Ruined $150 Shimano Deore hydraulic brakes

[MarkJohnston]

What about dual brakes?

One method is dual disc brakes, to help ease the heat buildup.
Needs to have flanges on either side of the hub, more costly.
Could do that front and rear.

Also use quality disk pads from a known entity (bike store) not generic pads and not from an unknown source like most of the sellers on alibaba/aliexpress, as those could be counterfeit.

Another method is to have a lever activating two cables, disk + vbrake. I had some cheap levers with two cable mounts, but there is also stuff you can buy for regular levers that split the cable into two.
It was to finicky for my liking. Problem Solvers might have something.

I literally have rid 2 days in a row with no brakes, only eabs low on a dd hub, front. You hook it up to the Wuxing levers, or check out Grintech.
https://ebikes.ca/shop/electric-bicycle-parts/ebrakes.html

Hehe. I think I have the rims to run two front brakes at once. The hydraulic lever is the issue

 

[markz]

Yes, yes it is.
Hehe

Whats the plan stan?
*Whats the rush that you got to go so fast, why can't you slow down?
Just get a direct drive hub motor, with regen braking or eabs-low/high braking.
Hippy protestors will be outside your abode with signs saying "Save the brake pads"

The hydraulic lever is the issue

 

[MarkJohnston]

I have the really good Shimano metal sintered pads for saint and zee. They last about 1000 miles under current conditions. I burn through em once a month.

 

[speedmd]

One thing is clear. Brakes need to have standard, published metric's. Heat- temp limits, energy dissipation /time and or possibly duty cycle are a few I would like to know before specifying them for a tubby on a high power e-bike. We are all just pissing in the wind without them. Plastic piston seals? Did I read into that correctly? WTF Any thoughts to retaining a lawyer so you can at least get a new pare of shorts? :lol:

 

[MarkJohnston]

One thing is clear. Brakes need to have standard, published metric's. Heat- temp limits, energy dissipation /time and or possibly duty cycle are a few I would like to know before specifying them for a tubby on a high power e-bike. We are all just pissing in the wind without them. Plastic piston seals? Did I read into that correctly? WTF Any thoughts to retaining a lawyer so you can at least get a new pare of shorts? :lol:

It's probably all trade secrets. They don't want people ripping their R n D. Just so ya know these brakes ARE ebike rated though.

 

[mxlemming]

I've raced the megavalanche 3 times with a front deore disc and 200mm rotor. Me and bike weigh 220lbs together... 100kg
That's over 2000m descent in less than an hour.

That's over 544W on average being disippated, of which a large proportion goes into the front brake.

Even at 50% heavier than my setup, there's no way you are putting a higher load on your brake than when I race the megavalanche. Just no way.

There's something else going on here. Those deore brakes don't last that long anyway.

Better pads, bigger rotor... By the time your at 200mm discs, bear in mind there are plenty of downhill racers doing 500m vertical descents in about 4 minutes without killing those brakes.

 

[markz]

It might have been mentioned, but maybe you bought a counterfeit caliper.
Could very well be the case with the usual back alley sellers from the usual suspects (ali's/am/e)
But if you bought from a known entity like your local bicycle store then no need to worry about that.

 

[JackFlorey]

It's a direct drive hub motor, no gears, no Regen brakes.

A direct drive hub motor is capable of regen. 90% of controllers out there are capable of regen; if you have one of those 10% you might have to upgrade to get it.

 

[JackFlorey]

No. Unless you have a low torque motor, that's a great way to wreck your hub motor's axle and your bike's frame. I'll pass.

I've been using regen since my first hub drive (a Tidalforce in 2003.) No significant problems up to 2500 watts. The only issues I've had:

1) You have to use a torque arm. Those flatted axles plus nuts in the dropout can work OK for one direction of torque, but the constant back and forth tends to loosen nuts quickly.

2) The torque arm has to fit pretty well. Both the cheesy/short RadBike torque arms (a stamped piece of metal) and the excellent ebikes.ca arm (machined out of a piece of steel) work fine.

 

[Chalo]

It's a direct drive hub motor, no gears, no Regen brakes.

A direct drive hub motor is capable of regen. 90% of controllers out there are capable of regen; if you have one of those 10% you might have to upgrade to get it.

I don't think I've ever worked with a non-programmable controller that had on-demand regeneration capabilities.

