Topic: Rear axle Question for Prepared Class (CP)

[westcoast racer]

Can a tech official please tell me if a quad axle is legal or not.  There is no suspension.  The center bearing housing mounts to the "original frame" as stated in the rule book.  It is a solid axle with hubs secured with a nut and cotter pin.  Here is a picture.

http://www.heymow.com/index.php?action=dlattach;topic=18911.0;attach=6166

If mounts go back to the top and side of the original frame as the rules state, can it be used?

I would like anyone else to give me their opinion.

Is it unsafe?

Does it give the mower enhanced performance?

[Jeff McKelroy]

Personally, It's better to have never asked the question, especially since it appears you have already built it.  But since you asked, I look at it this way:

1. Are there supporting bearings on either side of the frame?
2. Are there/is there supporting means to prevent rotation and separation from the mower frame?
3. I don't know if there's a power increase, but is there an increase in driveline efficiency?  Less is more.
4. How do you plan on connecting the rest of the powertrain to it?  RAGB's are not legal in C/P.
5. Is someone going to consider this a right-angle gear box?  It is, after all, a gear box?

I'm not a tech inspector by any means, but when we are checking mowers in, we look for a lawnmower driveline.  Even if there is no advantage (which I doubt), other racers will see that and declare it to be an unfair advantage.  So to keep peace, we probably won't allow that setup.

[westcoast racer]

Instead of the bearings being outboard and the sprocket and brake rotor being on the inside, they are in the center.  I am using a &00 tranny.  What was attractive to me about the axle was it was complete (bearings, sprocket, brake rotor, master cylinder, and hubs).  It was cheap ($75) and is strong.  I can find these all over the place from $150 on down.  They mount easy.  By how I was reading the rules, it's legal.

[BoNewCo]

Glad you are trying to get this issue resolved, Dan. As I have told you, my concern is that with the stock tapered axles, they are very narrow & the width cannot be adjusted. I realize that there is no minimum width but with your mowers being so narrow they tend to be very tippy. How wide are they? Also, I believe that they use 2 separate axles, not a one piece axle. Correct me if I am wrong.

[racinjason003]

I love that idea! Always cool to use what you have available. Most quads have 1 piece axles and you can upgrade to a longer axle. Also some places make different hubs to change the width. As far as being legal, I can't answer that, but still I like the thinking!

[Burwell555]

I don't see any reason as to why it would be deemed illegal as long as yu keep the wheelbase and mentioned and do not have working suspension. The only thing I would not like if I were in your shows is the weight of the axle itself. Their solid and heavier than a tube axle. Every building width adjustment or ride height adjustment would be out of the box thinking but definately doable off of the beaten path!! If your carrier bearing is set up like a honda 250r then you would even be able to adjust your chain without having an idler sprocket and still be quickly adjustable for gear changes at the track

[westcoast racer]

Both my mowers have quad axles.  They are 1 piece axles.  The one pictured here is from a 250R and the chain is adjustable without a tensioner as mentioned above.  The other is from a Chinese quad and I made the carrier pivot from the top with heim joints on the bottom for adjustment. The tapered axle doesn't worry me and I know it is actually stronger (I trust Honda Engineering).  I choose these axles because they are complete units with brakes and master cylinders engineered and designed to work they have splined hubs and sprocket carrier which are stronger then keyways.  

Bob, the width of Eric's is 37" with 6" wide tires , Shelby's is 40" with 8" wide tires.  They are more "tippy" because they are legal in rear tire size, width, length, frame height, and seat height.  I welcome anyone to tech these mowers.  They will pass with plying colors except for flywheel.  Since I don't run ARMA or USLMRA events, have never taken the flywheel off, or have the engine turn over 5000 rpm's, that's not a worry for me.  Hook the governor up and I can run the G/P class today.

[BIG AL 202]

THEY ARE DIFFERENTLY STRONGER! YOU COULD JUMP YOUR MOWER [I DON'T RECOMMEND IT]AND THAT WOULD BE THE LAST TO BEND! LOL GOOD IDEA!

[russell jennings]

i do tech at our track, i would let you run it, i would like to see alittle more support going from the swingarm to the mower frame tho. other than that good job getting it in there!

[westcoast racer]

i do tech at our track, i would let you run it, i would like to see alittle more support going from the swingarm to the mower frame tho. other than that good job getting it in there!

It is hard to see by this photo, but it has more support than what can be seen.  I may redo it to make it permanent.  Right now it bolts in place.  The second mower I built is permanent and is supported differently.