6 chain VS 4 chain Attex models

[jerseybigfoot]

I just put together a 4 stroke 18 hp ATTEX form a ST400 chassis in a Sportsman body.(GT2 trans) I used 1"ASTM A-108 Fatigueproof chromed rod material. 125psi minimum yield for the axles. I shortened the axles to keep the tires close to the body and used chevrons on 8" k rims. Ran all weekend @ Copper ridge with no problems. Pinned and welded the sprockets to each other and doubled the wall thickness on the left side center axle tube. The ST400 chassis allows the engine to sit under the rear cover without modification and still use rubber engine mounts.

[jpswift1]

I just put together a 4 stroke 18 hp ATTEX form a ST400 chassis in a Sportsman body.(GT2 trans) I used 1"ASTM A-108 Fatigueproof chromed rod material. 125psi minimum yield for the axles. I shortened the axles to keep the tires close to the body and used chevrons on 8" k rims. Ran all weekend @ Copper ridge with no problems. Pinned and welded the sprockets to each other and doubled the wall thickness on the left side center axle tube. The ST400 chassis allows the engine to sit under the rear cover without modification and still use rubber engine mounts.

Sounds like you did some serious work to that machine. I bet thats a nice rig! How many inches in did you move the axles by the way? I would imagine that being a little more narrow would help decrease the odds of bending plain jane cold rolled steel type axles. Could you post up some pics sometime too?

[hydromike]

I've only ever broken one axle, which was on one of the ST/400s. I've bent a couple axles, but for the most part it was going stupid-fast and going over obstacles with tires that were too hard. It's the axle bolts that tend to give up the ghost sooner, but I try to take it a bit more easy so I don't throw them to the 4-winds so soon. I started using grade 8's on the rear axle tubes, but the 503 ended up tearing the grade 8 bolt right through the axle tube. The bolt was bent, but the axle was fine. The axle tube was cut 3/4 of the way through. I only use grade 5's on both racers now. They're my fuses. Much easier to replace than axles, chains, sprockets, sprocket tubes or any of the other big components.

I'd love to go up to 1 1/4" splined axles, but it's not in the budget. For as often as I use my machines, the 1" puppies are still adequate if I behave myself. If I did this for money and had to win races, I'd find the cash fast, though...

[Don]

[QUOTE=hydromike;1068] the 1" puppies are still adequate if I behave myself. [QUOTE]

....and when did this behavior begin, Mike?


I've broken some axles, some from "stupid sticking", some because I used old axles, and some because I was using cold rolled (bend axle, straighten axle, repeat, repeat, axle breaks). I'll be using 4140 from now on, thanks to the information I got from the people on this board.

Whipper- Except for the cold rolled steel axles, they almost always break at the sprocket bolt in my experience. I've been using 3/8" grade eight bolts, and they still do shear, but it's usually a cleaner break and thus an easier fix than softer stuff.

As long as you're changing the drive train on your fire-breathing four-stroke Attex, are the old axle sets up for sale?

Don

[liflod]

I think I have broken 3 axles. I believe all of them were original. I replaced mine with 4140 CM. Mine broke at the hole also. I'm sure it has to do with the stress of bending put on it at that particular point over years of abuse. That could be improved by supporting the axle closer to the sprocket. I also think my first failure was due to improper chain tension (too tight). I have bent a few of the CM axles, but something has to give and usually the trees dont give. I liked the cold rolled axles that were on one of my machines, because you could just bend it back into shape by removing the wheel and smacking it with a 15lb sledge

[whipper-ag]