[EDIT: After posting this, I remembered that parameter in all the many KT controllers I've used, where I check to make sure regen isn't turned on. I guess those are programmable enough that my above statement is still true, but... yeah, there are a lot of controllers that support regen. Now back to what I was saying.]

At most, they apply some braking force when you descend a hill faster than the motor's free speed, and send the regenerated juice back to the battery. This effect is passive and you can't turn it off except by disconnecting the motor phase leads.

 

[Chalo]

1) You have to use a torque arm. Those flatted axles plus nuts in the dropout can work OK for one direction of torque, but the constant back and forth tends to loosen nuts quickly.

It does that even with a torque arm, unless it's the clamping kind. Any flatted-hole torque arm you can put on the axle without a fight will allow it to torque back and forth and thereby loosen the axle nut. The movement can be very tiny, but repeated enough times it will turn the nut around.

I replaced a tube on my Leaf front hub motor yesterday. The wheel hadn't been off since I don't know when, and the axle nuts were noticeably looser than when I installed them. The torque arm I made for that fork is thick and tight-fitting enough that I have to wiggle and push it into place. The axle slot is tight enough that I have to shove the wheel to drive it home. And the bike doesn't have regen! If it did, I expect I'd have run into trouble long before now.

 

[Manbeer]

Crazy thought but are you using the wrong brake fluid or fluid that is contaminated? I just lock up my brakes everywhere because it's more gratifying to buy new tires than pads

EDIT:
"scientifically speaking, braking is converting fun into heat" -Seth's bike hacks

 

[markz]

My torque arm was tight, I spent the extra time to grind the steel down and have it tight.
It wasnt clamping.
The constant e-abs-low I had hooked up and throttle action, rotated the axle back and forth actually did wear the hub motors axle threads down and wore away some steel and made the axle flat fitment looser. I used 1/4" steel plate from HD/Lowes so I dont know what kind of steel, hot or cold.
I will do a clamping t.a. next with some better steel from an actual metal supplier, Metal Supermarket. Not sure if I want to go tool steel, there was a thread on ES, debating the merits that lots chimed in on that I need to find, gosh I'd say its precovid so 2yrs ago.

 

[LewTwo]

I will do a clamping t.a. next with some better steel from an actual metal supplier, Metal Supermarket. Not sure if I want to go tool steel, there was a thread on ES, debating the merits that lots chimed in on that I need to find, gosh I'd say its precovid so 2yrs ago.

It has been nearly 40 years since I did tool and die design but best I recall good tool steel does not bend ... even a wee bit. If you are going to make a "clamping" TA then you need at least enough flex to make it "clamp".

 

[markz]

I have not looked into it yet, but I thought people were doing a relief cut. Make the slot for the axle, then in the middle do a thin cut to get that flex.

It has been nearly 40 years since I did tool and die design but best I recall good tool steel does not bend ... even a wee bit. If you are going to make a "clamping" TA then you need at least enough flex to make it "clamp".

 

[DogDipstick]

On Topic:

i love my Hayes 8 inch.. It blackens regularly on application and can turn red hot pretty easy.. but I havnt faded or lost brakes or anything. MT520. I had Deore single pistons but I could get them to fade to nil.. .all braking power gone when you get them hot enough.

Off topic:

It has been nearly 40 years since I did tool and die design but best I recall good tool steel does not bend ... even a wee bit. If you are going to make a "clamping" TA then you need at least enough flex to make it "clamp".

It bends a little before you harden it, right? No?

A wee wee tiny bit? Lol. I may be wrong... never tried to "bend" unhardened (tempered) tool steel..Yes it wont flex or bend at all.. when tempered: ... I have about 600lbs all neatly wrapped in brown paper with the graphs on it ... here.. Every shape and size. Something we collect when we see it.

Yeah you wont bend properly tempered tool steel. Lol.

 

[Chalo]

It has been nearly 40 years since I did tool and die design but best I recall good tool steel does not bend ... even a wee bit.

It doesn't yield (until it fractures), but it flexes just as much as regular structural steel.

Also, the hub axle isn't made from really good tool steel. There's not any benefit to a torque arm that's harder than the axle.

 

[MarkJohnston]

It might have been mentioned, but maybe you bought a counterfeit caliper.
Could very well be the case with the usual back alley sellers from the usual suspects (ali's/am/e)
But if you bought from a known entity like your local bicycle store then no need to worry about that.

