Brake upgrade for hard commuting

[RustyKipper]

Hey guys,

I have a brutal 14 mile each way commute between 2 city’s, the terrain is very hilly often freewheeling at well over 30 MPH and then braking to a stop at the bottom for junctions etc. City riding is in the mid-twenties with constant braking to avoid potholes, debris, cars, zombies , (well, ok people text walking oblivious to everything around them) etc., Also I have to match traffic speed so I can turn right, this also means heavy braking. The best bit is the 30-45 degree sheer drops in a muddy rock and root laden forest, these need very controlled braking. The bike weighs in at just under 30Kg (66lb) and I’m 82 Kg (182lb)

My current setup is front 203mm rotor rear 200mm rotor with Avid BB7 callipers and EBC sintered pads (when I can get them). This all works quite well albeit with too little modulation or feel so I've had a few broken bones from flying over the handlebars in the dry or the bike sliding out in the wet. I'm just getting frustrated changing pads every few weeks, the BB7 callipers are a right faff to change pads and set up and they take constant adjustment to take up the pad wear, I tried some organic pads once and had to adjust the callipers every day, the pads were down to the metal within days. It often rains in this part of the world this makes the pads wear even quicker.

So what are you folks using for the more adventurous commuting? I want to go the hydraulic route, I would like some longer lasting pads with less adjusting, easier to fit, better feel and noisey as possible as I have to share many routes and tracks with pedestrians where the traffic noise is very loud or people are listing to music or text walking ect so they can't hear my bell or me shouting at them, I find that if my brakes sound like a buss coming up behind them they DO hear me!

 

[cal3thousand]

What is likely happening is that you are exceeding the heat shedding capability of the pads. Do you have a DD motor? I would suggest using Regen on the steep and long declines and reserve your mechanical brakes for control and additional force.

Also going to a better caliper with a larger pad will help. Those BB7s are relatively small compared to a Shimano Zee or Saint pad. I personally use Zee's and I think they are a great balance in price and performance.

 

[RustyKipper]

oh wow, they look perfect, the pads do look a lot bigger they seem a good price as well.

Unfortunately no I have a 500W geared rear hub motor, I would absolutely love regen, even if I was just dumping the power into a resistor.

 

[cwah]

Just swap it to a DD motor and you'll thank me. I used to change my brake pad every couple of months as well as brake fluide. Then readjust the disc.

At 30mph on a heavy bike you are wearing really fast the bike component.

I've since changed to DD with variable regen and I haven't changed my brakes for 18 months now. So much more convenient

 

[amberwolf]

You could also add rim brakes in addition to the disc. I'd use separate brake levers for those so that they could be used with or without each other.

The rim brakes might not work as well in the wet as the disc depending on contaminants on the rims vs the discs, the rim type and condition, and which pads you use (koolstop salmon or dualcompound is my preference) but in other conditions you could use them easily, and they'd still provide extra braking regardless.

Plus, good rim brakes might have more modulation than discs, depending on the disc caliper/lever.

At some point, though, your braking power will exceed your tire traction, and at that point you'll need to change tires (probably wider for more contact patch surface).

 

[flat tire]

You need regen and it sounds like you are piss poor at using brakes if you're going over the bars or lockin em up too much in the wet.

 

[RustyKipper]

You need regen and it sounds like you are piss poor at using brakes if you're going over the bars or lockin em up too much in the wet.

I thought I mentioned lack of modulation.


Thanks guys, I think a DD motor would help massively, what controller are you chaps using? Are you using regen to put juice back into the battery or purely just to load the motor. I am thinking about some sort of AWD maybe with a DD motor up front as this is part of my route, it goes on for about a mile





Its a bad picture but there is a 30 degree gradient coming down from the right, this needs something with good brake feedback and a delicate touch.

I have about 700 feet of decent on the way into work so any regen energy would be of benefit on the way home as well as helping extend pad life.

