Birty Dastards Jeep Club
Tech Forum => Workshop => Topic started by: Dtimot8 on January 04, 2013, 06:25:32 PM
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The non techy from deepest Kent wants to try and understand the Physics etc behind the title.
I want to find the solution to this problem in advance of all of those highly skilled and trained engineering types
I don't depute that they will go bang - but why ??
is it something to with unsprung weight (note chucks in tech term) - if so would using a bigger alloy wheel help ie a 35" tyre on a 15" has to weigh more than a 35" tyre on a 20" rim
If its not that then it must be traction BUT I find it hard to believe that the contact patch (sort of tech term) is that much greater on a 35" or 37" than a 33"
Unless a substantial alteration is made to the torque multiplication (now that is defo a tech term) there isn't that much more power going through the tyres - I note everyone's previous comments on changing to 4.56 only a 10% gain on currently installed 4.10
AHH i think I'm about to answer my own question standard is 3.07 which is a 50% gain in torque
Now chaps have i answered my own question or am i chatting s**t as usual
Regards Lord Tim
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intead of all the physics remember your axles, uj's etc were designed for 28" tyres
as soon as you starting modifying you put extra stress on things
go up to 31's and because of the safety factor designed in you usually are ok
33's then you need to start beefing stuff up on the drivetrain as the extra weight, grip available alters
35's and then your into a different game again
What exactly are you trying to do or upgrade to ?
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Tis all about weight and stuff......If you hold a 2 foot piece of pipe in you hand and twist it.....NO PROB
Try that at the same speed with a 4 foot length .......your wrist WILL hurt......
Big tyres break small axles.......
If you trawl Pirate you'll find the details of what axles can take what ft/lbs of twisting force........
Cough cough.......Dana 60 s will be your friend :icon_super:
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in basic terms it's leverage, think of the diameter of the wheel/tyre as the length of a lever, the longer it is the greater resistance force can be applied
your engine produces rotational force, it goes through the gearboxes and prop and then this force has to change direction vis the diff to the half shafts, at the other end of the half shaft the wheel is trying to stop the rotation (back to lever idea) so the bigger the tyre the greater leverage can be applied to counter the rotational force, the diff ratio should apply enough mechanical advantage to overcome the resistance from the wheel, if not the excess force has to go somewhere and that is usually the diff, a UJ or half shaft going bang
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Biggest cause (not the only cause)of axle breakages (by that i mean half shafts) is the LOUD pedal and the person in charge of it .
https://www.youtube.com/watch?v=gYubjRHH3rw (https://www.youtube.com/watch?v=gYubjRHH3rw) start from 3.26min
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yep, some folks dont help with the right pedal
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Man-a-live, this is easy...
It's either the "RED MIST" or "TESTOSTERONE EFFECT" you can hedge your bets with man size Dana 60 upwards for leverage, then again you could study science and the pye equation!!
Thinking (I know, I know) about this we need to consider the H.D.I.Y.P.E!!! This also needs to be considered.
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so my mission is .......
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so my mission is .......
off road on whatever you got, dont get obsessed by going really big because its the thing to do, you can have so much fun on small lifts etc, Mr H knows this :icon_winkle:
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so my mission is .......
off road on whatever you got, dont get obsessed by going really big because its the thing to do, you can have so much fun on small lifts etc, Mr H knows this :icon_winkle:
:iagree:
just look at the fun had in lil'yella, set of tyres and a recovery point, thats the only real mods done to it
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loathe as I am to credit the bourgeoisie H with anything he did tell me that after a while he got bored goin home with summink busted - and TBH after this years CF it kinda sunk in
its why i might by a ghay assed TJ until I track down my Sugga
of course there is no accounting for red mist & a V8 after a night round the campfire supping some god awful shite someone has home brewed :003:
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ghay assed tj's do the job but you still gotta drive them
abuse will deffo mean breakages :icon_winkle:
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Indeed, even a $10 Teen can only bend so much!!!!
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Indeed, even a $10 Teen can only bend so much!!!!
indeed, even if you spend a few more dollars making her bend some more :icon_winkle:
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You see !!!
these damned engineering types have it all sorted
No chance for the idiot to take over
all points duly noted
way to wimpy and sacred to do d60 or even d44 for that matter
UJ's and recommendations from previous post to be purchased
Regards Lord Tim
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Most axles, UJs and diffs I've seen go bang have been when the wheels have been spinning from too much load pedal / determination and then hit something with grip. Imangine bouncing a Jeep up a rocky climb, a front wheel comes off the ground and is spinning and then bounces back down on a grippy bit of rock - the weight and gravity pushes a spinning wheel with all that enery into a grippy surface, squashes the tyre into it for more grip and with lockers in the energy breaks something. Having the wheels turned at the same time just adds to the potential for breakage.
It's a mix of driving carefully, blinging up your axles or fitting bigger axles that minimises the number of breakages. Heavier tyres and spinning mass does affect it too but there is always the potential for it to happen no matter what you do - especially if you're prone to 'competitive' behaviour
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Yep and when they go bang out comes the wallet and out goes $$$$$$ in repair bills. AMC 360, 33" tyres, a bit vigrous on the loud pedal and bouncing the front end up a rock climb did this
(https://birtydastards.com/frm/proxy.php?request=http%3A%2F%2Fi274.photobucket.com%2Falbums%2Fjj254%2Fandrewspalding%2FDSCF0022Copy.jpg&hash=6ed2bb62ad17472af2f8d83280800ba3b09ae56b)
(https://birtydastards.com/frm/proxy.php?request=http%3A%2F%2Fi274.photobucket.com%2Falbums%2Fjj254%2Fandrewspalding%2FDSCF0026Copy.jpg&hash=b121811d9e8164b61a474357f46609b47dcadc4f)
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manual gearbox?
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Yes and D30
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thought so,its why i prefer auto's