I thought about that. But it's back country. check it out. I doubled checked with Shimano.

https://www.backcountry.com/

Maybe my ICe tech shimano rotor is fake?

 

[MarkJohnston]

I've raced the megavalanche 3 times with a front deore disc and 200mm rotor. Me and bike weigh 220lbs together... 100kg
That's over 2000m descent in less than an hour.

That's over 544W on average being disippated, of which a large proportion goes into the front brake.

Even at 50% heavier than my setup, there's no way you are putting a higher load on your brake than when I race the megavalanche. Just no way.

There's something else going on here. Those deore brakes don't last that long anyway.

Better pads, bigger rotor... By the time your at 200mm discs, bear in mind there are plenty of downhill racers doing 500m vertical descents in about 4 minutes without killing those brakes.

Ok So what do you recommend as an upgrade? Saint or Zee?

 

[MarkJohnston]

Crazy thought but are you using the wrong brake fluid or fluid that is contaminated? I just lock up my brakes everywhere because it's more gratifying to buy new tires than pads

EDIT:
"scientifically speaking, braking is converting fun into heat" -Seth's bike hacks

Fluid is correct.

 

[MarkJohnston]

I have one torque arm on ebay cheapo steel. I feel like the hose clamp is the weakness on these. Also it has weak point with a lock nut and bolt. I need to go to a welding shop and get a tack on it.

 

[mxlemming]

I've raced the megavalanche 3 times with a front deore disc and 200mm rotor. Me and bike weigh 220lbs together... 100kg
That's over 2000m descent in less than an hour.

That's over 544W on average being disippated, of which a large proportion goes into the front brake.

Even at 50% heavier than my setup, there's no way you are putting a higher load on your brake than when I race the megavalanche. Just no way.

There's something else going on here. Those deore brakes don't last that long anyway.

Better pads, bigger rotor... By the time your at 200mm discs, bear in mind there are plenty of downhill racers doing 500m vertical descents in about 4 minutes without killing those brakes.

Ok So what do you recommend as an upgrade? Saint or Zee?

Saint or Zee will both take a bit more but not that much, similar size pads and rotor means similar pretty and heat dissipation.

Shimano doesn't have replaceable piston seals. Hope, formula... Do but$$$. Nice hope tech v4 with 203 rotors if you've got the money, something like that is half way to a motorbike brake.

But my point is, I doubt you're cooking your brakes. Pic of the rotor?

If you are cooking them, you're probably riding around with them half on or starting at the top of a mountain and dragging then at 10mph to the bottom.

Try running regen for all brake dragging activities.

 

[MarkJohnston]

rotor

 

[mxlemming]

rotor

Yeah, that really doesn't look very cooked. Just a bit old and dirty. Some of my rotors have turned blue-brown from heat.

Are you sure your brake is even cooked? Not just dirty old jammed up? Not something a can of brake cleaner could fix?

 

[MarkJohnston]

Its says it's the Shimano XT SM-RT86- M Rotor - 6-Bolt. This one says it's the same except for a -S after the model number. They both look very similar. If it is a forgery it's a very good one.

https://www.backcountry.com/shimano-xt-sm-rt86-rotor-6-bolt?CMP_SKU=SHI001B&MER=0406&skid=SHI001B-ONECOL-S180MM&mr:trackingCode=6B3420C0-4C4D-E311-9C6B-BC305BF82376&mr:referralID=NA&mr:device=c&mr:adType=plaonline&CMP_ID=PLA_GOc001&utm_source=Google&utm_medium=PLA&k_clickid=_k_Cj0KCQjw8eOLBhC1ARIsAOzx5cF4gcO8h4lvhj9xWS2RldLD5uPpVaOtqwlihwBVu6LUwVGskroDyPgaApYzEALw_wcB_k_&utm_id=go_cmp-12868123420_adg-121976316672_ad-517539118271_aud-1124940132869la-983202698777_dev-c_ext-_prd-SHI001B-ONECOL-S180MM&gclid=Cj0KCQjw8eOLBhC1ARIsAOzx5cF4gcO8h4lvhj9xWS2RldLD5uPpVaOtqwlihwBVu6LUwVGskroDyPgaApYzEALw_wcB