# under-chainstay U-brake: why?



## wedge (Jun 24, 2006)

I vaguely remember that design a long time ago but what was the thinking behind that?


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## Rumpfy (Dec 21, 2003)

Quite a few of us here have bikes with chain stay mounted U or Roller Cam brakes.

I don't quite recall the thinking behind why. Chain stays stiffer than seat stays?


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## Tracerboy (Oct 13, 2002)

I do remember.The under-stay u-brakes were located there because this area was stiffer than the traditional seat-stays. I guess that's why wish-bone rear stays appeared soon after,to stiffen up this area for the rear brakes.


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## shiggy (Dec 19, 1998)

wedge said:


> I vaguely remember that design a long time ago but what was the thinking behind that?


Chainstays were (are) stiffer than the seatstays. The cable run was straighter and less housing required. All together it could make for better performance (until it got muddy).


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## Fillet-brazed (Jan 13, 2004)

wedge said:


> I vaguely remember that design a long time ago but what was the thinking behind that?


Its stiffer down there. To have really powerful brakes you need a stiff mounting place otherwise you end up with brake lever mushiness.

The monostay might add a slight bit of stiffness to the seatstays (a brake bridge serves almost the same purpose braking-wise), but it lessens the torsional rigidity of the frame for singlespeeding type of loads. Especially on a Bontrager with that 1/2" or 5/8" diamter mono tube.


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## mtber3737 (Dec 23, 2004)

*This was the cat's meow at one time....*



Rumpfy said:


> Chain stays stiffer than seat stays?
> 
> 
> > According to Ross (Mr Salsa), the chain stays offerred a much stiffer mounting and would not flex under heavy braking.... unfortunately tended to clog up with mud in the wetter climates... we all can't live in SoCal!
> ...


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## Rumpfy (Dec 21, 2003)

mtber3737 said:


> Rumpfy said:
> 
> 
> > Chain stays stiffer than seat stays?
> ...


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## Boy named SSue (Jan 7, 2004)

wedge said:


> I vaguely remember that design a long time ago but what was the thinking behind that?


to make bikes from the late 80's easier to date.


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## mtber3737 (Dec 23, 2004)

*Unfair....unfair!!!!*



> Rumpfy: speaking of which!


Ahhh man, that's like pouring salt in an open wound...och! It's like looking at your former wife in somebody else's bedroom :eekster:

The old girl still looks pretty good, although that stem is a bit much 

Best,

OMR... 
SoCal


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## Rumpfy (Dec 21, 2003)

mtber3737 said:


> Ahhh man, that's like pouring salt in an open wound...och! It's like looking at your former wife in somebody else's bedroom :eekster:
> 
> The old girl still looks pretty good, although that stem is a bit much
> 
> ...


Haha! 
I didn't mean to pour salt. Its in a state of flux currently.

The stem is a Cunningham fit finder stem as I'm trying to find a comfortable fit for running dirt drops for it as an option. I'll have to have a custom stem made for it.


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## Boy named SSue (Jan 7, 2004)

mtber3737 said:


> Ahhh man, that's like pouring salt in an open wound...och! It's like looking at your former wife in somebody else's bedroom :eekster:
> 
> The old girl still looks pretty good, although that stem is a bit much
> 
> ...


That is the one that was set up ss in another thread. Damn, I always liked that Salsa. One of the nicest of the breed.


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## azjeff (Jun 3, 2006)

You could at least cover up the rest of your stash. Man rft:


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## hollister (Sep 16, 2005)

You could at least cover up the rest of your stash. Man rft:[/QUOTE]
but then i couldnt stare at all the stuff in the backround.........


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## majura (Jun 30, 2005)

Please no flaming, but I believe MBA had an article about it way back, which was then re -published a few issues ago.

As you've all said, it was believed that it was stiffer on the chainstays and hence would provide better braking. However, according to MBA the cable routing for the brake resulted in un-even contact with the rim (or something... as I vaguely recall). In which manufactures went back to the seat stay due to safety issues?? Not entirely sure... maybe someone with the copy on them (all my copies are back home and not in my dorm room) could straighten it out?


