pedromj

Hi,

Since the last month I noticed that my (very standard black) front brake pads had reduced their performance a lot when not applying too much strength to the brake levers. I have also noticed that for such strength they sounded like rubbing a piece of paper instead of the typical rubber sound. Then I decided to switch them by a pair of Kool Stop Salmon but the "paper rubbing" sound is still there. I removed these pads and saw that they had a black surface, I supposed that with some remains from the previous pads. I cleaned the pads and the rim with alcohol and an eraser to remove as much black rubber as I could. Although braking improved when applying a lot of strength, when applying less strength they perform in the same way as the old half-worn-out pads. Is this normal? Do you recognize my situation? What do you recommend me?

Regards,
Pedro

lostarchitect 

What is the condition of your rims? It sounds like you might have a lot of aluminum coming off the braking surface and ending up in the pads.

JerrySTL

Assuming the rims are not carbon fiber, I suggest cleaning the braking surfaces with extra fine steel wool and rubbing alcohol.

I've used KS salmon brake pads for a few years now and they work well for me.

pedromj

My rims are less than a year old and I have checked that their braking surface is in a good condition. I thought that the problem was coming from aluminium bits being catch by the pads but I have cleaned them twice and there is no sign of aluminium in them, just some rubber from the old pads.

I have cleaned the braking surfaces with rubbing alcohol and a cotton piece. That removed a lot of black rubber from the old pads but not too much. I have also cleaned them with an eraser and this removed much more black rubber and they look totally clean. I have used the eraser to also clean the salmon pads, and they looked also clean (removing all black rubber that was stuck there when I removed them).

After this, the performance of those pads when slightly pressing the brake levers is marginal but their performance when fully pressing the brake levers has improved a lot. However I am wondering whether they should work better than the old pads in both conditions.

Do you think that sanding a bit the new salmon pads can help?

HillRider

Brakes of any kind shouldn't "grab" hard when using light hand pressure. At that point you want to slow down gradually or moderate your speed, not stop dead. If the brakes will lock up your wheels when pulled hard, that's more than acceptable performance.

To paraphrase what you said, your brakes SHOULD perform marginally with light hand pressure.

pedromj

I know that the brakes should not "grab" the wheel by slightly pressing the brake lever but the "rubbing paper" feeling (and sound) is different to what I consider normal. I grew up learning that non-typical feelings and sounds usually indicate that something is wrong. However, I have to re-learn it because things have changed (a lot) in the almost fifteen years I had been out of the world of bicycles. Therefore, I think that my best option is to wait a couple of weeks with the new pads to see if the braking feeling (and sound) becomes what I consider a normal feel. Thank you all for your help.

Al1943

Have you tried sanding the brake pad surfaces?
Is it possible that there is some oil on the rim's braking surfaces or pads?
Koolstop salmon pads are the best that I've tried.

pedromj

I didn't tried because they were new. Should I sand new brake pads?

I'm pretty sure there is no oil, I've cleaned the breaking surface with alcohol and I had previously cleaned them with a bit of degreaser and water. In fact, when I was a teen, if some oil fell to the rims by mistake, they did not brake well but felt very smooth . It is not the case now.

Kopsis

Is the alignment of the pads relative to the rim good? If the pads aren't contacting the rim squarely, you might get the symptom you describe. With light pressure only part of the pad touches the rim. You'll feel it dragging but won't get much braking. With increased pressure the pad "squashes" down and fully contacts the rim and performance improves.

