Heavy Duty Ebike Brakes Suggestions?

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BionicBlitz   100 mW

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Heavy Duty Ebike Brakes Suggestions?

Post by BionicBlitz » Aug 02 2019 10:19am

have a custom qs205 ebike that weighs in at about 150 lbs and with me (170lbs) any decent sized hill will get my front and back 203mm magura mt5 brakes glowing. i have regen on my sabvoton 96100 but it doesn't enable untill around 106.8v (running 28s li-ion 117.6v fully charged)

any suggestions? willing to use dirtbike brakes if theres some that'll fit reasonably well or how to change the activation voltage of regen (ive looked on app and computer) thanks
qs205 5t, 28s li-ion 36Ah, 120a esc, homemade frame.

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Compoundbike   1 W

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by Compoundbike » Aug 02 2019 3:43pm

Im also wondering, those maguras are not enough strong for braking.

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E-HP   10 kW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by E-HP » Aug 02 2019 5:47pm

BionicBlitz wrote:
Aug 02 2019 10:19am
have a custom qs205 ebike that weighs in at about 150 lbs and with me (170lbs) any decent sized hill will get my front and back 203mm magura mt5 brakes glowing.
Are you already using heat sinks?

flat tire   1 MW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by flat tire » Aug 02 2019 6:03pm

Motocross brakes are probably the lightest for little money.

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BionicBlitz   100 mW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by BionicBlitz » Aug 02 2019 7:33pm

heatsink what exactly? the rotor? not sure thatd be enough. i can get it to turn blue and have it warping in 5 seconds.

the magura brakes are plenty strong. can lock up both tires full speed.


id love motocross but not sure how to mount them
qs205 5t, 28s li-ion 36Ah, 120a esc, homemade frame.

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by flat tire » Aug 02 2019 8:09pm

Presumably you would need custom adaptors for both the caliper and rotor.

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Drunkskunk   100 GW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by Drunkskunk » Aug 02 2019 8:46pm

It's pretty clear the problem is the rotors, not the calipers, but I have boiled the fluid on brake calipers from hard braking without getting them to actually glow. That said, I have a few ideas on rotors.

How much glow are you getting? If it's just a bit at the most extreme moments, you might be able to try 223mm rotors. 9 inch have worked for me on the Monster bike pushing similar weight, but with fewer hills.

MC brakes would be hard to mount, and expensive to do. Dual rotors on the front might be almost as expensive. both are options if you can throw a lot of time and money at the problem.

You could take grinder to a 9 or 10 inch circular saw blade, knock off the teeth, and have a solid rotor.

You can have a 9" or 10" solid disk custom cut out of spring steel, perhaps twice as thick. you might also need to take apart the caliper and add a spacer between the two sides to handle the extra width. This was my plan C on the Monster bike, but the 9" 223mm ended up being enough.
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Re: Heavy Duty Ebike Brakes Suggestions?

Post by flat tire » Aug 02 2019 9:27pm

Uh yeah except the Magura calipers have an opening too thin to accept rotors with enough thermal mass without going WAY beyond the ~200mm bicycle diameter. 223mm rotors won't fix his problem lol.

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MadRhino   100 GW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by MadRhino » Aug 02 2019 10:07pm

First, the MT5 for the rear is OK, for the front I like better. You can convert your MT5 into MT7: add the lock pins (or cutter pins) and use the 4 pads system, then try to find a good deal for the MT7 lever.

Rotors are making a big difference. The Magura rotor that I like is the Venti, even better the Hope 225mm vented rotor, and Hayes does make a cheap heavy 225mm too. All of those have the thickness required for Magura. The Gustav is the best brake for an ebike, with the Hope M6. Both are hard to find, and expansive nowadays.

Pads too, are making a difference. Racing pads (natural) are wearing fast but easy on the rotors. Any brand natural pads are OK, and best is to buy a full card (12 sets). Sintered are not that bad but you need to be careful replacing them pretty long before they are worn out. Bi-metal and ceramic are wearing the rotors.

