Uber tuning Avid Mag arms- Mtbr.com
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  1. #1
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    Uber tuning Avid Mag arms

    I happened to notice (as I`m sure you have too) that the Avid V-brakes have a natural cut-a-way on the back of each arm. I thought to myself, that would be a excellent guide for machining purposes. So I got in touch with AndrewTO - a poster here, and a top notch machinist. Thanks Andrew.

    I just finished painting the arms. They weigh 48g from a stock weight of 57g. I haven't yet tried them because my bike is in pieces and it's damn cold in Canada.


  2. #2
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    Hi !
    It is cold up here I can tell !

    Are you able to bend the arms with your fingers ? Do you think they lost lots of stiffness ? Keep us informed !

    They look neat by the way !

    Jean-Sebastien
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  3. #3
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    There is no flex in the arms when I use hand strength to bend them. Actually I`ve really tried to snap them with my hands... they are still very strong.

  4. #4
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    Don't thank me yet - you still gotta ride them!

    And here i'm building up my first SS and need brake's!

    Keep us posted on how they work.
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  5. #5
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    I would not use these v-brake in a long downhill...
    I heard that Avid stop the Mag production for any reliability problems, I don't know after this tuning how much these arms will survive...

  6. #6
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    Looks scary, but I'm glad that some people have the guts to try stuff like this. Keep us updated!

  7. #7
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    dibs...

    Dibs on being his beneficiary!!

  8. #8
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    No....

    Quote Originally Posted by scapin
    I would not use these v-brake in a long downhill...
    I heard that Avid stop the Mag production for any reliability problems, I don't know after this tuning how much these arms will survive...
    ... They cancelled production when one of their metal workers was buned to death when he dropped his keys in the magnisium shavings and dust on the floor, and it ignited.

  9. #9
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    Good job!

    Excellent job on the machining! What tools were used?

    Cheers,
    Trevor

  10. #10
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    there have got to be safer ways to save a few grams...

  11. #11
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    Yes, I never dremel these components. If a tuned derailleur crack you can came back home, if a brake arm crack...
    Last edited by scapin; 02-15-2006 at 11:31 AM.

  12. #12
    Time to go farther
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    I'm sure they're strong enough. I've got some arms that are almost half the weight in CAD and they FEA fine so far. I haven't had time to machine a set though.
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  13. #13
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    No good

    Quote Originally Posted by Pivvay
    I'm sure they're strong enough. I've got some arms that are almost half the weight in CAD and they FEA fine so far. I haven't had time to machine a set though.
    What a stupid deductive reasoning, they aren't the same arms! I would know what Avid engineers think...

  14. #14
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    Quote Originally Posted by scapin
    What a stupid deductive reasoning, they aren't the same arms! I would know what Avid engineers think...
    How do you know what the arms I have drawn look like?
    On-One Lurcher SS
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  15. #15
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    Quote Originally Posted by tmaybee
    Excellent job on the machining! What tools were used?

    Cheers,
    Trevor
    Hey Trevor! Tools used were an upright manual milling machine using a drill, followed by an endmill. After that it was handwork using a Dremel-type tool, just an industrial version backed with 100 psi. Carbide ballnose and endmill on that. Finished on top_ring's request using vapor-hone (think very fine sandblasting). He'll paint them himself.

    I say kudos to you top_ring for having the BALLS to try something a little out of the box. You don't know untill you try, right?
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  16. #16
    MaLóŒ˘*size=
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    i think magnesium is not a good material for this kind of tunning, maybe shaving, but not big drilling. Anyway just try them hard and test them first.

  17. #17
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    Bad Idea...

    I have these exact arms and I've learned to be careful when tightening the brake cable pinch bolt. The whole arm will twist if tightened too aggressively. This kind of material removal is foolish and the component wasn't designed to be used in this way.

    Don't do this unless you weigh 105# and brake with your feet.

  18. #18
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    You did a nice job AndrewTO - they turned out pretty sweet looking.

    I would test them on flat pavement for at least 2 weeks but they should be strong enough.
    The front brake would be more of a concern no?

    Maybe I'll get you to do my Mag arms as well ...j/k ...I don't know if I'd feel safe racing like that ...maybe slightly smaller holes or less removed from the front brake...

    What colour are you planning on painting them top_ring?

  19. #19
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    are you planning on rough forging then machining away excess? No? Then they aren't the same. Cold forging can leave a lot of residual surface strain, making your FEA for [I'm guessing] strictly machined parts completely meaningless.

    and that's assuming you are using the same alloy avid does.

