what is the best way to get the phattest grind possible??

Discussion in 'Observed Trials Discussion' started by sebLG, Feb 17, 2004.

  1. sebLG

    sebLG New Member

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    hey all,

    im just wondering because i and getting koxx bloxx what is the best way to get the phattest, deepest, heaviest grind i can possibly get . it will be on a koxx rear rim, which is kind of gay coz i hav heard that they are really soft (??) ...

    thanks!! cyall .

    Seb... :Wavey: :Wavey:

    ps : sorry if this has been asked millions of times .
     
  2. oicdn

    oicdn Look at my member...

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    Angle grinder.....or alot of time with a dremel......
     

  3. Janson

    Janson prevent plate usage!

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    Use a metal cutting disc.
     
  4. AndyT

    AndyT New Member

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    the biggest problem is people are little pussies and they don't push at all on the grind, then they complain when their grind is shitty.


    PUSH it into your rim. You should be pushing so hard that if you stayind in one spot for more than half a second you will go through your rim.
     
  5. oicdn

    oicdn Look at my member...

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    ^^^^^ :werd:
     
  6. sebLG

    sebLG New Member

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    how would a bench grinder do? also my grinds arent really THAT shitty, but i know there can be better ... but also they never last long enough . like a week or two at the longest til im using tar . also how to actually do it, i usually use the corner of the grinding disc, should i be using it flat?
     
  7. oicdn

    oicdn Look at my member...

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    You can use either. Alot of people seem to cross hatch thier grinds.....instead of the grind only opposing the rim for foreward movement, it utilizes MAXIMUM stopping grooves for both directions. Kinda how slotted rotors for a car are only slotted to give maximum stopping/breathability grooves for only going foreward.....since trials braking is in both directions...cross hatching is the most effective....
     
  8. Gardenfan

    Gardenfan New Member

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    Ya... slotted rotors are not akin to a grind on bikes. Not even close. :rolleyes:
     
  9. oicdn

    oicdn Look at my member...

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    :squint: :rofl: I was talking about the direction of the slots on the rotos, how their pattern "bite in" to the pads when going foreward, but when in reverse, the direction of the slots isn't as optimal to braking as it is going foreward...hence CROSS HATCHING so you get the "biting in" in both foreward and rear-ward directions....

    I guess people don't visualize much on this list :rolleyes:
     
  10. sebLG

    sebLG New Member

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    lol, whats cross hatching and how do i do it? and again do i grind it flat against the grinding disc or on the corner? haha, i am too stupid to make decisions for myself so tell me which to use rather than both lol :greddy2:
     
  11. Gardenfan

    Gardenfan New Member

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    Lol, I have been putting a 'cross hatch' pattern on my rims a lot longer than you have been riding lol. I can visualize perfectly well what you were talking about, I am just saying that your referance to a car application is completely wrong. The slots do not dig into the pads, that is not what they are there for. Neither are holes if the rotors have them.
     
  12. OTAdmin

    OTAdmin Got more product than Ron Popeil Staff Member

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    i grind using the corner of the disk.
     
  13. Zyzzyx

    Zyzzyx New Member

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    :rant2:

    Grooved, slotted, and drilled rotors on a car have nothing to do with 'adding bite' to the brake pads. They allow an escape for gasses built up from the extreme temperatures on the surface of the brake pads under extreme braking. If not there, the pads could essentially 'float' the tiniest bit on a layer of air between the pads and the rotor. They can also have a very minor effect of cooling the rotor, more so with the drilled rotors.

    However, on 95% of the vehicles with slotted/drilled rotors its for looks above all else. And even that remaining 5% will rarely get their brake systems to the point of truly needing the slots/holes.

    And I guess you haven't seen the elliptical slotting patterns, that end up having the slots 'go both ways' on one rotor.


    Ok, and I just re-read your first post, "...only slotted to give maximum stopping/breathability..." With mention of 'breathability' I'd like to give you some credit for understanding what I just rambled about. Still, does nothing for 'bite' on a car, especially since most grooves are chamfered or rounded when made.



    We now return to your regularly scheduled biketrials ramblings.
     
  14. oicdn

    oicdn Look at my member...

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    Really? I thought they were just there? It's an OBVIOUS venting property. BUT, if you've ever read any of the testing between the 3 various types. Slotted rotors provide 8% more braking effieicency from the grooves. Cross drilled provide and additional 2% of stopping force. Slotted AND cross drilled provide NO ADDITIONAL BENEFIT although there is speculation that the slotted "grooves" provide "bite" Others claim it DECREASES performance by lack of braking surface....The lack of braking surface can do one of two things depending on your driving application, which are really hand in hand...cause increased brake usage from "lack" of power, and increased brake fade.....