Next, brake more aggressively. I mean, long dragging the brakes is killing them. Better brake neat and short.
Make it fool-proof, and I will make a better fool.
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BionicBlitz   100 mW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by BionicBlitz » Aug 02 2019 10:14pm

thanks, ive considered the 223mm thing but not sure itd be enough... i have plenty of stopping power but its just the heat.... lost brakes twice now (intentionally in a safe spot just to see whst my limit was) and its not really too safe. il try the sawblade thing if i can find a stainless blade. would solid be better or some holes?
qs205 5t, 28s li-ion 36Ah, 120a esc, homemade frame.

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E-HP   10 kW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by E-HP » Aug 02 2019 10:36pm

BionicBlitz wrote:
Aug 02 2019 7:33pm
heatsink what exactly? the rotor? not sure thatd be enough. i can get it to turn blue and have it warping in 5 seconds.

the magura brakes are plenty strong. can lock up both tires full speed.


id love motocross but not sure how to mount them
I had seen this article when I was looking at rotors. Not sure how much heat they dissipate, but at least they slightly increase the thermal mass:

https://singletrackworld.com/forum/topi ... trix-pads/

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amberwolf   100 GW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by amberwolf » Aug 02 2019 10:45pm

BionicBlitz wrote:
Aug 02 2019 10:14pm
would solid be better or some holes?
You're looking for more thermal mass, if overheating the rotors is the problem.

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E-HP   10 kW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by E-HP » Aug 02 2019 11:14pm

amberwolf wrote:
Aug 02 2019 10:45pm
BionicBlitz wrote:
Aug 02 2019 10:14pm
would solid be better or some holes?
You're looking for more thermal mass, if overheating the rotors is the problem.
Yup, but depends on how long. At some point, the advantages of more thermal mass are outweighed by the advantages of heat dissipation.

Design and Analysis of Solid and Cross-Drilled Disc Brake Rotors

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MadRhino   100 GW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by MadRhino » Aug 03 2019 5:10pm

Solid brake rotors, need to be vented anyway, or else they are crap technology from the last century.

From what you say, my guess is that you are a brake dragger. You need to learn efficient braking, and you need brake levers with adjustable bite point. Maybe you need to tune your brakes to clear the rotor.

All riders like to have at least one finger on the brake at all time; but some are, consciously or not, making slight braking contact long before they need to brake. Some are slowing down hills holding brake contact. Brakes are efficient when used short: short braking distance, short bursts to slow down.

Make sure your rotor is free of contact when riding or freewheeling; and when you brake do it short and neat, clearly feeling the rear unloading.
Make it fool-proof, and I will make a better fool.
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markz   100 GW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by markz » Aug 03 2019 8:36pm


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MadRhino   100 GW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by MadRhino » Aug 04 2019 10:14am

markz wrote:
Aug 03 2019 8:36pm
Look at the 255mm discs
https://www.bicycledesigner.com/bike-pa ... 255mm.html
29$ of rotor, and 40$ of design to make them square. :D

That is 69$ of rotor

Image
Make it fool-proof, and I will make a better fool.
Current bikes
Street: https://s20.postimg.org/ewrvugywt/Session_04_2015.jpg
Dirt: https://s20.postimg.org/lbqwr55ml/IMG_0157.jpg

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efMX Trials Electric Freeride   100 kW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by efMX Trials Electric Freeride » Aug 04 2019 10:19am

how about a link, not just blurry pic? :)
some ride & sk8 videos:
metacafe.com/channels/NATAS666DAMIEN
http://www.youtube.com/natas666damien
i have nothing for sale.. :)

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MadRhino   100 GW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by MadRhino » Aug 04 2019 11:15am

efMX Trials Electric Freeride wrote:
Aug 04 2019 10:19am
how about a link, not just blurry pic? :)
Sorry, I just searched for a pic. Presumed stupidly that everyone would recognize a Hope 225mm rotor. They can be purchased direct at Hope factory. Very few resellers are stocking them nowadays.
Make it fool-proof, and I will make a better fool.
Current bikes
Street: https://s20.postimg.org/ewrvugywt/Session_04_2015.jpg
Dirt: https://s20.postimg.org/lbqwr55ml/IMG_0157.jpg

markz   100 GW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by markz » Aug 04 2019 11:27am

