How much are these rear disc brake kits increasing track width?

Discussion in 'Suspension, Steering, Brake & Wheel Topics' started by 1971CamaroGuy, Feb 21, 2018.

  1. 1971CamaroGuy

    1971CamaroGuy Veteran Member

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    Oct 31, 2004
    Arkansas
    I'm looking at this kit

    https://www.ebay.com/itm/162892908176


    and it says :

    "All disc brake kits will move your rim out toward the fender of the car up to 3/4" depending on your style rims. It is hard to say how much total offset it will be as all rims are not standard."

    This seems pretty excessive so I thought I would check with you folks and see if anyone has used one of these and can comment on what their experience was?

    I don't see how rim type matters, the kits gonna either move the current wheel position out more or it won't. From what i am finding out on some other sites that use similar kits it moves it out 1/8" per side depending on how thick the rotor hat is. Which would make sense.
     
  2. badazz81z28

    badazz81z28 Veteran Member

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    That’s totally dependent like you said based on the rotor hat thickness. Personally I have never really seen a rotor hat that 3/4” thick...that’s thick! Maybe on a HD dually pick up.

    A more appropriate thickness is closer to 3/8”. Then subtract the drum face thickness which is like I don’t know 1/8”?

    So your looking at the wheels being pushed out 1/4” which wouldn’t be noticeable with stock wheels.

    The rims are what they are...you’re right the rim doesn’t matter.
     
  3. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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    That's something I didn't think about when I converted my rear brakes, should have compared the thickness at mounting points between drum and rotor. I have 275/40x18 on the rear, it didn't cause an issue.
     
  4. 1971CamaroGuy

    1971CamaroGuy Veteran Member

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    Can you tell me the specs on the rims your using? Width, backspacing and offset?

    I am looking at some 18x9.5 rims with 5.5" BS and 6mm offset for the rear and fitting these on the stock drums would work, it would be close but would work.

    trying not to roll the fender lip unless I have too, that would be a mess on a painted car
     
  5. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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    Ringgold, GA
    This is the wheel I'm using; http://www.boss338.com/partnumber.php?partnumber=33879912&number=3
    They advertise the backspace as 5.03 and I was getting a slight rub on driver side when I compressed the rear real hard, this was before I installed disc brakes.

    Mine does sit fairly low, the lip to wheel center is 13 5/8". A 5.5 b/s would likely work better.
     
  6. 1971CamaroGuy

    1971CamaroGuy Veteran Member

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    cool thanks, according to your specs the wheels I am looking at will sit about .39 further inside the wheel opening..I think I will be ok
     
  7. badazz81z28

    badazz81z28 Veteran Member

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    When I used the TA rear disc which are probably the same rotors as your link, I ran a 275 tire on a 17x9, no offset and the closeness was with the e-brake cable. Fender lip was fine
     
  8. 8pack

    8pack Veteran Member Lifetime Gold Member

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    Pittsburgh, PA
    I am trying to solve for that problem....I have the 79TA rear brakes...I have done a bunch of measurements and I was looking at a 18x9.5 with 5.5” backspace but I think the ebrake cable might be a problem...how did yours wind up?
     
  9. 1971CamaroGuy

    1971CamaroGuy Veteran Member

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    I got my rear brake kit in this week and wheels should be where next week for my install...I def plan on taking some measurements myself
     
  10. badazz81z28

    badazz81z28 Veteran Member

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    May 4, 2001
    Las Vegas, NV
    I think with that much offset the e-cable will rub the tire. I had 5” BS (no offset with a 17x9) and the driver side rubbed. I got the passenger side to tuck and I clamped it to the frame to hold it back.
     

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