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Putting early 90s MTB back on the street

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Putting early 90s MTB back on the street

Old 07-09-21, 07:10 AM
  #26  
Xwang
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Today I spent three hours working on the bike.
First of all I checked again that front and rear wheels were true and correctly centred on the frame.
They already were so and I just made some fine tuning tightening some spokes with an eight of nipple turn.
Then since the rear brakes were already removed from the bike I spent about two hours trying to minimize the joke angle and maximize the cantilever one. Moreover I've grinded off with a file the surface of the rear pads.
Now the rear v-brakes are very near to the rim and I've got some braking power.
I tried to grind off 0.5mm from the front pad too, but without clear improvements so I think the improvement I obtained for the rear one was due to the increased mechanical advantage.
To increase the mechanical advantage to the front brake I've to wait till the shop opens to get a new brake cable because the one which is currently on the bike is too short.
Moreover I've to slight move rear brakes away from the rim (let's say 1mm) because now they are on the verge of touching the rim.
Now when I squeeze the rear brake lever it still deflects till touching the handlebar, but with a lot less effort and as soon as pads start touching the rim some braking force is created even without putting a lot of force.
However probably better pads needs to be used.
The current ones are 50mm long, is there any gain in taking longer ones (70mm)?
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Old 07-09-21, 10:06 AM
  #27  
arex
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Tektro makes very decent brake components that aren't very expensive.

+1 on the Kool Stop salmon brake pads. They just plain work.
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Old 07-09-21, 04:54 PM
  #28  
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Thank you to all for your help.
I managed to set up the front brake too (with a longer cable and a reduced yoke angle).
These are the photos:


Front brake with joke lowered at the maximum possible position

Rear brake
I still can reduce a bit (1 or 2 mm) the distance between front pads and rim, however now the bike brakes better because I don't have to squeeze the handles with all my force to get a poor deceleration. Now the effort on the handles is less and I get a better deceleration.
I asked to the local shops for the Kool Stop pads, but they don't have them. They proposed me the Shimano BR-CT91 instead. Are they good too? What about pad length? Is it better to have longer pads?
The bike now is already usable, but better pads could give a better deceleration and if they have a longer pin, I could try to increase the cantilever angle again to get more mechanical advantage.
I noted that cantilever arms are free to move about 2 or 3 mm along the attachment. If it is not normal I could add a washer to limit or block that movement.
Moreover the stranding cables are still the original ones. Could changing them with newer ones improve the braking power again (the seller at the local shop told me that they are going to arrive tomorrow)?
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Old 07-09-21, 11:02 PM
  #29  
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Shimano pads are also good. The Koolstops are a bit better, but not that much.

Longer pads create more friction at the same pressure, in theory, but I don’t think it will be necessary, once properly set up.

Grab the pads the LBS has, (no ****** El Cheapo Chinesium ALB pads - they have them too))
Set them up so that you hit the sweetspot angles with the brakes applied, you’ll be fine with what you have

Oh, and there is no point in changing the straddle cable to a newer one, only if they look like crap. Steel cables don’t stretch.
if it ain’t broke - don’t fix it.
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Old 07-10-21, 02:09 AM
  #30  
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New pads (You said they're rock hard, and while filing them down helps a bit, the rubber is toast.)

New levers. (if your levers are visibly bending when you squeeze them, your brakes won't work right.)

New quality cables and housings. Cable housing is crucial to the way brakes work. Cheap housing compresses when you squeeze the lever. Even if you changed to V-brakes, which I wouldn't bother with on this bike, you'll need new levers anyway, because the cable pull is different. Good V-brakes aren't cheap, and cheap ones aren't good.

Those brakes are never going to be great, being low-end stamped steel short-arm cantilevers, but they can be good enough to stop the bike if they're set up right. There are ISO testing standards for bicycle brakes, and every brake Shimano sells passes them.

--Shannon
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Old 07-16-21, 01:39 PM
  #31  
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Today I managed to install the new shimano pads.
Their pin was too large and so I had to take the cantilever from my brother's bike.
Now the bikes brakes correctly.


My brother's bike cantilever mounted on mine with new shimano pads

Less configurations available on these cantlever

More cantilever angle

Rear brake

Other details

These cantilevers do not have to move the pad's pin vertically or to set the toe.
However they work pretty well.
One of them has about a degree of unwanted toe, so the pad touches the rim only with one extremity, but with use it will contact correctly.
So the restoration is complete.
Thank you very much.

Lesson learned: never buy cheap unbranded brake pads!!!
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