First off , Don, I'm so relieved that you change the material from this morning's post of 7170 to 4140. I spent a lot of time stumping some big steel companies today asking about 7170. I thought it was some new chryptonite material. With that much carbon in it, it probably would break if you dropped it on the ground. I knew it had to be a typo. Funny how this thread went from 6 chains vs 4 chains to axles. I know most everyone knows this, but it might be helpful to those that don't know about a body bound bolt. One of the reasons most people shear a bolt or break an axle where the bolt goes thru the sprocket tube is because the hole is drilled too big and no matter how tight you get that bolt, eventually the tube will rock back and forth and shear the bolt or break the axle, whichever comes first. A good remedy for that is to get a longer bolt with a longer shoulder. Make sure the shoulder of the bolt is long enough to go all the way thru the axle tube. You may have to shorten the threads on the bolt. (ex. the shoulder of a standard 3/8 bolt is
.370 and the threads are even smaller. The hole should be drilled with a 23/64 drill (.3593) . Reem the hole thru the axle tube & axle at the same time with a .370 reemer. If you don't have one, you'll have to buy one. The hole has to be the same size as the bolt. That is known as a body bound bolt. Because everything is so tight, it won't rock back & forth and wallow out the hole. If the hole is right, you'll have to hammer the bolt thru because it's size on size. Of course if you're running 1" axles, you can't do a repair by going to a bigger bolt. It just weakens the axle more at the hole. If you have the room, 2 body bound bolts per axle is even better. It will also help with hollow axles. Use a jam nut so it won't loosen up. Everything I've said is null & void, if you hit trees, trailers & big rocks.
While we're now on the subject of sprockets, just a reminder that if you're making your own sprocket tubes or buying them, make sure they're not farm sprockets. Get good flame hardened sprockets. Nothing ruins a chain faster than a soft sprocket that's lost it's form. That's all I gotta say about that.
So what do you all think about O-Ring chain?

[Don]

Not so much a typo as having bad numbers in my head, but thanks, Whipper.

I found out through trial and error that buying bolts the right length with threads that continued past the axle tube was not a good idea. They almost always broke right at the end of the threads. I started buying overlength bolts and cutting them down, and that cured it. Same deal with the ag sprockets- you can get them dirt cheap, but you get what you pay for. I've found some weren't even concentric with the center drilling.

[jpswift1]

Hey guys, on my ST/295 frame (4 chain) I was missing an idler sprocket and I got one that fit that was off a 400 Chief frame and it had a couple more teeth than the 295 sprocket. I would think that its OK to use this, I just might need a slightly longer chain or have to adjust my tensioner to compensate for the extra two teeth or so on the idle sprocket on that side, but what would you guys think?

[whipper-ag]

It's OK to use it's just an Idler, it can be any size. Just add a link or two, I would make sure the teeth are flame hardend.

[jpswift1]

I just had to resurect this older post because I had a few questions about those 4140 axles for the Attex. About how much would each axle cost to be made? Also, would you guys recomend shortening each axle about 1/2" to 1" to bring the wheels closer to the frame/body and take some stress off the axles?

[George]

would you guys recomend shortening each axle about 1/2" to 1" to bring the wheels closer to the frame/body and take some stress off the axles?

I was thinking of doing the same thing Jeff. I don't see how it could hurt. I would imagine the gain in strength would out weigh the loss in wheel base.

[jpswift1]

Gerorge, did you ever try the 4140 axles or speak to anyone that has? If they're not that much more than the standard cold rolled axles I would go for them in a second.

[George]

Gerorge, did you ever try the 4140 axles or speak to anyone that has? If they're not that much more than the standard cold rolled axles I would go for them in a second.

I've only used the cold rolled. I've heard that one of our friends had some custom super axles made....guess I had a hand in that decision.

[whipper-ag]

I was thinking of doing the same thing Jeff. I don't see how it could hurt. I would imagine the gain in strength would out weigh the loss in wheel base.

Guys, Quite honestly, I don't think you'd want to move the tires in. First, by narrowing your wheel base, it would just make it easier to roll over, second, moving it one inch is not going to make it any stronger, because even if your tire hits something, it will still bend. You need an axle made out of better material for strength. 1018 cold roll & 1020 dom tubing is not the best material to use for an axle. Most people use it, including the manufacturers , because it's cheap. I'd hate to see you spend money to do what your talking about & then be disappointed. I would recommend using the 4140 pre-heat treated TGP (TURNED, GROUND & POLISHED) . The finish size of 1 1/4" TGP would be 1.249 -1.2495 & the bearings would slide on perfect. If your axles need to be splined, well, you know who can do that. I can't quote axles unless I know exactly what you need. Ex. diameter, splined, solid, location of holes, wheel hubs? Anyway, better material is the answer, not shortening the axles.
Whipper

[Roger S]

Whipper, have you seen any 1.25 axle material with a small hole through the axis? I was thinking about on the fly/driver adjustable tire air pressure.