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-   -   do I have to check disc pads or can I just wait for a scraping sound? (https://www.bikeforums.net/bicycle-mechanics/1162748-do-i-have-check-disc-pads-can-i-just-wait-scraping-sound.html)

rumrunn6 12-23-18 03:01 PM

do I have to check disc pads or can I just wait for a scraping sound?
 
Promax dsk-310 mechanical disc

Bill in VA 12-23-18 03:55 PM

If you use that strategy for your car, by all means go for it, but I would check the pads whenever I air up and/or when I check bolts for tightness.

Disclaimer: I do not have discs on my bicycle, and have not looked at your model disc, but the ones I have looked at in shops, I could see the edge of the pad.

If it is hard to discern the pad material from the backing plate, on my car I painted a line of typists "white-out" correction fluid from the backing plate to the edge of the pad under the inspection hole of the caliper. Very east to see through the inspection hole and if it is covered with dust a Q-tip will wipe the dust off. I do that whenever I replace the pads.

fietsbob 12-23-18 04:38 PM

Promax dsk-310 mechanical disc

Depends, how lazy are you?
I changed my Avid BB7 Stock pads because I did not like how they worked ...

http://www.promaxcomponents.com/wp-c...weo58qmzi8.jpg

Andrew R Stewart 12-23-18 06:43 PM

To be cynical- That's a really good method, wait till the rotor is getting all chewed up before paying attention. Andy

ogmtb 12-23-18 07:13 PM


Originally Posted by Andrew R Stewart (Post 20716699)
To be cynical- That's a really good method, wait till the rotor is getting all chewed up before paying attention. Andy

The rotor is harder than the backing plate.

In the real world the rotor is unscathed but slowing down becomes problematic. (see avatar)

cyccommute 12-23-18 07:35 PM


Originally Posted by rumrunn6 (Post 20716495)
Promax dsk-310 mechanical disc

Some people seem to be able to wear out a set of pads in an afternoon...if you believe some of the argument presented on the Bike Forums. On the other hand, you can check them once in while, use them sparingly and not worry too much about it. I have pads that are at least a couple of years old and still in good shape. I havenít really even needed to adjust the pad width yet.


Originally Posted by Andrew R Stewart (Post 20716699)
To be cynical- That's a really good method, wait till the rotor is getting all chewed up before paying attention. Andy

The rotors probably need replaced more often then they are on bicycles. They do wear out.

That said, rotors are cheap...only about twice the cost of a set of pads. Itís not like a car where a rotor replacement is a significantly costly affair.

Spoonrobot 12-23-18 07:38 PM

The difference between a new rotor and a rotor at the end of its life is between .4-.7 of a millimeter. It's possible to destroy a new rotor by braking with the backing plate one time. Pads can be checked, for free, with your eyes. Sometimes you don't even need to bend down.

ogmtb 12-23-18 09:12 PM


Originally Posted by Spoonrobot (Post 20716754)
The difference between a new rotor and a rotor at the end of its life is between .4-.7 of a millimeter. It's possible to destroy a new rotor by braking with the backing plate one time.

In related news, the sky is falling!!!

DrIsotope 12-23-18 09:17 PM

Mechanical calipers are easy-- every one I've ever used would run out of pad adjustment before they could put the pad backings into the rotors. With the current hydro calipers, it doesn't seem to be an issue either, as after ~3,000 miles, the pads show no visible wear.

bikeme 12-24-18 01:34 AM

You don't need to wait for scraping to tell--your brake levers would be against your grips in order to stop if that worn. It's easy to check. I have Shimano and you can see the pads without taking them out. If in doubt because of dust or very worn, I just pull the cotter pin or bolt and slip out the pads to check. They get switched if thin enough to be close to the pads' spring. I guess I use 1 rotor to 2-3 sets of pads usage?

fietsbob 12-24-18 11:36 AM

taking the wheel out and looking is too much work ? have a minion do it for you..

pdlamb 12-24-18 02:11 PM


Originally Posted by fietsbob (Post 20717446)
taking the wheel out and looking is too much work ? have a minion do it for you..