MadRhino wrote:
Aug 04 2019 11:15am
efMX Trials Electric Freeride wrote:
Aug 04 2019 10:19am
how about a link, not just blurry pic? :)
Sorry, I just searched for a pic. Presumed stupidly that everyone would recognize a Hope 225mm rotor. They can be purchased direct at Hope factory. Very few resellers are stocking them nowadays.
225 is too wimpy, the larger the # the better, hence 255, pretty much in every case that statement rings true. The larger the better!

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MadRhino   100 GW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by MadRhino » Aug 04 2019 11:33am

markz wrote:
Aug 04 2019 11:27am
MadRhino wrote:
Aug 04 2019 11:15am
efMX Trials Electric Freeride wrote:
Aug 04 2019 10:19am
how about a link, not just blurry pic? :)
Sorry, I just searched for a pic. Presumed stupidly that everyone would recognize a Hope 225mm rotor. They can be purchased direct at Hope factory. Very few resellers are stocking them nowadays.
225 is too wimpy, the larger the # the better, hence 255, pretty much in every case that statement rings true. The larger the better!
Then buy rim brakes

Rotors are not born equal. Some last a month, others 5 years.
Make it fool-proof, and I will make a better fool.
Current bikes
Street: https://s20.postimg.org/ewrvugywt/Session_04_2015.jpg
Dirt: https://s20.postimg.org/lbqwr55ml/IMG_0157.jpg

markz   100 GW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by markz » Aug 04 2019 11:42am

True, but consumers dont care about rationality.
MadRhino wrote:
Aug 04 2019 11:33am
Then buy rim brakes
Rotors are not born equal. Some last a month, others 5 years.

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efMX Trials Electric Freeride   100 kW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by efMX Trials Electric Freeride » Aug 04 2019 11:52am

MadRhino wrote:
Aug 04 2019 11:15am
efMX Trials Electric Freeride wrote:
Aug 04 2019 10:19am
how about a link, not just blurry pic? :)
Sorry, I just searched for a pic. Presumed stupidly that everyone would recognize a Hope 225mm rotor. They can be purchased direct at Hope factory. Very few resellers are stocking them nowadays.
sure, I recognize it.. but what about the OP and other readers.. ppl come here for detailed info and help, so thanks for the clarification and source.. you know what they say about assumptions;)..
some ride & sk8 videos:
metacafe.com/channels/NATAS666DAMIEN
http://www.youtube.com/natas666damien
i have nothing for sale.. :)

Peterfr12   100 mW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by Peterfr12 » Aug 04 2019 3:31pm

Hi

if the rotor are not big enough to dissipate heat use thicker one. instead of the 1.8 mm you can order rotor with 2.3 mm thickness.
diameter is still 203 mm. there are 4 pistons.

google G-SPEC E-MTB

i have nt tested them since i am still building my setup.

i ordered them here from a French company
https://lmxbikes.com/en/chassis-parts/8 ... r-lmx.html
but you can find them here too
https://www.empoweredcycles.com/product ... 03mm-front

good luck

best regards,

Peterfr

markz   100 GW

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by markz » Aug 04 2019 3:41pm

I never knew that, good stuff :thumb:
Peterfr12 wrote:
Aug 04 2019 3:31pm
if the rotor are not big enough to dissipate heat use thicker one. instead of the 1.8 mm you can order rotor with 2.3 mm thickness.
diameter is still 203 mm. there are 4 pistons.

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Re: Heavy Duty Ebike Brakes Suggestions?

Post by pullin-gs » Aug 09 2019 2:58pm

I went to larger rotors.
All I had to do was make sure everything clears OK with new rotors, buy a pair of caliper mounts for new rotor size.
I did go with floating rotors whose rivets rubbed a bit on caliper, so I had to do some minor dremo tool grinding on caliper frames.
Braking is much better.

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