    As you know normal brake discs have a smooth, flat surface. Holes and slots in the face of the disc have a number of purposes.

    Firstly removing gases from the face of the disc, these gases greatly reduce the coefficient of friction. Disc pads, when hot, expel gases. These gases form a cushion between the face of the disc and the pad.

    It takes a tenth of a second to squeeze these gases out on normal rotors. Now this does not sound like a long time, but consider this. When a vehicle is travelling at 100km/h, it is moving at a rate of 30 metres per second, therefore a tenth of a second is three metres. So in essence when the brakes are applied the vehicle travels for three metres squeezing out gases, and not creating friction to slow the vehicle.

    Another problem that occurs when the build up of gases is not released is that the pad material becomes hardened and glazed, greatly reducing the amount of grip between the pad and disc. Cross-drilling and slotting allow these gases to be removed immediately, also helps to deglaze the pads, increasing the grip between the pad and disc, hence shortening the braking distance.

    Cross-drilling and slotting makes the disc surface uneven so water and dust cannot develop into a thin layer that becomes a smooth, glass like surface and can greatly reduce the coefficient of friction.

    Cross-drilling and slotting work effectively to reduce the main problems that occur in brake systems.

    But there are some tradeoffs, such as a shorter pad life of approx. 10% so if your getting 40,000kms from a set of pads this can be reduced to 36,000 kms, a small price to pay for better braking performance. Also the cross-drilled rotors are more prone to cracking under extreme conditions, such as racing.

    Both the cross-drilled and slotted and just slotted discs have the same performance qualities.

    So the question is do I fit cross-drilled and slotted discs, or just slotted discs?

    This question has to be asked of the driver, what is the main use of the vehicle?

    Is the vehicle used for racing, or driven extremely hard?

    Does the vehicle go off road?

    If the answer is yes to either of these questions, slotted only discs should be recommended.

    If the driver of the vehicle only drives on the street, but drives it hard occasionally, and has nice open wheels where the rotors would look good as well as perform, recommend the cross-drilled and slotted.

    So in the case of slotted rotors really being used to let gases escape is more or less of a byproduct than it is for actual stopping force as the way the grooves are hatched, when rolling foreward, point INWARDS....if you wanted MAXIMUM venting, you would have the hatching backwards, so the slotting goes outwards.....If you ever get a chance to look Indy cars, or even nascar( :greddy2: ) cars, you'll notice they utilize CARBON SLOTTED rotors, not cross drilled as most "racers" think is the best choice....great for venting, but not actual stopping force...the hatching REALLY IS for bite and deglazing of pads, venting is just a "byproduct"....
    This was my physics project in High School....

    :bigthumb: :eek:wned: :D
     
  15. Patrick

    Patrick New Member

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    Good advise Andrew.. My rim is sharp as shit now..
     
  16. AndyT

    AndyT New Member

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    Good job patrick, seriously. There are a few certain people who cannot grind at all, and I will laugh at them (no not just you martin and cam).
     
  17. Elan

    Elan steve french

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    ME :ugh:
     
  18. OTAdmin

    OTAdmin Got more product than Ron Popeil Staff Member

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    yep
     
  19. Elan

    Elan steve french

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    ah, i should have put ME!

    ah, but i am getting a new rim..soon. so it will have a decent grind on it probably.
     
  20. Gardenfan

    Gardenfan New Member

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    I didn't read all of that, but I will tell you this, the slots are for venting purposes, while the holes are for weight, and venting, as well as to help cool the rotor down in the phase that it isn't running through the caliper. The holes are also almost always a major source for failure on most rotors, as they are usually drilled after the rotor is forged. Some companies(Porsche) Mold the holes into the rotor at the same time eliminating this problem. So now you know that 90 percent of the 'performance' rotors on the market are a gimic, as they usually are not properly engineered, and are more about looks. The only time you need real venting in the rotors are in a true race application. Doesn't help much on the street, and certainly not by 3 meters lol.

    The point of all this is that they are not akin to a grind. The reason a grind works on a bike, is the pads are of a softer material, such as rubber. This grips the sharp edges of the grind, and allows the grind to bite in. This doesn't work on a car/or bike disc brake because the pads are usually metal, or have metal in them. Any sort of grind would be gone in seconds, and wouldnt be good for performance at all, in fact it would be detrimental.