Can I order a minion with Amazon Prime? I'm too cheap to hire one locally. :)

rumrunn6 12-24-18 03:17 PM


Originally Posted by fietsbob (Post 20717446)
taking the wheel out and looking is too much work ? have a minion do it for you..

no, I have looked but I can't tell. I think I have to remove the pads to inspect them. in fact, I've tried wiggling them out on more than one occasion but they didn't budge. I probably have to remove a thru bolt to get them free :foo:

KraneXL 12-24-18 04:37 PM


Originally Posted by fietsbob (Post 20717446)
taking the wheel out and looking is too much work ? have a minion do it for you..

Why I believe in and heartily support my LBS. Are there wear indicators for discs?

Wattsup 12-24-18 04:43 PM

You want to wait until you see sparks.

rumrunn6 12-27-18 10:26 AM

just saw this, thought I'd share


fietsbob 12-27-18 01:10 PM

Planning ahead?
 

Originally Posted by KraneXL (Post 20717803)
. Are there wear indicators for discs?

Notice how thick the friction material is, perhaps, measure it ?.. and then before each season , measure again ?

you can see the pads once you take the wheel out, can't you?

removing the disc pads is not difficult.. I used some course carborundum grit paper
to remove the glazed surface on my BB7 original pads ,

then replaced them (Kool Stop Organic), and then replaced the caliper with a different type..





...

...

bikeme 12-28-18 02:57 AM


Originally Posted by rumrunn6 (Post 20717739)
no, I have looked but I can't tell. I think I have to remove the pads to inspect them. in fact, I've tried wiggling them out on more than one occasion but they didn't budge. I probably have to remove a thru bolt to get them free :foo:

There is either a cotter pin or a fixing bolt with a small circlip that keeps the pads from falling out. You must remove it to remove the pads. Note the sides and direction the pads come out/go in and be sure to replace the pin or bolt with the circlip!

rumrunn6 12-28-18 07:45 AM

gotta look again for an easy way to slip them out

https://cimg7.ibsrv.net/gimg/bikefor...b913604028.jpg

https://cimg0.ibsrv.net/gimg/bikefor...12dcf87dc3.jpg

mackgoo 12-28-18 09:02 AM

Is that the way you would determine you needed w blocks with the old style caliper brakes?

kaos joe 12-28-18 12:19 PM


Originally Posted by pdlamb (Post 20717651)
Can I order a minion with Amazon Prime? I'm too cheap to hire one locally. :)

I'm watching this thread closely, as I'm new to both disk brakes and minions and have a lot to learn.

https://cimg2.ibsrv.net/gimg/bikefor...1bdd8245c7.jpg

wgscott 12-28-18 12:28 PM


Originally Posted by rumrunn6 (Post 20717739)
no, I have looked but I can't tell. I think I have to remove the pads to inspect them. in fact, I've tried wiggling them out on more than one occasion but they didn't budge. I probably have to remove a thru bolt to get them free :foo:

The procedure is very straightforward:

Shimano:

1. Remove little clip from the inside end of the retaining bolt.
2. Remove retaining bolt.
3. Remove pads and spring as one unit.
4. Look at pads.
5. Replace pads if worn down, otherwise just put it back together.

SRAM/Avid:
1. Remove brake levers
2. Remove brake calipers
3. Remove rotors
4. Sell on eBay
5. Replace with Shimano

Spoonrobot 12-28-18 12:38 PM

You don't need to remove anything to inspect the pads, a flashlight helps. You look down from the top and visually confirm the remaining pad material - 0.5mm is easy to see and often "very close to the backing plate" is good enough.

wgscott 12-28-18 12:44 PM


Originally Posted by Spoonrobot (Post 20722033)
You don't need to remove anything to inspect the pads, a flashlight helps. You look down from the top and visually confirm the remaining pad material - 0.5mm is easy to see and often "very close to the backing plate" is good enough.

I can get a pretty good idea for the state of the pads just from the feel of the brake levers.

I think until someone knows what to look for, removing them is the most unambiguous approach.

fietsbob 12-28-18 05:28 PM

The Scuttlebutt from the 1st use of a disc brake bike in the worlds Cyclocross championships race, a few years past,

was the holes in the disc retained enough of the Sand pit the brake pads would not last an hour..( Sr Men's race is 60 minutes to the last lap bell.. )

So they flew in some made overnight, without holes in the edge, so no place to retain that sand..

So .... you could be scraping metal sooner than you think..


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