Monday, March 28, 2016

Vintage Cantilevers: Choices, Choices

I'm selecting brakes for a project, and I have a couple of choices. I thought readers might be interested in what I have.

Both sets of brakes are wide-profile cantilevers from Shimano. One set is from the early '80s Deore group (some might remember that as the "deer head" set), designated as MC-70. They were one of the top choices for touring and mountain bikes from '83 through about '86. Understand that mountain bikes were still in their infancy, touring bikes were all the rage, and there wasn't nearly as much difference between mountain and touring bike components at the time.

The other set is from the next generation Deore group -- the MT-60 group, which featured Shimano's first indexing mountain bike derailleur. To be more exact, mine are marked MT-62, though the main difference was in the shifters (changed from 6-speed to 7-speed indexing) while the brakes are pretty much the same as far as I can tell.

Looking at the older vs. newer brakes (yes, old vs. new is all relative when they're all in the neighborhood of 30 years old), you can see some similarities and some differences:

On the top are Shimano MT-62 cantilevers from the later '80s. Just below them are a pair of MC-70 cantis from about 1983.
The MC-70 brakes were great looking, with more visually interesting details than the newer brakes. Notice the "shadow lines" that are forged into the arms. I'm not sure how they compare in weight, but they look lighter, and slightly more "right" for a classic road bike. The old brake pads have a lot of surface area, but the brakes would likely be improved greatly with a set of modern compound shoes. That's true of most older brakes in my opinion. Being a 33-yr. old used set of brakes, the chromed hardware has some rust. On the outer surfaces, they can be cleaned up pretty easily, but down inside the allen-head sockets, it's unlikely I'll be able to do a lot to improve them.
The MT-60/62 brakes are similar in overall dimensions and geometry to the MC-70 pieces, and the toe-in adjustment mechanism is almost identical (that's the serrated black ring just behind the brake shoe post). But they have a smoother, more "streamlined" look than the older model. They're still very nice, though - and not too "mountain-bikey" for a good road bike. This particular example has the advantage of being virtually new old stock, so cosmetically they are about perfect. 

Two details make the newer brakes functionally an improvement over the previous generation: The "SLR" (Shimano Linear Response) feature balanced lighter spring tension in the brakes with spring-loaded levers for smooth braking action (Dia Compe did the exact same thing and called it BRS, or "Balanced Response System"). And the newer brakes also include a means to adjust spring tension for easier centering -- something that most modern cantilever brakes have today, but is not present on the MC-70s.
That's a handy feature that makes centering the brakes much easier. Unfortunately, it is missing from the earlier generation brakes.
An interesting side note. When Campagnolo entered the mountain bike market in the late '80s, their top-of-the-line cantilever brakes appeared to be closely modeled after the Shimano MT-60 series brakes. Coincidence? Probably not, but Valentino Campagnolo would likely attempt to castrate me for suggesting it. The brakes were offered as part of their top mountain groups, as well as a short-lived tandem component group. One difference in the Campy version was that the Campys had spring tension adjusters on both the left and right units -- a nice touch, but not exactly necessary.

Ultimately, I've decided to go with the newer MT-62 brakes, which I'll be pairing up with a nice set of Dia Compe road levers. I slightly prefer the styling of the older MC-70 brakes, but the "like-new" cosmetics of the newer set, along with easier setup that comes from adjustable spring tension makes them hard to beat.

More to come. . .

17 comments:

  1. The spring tension adjustment makes that decision pretty easy...

    They look to be in really good shape. A few minutes worth of a rubdown with some Mother's mag polish would probably bring a mirror shine to them. I can't wait to read more about the project.


    Wolf.

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  2. For cleaning rust out of allen bolt heads I find you can some steel wool Q-tips just by taking a wad of steel wool and twisting an appropriately sized brad-point drill bit into the wool. Then just take your steel q-tip and twist it around wherever the hard to reach rust is. Works great.

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  3. They are both great-working brakes and work well. One Shimano canti from that era had an anchor bolt for the straddle cable that was all but impossible to tighten because it wasn't "keyed", as most brake anchor bolts are. I'm not sure of whether it was the MT-70 or some other model; what I remember is that it had an allen-head anchor on one side.

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    1. I'm aware of that problem you mention, though I was trying to figure out which specific model that was. I thought it might be these, but the anchor bolt does have one flat side that butts up against a shoulder, which should allow it to tighten. However, not having tried to set these up, it's possible there could still be a tightening issue that I'm not seeing.

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    2. Justine - I just went back and looked more closely at those MC-70s, and you're right -- those must be the ones you're referring to. There is a washer that is flat-sided and won't spin, but the anchor bolt itself is not keyed in any way to keep it steady when tightening. There's not even a slot (for a screwdriver) or an allen-head socket in the back of the bolt to hold it steady when tightening. Well, there's another good reason to use the MT-60s.

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    3. Brooks--I don't understand why Shimano did that!