 

[macribs]

I can recommend Hope Tech 3 V4 setup. I was initially getting shimano saint m820 setup but then I tried a bike with hope setup. Modulation was perfect. The hope tech 3 replaced the old Hope M6 Ti setup, which was good brakes but I warped discs one time too many and getting discs, fittings, bladders and even pads for the M6 Ti is getting harder and harder. I tried to bid on a custom box set of M6 pads and double/twin disc + fittings set but lost so I switched to Tech 3. Tech 3 got braided lines. Also get the vented floating double hope rotors. They can take a lot of heat.

 

[kingjamez]

My bike weighs a ton and I have a lot of starts and stops on my 10 mile commute, not as bad as yours sounds though.

I too highly recommend going the regen route. It makes a massive difference in brake wear and performance. I really don't care much about putting energy back into the battery pack, but I do very much like not having to put bike parts not designed for bikes as heavy as mine under great stress.

For taking over when the regen isn't enough, I use Shimano M675 SLX brakes and have been very happy with them. It's amazing how much better hydraulic brakes are vs. mechanical.

I learned to love regen driving my Nissan Leaf, it's one of those things that once you've used in one place, you want to have it everywhere.

-Jim

 

[billvon]

Thanks guys, I think a DD motor would help massively, what controller are you chaps using?

Given that you are regularly doing over 30mph downhill (i.e. faster than base speed) you might consider an Ebikes.ca Phaserunner - since it will do field weakening (i.e. you can go faster than base speed.) Regen power is also very controllable.

Are you using regen to put juice back into the battery or purely just to load the motor.

I use it to put power back in the battery; easier that way. The one time this DOESN'T work is when you are near full charge. Full regen when I am close to full charge will easily push my (dumb) controller over 42 volts to the battery.

 

[RustyKipper]

I'm loving the idea of regen however in the UK we have a 250W limit so anything larger has to be a bit stealthy to fly under the radar, it looks like a direct drive hub will be a bit large and obvious even a single one in the rear.

I took an old front gear hub motor apart last night to see if I could either do away with the reduction gears so in effect give me a mega front hub dynamo (ok it would be an alternator). I would likely have to power it with a controller to overcome the 'cogging' effect and give some amount of drive to the front. I also thought about fitting steel gears, filling with ATF and defeating the clutch and powering the hub full time from a controller then under braking rectify the 3 phase output and use some MOSFET PWM chopper arrangement to give some variable regen, I'm not sure how long the motor would last, this motor died after only 5000 miles of 'normal' use, it would also be a bitch to pedal 14 miles home riding against the motor, up hill and into the wind if the controller failed! It would also limit my top speed, it is essential that I can exceed 30 MPH otherwise I can't merge with traffic to turn right.

I don't want to give up on the idea, my inbound commute is using 100% solar power harvested from the previous day, it is a shame to waste all the kinetic energy.


In case you are interested here is a x10 speed video clip of my in bound commute on a sunny summers day, its dry, warm and daylight, and the traffic is quiet, I'm in no hurry to get to work, coming home on the other hand is a totally different story. Sorry about the quality.

[youtube]mEfKJWKQZ3o[/youtube]

https://www.youtube.com/watch?v=mEfKJWKQZ3o

 

[RustyKipper]

Hey guys,

Its been a while since the above post, thought I might give a quick update.

I bought a pair of 4 pot Zee hydraulic brakes for the off road commuter to replace the mechanical Avid BB7's. Wow, words can't describe the improvement in modulation. The Avids would grab and lock the wheels, these are just perfect, I can't recommend them highly enough. To prove the point about modulation I have a 200mm rotor on the rear with a 4 pot calliper (yes I know its over the top) but it is very rare for the rear wheel to lock, I generally just use 1 finger on the rear lever and 2 on the front.

I have a 30 degree muddy decent on the way to work, this must be the ultimate test of braking sensitivity!

 

[Obiwan007]

It sounds like you have found a good solution but still, you would love some regen braking. It makes a big difference. I know that would require a motor swap though. Don't forget that if you go that route you will need to have e-brake cut-offs to go with your quality hydro brakes. Big problem in the past, but now made easy with the TripWire switches available through Grin. Works on nearly every brake set out there, easy to install and nearly bullet proof in operation. It always an issue if you want good quality, high performance brakes because the the few hydro brake sets out there that include switches are neither.