Radrover break pads do not work.

[Mtolesen]

Hello,
I went on my Radrover, and found that the rearwheel break only brake very weak.
I tried to adjust them, but still not good brake power.
Then i changed the brakepads with new one......still now good, only very moderate brake function.
Has anyone observed similar, and how did you fix it?
The disk seems very clean, shall i try to clean it or sand it?

[Ddaybc]

Hi Mtolesen,
Whatever you do, don't sand your brake discs. Clean them with either Acetone, Isopropyl Alcohol or actual brake cleaner.

Remove your brake pads, place a piece of 120 grit or even 180 grit sandpaper on a flat surface.  Lightly sand the brake surface of the brake pads on the sandpaper. When finished, clean the pads with the same stuff you cleaned your brake discs with.

Reassemble your brakes, adjust them as per your owners manual or Youtube videos and then break in the freshly cleaned brake pads. Look on Youtube for how to do it. It's relatively simple. Once done, you should have good brakes.

I hope this helps. If not, take your bike to a bike shop. They will be happy to do it for you.

[handlebar]

I think you have a 2019, and I guess it has mechanical brakes. This is what works for me.

Is the rotor free of oil? Sometimes I wipe mine with a little contact cleaner on a paper towel. Once, when I thought the pads were contaminated, I took them out and cleaned them. I think I sanded slightly to remove any glaze, then washed them and let them dry.

With the pads back in, I leave the bolts that mount the caliper about 1/4 turn loose so that the caliper can slide into alignment. If the cable won't let the lever on the caliper open all the way, I loosen the cable.

On the side toward the spokes is an allen screw head about 2 cm in diameter. Using an allen key that came with the bike would be awkward. Instead, I reach through from the other side of the wheel with an allen bit on a 6" shaft. I screw it in until the wheel won't turn, then back off a click or two until the wheel turns freely.

There's a barrel adjuster at each end of the cable housing. I like to screw them in all the way to loosen the cable, then loosen the pinch screw on the caliper to pull out any slack. If I tighten the pinch screw and I can pull the hand lever all the way to the handlebar, I tighten the cable with the barrel adjustors.

Then I hold the brake on by using a clove hitch to lash the lever to the handlebar. This holds the caliper in alignment by clamping it to the rotor. Then I tighten the screws holding the caliper to the bike. Tightening one all the way while the other was loose, might pull the caliper out of alignment. I tighten them in stages, going from one screw to the other.

I unlash the lever and if it's not quite to my liking, turn the barrel adjusters.

You say it's the back brake. I find back brakes more troublesome because turning the handlebars back and forth causes the cable housing to stretch, little by little. Stretching the housing is like shortening the cable, causing the pads to drag and wear. Pulling the lever compresses the housing, and the lever may go all the way to the handlebar without putting much pressure on the pads.

I can tighten a stretched cable housing by switching off the battery and lashing the lever to the handlebar overnight. If the housing is badly stretched, doing it on subsequent nights may bring more improvement.

I hadn't had my Radrunner long when the rear pads wore out. It was partly from cable stretch and mostly because the caliper had come from the factory misaligned. Because I used the brakes together and didn't need to pull hard, I didn't know the back brake had stopped working until the day I grabbed the lever to lock the wheel so I could turn the bike over backward.

Even with proper adjustment, the new pads didn't grab very hard. That's because they needed bedding in. The usual method is to use one brake to slow fairly hard from 20 mph but not to a full stop. Each time, heat from friction will transfer a little material to the disk, but if you were to brake hard to a full stop, the hot pads would leave a clump of material stuck to the disk, causing bumpy braking. Some manufacturers recommend repeating it 50 times.

[Mtolesen]

Hi handlebar and Ddaybc,
Thank you very much for your very detailed explanation, i tried to adjust like yoy explain, but the brake still do not really block nice, like the front brakes, the backbrake is still very weak, is is strange with such a simple construction?.maybe it is because the cable to the back brake is longer, and there by more stretched, and thereby lot of the power are lost in stretch instead of being transfered to the brake?.

[handlebar]

Hi handlebar and Ddaybc,
Thank you very much for your very detailed explanation, i tried to adjust like yoy explain, but the brake still do not really block nice, like the front brakes, the backbrake is still very weak, is is strange with such a simple construction?.maybe it is because the cable to the back brake is longer, and there by more stretched, and thereby lot of the power are lost in stretch instead of being transfered to the brake?.

Yesterday, I discovered that my cable housing was stretched again. I compressed it overnight by leaving the lever lashed to the handlebar. That removed enough stretch that today I had to loosen the pinch screw and pull the inner cable shorter. I'll lash the lever to the bar again tonight to see if there's more improvement.