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    4. Actually, it was a good idea, but poor execution. The idea would have been to let the straddle cable move or pivot a small amount when the brakes are applied. Picture it, as the brakes are applied, the brake arms move upward and inward, the angle where the straddle cable meets the arms would change slightly. Allowing the attachment point to swivel slightly lets the angle change without putting stress on the cable. Unfortunately, they didn't design in a way to hold the clamping bolt still when tightening the cable. Just putting a screwdriver slot or a recessed allen head socket into the back of the bolt would have allowed easy tightening, and still allow the cable to pivot slightly in use. Jan Heine's blog had an article today about brakes and mentioned the benefit of a pivoting attachment point. Good design - poor execution, in this case.

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    5. Actually, it was a good idea, but poor execution. The idea would have been to let the straddle cable move or pivot a small amount when the brakes are applied. Picture it, as the brakes are applied, the brake arms move upward and inward, the angle where the straddle cable meets the arms would change slightly. Allowing the attachment point to swivel slightly lets the angle change without putting stress on the cable. Unfortunately, they didn't design in a way to hold the clamping bolt still when tightening the cable. Just putting a screwdriver slot or a recessed allen head socket into the back of the bolt would have allowed easy tightening, and still allow the cable to pivot slightly in use. Jan Heine's blog had an article today about brakes and mentioned the benefit of a pivoting attachment point. Good design - poor execution, in this case.

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  4. There were some cantis I vaguely recall that had a tensioner hidden behind the bolt. It had to be adjusted/held in place with a cone wrench and then the brake bolted down. Maybe Suntour?

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    1. Yes - those were SunTour. I have a set on my old Stumpjumper, though they were not the original brakes for that bike. Some people don't like those ones, but I've found them relatively easy to set up.

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    2. Thanks Brooks. I can't quite remember what bike these were on, maybe a first generation Schwinn "cross" (not cyclocross) bike. I remember thinking it was a real improvement over previous cantis.

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  5. Regarding the rust in the allen holes?

    My first job in a shop, the head mechanic was awesome. Part Zen master, part absent minded professor.

    He did this with all his bikes, and honestly, it works great, and solves the issue completely.

    A dab of grease on your finger, smear it heavily into the hole, wipe over the top with a rag.

    Extra credit for using some colored grease such as Bullseye (red) or Phil Wood (green) or more modern, Maxima which is blue.

    Cheaters version of having Campy Cobalto's.....

    When you insert a key, it simply squishes out of the way replace when done!

    I use it with all roadies headset adjustment bolt, as they tend to sweat all over it, keeps it from looking fugly in short order.

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    1. That would help prevent it from happening. I've done something similar with Allen head stem bolts, where sweat will often settle in. White Lightning, which is a white wax-based chain lube -- I'd put a couple drops into the bolt, then it dries leaving a thick white coating that would be almost unnoticed. Then, like you say, you can still get a tool into it when you need to.

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  6. When I have chrome Allen bolts that are rusty in the sockets I make a paste of Barkeepers Friend powdered cleanser and water and fill the socket. Let it sit in there for 10 or 15 minutes then rinse it out and it usually looks like new. If not do it again and see if that takes care of it. That brand of cleanser contains Oxalic Acid which (you probably already know) dissolves Iron Oxide but doesn't affect Chrome. I use it on all sorts of rusty stuff...

    Spindizzy

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    1. Thanks for the tip. I'll have to give it a try sometime.

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  7. Are the Shimano MT-62 brakes compatible with a 27" frame with 700 wheels?

    I'm trying to fit 700 wheels on my KHS Special, 80's touring bike. People on the web have confirmed that the Shimano BR-MC70 brakes work well for this conversion, as do the Dia-Compe 981 canti brakes.
    At the moment, I'm trying to decided between Dia-Compe Cantis vs. Shimano Deore XT cantis. The SLR feature seems very useful. Would be nice to have have that adjustment feature for my project, if possible. Ultimately, durability and smooth functionality is what I prefer when it comes to making a choice.

    Any input from any of you O.G. riders would be greatly appreciated.
    Btw, Retrogrouch, thanks for the wealth of info.

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    1. You're converting from 27" to 700c? It's possible they'll work, but I couldn't be certain. So much of it becomes dependent on the right brake model and design -- how much vertical adjustment is there for the pads? More importantly, because the brakes move toward the rim in a fairly tight radius arc of movement -- inward and downward -- the amount of pad angle adjustment becomes crucial (as in vertical angle - not "toe-in" angle). In some cases, one can find a brake with long vertical slots that allow a lot of up/down adjustment, but it could be impossible to get the brake pads to contact the rim at a useable angle. Some older road bikes with cantilevers have the mounting posts spaced much closer together than mountain bikes or even more modern bikes, which can further complicate things. Even rim width can affect the success of the conversion. And in all of this, it can be impossible to know if a set of brakes will be workable until you actually try them. Unless one has a huge stockpile of different cantilever brakes to experiment with, that kind of trial-and-error can get expensive.

      Having said all that, older style brakes like these and the older Dia Compe models are probably more likely to work than some of the newer brakes with their threaded-post "V-brake" style pads.

      The SLR feature won't have any affect on the adjustability of the brakes, but it does make for nice, smooth, light action when applying the brakes.

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