Is wheel base an issue???

jktcummins

jktcummins

24v GOD!!!! HAHAHA
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Apr 1, 2007
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Ok guys i am in the process of building a puller. I really want to know how you guys feel about using a single cab??? If yall could let me know what your thoughts are. I really need to get this project going.
 
In the same boat, older experience guys say longer is better, but have no facts. A regular cab is lighter therefore more hanging weight out front. I see the leverage advantage of a longer truck but when you can hang 800 to 1000 pounds more out front, it's gotta make up for chassis length. I say run what you have, I don't see a huge difference either way just my opinion.
 
thats what i was thinking. But i have noticed that it seems like at the track the longer wheel base trucks always seem to do better. But then again maybe its just cause the short wheel base trucks are tricked out as much as the long wheel base trucks at that particular event.
 
I have seen the regular cabs bouncy like a kangaroo. I can hang almost 900 on the front of my extended cab long bed truck in an 8000lb class. I haven't gutted the interior yet either. What does a regular cab weigh? Shouldn't be too hard to figure out which one has the most leverage. I thought the weight difference was only like a couple hundred pounds.
 
Ok - pulling chassis 101

Hitch length is usually limited to a percentage of wheelbase, or in many cases must be a minimum length measured from the rear axle centre.

if it is a percentage of wheelbase the longer truck is at an disadvantage every time - less leverage - and the truck tends to want to bend in the middle tryin to lift the front wheels/weightbar - which also causes bouncing

If you have a minimum length rule - or it must be the furthest point behind the truck or past the box, then calculate wheelbase vs leverage - usually the standard cab comes out best overall

for an all out puller there is no way hands down you can beat a stripped standard cab because you can move so much weight forward.

now sure there are exceptions - always is, and of course this is bare bones - there are many many factors that may make a small diffference - but overall this is ballpark:Cheer:

take a look at the truck in my signature - its 8" shorter than a standard cab for calculated exact best leverage to weight to wheelbase ratios
 
This truck got down to 6000lbs, That was 5 years ago when he was trying to pull in a 6200lbs gasser street class. There were no rules against diesels. The next year there were...lol



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How did he get down to 6000lbs?

I figure my truck is like 6900, without a spare, tailgate, rear bumper. I figure I could lose some of the interior, maybe 200 there. Still like 700lbs short.
 
Aluminum were it could be used (ie.Spring blocks) Light race seat,no carpet, Ditch the dana 80 for a light 14bolt. There is some idea of what was done. The PVC pipe was custom, intended for dyno use only.
 
hmm guess you need a Ford
my 91 F350 one ton camper special with a cummins in it fully dressed only weighs 5600 lbs with me in it an a full load o fuel
 
It has been 4 years since I last figured this out or tried to explain it....I brought this exact question up to my Physics College Prof when I was taking Engineering and by figuring out all the variables and moments involved in the equations we found that my truck having a wheel base of 168" and 800lbs out to 60" past the center of the front axle would be the exact same as a
133" reg-cab long box chevy having 4 times that amount in the weight box. We found this out by having the hitches equal and playing with numbers untill the weight on the front tires (touching the ground) where equal between trucks. What I found though was that with the weight difference on the front, front tires pushing down being equal...the weight pushing down on the back wheels was substantually more with the longer wheel base truck (this was with "X" amount of weight pulling down on the hitch and being equal to both trucks.

In the end...honestly, unless you are pulling on the same tracks every weekend...I think its all a crap shoot!!!! My setup works great on the nice tight power tracks but totally sucks on the loose stuff where all I do is blow out the tires. If I try not to do it by keeping out of the trottle I am loosing my water injection and losing boost and fall way short.

Ryan
 
I don't know but our reg cab hooks hard, thats why it's remained un changed for now. reg cab 2000lbs on the nose, and no bouncing, just works well. Hooks hard enough to break 3 1410 yokes off the dana 80 and 2 np241 main shafts, i guess the u-joints aren't the weak link, hopefully the 1480 joints and np271 will fix that.
 
I think it is all a crap shoot myself. Run what you have. I dont see a lot of difference either way. You will probably find more difference in the tires and hitch setup than anything.
 
jktcummins said:
Ok guys i am in the process of building a puller. I really want to know how you guys feel about using a single cab??? If yall could let me know what your thoughts are. I really need to get this project going.
Click to expand...

Building a puller with a short wheel base is like going into a fight with a broken nose...
 
goin to a pull with a long wheelbase truck is a broken nose - its bendin in the middle - all ya gotta do is watch videos under power.

Ryan has it almost correct. But unfortunately in the real world the hitch length on his truck would not be the same length as a shorter truck. All your physics example did was show the difference in weights needed to equalize using the same hitch 800 vs 3200 or so and let me tell u I wil l takethat 3200 on the front any time when the hitch is a percentage of wheelbase

For example a regular cab hitch might be 42" long whereas a cab n a half would be 44" when it is say 35% of wheelbase

The leverage differnce of two inches is on the order of tons pressure on the rear tires

You really have to take hitch length into account.

But hey - maybe thats why so many diesel boys be breakin thier trucks - hard takeoffs from a wrong hitch, or bounce from chassis flex
 
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seeker1056 said:
goin to a pull with a long wheelbase truck is a broken nose - its bendin in the middle - all ya gotta do is watch videos under power.

Ryan has it almost correct. But unfortunately in the real world the hitch length on his truck would not be the same length as a shorter truck. All your physics example did was show the difference in weights needed to equalize using the same hitch 800 vs 3200 or so and let me tell u I wil l takethat 3200 on the front any time when the hitch is a percentage of wheelbase

For example a regular cab hitch might be 42" long whereas a cab n a half would be 44" when it is say 35% of wheelbase

The leverage differnce of two inches is on the order of tons pressure on the rear tires

You really have to take hitch length into account.

But hey - maybe thats why so many diesel boys be breakin thier trucks - hard takeoffs from a wrong hitch, or bounce from chassis flex
Click to expand...

Some of the weakest frames out there are the 94-95 regular cab dodges.
The percentage hitch rule would definately help the regular cabs, but I think that most organizations would just let people hang weight to equalize the field.
I think I if I remove my back seat I could be down to with a few hundred lbs. of a reg cab. Myabe 300. I mean your talking 20" of frame * 2, sheet metal two small windows, and then drive shaft length.
 
The percentage would help, but most assoc. are just reese style hitch, or no farther forward than axle centerline. Hook point rear most point of truck. I think longer is better, but the question still remains....how much better? Better all around or in just certain situations.
 
if you allowed to hang weight its 6 in one 1/2 dozen in the other. the trucks are pretty equal. when your not allowed to hand weight is where the longer wheel base will help. a ext cab will still hook or at least try to and most reg cabs will bounce.
 
zstroken said:
Some of the weakest frames out there are the 94-95 regular cab dodges.
The percentage hitch rule would definately help the regular cabs, but I think that most organizations would just let people hang weight to equalize the field.
I think I if I remove my back seat I could be down to with a few hundred lbs. of a reg cab. Myabe 300. I mean your talking 20" of frame * 2, sheet metal two small windows, and then drive shaft length.
Click to expand...

Why would a regular cab frame be weaker than a ext cab, and why are the 94-95's the weakest? I thought the frames were pretty much the same up to 03?
 
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