It's also been my experience that any new brake pad needs some time to "bed in" (wear down the pad surface so it is perfectly matched to the rim surface). Until this happens, it takes extra force at the lever to achieve full performance. Lightly sanding new pads might speed this up (depending on material) but don't go crazy (you're just trying to scuff the pad's surface, not remove a bunch of material).

pedromj

I am pretty sure that the alignment is OK. I'll have to wait to see if the problem disappears when they wear a bit. If not, I will try cleaning and slightly sanding them.

cycledogg

I have used Kool Stop Salmon pads for years and swear by them. I would suggest using a very fine sand paper to moderately sand down the surface of the rim. Best done with tire removed. After that, wipe down with a clean soft cloth. Next, use a "metal" finger nail file and clean the surface of the brake pads, removing most or all of the black color on the pads doing so as level as the design of pad. I say this due to the slant of the pads commonly referred to as the "toe" of pad. Once finished, wipe surface with soft cloth. Install pads to brakes, centering pads to rim width. I personally do not "toe in" my pads but adjust so pads fully touches surface of rim when applied. I also like my brakes tight so it takes a light touch to apply breaking. Pads are approximately 3mm from rim. Granted, my wheels are trued to within 1mm as so I can set breaks close to rim. Fine tune with rear due to lateral movement from climbing and hard sprint. Keep in mind, that over time and a lot of down hill riding, pads will "glaze over" and need resurfacing periodically done as described with nail file. I hope this helps your issue.
Cheers

pedromj

A lot of information, thank you all.

I also like to have the pads as close as possible to the rim, I have them a bit more than 2 mm from the rim in the front wheel and maybe 5-10 mm in the back wheel (I do not like braking with the back wheel because it slips with any strength).

I will take into account your maintenance recommendation for the next time I remove the wheel and tire.

Also, I hope that in a warmer season (spring is close) the pads can be able to sit better on the rim surface and the remaining micro-pieces of the old pads will be mostly removed.

FastJake

What kind of shape are your cables/housing in? Most shifting/braking problems are cable related. If they have excessive friction, or the housing is poorly routed, or poorly cut, or deteriorated, you will not have proper stopping power.

pedromj

I do not think that the problem is in the cable, I've checked the angles. Using a bit of engineer analysis, the problem should be related to some small pieces of rubber from the old pads that is glazed or something like that so it reduces the sticky properties of the new pads. I've tried to clean them with the methods described above but it seems that there are still some remains of such old rubber stick to the rim or new pads.

2_i 

What is the brand, age and shape of your brakes? There can be big differences in performance of rim brakes. Good brakes are rigid and marginal flexy and wobbly. Good pads will not compensate for arms that do not hold.

pedromj

My brakes are from a cheap brand (BTwin) but they worked fine, quietly when slightly pressing the levers and with a good feeling, until a week before I decided to install the Kool Stop Salmon pads. Now they sound and feel like "rubbing paper" unless I apply more strength. I can stop the bike when needed but for low-speed stops they worked better before (even with worse pads).

From my sensation and what has been said in this thread, I assume that the problem is that I did not manage to clean the rim properly, so I have to do a thorough cleaning, or that the new pads need to bead into the rims, so I have to wait.

2_i 

Cheap brakes can bring a host of problems. I would suggest to look in the long term at such brakes as Avid Single Digit 7. While expensive at first, they actually save money in terms of pad and rim wear. It sounds though like you need at first to take care of what already happened.

pedromj

I know and I am investing in long-term components as soon as they need to be replaced or I can afford them but, as you said, I have to resolve this problem first and then think in purchasing better brakes.

zacster

A picture is worth a thousand words... And a video is even better.

niuoka

my two main commute bikes run Kool stops and I love em. One bike has the dual compound and the other has the all salmon. The all salmon did seem to take a bit longer to get to work correctly. It may be the bikes or bakes or me, but the all salmon were more touchy to install and adjustment. Both bikes have trued wheels, both bikes I cleaned the rims very well before install. I don't think just alcohol will clean them like you tried without something to really scrub with. I have had good luck just with scotch brite pads and regular soap and water, then followed by just a wipe down with mineral spirits.
one time I tried some automotive brake clean and in spots it lifted the black finish off my old rims

you did however mention that a week before you installed the pads that the brakes were getting funky...so I would strongly look at other issues as well

Wanderer

If it were me ---- I'd disassemble the brakes, completely, clean, and lubricate. Reassemble, after also checking cable movement.Then, I would check alignment and contact with pads/rim. (It goes without saying, that I would clean the rims and pads with alcohol and a coarse rag, until it stayed clean. )

I've never had to sand Kool Stop pads.