  20. #20
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    Quote Originally Posted by eurorider
    You did a nice job AndrewTO - they turned out pretty sweet looking.

    I would test them on flat pavement for at least 2 weeks but they should be strong enough.
    The front brake would be more of a concern no?

    Maybe I'll get you to do my Mag arms as well ...j/k ...I don't know if I'd feel safe racing like that ...maybe slightly smaller holes or less removed from the front brake...

    What colour are you planning on painting them top_ring?

    I have found a color match (gray auto paint) at Canadian Tire. They look so close to the original color you`d swear Avid painted them. Because of the "vapour" blasting that Andrew did the paint adheres very well.

    As far as testing goes, I would never place them on the front wheel and go screaming into a corner with total abandon. These will be lightly tested on the rear for at least two weeks and then slowly put through the paces. Besides, the bike they`re going on is not something I`ll be taking off road very often. A Kona King Kahuna (rigid Ti).

    Because this was an extra pair, I thought what the heck, let`s give it a try. I have literally tried to break them with my hands. There is no sign of flexing. I figure if they`re going to break they will just fail/snap. I also think that you could get away with just machining the lower arm portion and leave the top, thinner piece untouched. My guess is that would be where they will fail because the material is thinest at that location. As Andrew says, "you never know til you try".

  21. #21
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    Top Ring....have these brakes lasted? If so, is there any chance of posting that pic again? (It's not showing any more)

  22. #22
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    Quote Originally Posted by the remery
    Top Ring....have these brakes lasted? If so, is there any chance of posting that pic again? (It's not showing any more)
    Yes, they are still going strong.

    MachinedAvids72dpi.jpg

  23. #23
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    ooooooooooooooooohh!! Very nice

  24. #24
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    hey, that long cable end is heavier than the magnesium you milled away putting yr life at risk ... cut it !
    :-)

  25. #25
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    still heavier than Vuelta Magnesium arms...

    Quote Originally Posted by top_ring
    I happened to notice (as I`m sure you have too) that the Avid V-brakes have a natural cut-a-way on the back of each arm. I thought to myself, that would be a excellent guide for machining purposes. So I got in touch with AndrewTO - a poster here, and a top notch machinist. Thanks Andrew.

    I just finished painting the arms. They weigh 48g from a stock weight of 57g. I haven't yet tried them because my bike is in pieces and it's damn cold in Canada.

    nice work although i would be a bit scared.
    and all the tuning still doesn't get them to weigh as little as the Vuelta Magnesiums.

    the Vuelta magnesiums weigh 67g including return spring, the Avid Mag 89g...so 22g heavier. you shaved 9g off...so they are still 13g heavier (26g for the set front and rear).

    by the way - you should set them up better! they need slimmer spacers to stay parallel in your bike. as they are they are looking to the outside.
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  26. #26
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    Quote Originally Posted by top_ring
    Yes, they are still going strong.

    MachinedAvids72dpi.jpg
    Those are absolutely beautifull! Very nice work.
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  27. #27
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    i think you guys are exaggerating the result of an arm breaking. i don't think it would be any worse than a cable snapping, which has happened to me plenty of times with no ill results. as long as you still had a front brake i think you would be ok.

  28. #28
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    Quote Originally Posted by nino
    nice work although i would be a bit scared.
    and all the tuning still doesn't get them to weigh as little as the Vuelta Magnesiums.

    the Vuelta magnesiums weigh 67g including return spring, the Avid Mag 89g...so 22g heavier. you shaved 9g off...so they are still 13g heavier (26g for the set front and rear).
    Thank you. You shouldn't be scared.

    Making these the lightest brakes in the world was not the main objective. Making them lighter for little money was the purpose along with a few other things. Besides, have you seen about other Mags that are lighter? I doubt it. Same goes with Type F BB7s.
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  29. #29
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    Funny how this post has been resurrected. The material used on these arms are plenty strong. Only a hammer would destroy them. Andrew - you are the greatest. (How's that Ti frame working out?)

  30. #30
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    Quote Originally Posted by top_ring
    Funny how this post has been resurrected. The material used on these arms are plenty strong. Only a hammer would destroy them. Andrew - you are the greatest. (How's that Ti frame working out?)
    Man, I need somebody like Andrew for a few projects I have in the hopper. I'll say agian, that is some stunning work.
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  31. #31
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    Quote Originally Posted by top_ring
    Funny how this post has been resurrected. The material used on these arms are plenty strong. Only a hammer would destroy them. Andrew - you are the greatest. (How's that Ti frame working out?)
    Me? Naaaaahhhh!!!

    I try.

    I'm mostly glad to hear they're still holding up!