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## Rumpfy (Dec 21, 2003)

azjeff said:


> [/QUOTE]
> 
> You could at least cover up the rest of your stash. Man :prft:[/QUOTE]
> 
> Nothing good, just broken frames and unfinished projects. :cool:


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## Fillet-brazed (Jan 13, 2004)

majura said:


> Please no flaming, but I believe MBA had an article about it way back, which was then re -published a few issues ago.
> 
> As you've all said, it was believed that it was stiffer on the chainstays and hence would provide better braking. However, according to MBA the cable routing for the brake resulted in un-even contact with the rim (or something... as I vaguely recall). In which manufactures went back to the seat stay due to safety issues?? Not entirely sure... maybe someone with the copy on them (all my copies are back home and not in my dorm room) could straighten it out?


dorm room? I thought MBA was for 7th grade and under?


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## Bigwheel (Jan 12, 2004)

Not sure who was the first of the old schoolers to put their brakes on the chainstays but for sure it was someone from CA. The big problem was that it became a "fad" and all the companies were quick madman: ) to jump on the bandwagon and there was a model year there in I believe 89' when you couldn't hardly find a storebought bike without that feature. I think that GT did theirs, albeit with U-brakes on the seatstays, and Bridgestone was the only brand that actually used rear canti's and they sold out before June. To those that lived and had to sell bikes in parts of the country that had mud to deal with it was a major problem. I know it affected me at the time at least.


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## Rumpfy (Dec 21, 2003)

Bigwheel said:


> Not sure who was the first of the old schoolers to put their brakes on the chainstays but for sure it was someone from CA. The big problem was that it became a "fad" and all the companies were quick madman: ) to jump on the bandwagon and there was a model year there in I believe 89' when you couldn't hardly find a storebought bike without that feature. I think that GT did theirs, albeit with U-brakes on the seatstays, and Bridgestone was the only brand that actually used rear canti's and they sold out before June. To those that lived and had to sell bikes in parts of the country that had mud to deal with it was a major problem. I know it affected me at the time at least.


I don't think I've seen or know of any Yeti's or Slingshots that went the U brake under chain stay route... 

But yeah, more bikes than I thought I'd ever own are U or Canti mount.


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## MendonCycleSmith (Feb 10, 2005)

wedge said:


> I vaguely remember that design a long time ago but what was the thinking behind that?


To sell more brakes, due to all the bouncing off logs and rocks they were prone to doing


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## Bertleman (Feb 10, 2004)

It's because the roller cam was so powerful it would flex the seat stays, but not so much on the chain stays. As for the so called mud problem I had no issues with my chain stay mounted roller cam while living in Eugene Oregon. If it was muddy enough (and it was) to clog my chain stays my buddies cantis would be cloged as well, plus my roller cam always worked smooth as butter because of the grease ports. The real reason it the clean lines and not snagging on the top tube mounted cable stops.


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## LIV2RYD (Jan 17, 2006)

I rode the crap out of a Mongoose ATB in New England for 5 yrs using that setup. Mathauser made a great set of pads that held up well and laughed at the mud. Wish I still had that bike, you never forget your first ride.......


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## shiggy (Dec 19, 1998)

majura said:


> Please no flaming, but I believe MBA had an article about it way back, which was then re -published a few issues ago.
> 
> As you've all said, it was believed that it was stiffer on the chainstays and hence would provide better braking. However, according to MBA the cable routing for the brake resulted in un-even contact with the rim (or something... as I vaguely recall). In which manufactures went back to the seat stay due to safety issues?? Not entirely sure... maybe someone with the copy on them (all my copies are back home and not in my dorm room) could straighten it out?


The cable ran straight to the middle of the brake, right where it was needed. Actually easier to do than seatstay brakes.

The down sides of the bottom mount brakes is they tended to be neglected and the adjustment would go off and/or pads wear out without being noticed;
created a very tight area around the chainrings and chainsuck could really jam the chain in tight between the brake and rings;
mud build up was AWFUL! With the SunTour roller cams even sand and dry dirt could effect the brakes adversely (I made covers for the cam plate and rollers). For some reason the WTB Speed Master roller cams did not suffer from this as much.


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## shiggy (Dec 19, 1998)

Bertleman said:


> It's because the roller cam was so powerful it would flex the seat stays, but not so much on the chain stays. As for the so called mud problem I had no issues with my chain stay mounted roller cam while living in Eugene Oregon. If it was muddy enough (and it was) to clog my chain stays my buddies cantis would be cloged as well, plus my roller cam always worked smooth as butter because of the grease ports. The real reason it the clean lines and not snagging on the top tube mounted cable stops.


