Opinions on my awd utv build.

[karting_krazy]

hello I am just about to order parts for my shaft drive awd kart thats going to be an all season machine that can go through ****. Its top speed is only 12mph and its running a 550cc b&s horizontal engine. Heres where I want your guys opinions I have come up with a drive train Im pretty confident will worn and I want to know if you see any problem with it or improvements needed. First the rear and front gear boxs. They will be 2 of these http://www.ebay.com/itm/1-1-RIGHT-A...165?pt=LH_DefaultDomain_0&hash=item3f36446b0d connected all with 1 inch axles shafts on pillow blocks with these UV joints http://www.surpluscenter.com/Brands/G-G-Mfg/1-KEYED-12-HP-UNIVERSAL-JOINT-1-2730.axd In the middle of the kart the axle will have a sprocket mounted to connect to the clutch on the engine. I hope you can understand what im thinking.

 

[Scout]

1800 rpm max input speed max on the gearbox, and 1000 rpm max on the u-joints… I think you'd better rethink your parts.

 

[Scout]

After second thought, if it is geared down before the gearbox, then they would probably be ok, The U-joints on the other hand, may or may not work. If they were forged they'd probably handle it.

 

[itsid]

Wait.. horizontal engine.. sprockets??

that means you intend to run a chain horizontally?

That isn't a good idea, chains don't like that too much.
the slack will wear the sprockets and linkplates really fast,
and then it'll either slip off the sprocket or break.

use a v belt and pulelys, that'll be a better idea on a horizontal engine.
there are v belt cent clutches as you might already know.. so not much to change in your plan

'sid

 

[n3480h]

Looking at the picture of the gearbox in the first link, the input shaft (#1) turns clockwise, the left output shaft (#3) turns clockwise, and the right output shaft (#2) turns counter clockwise. I don't understand how that will work when the two output shafts turn in opposite directions.

 

[itsid]

Looking at the picture of the gearbox in the first link, the input shaft (#1) turns clockwise, the left output shaft (#3) turns clockwise, and the right output shaft (#2) turns counter clockwise. I don't understand how that will work when the two output shafts turn in opposite directions.

they don't!

that's magic... they turn in the exact same direction!

stand on the left side of your car.. moving forward your wheels need to turn counter clockwise,
now stand on your right side of your car.. and magically moving forward means they turn clockwise.

'sid

 

[fowler]

Note the uni will do more than 1000 rpm

As long as the angle is at or very close to 0 degrees


Look up "surplus centre u joints" for a write up I did on them


Also what are u going to do for a diff

The front will need a diff
U might get away with it for the rear

 

[machinist@large]

Looking at the picture of the gearbox in the first link, the input shaft (#1) turns clockwise, the left output shaft (#3) turns clockwise, and the right output shaft (#2) turns counter clockwise. I don't understand how that will work when the two output shafts turn in opposite directions.

they don't!

that's magic... they turn in the exact same direction!

stand on the left side of your car.. moving forward your wheels need to turn counter clockwise,
now stand on your right side of your car.. and magically moving forward means they turn clockwise.

'sid

Sid wins this round, but n3480h raised a valid point. I've seen and used both types in my career, and many of them look identical if you were just looking at one on the bench. In this case, Surplus Center included the proper schematic showing which type this one is. From what little I've seen of eBay that makes them the exception.....

Note the uni will do more than 1000 rpm

As long as the angle is at or very close to 0 degrees


Look up "surplus centre u joints" for a write up I did on them


Also what are u going to do for a diff

The front will need a diff
U might get away with it for the rear

Unless the OP is planning to use this thing a logging mule, the u-joints should work (famous last word's). I completely agree about the front differential, especially if the wheelbase is short. The rear would just be the same as any live axle kart.

 

[Scout]

I was thinking about the u-joints too. They are rated for a speed at an angle. What is the speed rating at say 45*?

 

[firemanjim]

I was thinking about the u-joints too. They are rated for a speed at an angle. What is the speed rating at say 45*?

You can't run 1 joint at a 45* ..... 15* is max, for clearance issues.....

 

[machinist@large]

You can't run 1 joint at a 45* ..... 15* is max, for clearance issues.....

And the 15° allowance is for lower power/speed operations. If you have ever driven a straight axle 4×4 with 4wd engaged you would know (or learn quickly) that binding on the joints starts to try and rip the steering wheel out of your hands when you try to turn more 5~10°......

 

[fowler]

Silly american trucks

Thats why all other manufactures use birfeild joints

I can get both diffs locked in and turn full lock in my landcruiser
Lol

U can get 45 out if one

Pto shafts on tractors are a prime example

And they run at 540 or 1000rpm

 

[Scout]

Locked in like you have a selectable locker up front? or like a clutch type differential? There is a big difference between the two, and I doubt you can turn as well as you claim

 

[Scout]

U joints have one small issue, that is they slow down and speed up ever so slightly as they turn, and it gets worse the greater the angle. Birfs don't do that, but they are a little more complicated.

 

[fowler]

Locker as in e locker
Spider locked to diff centre

Would snap axles if I attempted it onroad

Relies on wheels spinning of course

Iv driven an old f truck a few times

Was a pig trying to turn in low range
With the old double carfield joints