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bad turning radius

Discussion in 'Flat Fender Tech' started by 47v6, Nov 7, 2014.

  1. Nov 7, 2014
    47v6

    47v6 junk wrecker! 2023 Sponsor 2022 Sponsor

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    Dana 25 with 31x10.5x15 tires. rubs on springs when turning. its annoying. What have you guys done? is the dana 30 the fix for this issue?
     
  2. Nov 8, 2014
    flatyfreek

    flatyfreek Member

    Hillsburrito, OR
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    What wheels?
     
  3. Nov 8, 2014
    tarry99

    tarry99 Member

    Northern California
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    The 30 would give you another 1.5" more width per side.........you could consider a spacer but I would not go very much............hanging the wheels out further is hard on bearings and other components up front.
    Set the spindle stops on the housing so they do not hit.............
     
  4. Nov 8, 2014
    Jeepenstein

    Jeepenstein Me like Jeep..

    North Central FL
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    Your wheel offset is wrong.. Either get new wheels with a deeper offset or spacers.. I'm not afraid of spacers.. never had an issue with them..
     
  5. Nov 8, 2014
    47v6

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    i have some aluminum rims i got with the tires in a junk clean out. The came off the dana 30 / amc 20 setup. I have no clue about offset or whatnot. what i really want is some 33x9.50x15 tires that aren't a million bucks. I have 2 dana 30 narrow tracks one with disk and one with drum. I rebuilt the 25 before i got those.
     
  6. Nov 8, 2014
    Daryl

    Daryl Sponsor

    Bonney Lake, WA
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    Yes a Dana 25 takes about 2 acres to turn around. Narrow track Dana 30 is the best answer. Direct bolt in with zero drawbacks. Someone will chime in with the spicer axles from a 27 will give you 2 degrees more ability but not really worth the effort. And when someone points out that the 30 is wider, it was on the CJ5 from 72 to 81 also so no problem. Not one single thing about a 25 or 27 is better then a 30.
     
  7. Nov 8, 2014
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    Go D30 and don't look back - Disc, OX locker and 4.88 axle sets are great. I run the 33X10.5s on mine.
     
  8. Nov 9, 2014
    47v6

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    I have disk brakes on my dana 25. Spent the money to upgrade and then came across 2 dana 30s for really nothing after I scrapped out the garbage. Really the only reason I haven't swapped it in already is because I would need to change gear set from whatever it is now to 5.38 to match the tapered dana 44. Never done a R&P job. seems like people have real problems with them. Since I don't know the ratio I may or may not need a new case. I also want to run 33's as i have 4" wrangler lift springs.
     
  9. Nov 9, 2014
    jeep2003

    jeep2003 Well-Known Member

    Upstate NY
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    sounds like the wheels are your problem. if your ok with the actual urning radius you can simply adjust the turn stops on the back of the knuckles. but spacers or different wheels will help alot. I was surprized how much farther mine turned with just a 5/16" spacer
     
  10. Nov 9, 2014
    47v6

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    any tire over 7 inches wide with any stock rim and a dana 25 has been a problem for me. Im clear with the stops and their adjustment. I could put spacers in there or get a different rim or i could just regear my dana 30, install it and be done with it. When i get around to it there will be a complete disk brake setup for sale for the dana 25/27 axle. Its basically new too. less than 50 miles so far. I never would have bothered with the 25, but i got it for free well before my dana 30's.

    who has done a R&P to 5.38 on a dana 30? the carrier break is 3.73? most of these have 3.07 or something?
     
  11. Nov 10, 2014
    DoubleBit

    DoubleBit Member

    East of Auburn, CA
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    Hmm, "any tire over 7 inches wide with any stock rim and a dana 25 has been a problem". This must be why I never perceived any "problem" with my old d25. Just has stock-ish wheels and 7.00x15s on my rig. I thought the turning radius was good and workable/tight. Then my other 4wd is a '94 Dakota, it's the smallest truck I've ever seen take as much room as a 1t crew cab to turn in. My best guess is your wheels/tyres are your problem. Oh, and remembering the short wheel base, increases in track/width will surely diminish stability.
     
  12. Nov 10, 2014
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    If you find a drum brake 30 most of the disc brakes parts will probably fit depending on which disc conversion you did.

    The case break is 3.73-1 down to 5.38-1 is 4 series and 3.54-1 and up to 2.73 or so is 3 series on a Dana 30.
     
  13. Nov 10, 2014
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Can you explain this? My experience is just the opposite but I'm always open to learning new things.
     
  14. Nov 10, 2014
    Daryl

    Daryl Sponsor

    Bonney Lake, WA
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    Maybe take the advice of someone who has run dozens of old Jeeps with Dana 30's over someone who has only driven one stock Jeep with narrow wheels..... Just Sayin.
     
