Truing this Disc rotor is trying my patience

[ClintBX]

Hi ESFMs,

I'm at my wit's end getting my rear disc rotor to stop clipping at that one spot.

I have a 203mm rotor on my DD hub motor and am using a TRP Spyre mechanical caliper. The rotor is an alligator wind cutter.

The rubbing part is exactly where the valve stem of my tire is.

I've spent the past 2 weeks trying to true the area with my parktool truing tool and it doesn't seem to matter how gradual I'm being, I always over correct. And when I go to back out of that, I'm right back to square one.

The warp isn't very visual either. I can only see where it's out by spinning it fast enough.

I've tried recentering the caliper several times, sanded and cleaned the pads and cleaned the rotor.

I'll upload a video. Tell me what you think.

Clinton

 

[E-HP]

In fact, they are more forgiving than hydraulic discs because the pads retract more away from the rotor when cable tension is reduced/lever released.

The disc must be pretty out off true if that's the case. Although replacing it seems simple, but sometime removing the rear wheel is a bigger deterrent than the swap itself.

 

[Chalo]

The discs Clint have are about the best mechanical disc brakes in the industry. [...] vice like stopping power with very little lever effort.

That's not "best". Folks who want to stay rubber side down should use brakes that can deliver abundant stopping power, but require a firm squeeze to do it. That way you don't fall off because you accidentally used too much brake for conditions.

Any brake that can stand your bike on its nose on flat dry pavement has all the power it's possible to use. After that, "best" is a matter of getting precisely as much braking as you expected. Maximum braking with minimum lever effort works against this goal.

 

[DogDipstick]

Eww. That's proof that he's using the wrong IS or post mount adapter, or else using an adapter than needs spherical adjusting washers but doesn't have them.

Hahaha I have gotten so sick and tired of searching Amazon or eBay for the best and most correct adapters that I just began making them myself. For real, they might just be a mm or two off here or there, looks right, you buy it, and it doesnt work. I got ten adapters here that were mis-bought. So strong is the thinking " Oh this one looks right" but for real there are a lot of available combo adapters.

So i present to you adapters by DogDipstick. I might fancy it up a little more, but in reality, this is faster than Amazon Prime.
I am getting good at it. Who wants to search for two hours. I got done in one anna half.

 

[DogDipstick]

The discs Clint have are about the best

BAHAHAHAHAHAHAHAHA......

.... R U tellin me... that these " Alligator Wind Cutters" .... are teh ( quote) BEST DISKS IN THE INDUSTRY?



Excuse me while I laf alittle more.

HaAHHAahHahahahaha Bahabahabaha bah hahahah bah hah ha HAHAHAHAHAHA BAHAHAHAH ha ha hhhhheee ha

Ok, I am done.

I do not agree with, the thought, of these holding the podium, for the the best disks in the industry.

Personal opinion. Take it or leave it. To me they look like some weird cross of the drillium industry applied to moto brake rotor styling... price set and sold to the world of general use MTB.... and in effect beeing just about the worst style of rotor you could buy and put on an ebike. I would ditch the " Alligator" idea. Speed holes, fake out-of-phase waves, and cheap laser cut rotors are not meant for fast ebikes.

I posted above a pic of a Magura MT5e. That is a strong caliper... on a strong floating MD-P 220 rotor, even more so when paired.

That is a strong brake. Based on my limited experiences with bicycle braking systems.

 

[DogDipstick]

Who said anything about rotors? God you guys are clueless...lol.

How silly of you. Did you glean that from discussion? English your first language?

The discs Clint have are about the best

................. :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: .............................

 

[Chalo]

The discs Clint have are about the best mechanical disc brakes in the industry. [...] vice like stopping power with very little lever effort.

That's not "best". Folks who want to stay rubber side down should use brakes that can deliver abundant stopping power, but require a firm squeeze to do it. That way you don't fall off because you accidentally used too much brake for conditions.

Any brake that can stand your bike on its nose on flat dry pavement has all the power it's possible to use. After that, "best" is a matter of getting precisely as much braking as you expected. Maximum braking with minimum lever effort works against this goal.

How silly of you. Did you glean that from discussion? English your first language?
The word you are groping for is 'modulation'.

TRP Spyke and Spyre dual piston disc brakes have 'superb' modulation aka brake pad pressure sensitivity relative to lever pressure to prevent your silly assertion. I ride them in fact almost every day.
You should learn more about brakes before you chime in. I know. Hasn't stopped you before.

I like Spyke and Spyre brakes fine, and I don't think they're overkill. But I also don't find them to be better than BB7. My main quibble with them is that they require more frequent adjustment than BB7. When mounted on a hub motor, they have the further disadvantage that you have to remove the caliper or the wheel to adjust the inboard pad, which makes precise adjustment difficult.

My point was that "moar power!!!!" isn't the same as better brakes.

The strongest bicycle brakes I ever used are some linear pull rim brakes I made over 20 years ago. They are hugely powerful, but like many hydraulic discs they are prone to braking undesirably hard when applied lightly.





I'm proud of how powerful and effective they came out, but they're not my favorite brakes to use. If I had to choose a favorite among all my brakes based on how they feel and work, it would be the chainstay mounted U-brakes on my old Fuji Sundance e-conversion. They can skid the wheel any time, without any special effort. But they never do unless I want them to. They have a nice snappy feel, and I always get exactly as much deceleration as I wanted and expected.

My BB7 and BBDB brakes work very well, but between less desirable feel and their unpleasant scraping sounds, I don't like them as much as my better rim brakes. They're still my favorite disc brakes overall, though.