I _DID_ have mud issues with my SunTour roller cams (and other brakes that fit the same mounts in Eugene OR as did my buddies with bottom mount brakes. The WTB rcs are functionally better in muddy conditions but still suffered from excessive mud build up.


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## Sixty Fiver (Apr 10, 2006)

My Kuwahara has a Shimano "Shark Bite" U-brake and delivers some serious braking power and isn't unduly affected by dirt, mud, or at this time of the year...snow.

You do have to practice good maintainence as when things are out of sight they are also often out of mind.

Another benefit of the stay mounted brake is that when one has an XC touring bike like the Kuwahara the gear that gets strapped to the rear rack doesn't interfere with the brake cables or vice versa.


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## MrOrange (Jun 21, 2004)

*YeaH*



Boy named SSue said:


> That is the one that was set up ss in another thread. Damn, I always liked that Salsa. One of the nicest of the breed.


Nice fork too! Yum. Also nice to see the background . . . my basement looks very similar


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## Rumpfy (Dec 21, 2003)

MrOrange said:


> Nice fork too! Yum. Also nice to see the background . . . my basement looks very similar


They like having company.


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## Bigwheel (Jan 12, 2004)

Rumpfy said:


> I don't think I've seen or know of any Yeti's or Slingshots that went the U brake under chain stay route...


That's why I said store bought. Meaning the overseas manufactured brands which got burned by that trend somewhat by reading too much MBA.:nono:


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## Fillet-brazed (Jan 13, 2004)

shiggy said:


> I _DID_ have mud issues with my SunTour roller cams (and other brakes that fit the same mounts in Eugene OR as did my buddies with bottom mount brakes. The WTB rcs are functionally better in muddy conditions but still suffered from excessive mud build up.


In Oregon they might not be ideal, but in CA they work pretty darn good.

These stainless steel mud shields would help a lot Im sure:


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## Sixty Fiver (Apr 10, 2006)

Those stainless mud shields are also called cable guides.


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## Fillet-brazed (Jan 13, 2004)

Sixty Fiver said:


> Those stainless mud shields are also called cable guides.


take a gander at the brake.


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## Sixty Fiver (Apr 10, 2006)

Fillet - I didn't see the guards at first glance and now wonder how well they work at keeping mud out of the workings.

I've been up for 20 hours and am thinking I'd better zonk here.


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## colker1 (Jan 6, 2004)

Rumpfy said:


> mtber3737 said:
> 
> 
> > Rumpfy said:
> ...


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## Velocipede (Dec 24, 2006)

*U to Canti*

I may have already asked, but is there a way to convert U brakes over to Cantis?
Kind of a pain since the pivots are in different locations...


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## Rumpfy (Dec 21, 2003)

Velocipede said:


> I may have already asked, but is there a way to convert U brakes over to Cantis?
> Kind of a pain since the pivots are in different locations...


There isn't any adapter that I know of.

You'd pretty much have to knock off the U-brake mounts and weld on Canti mounts.


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## CraigH (Dec 22, 2003)

Velocipede said:


> I may have already asked, but is there a way to convert U brakes over to Cantis?
> Kind of a pain since the pivots are in different locations...


The BMX guys apparently had an adapter, but I never did track one down.

They also had an adapter to run a U-brake on canti mounts. I've heard that most BMX bikes have now gone to V-brakes.

One way around the U-brake thing if you are looking for improved performance is to use Magura HS-33 or HS-22. I did that for U-brake equipped beginner trials bike.

http://forums.mtbr.com/showthread.php?t=13890
(The pic links are broken due the MTBR photo server change a while ago. I'll try to find the pics and fix the links in the thread above.)


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## fog (Jan 14, 2005)

I had the rear U brake on an old Ritchey Super Comp and it never stopped with a hoot.
I put a WTB roller cam on and it worked great and I never had a problem. I was living in Colorado at the time. I wish I still had that bike.
Wayne


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## CraigH (Dec 22, 2003)

CraigH said:


> I'll try to find the pics and fix the links in the thread above.)


Pic links in above thread are fixed now.


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## Velocipede (Dec 24, 2006)

Taking another look at the Cannondale, the pivot posts are threaded into the frame with
M10 threads! Should make it that much more difficult to find an adaptor, since the posts are usually M8. Might have to make one up myself!!


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