of which piston is sticking. THen do the same on the other side, this will free up the stickyness and then get the pistons perfectly centered and squeeze the lever again. Repeat untill correct. :thumbsup:
I tried to re-align the pads last night and I also tried to straighten the rotors by pushing/pulling on the spider. So far the rubbing is gone. From time to time after applying the brake the rub will be there. What's interesting is that after a couple of rotations the rub disappears without me touching the rotor. I will try to get some ride time tonight. Thanks for all the help.
"What's interesting is that after a couple of rotations the rub disappears without me touching the rotor."
You mentioned that one piston was moving slower than the other. If the rotor only catches a pad a couple of times before running silently, then it's likely that it's the slow piston which is the culprit. As I said earlier, the piston seals will loosen up a little with a few miles on the trail, so this problem shouldn't persist.
Enjoy your ride...
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Mountain Bike Reviews Forum
15.4M posts
515.2K members
Since 1990
A forum community dedicated to Mountain Bike owners and enthusiasts. Come join the discussion about bike parts, components, deals, performance, modifications, classifieds, trails, troubleshooting, maintenance, and more!