Kapusta

Years ago I tried cleaning a set of Al rims with alcohol to see if it made a difference.

A lot of dirt came off.

It made no difference.

bigd777

I used Mavic Abrasive Rubber with water

elcyc

AFTER a cleaning with paper towel + your favorite degreaser (or alch), how about scrubbing the rim with, say, Crocus cloth* (or similar)?

BTW: These are my wheels/rims:
26" (559) MTB Wheel set Brutal Beast Deore/Rhyno Lite 32 Spoke
https://www.harriscyclery.net/produc...spoke-1676.htm

*The soft abrasive is similar to 1500-2000 grit and good for fine hand-polishing of soft nonferrous metals. Also known as crocus cloth.

63rickert

400,000 lifetime miles. I have never cleaned the braking surfaces of my rims. Brake pads get sanded or cleaned when necessary. Top surface of rim gets cleaned if dirty. Salt, mud, all sorts of general filth ends up on topside of rim. Braking surface is cleaned by the pads. On other people’s bikes it will happen that excessive oiling of an internal gear hub or even excessive oiling of the chain will lead to an oily rim that needs to be cleaned and I have done that. Can’t imagine a reason other than OCD to clean a rim for braking.

caloso

I just wipe them with the sponge when I wash the bike generally.

elcyc

Given all your responses , mine are probably cleaner than usual for BF.
So the lack of grabbing friction (or other factor) -- i.e., reduced braking ability -- on the front wheel REMAINS a mystery. **********???

theavidrider

thanks, idk why I didn't think of this sooner...

spelger

i ride road, never in the rain, never through puddles (or into poodles), and always slow down for water on the road. i *never* clean my rims. i descend down lots of hills through the limited mountains i have near me. rims look good. breaks break good.

wait while i get my flame suit on...ready...aim...fire!

63rickert

Responses on this thread have been primarily about beauty rituals and obsessive-compulsive clean freaks at play. Normal for BF. You wanted to stop? This is a question about getting the bike to stop?

Rear brake is for slowing. Front brake is for stopping. When the bike decelerates weight is transferred to front. Under hard braking, or hard downhill braking, 90% to 100% of braking power comes from front brake. Under very hard braking rear brake does nothing noticeable. It will even happen that the rear wheel lifts off the pavement and the bike is still under control. You have to have a front brake that works. Pampered pretty bike is optional. A bike that stops is not optional. Find out what is wrong with that brake.

elcyc

Agreed.
But I'm kinda running out of "options" ... the front brake pads are brand new ... Kool-Stop Eagle Claw, same as rear (those are 10 years old! But the rear braking is good.
The brake cables (front/rear) are relatively new and are in good condition.
When I squeeze the front brake lever, the bike should stop quickly, even lift the back end. But what happens on a hard (emerg. stop) squeeeze is that the cable slips thru the caliper clamp. (Yes, that's as tight as it SHOULD be w/o risking cutting into the cable).
I've experimented with the pad/rim gap. Makes no diff.
One possible conclusion is that, after 16 years of use the rim's "braking surface", if there is such a thing, has worn away. But, if that were the case, my pads would have worn out first. Right? My general bike use is very light "commuting" and grocery getting. I'm, by nature, a very gentle biker, use BOTH front and rear brakes, don't ride fast or hard, and proactively coast to slow down as much as possible --- indeed, I have only gone thru 1 set of Kool-Stop pads in the last 16 years.
The brake calipers and hand levers are original to the Gary Fisher. (Shimano Alivio, 1993). They MIGHT be the culprit, but I don't see/feel much slop.

63rickert

h
Sorry for slow response, ongoing problems with logging in to site.

Pinch bolt/cable clamp should not slip. Should be engineered as one of most reliable bits on bike. Have personally never known one to fail. Also easy to replace. Replace that clamp now.

Rims that are worn out still brake fine. A worn rim will show very visible wear. The sidewall of rim will be cupped and thin. I could look up minimum safe thickness but very doubtful that is the issue here. What happens in the end is tire pressure fractures the sidewall of rim. There is never any warning via poor braking performance.

Lastly you have a 27 year old low end Shimano brake. Shimano never engineered for anything but obsolescence. They always want you to buy new and improved constantly. I regard Dura Ace as non-durable parts. Everybody loves them anyway. Trusting aged Shimano is a gamble.

elcyc

About that cable clamp .... well, I'll assume full responsibility for how (tightly) I clamped in the past. But, as I noted here on BF some time ago, I had two terrifying snaps on Avenir-brand cables (once in 2009 and then 2013, both front). One of the most un-nerving bicycling experiences in all my years of cycling!
I think the consensus of that forum disc. was that the clamp was too tight and pinched the cable -- because that's where the cable snapped.

The rims (brake surface) are in pretty good shape. Not glass smooth, but very little "groove" wear.

Yeah, the old Shimano joints are not as nimble as they used to be.
I want an easy, "drop-in" solution.
The hand lever is integrated with the gear shifter. So replacing it will be more of a search for old parts.

The orig. cantilevers are center-pull :




And, if possible, drop in:

63rickert

Looks like a solution to me, calipers should fit. Levers will be some work, see if you can find good used.

elcyc

The more I dig into the subject, the more confusing the issue becomes. For example, some sources claim little to be gained in "upgrading" from center-pull to V-type cantilever.
Also, I might have to upgrade the hand-lever assembly in order to get a V-type to work (dunno enough about this).

It's possible that I may able to squeeze some EXTRA performance based on tweaks suggested by Park Tool's video.
Specifically, choosing the correct straddle; and then adjusting it for best mechanical advantage:

elcyc

As far as replacement canti's ... there are the common Shimano Altus and Sunlite variety .
My 1993 Gary Fisher MTB has Shimano Alivio (I assume Altus replaced those or was an alternative to Alivio).
Anyone have experience with Sunlite ?

PumpedUpKicks

I'm running Dia Compe 981 canti's with Kool Stop brake pads on aluminum rims and sometimes they squeal loudly. For cleaning my setup use Dawn dish soap/water, dry, and finish with brake parts cleaner from O'Reilly. I've found that helps the squeaking stay away longer than isopropyl alcohol. Part of my problem too though is my bike is a 27" to 700c conversion so the pad angle has to be adjusted and perfect.

Korina

I don't, but I love the Tektro Oryx cantis on my converted mtb. They were the usual pain to set up, but after a year I have had zero issues. Good luck solving your problem.