1987/8/9? Mountain Klein build thread
- Thread starter Tsundere
- Start date
I really like this idea, nice and understated, almost anti-Klein with no in your face colours or overt branding.
Onto the brakes - the frame has removable brake studs that screw into the stays, the rollercams only just fit onto the studs and in fact require considerable force to get them on and to remove them, once in place they're held firm and will not budge at all.
My callipers are not the best so measurements may be inaccurate but I get 8.9 mm for the external diameter of the studs.
The only way I can find to get the brakes to move is to not tighten the studs fully to the frame, and to leave enough thread unscrewed to allow the entire assemblage to rotate freely. As rotation will be limited by the presence of the wheels and cables there would be absolutely no risk of them ever coming loose, it seems that it would work perfectly like that, the studs when left slightly unscrewed spin completely smoothly, but it just doesn't feel right to me.
Maybe I should look for alternative studs with a narrower diameter? The rollercams move fine and free on the front fork studs which measure at 8.8mm, so we're talking about 0.1 mm making the difference between free movement and absolute rigidity.
Any Rollercam experts please feel free to chip in.
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Mickeyspinn
rBotM Winner
Ermm...so if bolt left loose it's free to move? If bolt head/washer is seated on end of stud it locks up?
Have a look at head of bolt....studs need a very square under side of the head the face that pulls up onto mount..if it's got a taper it'll swell the the canti mount stud then lock up in the bushing
Have a look at head of bolt....studs need a very square under side of the head the face that pulls up onto mount..if it's got a taper it'll swell the the canti mount stud then lock up in the bushing
Dr Dremel
Fat Chance Fan
Just measured the studs on my Pinnacle frame (yet to be built up), diameter is bang on 9.0 and they are 11.5mm in length. I was just able to test them with U brakes, but they are moving fine. So I would hazard a guess that the problems lie in the brakes. I´d check if the brass inserts of the brakes and the small lip on the studs are really clean (look a bit mucky in the pic).
All U brakes/rollercams rely on the clamping of the bolt to fix the return springs as there are no holes for a spring on the frame/stud. So you should be able to tighten them down normally. If they lock up when the bolt is tightened the stud may appear to be "too short", or maybe the stack of brake arms/nuts is "too thick", so check if muck is still stuck in between parts? Are they assembled in the right order?
All U brakes/rollercams rely on the clamping of the bolt to fix the return springs as there are no holes for a spring on the frame/stud. So you should be able to tighten them down normally. If they lock up when the bolt is tightened the stud may appear to be "too short", or maybe the stack of brake arms/nuts is "too thick", so check if muck is still stuck in between parts? Are they assembled in the right order?
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Cheers, for the insights. I gave the studs a thorough clean and one of them is now fine, I think the other one is very slightly bent or out of shape, not enough to be visible but enough to stop the brake arm from spinning freely. I have sanded it lightly and this has helped, but it still won't seat the brake arm properly and the friction is still enough to prevent free movement.
What I don't want to do is sand away too much, it does feel like there may be a point where the arm will move and there won't be perceptible play, but if I cross that line then it'll be free and wobbly.
What I don't want to do is sand away too much, it does feel like there may be a point where the arm will move and there won't be perceptible play, but if I cross that line then it'll be free and wobbly.
Mickeyspinn
rBotM Winner
You got all the threads internal and bolts spotless? Grunge in them studs will also swell them! Got a blue permanent marker? That'll tell you what's going on
You'd be sanding for a while to do any major underisizing damage !
Dr Dremel
Fat Chance Fan
https://cycle-frames.com/collection...01076-2530-easton-u-brake-990-brake-boss-stud
Edit: Can´t remember the thread pitch on Klein frames, so be sure to get yours measured!
