iZip E3 Peak Rear Brake

[claucXC]

I have had my E3 Peak for a few months now and am generally very happy with it. I use it predominantly to commute with about 95% of my miles on the road. My question is about the rear disc brake. My brake feels very soft. It barely does any work when fully engaged. I can't get it to lock up either. I have taken it to an authorizied service center under warranty twice and the end result according to them is that this is an undersized brake system for this bike (Tektro Agura Sub). I was told on my last visit to ride the rear brakes to heat them up which, according to the mechanic, would make them work better! This means I cannot use the electric motor (motor cutoff on brake lever), I'll wear out my pads faster and I will probably have brake fade sooner as the pads and components get too hot!

Does anyone elses rear brake feel soft? I'm trying to get an idea if this is indeed a matter of an undersized brake for a heavy bike or if my particular brake is faulty.

 

[Dylan Garrison]

I have a new Dash. 300 miles. The brakes were adjusted at 200 miles and now they are complete mush again. I'd estimate I'm getting 20% from the rear and 40% from the front. Very dangerous on a bike that hits 28 with ease in downtown traffic. Taking it in to the dealer again tomorrow.

 

[MarcD]

Those brakes are not undersized in any way. While it could be a bunch of things, it sounds like they need bled. Mushy hydraulic brakes are usually air in the system.

When you say the shop adjusted them - what did they do. Most hydraulics have self adjusting pads. Maybe buy a service kit and bleed them yourself.

 

[HumanitiesHaze]

On each of the calipers there's a "R" knob to adjust the right pad into the caliper more. I find a combination of adjusting the wire (on the Dash), and the "R" knob gives me braking back. On the dash, you'll notice that if the pads are too worn down, the wire won't pull anymore because of the fulcrum of the wire against the caliper. It'll come to a point where it's physically impossible to pull the wire anymore, even tho you have plenty of lever still.

 

[MarcD]

Humanities: those are mechanical discs. The Peak has hydraulic. Different animal. No cable, no pad adjustment.

 

[HumanitiesHaze]

Humanities: those are mechanical discs. The Peak has hydraulic. Different animal. No cable, no pad adjustment.

No "R" knob of the otherside of the caliper?

 

[MarcD]

I have never seen adjustable hydraulics. Since I don't have a Peak I went and looked at the Tektro manual. No adjustment. They are like all hydros I have seen where you center the caliper and they are self adjusting.


There are only so many options:

1. They need bled because air is in the system

2. There is a leak and there isn't enough hydraulic pressure. If this were the case, you would have mineral oil on the caliper and neither person mentioned that.

3. Pads are contaminated. This isn't likely since they said it feels squishy. Contaminated pads would feel solid but wouldn't create enough friction to stop the bike.

Ergo, I go back to my original point: they likely need bled.

 

[claucXC]

Those brakes are not undersized in any way. While it could be a bunch of things, it sounds like they need bled. Mushy hydraulic brakes are usually air in the system.

When you say the shop adjusted them - what did they do. Most hydraulics have self adjusting pads. Maybe buy a service kit and bleed them yourself.

The shop told me they bled the brakes and replaced the pads on the first visit. The brakes felt mildly better but quickly got soft again.

If I knew for a fact it was just a matter of re-bleeding the brakes I would demand the service center do that and witnesses it...but I don't. That's why I'm trying to get input from other e3 peak owners (or anyone who uses the tektro agura sub disc brake) to see if the brakes are undersized or if I have a faulty/misadjusted unit.

 

[Brian(J)]

I have a new Dash. 300 miles. The brakes were adjusted at 200 miles and now they are complete mush again. I'd estimate I'm getting 20% from the rear and 40% from the front. Very dangerous on a bike that hits 28 with ease in downtown traffic. Taking it in to the dealer again tomorrow.

I am not at all surprised, I am at 550 miles and I've adjusted my brakes several times and carry the tools with me always. I think that is because the bike is heavy and moving very fast while stopping and braking a lot (at least when I am riding it) and that means more wear. I am no expert, but here are a few tips, I adjust the brakes using the cable adjusters at the lever and then at the caliper. When that is used up I use the pad adjusting wheel on the caliper, while returning the cable adjusters to their minimum position. At that point I have excellent brakes and when I start getting mush I use the cable adjusters as long as I can and then the pad adjusting wheel again. Be aware that one side of the pad seems to wear more than the other and removing/flipping the pads is very useful.

BTW, 80% to 90% of my braking is with the front brake only, the rest is front brake mostly. Helps in many ways, see Sheldon Brown on Brakes for more info on this.

 

[claucXC]

Update: I purchased a set of Kool Stop e-bike specific pads (P/N KS-D735E) and they work much better than the stock pads. I guess Currietech sized the brakes and pads with a bias towards soft (dirt) surfaces, which makes sense, but carrying a stronger pad such as the Kool Stop listed above as standard equipment would help a lot for those of us who ride pavement the majority of the time.