Bicycle Mechanics - rasping brakes, and damaged rims?

I bought my niece a used Trek 1500 which overall is in great condition. However, I noticed on unpacking that the rims were somewhat grooved, and when she rode it today there was a fairly loud rasping noise. It comes with Bontrager Select wheels and unnamed alloy brakes. From what I've read here it sounds like the pads need replacing immediately (probably with Koolstops). You can see the ridges in the pads (and maybe even metal inclusions) in the attached photo. Can I improve the situation by also smoothing the rim? What's the best way to repair it?

These rims have a "wear sensor" but I can't find any info on how to interpret it. Is the rim okay as long as the dot is still visible?

Are there Koolstops that will replace these pads, or do I need to replace the shoes too?

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Yes, KoolStop has inserts for these holders. You might also use some Scotchbrite abrasive pads to sand off the loose stuff on the rims so the replacement shoes don't load up so quickly. But don't get carried away trying sand the rim smooth. Your goal is to slow down the thinning of the rim, not speed it up.

Yes, KoolStop has inserts for these holders. You might also use some Scotchbrite abrasive pads to sand off the loose stuff on the rims so the replacement shoes don't load up so quickly. But don't get carried away trying sand the rim smooth. Your goal is to slow down the thinning of the rim, not speed it up.

Those look like tektro brakes with the ****ty stock pads. Replace with koolstops, or better yet swissstops. Koolstop is going the way of the dodo.

even current dura ace pads are good.
basically, anything but the stock tektro pads will be quite good.

Clear the crud from the slots in the brake pads. Then "deglaze" them a little with sand paper. Make sure the rims are clean and smooth out any burrs. Brake pads are cheap and new ones will be an improvement.

even current dura ace pads are good.
basically, anything but the stock tektro pads will be quite good.

Having ridden those for a season I can tell you they are still substantially subpar to koolstops/swisstops. They are head to head with them in the dry but as soon as it gets wet, you might as well not have brakes. In addition to picking up and trapping significant rim debris as well.

They really suck.

For a heavier rider at around 200'ish like myself I've found that both stock Tektro and stock low to mid level Shimano pads are all not just not good but actually damaging in the same way that you found on your niece's bike. Seen the bits of metal embeddd in the pads? They are there because these pads galled at the aluminium and then held the bit embedded in the pad material where it could tear away at the rim and build up the metal chunk in the pad just like using a snowball to make the big ball for a snowman. Any pad that picks up and galls like that needs to be tossed.

The salmon coloured (light rusty red coloured) Koolstop pads will not only not gall like your pads but they will actually make the rims look better aftr a few hundred miles of riding. After trying a heap of pads I went over to the salmon coloured Koolstops 100%. I won't even think about buying anything else for any rim brake.

Thanks for all the feedback - I've got KoolStops on the way and will do some gentle rim cleaning beforehand. The bike won't be ridden again until the fix is in - I can't stand that noise (particularly knowing that there are metal particles in the pads that cause the noise) and I don't know how the previous owner rode with that.

One question on the "wear sensor" since I can't find any info on Bontrager's site - am I correct in assuming that the rims are okay as long as I can see that black dot?

In the future pick out anything that gets embedded in your brake pads, ASAP.

Well, it's more accurately a "wear indicator" since when the braking rim wears down to where the black dot or indicator groove in the rim vanishes that it's time to lace on a new set of rims. "Sensor" implies that it'll whistle at you or something similar. But yeah, don't let all the chewing done by the pads to the present put you off. There's still going to be lots of life in the rims yet.

Those of us that have worn out rims tend to find that the braking response gets pretty grabby and very non linear due to the curve of the contact area. Some ignore it and run the rims until they get so thin that the rim splits and they get a flat tire. Others, like me, dislike the way the brakes respond on badly worn rims and swap rims before strength is an issue.

The salmon coloured (light rusty red coloured) Koolstop pads will not only not gall like your pads but they will actually make the rims look better aftr a few hundred miles of riding. After trying a heap of pads I went over to the salmon coloured Koolstops 100%. I won't even think about buying anything else for any rim brake.

+1
Salmon colored Koolstops are the best.