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Wheelbase questions

Discussion in 'Center Of Gravity' started by Hossbaby50, May 25, 2004.

  1. Hossbaby50

    Hossbaby50 3/4 ton status

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    I believe my next project truck is going to be a /forums/images/graemlins/yikes.gif 78 Ford F250 longbed. The wheelbase is 133".

    I am going to shorten the wheelbase and turn the truck into a rockcrawling Truggy project. I have been toying with the wheelbase. I want to be longer then a Blazer (106.5). I am thinking about running in the 115-125" range but need help deciding what would give me the best all around wheelbase length. Is the any magic formulas?

    My other question is the more COG question.

    How do I properly shorten and reinforce the frame? I would cut out a straight section if possible and then butt weld the 2 frame ends together. What else needs to be done to reinforce the frame around the cuts? Thanks

    Harley
     
  2. PJTPW

    PJTPW 1/2 ton status

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    I'm running 125" of wheelbase and I think it's ideal for Moab. At least with a heavy vehicle (4800 lbs). It makes the vertical stuff look easy. The main drawbacks are turning radius and breakover angle. I've got a lot of breakover, and am running a two piece rear driveshaft to help with clearance there.

    I've had a lot of people tell me to shorten it up, but I don't see any advantage to that at this point. I feel the extra wheelbase helps me more than it hurts me where I wheel. The only disadvantage on mine is the turning radius.

    Mine was 131" to start with and I moved the front axle forward 3" and the rear axle forward 9". I just mounted all the spring hangars and crossmembers 9" forward and chopped off the back.

    There are write ups on all my mods in my sig.

    Ryan
     
  3. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Easiest way is like I did it, just move the mounts and adjust for height changes (moving the rear mount into the arch).

    If you cut the frame, just make sure you don't cut vertically top to bottom. Their are multiple non-straight patterns that work equally well, you just don't want a vertical but (though technically it can be just as strong if done right). Look at it like this, think of gluing two blocks together butted together at the end. When you try to brake it apart by bending, it's acting like a fulcrum on the compressed side, pulling the but joint apart. Back and forth like that can eventually cause it to fail. Now stagger that same glued joint and you have more glue/connective surface which immediately makes it stronger, and you don't get it trying to lever itself apart. Not 100% accurate but it’s a way of visualizing what and why…

    And do NOT plate the back side. That is the classic frame splicing mistake and will lead to failures at the end of the plate. If you feel you simply must plate, then fish mouth or diamond cut the ends to spread the stress riser over more area. I personally have spliced many frames and the most I have ever done is use a narrow piece of scrap on the back side of a deeply beveled joint just as a blow-through backing. I’ve built log skidders (modified trucks used by very small logging operations, not the big equipment) and extended bed car haulers like this and I’ve never had a failure.

    Good luck…
     
  4. miniwally

    miniwally 1/2 ton status Premium Member

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    I am at 115" with my buggy. So far I have really liked it. I am also at 155" with my light wheeling rig/tow rig/daily driver. I also like this wheel base.
    Use what you want to use. I really think anything in the 110" to 125" would be okay. Shorter is better for break over and turning, this can be a big deal on tight trails.

    Frame spicing is already well covered.
     
  5. juanblzer

    juanblzer 1/2 ton status

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    I'm also planning on going to about a 112-115 inch wheelbase. If you've seen BadDogs truggy climb obstacles that most blazers can't climb, you know that a little more wheelbase goes a long way. I also am planning longer wheelbase so going fast is more stable (think prerunner). Oh, and I wouldn't mind having a longer rear driveshaft either. /forums/images/graemlins/grin.gif
     
  6. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I'm at 119". I like it.
     
  7. Canadian Trailblazer

    Canadian Trailblazer Registered Member

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    Just a quick question, is 106.5" the stock wheelbase for a '72 K5? If not, what is?
     
  8. Triaged

    Triaged 1/2 ton status

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    1st gen K5's (69-72) had a wheelbase of 104"
    2nd gen's are 106.5"
     
  9. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    [ QUOTE ]
    I'm at 119". I like it.