If your back brake feels spongy and you can squeeze the lever all the way to the handlebar, that could mean your cable housing is stretched. If you meet solid resistance from the cable and you still don't slow down very well, that could mean the pads need bedding (breaking in). There's a hill near me with a 6% grade. It's a good place to bed brake pads. I get up to 25 mph, use that brake to slow pretty quickly to 10, let it speed up to 25, and repeat. One ride down the hill won't bed brake pads, but I'll see an improvement.

[Mtolesen]

Thank you for further info handelbar.
I may have found out what the problem could be, it i like when i activate the rear brake, one end of one of the brake pad, do not reach the disc, meaning that the two brake pads on each side of the disc, only use a part of surface to brake, and that limit the brake power.......if this  make sense......i need to try to adjust this.

[handlebar]

Thank you for further info handelbar.
I may have found out what the problem could be, it i like when i activate the rear brake, one end of one of the brake pad, do not reach the disc, meaning that the two brake pads on each side of the disc, only use a part of surface to brake, and that limit the brake power.......if this  make sense......i need to try to adjust this.

My rear Radrunner brake came from the factory misaligned that way. I didn't realize it because I didn't understand the Radpower's instructions to check and adjust the alignment.

My method is simple. Slightly loosen the two allen screws that hold the caliper to the bike. Reach through the spokes with an allen bit on a long shaft and tighten the adjustment screw so that the inside pad clamps the rotor against the outside pad. Because the caliper can move with the screws loose, this will align it so the pads hit the rotor flat. Then back off a little so the wheel will turn freely.

The caliper is no longer clamping the rotor, so it could move out of alignment when you tighten the screws. That's why I lash the lever to the handlebar. That keeps the caliper clamped to the rotor while I tighten the screws.

[Mtolesen]

Hi handelbar,
That is excatly how i will do i, but it will be next year, since the bike is here in my summerhouse, and we are leaving today 😀, but thanks for all your help!
Kind regards
Martin

[mrgold35]

I have a two 2016 Radrovers with 4000 miles each I used for weekend fun rides at first.  Decided to work commute a year later at 18-22 mph range for 7-20 miles (depending if I take a detour to hit the single tracks on the way home).  I quickly found out the standard brakes are good for weekend trails; but, not up to par for emergency stops at 20 mph when a car runs a stop sign.  The pads glazed over pretty quick over time and I had much longer braking distances in emergency situations.  Narrowed down the issues to brake pad materials, stretching of brake cables, brake cables strands breaking, and realizing the current brakes were at their limits at max speed at my max cargo capacity.

Solve my issues with upgrading to TRP Spyre Mechanical brakes, TRP replacement brake pads, and jagwire MTB brake cables (cable only, reused the housing).

[inoxa]

One side of the brake is applied with the brake lever.  The other side is stationary and is adjusted with an allen wrench from the other side of the bike.  So what happens is when you pull the lever it pushes it to the other pad.

I have replaced my pads at least 3 times.  Current ones are the best.  No need for upgrade. 
There are quiet ones and noisy ones.  They make organic ones and metallic ones and ceramic ones.  The color of the metal that the pad is glued to is how you tell which one you have.  I think the colors are Green, Yellow, and Red.  I am currently using Green and very pleased.  Plenty of stopping power for me on the streets and high speeds. 

[handlebar]

I quickly found out the standard brakes are good for weekend trails; but, not up to par for emergency stops at 20 mph when a car runs a stop sign.  The pads glazed over pretty quick over time and I had much longer braking distances in emergency situations.  Narrowed down the issues to brake pad materials, stretching of brake cables, brake cables strands breaking, and realizing the current brakes were at their limits at max speed at my max cargo capacity.

Solve my issues with upgrading to TRP Spyre Mechanical brakes, TRP replacement brake pads, and jagwire MTB brake cables (cable only, reused the housing).

With the OEM mechanical front brake alone, I can stop my Radmission in 20 feet from 20 mph. That's 0.7 g, the same as a modern car. If I hadn't repositioned the bars and seat, a stop like that would send me over the bars or end over end. The back brake would be useless in a stop like that because the bike nearly stands on its front wheel.

I used to think my pads would glaze, but I decided it was a sort of polishing from light dragging caused by cable stretch, which really isn't stretch. The cure was to adjust the affected brake so that there was no drag, then on a hill repeatedly use that brake fairly hard to slow from 25 to 10. Each time, it heats the pad surface enough to transfer a little material to the disk for improved friction.

The Jagwire product that interests me is the linear housing. Because it's not made of a coil spring, it doesn't stretch. I largely correct stretch of the rear housing by lashing the lever to the handlebar to keep the housing under compression overnight. With a linear housing, I guess I wouldn't have to worry about that.