Since chain has such a high efficiency transfer rate, you might just want to consider 6 chains.There is one drawback to the 4 chain Attex, break the rear chain and your dead in the water. Or loose control of the car. If you loose the front or rear of the 6 chain, you can take it off and gimp back to the trailer on 5 wheels. eveyone gets to do that sooner or later.
Good point Whipper. This reminded me that I forgot another axle tube. My ST/400 ripped the drive sprocket on a center axle tube right off the tube, which made me loose all power to that side and I couldn't brake, either since the T-20 band wasn't really grabbing anything as the rest of the sprocket tube spun happily around as I ran into Liflod's trailer last year at CR. I wasn't thinking fast enough to hit the foot break.
This isn't a characteristic specific to the 4 or 6 chain machine; either setup would have the same result. Just a silly story...
~M
The first time I had my Attex in the creek, I managed to break the rear axle. This bound the only drive chain on that side. I had to remove it so the machine would roll. If I had the 6 chain set up, I could have at least driven the front 2 axles.
I learned later that I could have used the outer piece of the axle , which was long enough, to support the sprocket tube enough to get power to the front 2 axles.
I have also broken an axle tube after I broke an axle. You can reuse the sprocket by grinding the weld flush with the sprocket and use a press to press out the remaining sprocket tube.
Mike , thanks for reminding me about the foot brake. I don't have one yet on my Attex.I should have one or some day I'll be tumbling out of control like Apollo 13. I'll have to put that at the top of the list of things to do. You guys sure seem to break a lot of axles? Are you still running 1" axles? Thats why I coverted mine to 1"1/4, Do they usually break where the hole goes through the sprocket tube? What size bolts do you use? What kind of steel do you use? Have I asked enough questions? I've been making axles for high performance sand cars and trophy trucks for years, I might be able to help if you'd like a better axle.Let me know.
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?Originally Posted by jerseybigfoot
"Looks like you have a problem with your 4 wheeler........you're missin' two wheels there"
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...
Last edited by hydromike; 07-25-2007 at 09:12 AM. Reason: I spelled "ghost" wrong the first time... what an idiot..
[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
Last edited by Don; 07-25-2007 at 12:41 PM.
Stuck in the seventies- not in the swamp.
(6) Attex, a Hustler, a Super Swamp Fox, (2) Tricarts, (3) Tri-sports, a Sno-co trike, 3 Dunecycles, and a Starcraft! ...so far
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
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