Upgrading from 160mm rotors

[love2fly]

12 minutes ago, W@nted said:

Interesting topic. I have purchased new pads for my brakes, but how do I know the rotors are still in good condition?

If there is a significant ridge on the outer edge they are done. If they are OEM there will be a spec. You'll need a good vernier or micrometer.

[ChrisF]

25 minutes ago, W@nted said:

Interesting topic. I have purchased new pads for my brakes, but how do I know the rotors are still in good condition?

"Good condition" refers to at least TWO items:

 

1. Thickness - a badly worn disc becomes thin, and the tell tale ridge shows this up.

 

2. Contaminated - THIS is the one that affects your braking .... if in any doubt, clean with alchol.  If the rag is black ... well muck came off that disc !!  If in doubt I do sand it lightly, but obviously this impacts on the life of the disc, so apply discretion when doing this.

 

A slightly bent disc could also push the pads back further, resulting in a long brake lever ... but this you typically hear.

[Hairy]

1 hour ago, dasilvarsa said:

To Decontaminate Disks Take Disk Off the Wheel

Shield Car Wash Neat and a Nail Brush 15 Minutes per Side

Work The Dirt out of the Holes.

Be Careful Not to bend the Disks.

Do the same to the Pads but Only 2 Minutes.

If the Back Brake Can Lock the Back Wheel on Tar It's Working Good.

A bit more difficult to test the Front (OTB).

Does the shield car wash not contain a way of any sort?

[love2fly]

18 hours ago, HenryS said:

Here is an example of a rotor that should only be used with resin pads.
https://www.evobikes.co.za/product/shimano-center-lock-disc-brake-rotor-160-mm-sm-rt30-resin/

Interesting...maybe Shimano use lesser quality in their resin rotors? Never seen it on OEM Sram or KCNC and Quasxar for that matter. I was told to never use metallic pads AZ it wears your rotor quicker. Not true. I get plenty mileage and can ride in rain and not shred my pads.

[Steady Spin]

My take on this. 

I run metallic pads on Hope 203mm/180mm rotors. Bigger rotors = better stopping power = less need to drag the hell out of brakes to stop. 

Pads and rotors last longer since you use them less.

My rotors are about 8 years old (7500km +-) and only on the second set of pads. 

[W@nted]

Just installed new pads (semi metallic) on my level TL brakes. Previous pads were very shiny on the surface. Cleaned the disks with brake cleaner (rag had black residue).

Then followed the parktools method of bedding the brake pads. Added water. Jeez these pads squeel worse than n pig. Is it normal for new pads?

[Steady Spin]

2 minutes ago, W@nted said:

Just installed new pads (semi metallic) on my level TL brakes. Previous pads were very shiny on the surface. Cleaned the disks with brake cleaner (rag had black residue).

Then followed the parktools method of bedding the brake pads. Added water. Jeez these pads squeel worse than n pig. Is it normal for new pads?

I've always had squeal with metallic pads on Hope brakes. Makes me use them even less.

[W@nted]

1 minute ago, Steady Spin said:

I've always had squeal with metallic pads on Hope brakes. Makes me use them even less.

They were quiet until I poured water on them.

[RJClegg]

I had some time this afternoon; so decided to bed in the pads. Removed them from the callipers and lightly sanded them. Fortunately there is a nice hill just outside my house, so I used that. 

Did one brake at a time; 5 or 6 times down the hill pulling hard on it and releasing just before the wheel locks up. Did that about 4 times on each run. 

Braking performance has definitely improved. I can lock up the rear wheel easy enough on the tar. The front one, I am not 100% sure on. Pulling it hard and the wheel almost locks up. Not quite. 

The bite point is also later on the front brake - how do I adjust this? 

Will see how the feel on this weekends ride and report back. Going to order some rotors at the end of the month.

 

Thanks for all the help everyone, much appreciated! 

[ChrisF]

1 hour ago, W@nted said:

They were quiet until I poured water on them.

Lots of brakes make an awefull noise when wet ....  often hear this at the early morning start of events.  As soon as it dries out it is quiet.

[Grease_Monkey]

2 hours ago, W@nted said:

Just installed new pads (semi metallic) on my level TL brakes. Previous pads were very shiny on the surface. Cleaned the disks with brake cleaner (rag had black residue).

Then followed the parktools method of bedding the brake pads. Added water. Jeez these pads squeel worse than n pig. Is it normal for new pads?

Metalic pads are noisy when wet. No way around it.