    How's that steerer tube?

    The Eclipse is great! Running it as a rigid SS 96er right now and enjoying it - I wish I did this with all my previous frames. Don't know how long it'll last, though - looking at full 29ers with great intent!
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  32. #32
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    Quote Originally Posted by Axis II
    Man, I need somebody like Andrew for a few projects I have in the hopper. I'll say agian, that is some stunning work.
    Hehehehe. Thanks! Andrew has a lot of projects he wants to do for himself this year, too.

    If shipping wouldn't cost you so much i'd say ship the stuff and tell me what you want to do, but I think by the time they'd come back you could have just gotten whatever you wanted that was lighter to begin with. (shrug) IIRC, you're out somewhere in Europe, right? (sorry, bad memory from working with aluminum)
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  33. #33
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    Quote Originally Posted by AndrewTO
    Hehehehe. Thanks! Andrew has a lot of projects he wants to do for himself this year, too.

    If shipping wouldn't cost you so much i'd say ship the stuff and tell me what you want to do, but I think by the time they'd come back you could have just gotten whatever you wanted that was lighter to begin with. (shrug) IIRC, you're out somewhere in Europe, right? (sorry, bad memory from working with aluminum)
    Minnesota. Seriously, I may want to tap your skilz for my Look Fournales tuning project. Let me pull together my thoughts about what I want done and I'll PM you. Right now I have the fork in about 5 pieces on my workbench.
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  34. #34
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    Quote Originally Posted by Axis II
    Minnesota. Seriously, I may want to tap your skilz for my Look Fournales tuning project. Let me pull together my thoughts about what I want done and I'll PM you. Right now I have the fork in about 5 pieces on my workbench.
    HAHAHA! Minnesota. Yeah, just a little off.

    Seriously, sure. While i'm at it I can "work-in" that fork for you because you haven't ridden it yet. That and I have some ideas of my own if I ever buy one (mmmm, Fournales 29er! my pipe dream). Whenever is fine - i'm here for the using-and-abusing.
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  35. #35
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    ok suppose to do this work on both brakes...it's equal to suicide...you shaved off 9 gr but made the brake really fragile i think...also the alu bolt that keep the cable isn't the best solution...

  36. #36
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    About the work on those brakes,it's definitely a masterjob!But just going for the looks it doesn't seem that fragile for me...if you look at EL brakes they're also pretty thin.Of course the difference is that EL has done some tests on their brakes and Avid wouldn't recommend these kind of work on them...but they look sweet,that's for sure.
    What that alu bolt concerns,i wouldn't worry that much about it as there's also a washer beneath.If you put a good torque on that bolt(like 6-7Nm) it'll hold as good as a steel or Ti one!

  37. #37
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    I would trust this brake as much as the original one. I don't think braking will force it that much that it will snap!
    You've did it all by hand Andrew. Looks really good! I do have the same set of brakes (the Ti version, so not magnesium). would this be possible to do? And what would you charge for it if you can tell that?

    Thanks,

  38. #38
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    Quote Originally Posted by The Crimson King
    ok suppose to do this work on both brakes...it's equal to suicide...you shaved off 9 gr but made the brake really fragile i think...also the alu bolt that keep the cable isn't the best solution...
    I used to think the exact same thing. I bought a set of Vuelta / Miranda brakes from Nino a while back and opted to get the aluminum brake tuning kit he sells also. When I received it all my first though was "oh, aluminum for the cable bolt, too???? This guy's nuts. Well, okay, i'll give it a try - I don't believe Nino would sell something that would jeoprodize someone's life" and put it all on.

    Never, EVER once did a have a problem. The important part to remember, as $mokeyJoe pointed out, is that there's a washer underneath it. I'm not sure about other manufacturers, but the Vuelta/Miranda brakes use a washer with a little lip that bites into the cable. It isn't going anywhere.

    Besides, "aluminum is stronger".
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  39. #39
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    Quote Originally Posted by Ninko
    I would trust this brake as much as the original one. I don't think braking will force it that much that it will snap!
    You've did it all by hand Andrew. Looks really good! I do have the same set of brakes (the Ti version, so not magnesium). would this be possible to do? And what would you charge for it if you can tell that?

    Thanks,
    Started on a milling machine (we call it "roughing out" the material) then finished by hand. Incredibly tedious work. I don't know what was worse, these or the BB7s I did a while back.

    Re-read my response to Axis II - I don't know that it would be worth it. Shoot me a P.M. and we'll talk. I DON'T want to start getting into specifics of ANY kind here because I don't want to see Top-ring's thread get locked.
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