Chain Drive Drop Box

[78Jimmy]

I'm looking into using a chain drive box, instead of a tcase. As my angles are to much for a normal drive shaft. So this is my problem.

What would be a recommendation for a shaft..

what this will do, for those that don't know, is: Your tranny will input into the top shaft, held to the frame by pillow blocks, and in the middle have a gear. Below, there will be another gear used to reduce for the 2:1 or 3:1 or 10:1 if I chose, held on by a shaft, and pillow blocks.

I'm thinking of cold rolled for the shafts, but don't know enough about steel for a educated guess. Help

Thanks.

[Dopey Joe]

You talking about using this setup in a buggy or a dedicated trail rig, mud bogger or such?

[78Jimmy]

You got it.. If I do need to use it for on the road, I'll just drop the chain box, and run it in 2 wheel..

This will be a strickly offroad application..

[smalltruckbigcid]

Steel types really vary...but I would recommend "Stress Proof" shaft. Its a hardened alloy but $$$$. You can get away from the exotic alloys by increasing the shaft diameter but how much room do you have? What size and type of chain do you have in mind? Remember that dirt is not your friend on this kind of setup, mud is a great abrasive and will give lots of slop in the chain FAST. This will be high maintenance and have a herky jerky acceleration/decceleration. And a couple of other things...this will eat fuel and limit your speed to like about 30 mph max. Chains don't like real high speeds, except under certain conditions like t-case chains or timing chains...clean with lots of oil. Good luck but I think your asking for more problems than you want
George

[Dopey Joe]

A lot of trail only rigs will never see 30 mph...

A chain drive in and of itself should not be too ineffecient.

I *think* he's talking about some sort of enclosed setup. You could build it to be wheatherproof/watertight if you put the effort into it and run lube inside as well.

For a trail only rig (think buggy) you should be able to make it work acceptably if you build it smart. It's probably havesome down sides, but I can see some upsides too.

[78Jimmy]

I've seen many guys running them in the mud drags, so they shouldn't be too bad. I'm planning on Double 60 chain, and gear setup. I was thinking 1" - 1.5" shaft size. Probibly 12 or 13 teeth primary gear, and 24 - 30 on the secondary, but that will depend, I forget the gear diameter at the moment, I'll try to reduce the primary if possible..

I've heard of some guys running 3/4" shaft, but it sounds a little light for any duration of driving.

As long as the chain is kept tight, there shouldn't be any slope in it, I'm currently planning on using shims to maintain tension, and might incorporate an oiler setup down the road. If this works out and seems to be what I want to run.

[HeavyMetal]

Lots of Guys use them in Mud Drags (actually most of them that are really into it have chain drive...Less cost and maintnance))
Have a buddy that has built two different Monster Trucks with them...Work well with a 1800 HP Motors behind them...Also one of the has seen well over 70 + mph so I don't think speed is an issue...

For something that was for trail only and you didn't need 2 different ratios ( high/low ratio's) I think it would be the way I would go...

[78Jimmy]

It's just the shaft that I'd not to sure about, what do I get? or just ask the guys at the metal yard..

[smalltruckbigcid]

If they have it try 4340. I've been told that most cold roll does not heat treat very well, no personal knowledge or experience. The biggest headache will be chain tension...in both directions of rotation. Oh the 4340 is already heat treated and is fairly machineable. Good luck.
George

[78Jimmy]

Is there any real difference in the type of gears used? They all look the same, all see to be capable of 60 or 80 chain, is there anything I should look for?

I'm currently thinking of standard 60 gears, with weld on hubs, put a spacer, and run another on the shaft so that I can use db 60 chain.

Pillow block->Shaft->hub->Gear->Spacer->gear->hub->shaft->pillow block

Then attach a yolk on each end. Haven't decided if it will be key'd or welded..

[Logjam]

Use 80 pitch.

You need two flange bearings for each shaft. Surplus center has them for about $8 for 1.5" shaft. They also have 80 pitch sprockets for $19, and chain for $4 a foot.

Originally Posted by 78Jimmy

Is there any real difference in the type of gears used? They all look the same, all see to be capable of 60 or 80 chain, is there anything I should look for?

I'm currently thinking of standard 60 gears, with weld on hubs, put a spacer, and run another on the shaft so that I can use db 60 chain.

Pillow block->Shaft->hub->Gear->Spacer->gear->hub->shaft->pillow block

Then attach a yolk on each end. Haven't decided if it will be key'd or welded..

[78Jimmy]

What is the difference between the 60 and 80 pitch? and what does pitch refer to..

So for the questions, I know what they are roughly, just not specifics..

[Logjam]

Pitch refers to the spacing between links and the strength of the chain. 80 pitch is so cheap it just makes sense to use it.

Do you realize that if you want 10:1 with two sprockets, then you'd have to have a sprocket with 10x more teeth?

Also, the smallest sprocket will limit strength. If your input sprocket has a raduis of 3.5", and a 80 pitch chain has a tensile strength of 3500lbs, then 1000lbs will snap it. (foot lbs/radius/etc)

You're best bet is to use a series of 11 tooth to 21 tooth sprockets from surplus center. At $4 a foot, chain is a consumable item. The coser the flange bearings are together, the less exotic metal needed for the shaft. I'd use 1.5" mild steel. Its not going anywhere...before the chain...

[Logjam]

A 112 tooth 80 pitch sprocket weighs 170lbs and is 36" diameter. Speed holes would make it lighter.

A 12 tooth 80 pitch sprocket weighs 3lbs, and is 4.33" diamter.

2.15" radius on the 12 tooth.

Spicer sells 1310 and 1350 yokes with a 1.5" round bore. They are in stock in anchorage. Just weld the things on.

[78Jimmy]

How would a d80 effect the numbers then, would I have twice the tensile strength, of the s80.. I know it doesn't usually end up that way, but thought I'd check..

[Logjam]

Close to twice, but not quite.

Check prices at Alaska Bearing. Buying new-brand hurts big time. Surplus center is your friend.

Double 60 is about as strong as 80 single. American Name brand chains can be MUCH stronger than import chains.

Keep your reduction down to below 3:1 in chain. Put a 2wd transmission in the truck and run a divorced 205 behind it. I know of a few chevy divorced 205s selling for around 175.

Chain can be considered a consumable item if its only $40 for 10 feet.

[78Jimmy]

Thanks for the lesson.. lol.. Good information to know.

Well, I'm probibly not coming up to Alaska to pick up my parts, but I appreciate the offer.. I'm over in Canada, so I'll see what I can find local..

I'd like to run a 205 but driveline angles don't permit, so chain drop it is.

Which would you recommend, press fit, or welded onto the shaft.

What I was thinking is runing a weld gear and hub single, then place a spacer and a second gear and hub, aloting for the d80 wide. Would this be as strong, or just alot more hassle..