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Just thinking

Discussion in 'Early CJ5 and CJ6 Tech' started by LT4NOW, Jun 5, 2013.

  1. LT4NOW

    LT4NOW Member

    Hello everyone! Just thinking. I am three years into CJ5 ownership and have read a tremendous amount of info on these jeeps. I wonder what you all think on this, my CJ5 came to me with 31x10.5R15 tires. I do not know what it came with from the factory and I would love to know. Anyway I understand that when one puts larger/taller tires on any vehicle the brakes will be less effective and I have seen that my jeep does not stop that well even though I have rebuilt the entire system. I am planning to change over to front disk brakes but if I were to change the tires back to stock would the brakes then be OK? I am not an off roader so tire size is not a major concern to me. I have never driven an entirely stock CJ5 so I have no way to compare. What do you think, stock tires or brake upgrade? Thanks all! Tony L.
     
  2. Bob-The-CJ

    Bob-The-CJ Member

    My 65 is completely stock, including the rims and tire size and it does not stop well at all. But, 11 inch drums is easier and cheaper and they do work with stock tires
     
  3. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Do you have 9" or 10" brakes?

    We might be able to tell you what tire and wheel sizes you could have had originally, but we'd need year and engine info. Tables of tire sizes have been posted before - search old posts and you probably can find it yourself.

    Brake upgrades are popular regardless of tire size. Most drivers today would consider these Jeeps original brakes inadequate - we are simply used to much better brakes on modern cars. As mentioned, the 11" drum brake conversion works very well, and is popular.
     
  4. oldtime

    oldtime oldtime

    You did not specify the jeeps vintage nor its brake drum diameter.

    All 1953 through 1965 CJ's used the later design 9" Bendix system.
    That system only works well if kept in good condition and properly adjusted.
    The late 9" Bendix system works well if assembled using genuine OEM NOS parts.
    OEM NOS means using rivotted asbestos shoes and Wagner cylinders etc.
    This system works fine with early standard tires and Ross steering systems.

    The 1965-1971 Dauntless CJ's were original with a 10" Wagner brake system.
    The earlier ones are manual adjust and the final ones are a self adjust systems.
    The 10" systems work better than the 9" systems but not as good as the 11" Bendix self adjust.
    Here again the brakes work best with genuine OEM NOS parts.

    Besides brakinging force, the choice of tire width greatly effects the steering system.
    Ross steering systems mandate the use of narrow tread tires.
     
  5. LT4NOW

    LT4NOW Member

    Thanks for the replies. My CJ5 is a 1968 with the oddfire v6 and 10 inch brakes. I searched for the tire size table and came up with nothing. I am just wondering if I would still be unhappy with my brake performance if I went to stock tire size. Tony L.
     
  6. nickmil

    nickmil In mothballs.

    Unless a restoration or want to keep the stock wheels upgrade to 11" drums or discs. Well worth the effort and cost. That and Saginaw steering are hands down the best mods I've made to my Jeeps for drive ability and safety.


    Sent from my iPhone
     
  7. colojeepguy

    colojeepguy Colorado Springs

    My Jeep has 31" tires, and 11" drums all around. I'm quite happy with the braking performance, unless they get wet!
     
  8. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Just a comment - the 10" drums are ok ... I predict that you will notice a difference with the smaller wheels and tires, but I also predict that you won't be happy with the amount of improvement.

    Do you have your original wheels with the 31" tires? or wider wheels?

    Another issue is parts availability. The 11"x2" Bendix brakes used to convert to bigger brakes were used on many different cars and trucks, and the parts are widely available and cheap. Price and availability for your 10" brakes will be much worse.
     
  9. LT4NOW

    LT4NOW Member

    Thanks for all the input. I am going to do the disk brake upgrade. Tony L.
     
  10. Eaallred

    Eaallred Member

    I went with hanging pedals out of a 95 Isuzu and plumbed the stock brake system into the master cylinder. The brake booster is a very small diameter and fit under the hood excellently (I have a thread somewhere on here).

    With bone stock brakes and just the isuzu MC, my CJ5 stops like a modern vehicle, even with 33/12.5's on it.
     
  11. Glenn

    Glenn Kinda grumpy old man Staff Member

    Your original tire size would probably have been 8.55 x 15.
     
  12. LT4NOW

    LT4NOW Member

    Thankyou very much!