 

[DogDipstick]

...(*15-25kW+...) (*bicycle)...

Church mouse quiet.
fire breathing e-motos with 5K watt +

Thankyou for your opinion. I still think the rotors are not up to snuff. Disks... discs..... flat spinny things... that the grippy thing grabs onto... Whatever you want to call them. No matter what you do, the Alligator will not hold up to ebike use.

It is probally not even hub-centric.

There are reasons that rotors are hub-centric on every drum and rotor on the road from a modern vehicle today.

Such as that MDR-P 220mm is. Such as most of the better Shimano rotors are.

 

[Chalo]

I like Spyke and Spyre brakes fine, and I don't think they're overkill. But I also don't find them to be better than BB7. My main quibble with them is that they require more frequent adjustment than BB7.

To even compare Spyke and Spyre brakes to BB7 is absurd. BB7's basically suck. Extra adjustment? You need to work on your set up Chalo...joking.

Both my direct observation of Spyke and Spyre from servicing customer bikes, and feedback from cycle polo players who use them, indicate that hard application of these brakes makes the pad adjusters back off progressively (because they develop more cable slack than pad wear alone can account for). It's a small price to pay for a nice cable disc brake, especially if the back side of the caliper is accessible.

For whatever reason, they require more frequent slack removal than BB7. I'm not entranced by the gimmick of having two movable pads, though the mechanism is pretty clever and compact. Bicycle rotors are so thin and flexible that it really doesn't matter whether the caliper closes down on one side or both.

 

[99t4]

This is an easy fix.

Obviously. OP solved the problem 15 (now 16) posts ago.

 

[ClintBX]

This is an easy fix.

Obviously. OP solved the problem 15 (now 16) posts ago.

 

[LewTwo]

Most people can't adjust rim brakes let along caliper disc brakes.

An argument could be made that those people should stick with bicycles that have coaster brakes.

 

[Chalo]

Most people can't adjust rim brakes let along caliper disc brakes.

An argument could be made that those people should stick with bicycles that have coaster brakes.

Plunger brakes also OK.

 

[LewTwo]

People here like DYI. The vast biking and ebike community is not DYI. They couldn't adjust a derailleur if their life depended on it.
I know strong bike racers who can't turn a wrench.
I refer a lot of people to the local bike shop and they do pretty good work as well.

I grew up in different times, or different neighborhood in the 1960s. We had Auto Repair shops, Motorcycle Shops, Lawn Mower shops but the closest thing to a Local Bicycle Shop was the Western Auto store that stocked a range of pieces parts. If one wanted a bicycle repaired then they had best figure out how to do it themselves.

Maybe they had a LBS in the richie-rich neighborhood across town :?

 

[E-HP]

Most people can't adjust rim brakes let along caliper disc brakes.

An argument could be made that those people should stick with bicycles that have coaster brakes.

Plunger brakes also OK.

Fred Flintstone used his feet.

 

[LewTwo]

Pop quiz. What did this bike builder do wrong with this build?
https://www.youtube.com/watch?v=aB3-z5S9MXg

1) Made a video
2) Spent too much yen
3) Used silicon caulk on the bearings

 

[DogDipstick]

I want the PARK TOOL disk brake mount surfacer. It is only $515.95. I might get it for the shop. I can write it off.


Since we are on the topic of brakes.

Er.. I mean the topic of Park Tools.


https://www.parktool.com/en-us/product/disc-brake-mount-facing-set-dt-5-2

 

[LewTwo]

Nope. What the mechanic missed is a fundament of good rear derailleur shifting. ....

Actually, unless the pavements in his part of the world are much better maintained than those around here, his major mistake was building a "road bike".

 

[nicobie]

What a absolute miserable road to race on! My hat's off to those who can ride that at speed.

 

[ClintBX]

Ok, is been 4 days of riding since adjusting the brakes and the clipping sound has not returned yet. I have some thoughts.

Firstly, I think that centering the caliper by turning the pistons all the way in had made it way more accurate than the brake lever squeeze method (or squeezing the caliper itself by hand for that matter). My theory is that it eliminates cable flex.

Secondly, even though there's clearly a deviation at that one spot when I spin it in my wheel stand, the bearings are loaded differently when suspended off the ground. When I did my final adjustment, there was still the rubbing on that one spot but I decided to just loosen the barrel adjuster just wide enough to not rub, which resulted in more brake lever range than I feel comfortable with. However, I ended up tightening that adjuster on road significantly without reintroducing the rubbing. Maybe, it's better diagnosing these things with the bike upside down

Thirdly, I have an obsessive personality and demand nothing short of perfection. This didn't need to take 2 weeks to resolve.

 

[MarkJohnston]

Hi ESFMs,

I'm at my wit's end getting my rear disc rotor to stop clipping at that one spot.

I have a 203mm rotor on my DD hub motor and am using a TRP Spyre mechanical caliper. The rotor is an alligator wind cutter.

The rubbing part is exactly where the valve stem of my tire is.

I've spent the past 2 weeks trying to true the area with my parktool truing tool and it doesn't seem to matter how gradual I'm being, I always over correct. And when I go to back out of that, I'm right back to square one.

The warp isn't very visual either. I can only see where it's out by spinning it fast enough.

I've tried recentering the caliper several times, sanded and cleaned the pads and cleaned the rotor.

I'll upload a video. Tell me what you think.

Clinton

It's really hard to get it perfect even with all the correct tools. IT's super annoying. I bet chalo will tell you to avoid disc brakes. I would avoid all but the most high quality ones.