[Jehosefat]

15 hours ago, RJClegg said:

I had some time this afternoon; so decided to bed in the pads. Removed them from the callipers and lightly sanded them. Fortunately there is a nice hill just outside my house, so I used that. 

Did one brake at a time; 5 or 6 times down the hill pulling hard on it and releasing just before the wheel locks up. Did that about 4 times on each run. 

Braking performance has definitely improved. I can lock up the rear wheel easy enough on the tar. The front one, I am not 100% sure on. Pulling it hard and the wheel almost locks up. Not quite. 

The bite point is also later on the front brake - how do I adjust this? 

Will see how the feel on this weekends ride and report back. Going to order some rotors at the end of the month.

 

Thanks for all the help everyone, much appreciated! 

Be thankful that you didn't lock up the front brake. That's a quick way to an involuntary lie down. In general it will be much harder to lock the front brake than the back due to the "weight transfer" when braking.

To adjust the bite point, you can take the front wheel out and squeeze the front brakes a little, if you squeeze them just enough the pads will be closer to the rotor when you put the wheel back in. If you squeeze it too much then you won't be able to get the wheel back in and you will need to open the reservoir at the lever, pop in a bleed funnel and gently push the pistons apart again. Can be a bit of a hack so go very gently. This approach can be pretty hit and miss depending on a bunch of factors (like how true your rotors are)

[RobertWhitehead]

16 hours ago, RJClegg said:

I had some time this afternoon; so decided to bed in the pads. Removed them from the callipers and lightly sanded them. Fortunately there is a nice hill just outside my house, so I used that. 

Did one brake at a time; 5 or 6 times down the hill pulling hard on it and releasing just before the wheel locks up. Did that about 4 times on each run. 

Braking performance has definitely improved. I can lock up the rear wheel easy enough on the tar. The front one, I am not 100% sure on. Pulling it hard and the wheel almost locks up. Not quite. 

The bite point is also later on the front brake - how do I adjust this? 

Will see how the feel on this weekends ride and report back. Going to order some rotors at the end of the month.

 

Thanks for all the help everyone, much appreciated! 

By bleeding the brakes you'll get the lever to bite earlier. Are the rotors on your wheels centre lock or 6 bolt? Then where in Jhb are you based? 

[RobertWhitehead]

16 hours ago, W@nted said:

Just installed new pads (semi metallic) on my level TL brakes. Previous pads were very shiny on the surface. Cleaned the disks with brake cleaner (rag had black residue).

Then followed the parktools method of bedding the brake pads. Added water. Jeez these pads squeel worse than n pig. Is it normal for new pads?

In my experience: If your brakes start to make a noise you most likely have a caliper leak. You will find that if you remove the pads now again that they'll be shinny all over again. Put the bike on the stand an inspect the piston when pulling the lever. Be sure to remove the pads and add a block before conducting the experiment ????

[RJClegg]

1 hour ago, Jehosefat said:

Be thankful that you didn't lock up the front brake. That's a quick way to an involuntary lie down. In general it will be much harder to lock the front brake than the back due to the "weight transfer" when braking.

To adjust the bite point, you can take the front wheel out and squeeze the front brakes a little, if you squeeze them just enough the pads will be closer to the rotor when you put the wheel back in. If you squeeze it too much then you won't be able to get the wheel back in and you will need to open the reservoir at the lever, pop in a bleed funnel and gently push the pistons apart again. Can be a bit of a hack so go very gently. This approach can be pretty hit and miss depending on a bunch of factors (like how true your rotors are)

 

I had my weight at the back when trying to lock up the front wheel. But yeah, that is a sure way to be OTB. 

 

59 minutes ago, RobertWhitehead said:

By bleeding the brakes you'll get the lever to bite earlier. Are the rotors on your wheels centre lock or 6 bolt? Then where in Jhb are you based? 

 

I'll try bleeding them at the end of the month, right now it isn't too much of an issue. I did realise though that I need to spend a little time setting up the cockpit properly. Both brake handles are not in the same position and they should move in more on the bars. I'll do that before Saturday I think. 

Unfortunately they are not C/L - but the standard 6-bolt setup. I'm Randburg side. 

[Steady Spin]

1 hour ago, RobertWhitehead said:

In my experience: If your brakes start to make a noise you most likely have a caliper leak. You will find that if you remove the pads now again that they'll be shinny all over again. Put the bike on the stand an inspect the piston when pulling the lever. Be sure to remove the pads and add a block before conducting the experiment ????

Never seen that. Not even with brakes that haven't been bled or maintained for over 8 years. 

 

Odd