    [/ QUOTE ]

    My new Chevy has a wheelbase of 197"..... /forums/images/graemlins/peace.gif
     
  10. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    This week end I watched a very nice hybrid with S10 extended cab on 122" (IIRC) wheel base walk a water fall that several 106-113" (mine is 113") found impossible to climb. On other obstacles, the brake over would flip the table. I’m told the same rig was complete out of it’s element in Upper Hell where other shorter vehicles were having a much better time.

    I'm likely starting over again and I think I'll be looking at around 115, maybe just a bit more. And maybe a variable height system to help alleviate the brake over issue without sacrificing climb or off-camber work... Too bad it’s so hard to make a variable wheel base. Not sure, the only thing I'm sure of is that there are going to be some MAJOR changes after this week end...
     
  11. zcarczar

    zcarczar 1/2 ton status

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    I found out this weekend that a long wheelbase doesnt really make all that much difference. I spent the weekend wheeling with heavily modified jeeps and blazers and my SOA samurai. While I did have a tougher time on some of the larger ledges, picking a good line made all the difference, hell i walked over some ledges that the jeeps and blazers were having trouble with, which makes no sense to me considering the samurai has a wheelbase of 87" and everyone else was right around 100" and had much larger tires. /forums/images/graemlins/thinking.gif
     
  12. Sandman

    Sandman 3/4 ton status Author

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    [ QUOTE ]
    And maybe a variable height system to help alleviate the brake over issue without sacrificing climb or off-camber work...

    [/ QUOTE ]

    How about an ATV winch on the front suspension to compress it for climbs? I've thought about it.
     
  13. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Already planning on putting the front axle further forward so I can use the main winch to suck it down for major climbs. Not a bad idea though. Instead of "raise it up" as needed; "pull it down", then let off on it when I need more height... But for both ends, that would be a second winch in the back. Or maybe just air-bag the rear and use the winch on the front... Oh my god it never ends... /forums/images/graemlins/crazy.gif
     
  14. Sandman

    Sandman 3/4 ton status Author

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    Dont make it too complicated. /forums/images/graemlins/thumb.gif

    How about a really good skidplate to compensate for a bad breakover? /forums/images/graemlins/grin.gif
     
  15. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    I know what you mean. Simplicity (as well as common stock parts) has been my goal all along. And a good, smooth, AR skid would go a long way to minimizing those issues. But I really like the adjustability of air bags. But then you are vulnerable to blown lines or bags. Complexity combined with hard to locate (in a strange town, at mid-night, on a holiday...) is not a good thing.
     
  16. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    I found out this weekend that a long wheelbase doesnt really make all that much difference. I spent the weekend wheeling with heavily modified jeeps and blazers and my SOA samurai. While I did have a tougher time on some of the larger ledges, picking a good line made all the difference, hell i walked over some ledges that the jeeps and blazers were having trouble with, which makes no sense to me considering the samurai has a wheelbase of 87" and everyone else was right around 100" and had much larger tires. /forums/images/graemlins/thinking.gif

    [/ QUOTE ]

    The reality is that there is no ideal wheelbase. In a lot of areas, more wheelbase helps. In others, short is the only way to be. There is no cut and dry answer to the age old question, what is the perfect wheelbase?

    I've walked easily through places where a Blazer was spinning all over the place, and I've struggled where shorter vehicles made easy progress.

    Like I said, there is no right or wrong answer to this question.
     
  17. chubbybob

    chubbybob 1/2 ton status

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    it all depends on where you wheel.
    moab has very steep climbs where a short wheelbase wont even get your front tires up on so long wheelbase is where its at.
    the con short wheelbase seems to be where its at because of all the tight trees and corners.

    I personally like my long wheelbase @132"
    but will shorten it down to about 125" or in that area. a little tighter steering would be nice /forums/images/graemlins/waytogo.gif
     
  18. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Luckily it seems I'm right smack in the middle of every one of these discussions with where my truck is right now. /forums/images/graemlins/thumb.gif
     
  19. fwdjunky

    fwdjunky 1/2 ton status

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    Back to moving the rear shackles into the arch in the frame, how did you compensate for that? Did you add length to the hangers or weld plate in under the arch to bolt them to? Or is there another option that my overworked little mind isn't settling on at 4:40 in the morning? Thanks! Rich.
     
  20. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Longer shackles combined with the "shackle flip" effect work nicely. Just make sure the shackles are stout enough to handle the side loading.
     

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