  15. Nov 10, 2014
    DoubleBit

    DoubleBit Member

    East of Auburn, CA
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    Well now, I am not trying to start a mud slingin' contest but my comments are not without validation or substance. I have experience too. And, if y'all want and can run wide tires, by all means do so with joy. However, for myself I have experienced wide wheels on my own jeep and found it steered hard and heavy and uneven road surfaces caused it to be pulled around erratically. Perhaps with enough compensation/upgrades to the suspension the wide wheels would be okay, but on a stock manual steering jeep. I'll take the skinny farmer tires and wheels every day of the week. I also have experience building 1950s vintage hot rod pick ups, and again without substantial suspension mods, steering on steamrollers with an ackerman front end is inaccurate at best. And, I spent years/decades working as a tech, doing alignments and all manner of repairs. Again, my experience there was that wide aftermarket wheels without corresponding mods to aid in the stability of the vehicle was usually more a problem than an enhancement. Matter of fact at the dealerships I worked in, the customer usually had to pay extra for any work that required fiddling with their cool wide wheels.
     
  16. Nov 10, 2014
    nickmil

    nickmil In mothballs.

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    You said stability, meaning stable. What you are talking about now is handling. Two completely different things.

    As far as Ackerman angle, that is integrated into the steering itself, typically the steering arms and knuckles on these vehicles.
    Scrub radius IS affected by wider tires/wheels/offset, etc. and can/will affect handling. Again, that is something different than what you originally posted.
     
  17. Nov 10, 2014
    DoubleBit

    DoubleBit Member

    East of Auburn, CA
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    Sounds like we look at this thing differently and hopefully we can walk away from it friends. My comments are based on overall driving experience/getting the jeep down the road without a lot of fuss and being able to handle turns and such easily. So stability is part of the that overall handling/driving experience. From reading posts on this board over the years I know you know what you are talking about Nick. That being said, I'll drive my jeep and you can drive yours, it's a win win.
     
  18. Nov 10, 2014
    tarry99

    tarry99 Member

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    DoubleBit,.....................Sounds like you have had some wide wheels on your Jeep at one time or another and as a result have experienced some bad handling characteristics which would be the norm in most cases if other principles of steering geometry has either not been corrected or at least understood. Nick M also made mention to the same result in a prior post when he mentioned the effect of a wider wheel or tire and how it effects the tires Scrub Radius.
    In your case Excessive Scrub caused by a wide dished wheel , be it Positive or Negative increases steering effort and road feel as the steering is more susceptible to road shock.

    Having also posted on this same thread and mentioned that a quick fix to get more steering angle / clearance between the tire and hitting the spring could also be had by using some wheel spacers , while I also cautioned that to much spacer would just add to the problem of an already incorrect wheel offset or backspace that could also negatively effect how the Jeep handled and notwithstanding how hard the negative offset is on steering components as a result of the added leverage of the wheel hanging away from the spindle axis center line.

    Scrub Radius is the distance on the ground between the center line of the tire contact patch and the point at which the Steering Axis Inclination intersects the ground which also becomes the fulcrum pivot point on which the tire turns on. Outside or Inside of the center line and the tire is either turning inside or outside of the center line thus adding more effort and increasing wear on all components but more so on the tires.
    If you look at the first diagram there are normally 3 choices on wheels. One centered , One Positive Offset and one (Deep Dish ) that has a Negative Offset............of course in Custom wheels they can be built with any offset or backspace.........and when done correctly a custom wheel should be matched to the Scrub Radius or steering axis inclination of the given axle or components being used. Correct offset wheels or hub centered spacers are the easiest way to correct this in a Jeep........other vehicles that have the option of Camber adjustments that can also have an effect on correcting the scrub radius.

    Just a little information to all that may be having steering issues or are in the market for some new wheels. Hope this helps some folks understand this a little better.

    [​IMG]
    In the second drawing it shows the effect of wheel offset and how it effects the scrub radius............the wheel in this drawing is a positive offset wheel with the deep portion to the rear or inside........The Red Line matches up with the SAI at Zero while the blue line is a negative offset...........the positive offset wheel is typical for today's cars and trucks.
    [​IMG]
     
  19. Nov 10, 2014
    47v6

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    wow, i have learned a lot on they thread. I now understand the concept of offset in a rim. First off, I have no real drivability problems. In fact there is no comparison to the old ross/bellcrank/manual junk that I used to use in times past. I used all that old stuff, even had the larger ross box. It was all junk. The power saginaw upgrade with modern style tie rod/drag link is worlds superior to that old stuff. I know what Doublebit is saying. I had wide tires on my first 2A. it was a bear to steer and drive. it had all the old junk I have mentioned.I put narrow NDT's on it and it rode and drove fine for what it was. I rebuilt all of it. it was still junk. This time around I didnt want to deal with engineering problems that have been solved. I actually have 2 dana 30s. one disk and one drum. Probably going to regear the disk one and install all new parts. Im sure what i have done is not even close to perfect and may have a little more than a touch of "Bubba" in it, but its just so dramatically better than the original 2A stuff was. Guys, thanks for the encyclopedic knowledge base here.
     
  20. Nov 11, 2014
    DoubleBit

    DoubleBit Member

    East of Auburn, CA
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    Thanks Tarry. The illustrations help a great deal. It looks like the overall width is one problem and the offset if positive can keep your width in spec and keep your rig steering correctly. Then given that, your limit of wheel width is how far inboard you can add to it before interfering with/rubbing on things. If I could hazard one more question; does the addition of a spacer move your zero outboard or does it just add to the negative offset? My guess is it just adds to the negative, but I'd like to learn more about this if I can.
     
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