Viper STX live axle conversion / Help

[OzFab]

I'm modifying the existing frame. The subframe will reduce the overhang and produce a symmetrical chassis. I think this is the easiest way for me to perform the mod.

Ok, now I'm confused, are you modding the existing frame or simply adding a new rectangle frame to the top of it?

10" is my initial guess and is not written in stone. Currently I have a 66T, which OD is just 7 1/4". 72T OD is less than 9". I'll take your and Half-Breeder advise into consideration. Thanks!

One thing Tihm didn't mention, you may have enough space within the frame to fit the sprocket & a brake disc, you may have enough width to hold the engine BUT, where does the chain run in relation to the front end of the frame?

 

[fodio]

Ok, now I'm confused, are you modding the existing frame or simply adding a new rectangle frame to the top of it?

I'll add a new rectagle frame under the rear end of the original frame. See attached image.

One thing Tihm didn't mention, you may have enough space within the frame to fit the sprocket & a brake disc, you may have enough width to hold the engine BUT, where does the chain run in relation to the front end of the frame?

My initial idea is to center the engine in relation to the rear end. As a result the sprocket/chain will run 4" (10cm) aprox left from the rear end center.

Is that fine? Could you sugest something better?h

 

[Half-breeder]

IMHO... I'd do things like(the attachment)... and have plenty support/clearance for everything(even a TC in the future) aswell as a place to mount the brake caliper for disk brakes. Plus sliding the CoG up more for firmer turns(if there is enough caster present/built-in).

 

[OzFab]

That's exactly the way I was thinking of doing it, thanks for the pic, Tihm

The rear axle could, maybe, move forward a bit though...

 

[fodio]

IMHO... I'd do things like(the attachment)... and have plenty support/clearance for everything(even a TC in the future) aswell as a place to mount the brake caliper for disk brakes. Plus sliding the CoG up more for firmer turns(if there is enough caster present/built-in).

That's exactly the way I was thinking of doing it, thanks for the pic, Tihm

The rear axle could, maybe, move forward a bit though...

Thanks to all the contributors! Great ideas and interesting discussions.

I'll start the mod with your last input and I'll be sharing pictures of the progress.

Once again thanks!

 

[fodio]

Step 1: cut 2 24"x1" and 2 13"x1" square tube
Step 2: drill 1/2" hole to attached pillow block bearings

Next steps: (some initial ideas) pre-assemble axle to confirm positioning, weld rectangle, remove engine support & old axle, attach rectangle to frame (welded), weld engine support in new position, install brakes & engine & axle, test and paint

 

[OzFab]

You did put spacers inside the two side rails, didn't you? If you tighten the bolts as it is, you will crush the tube...

 

[fodio]

Step 3: engine and wheels removed.

 

[fodio]

Step 4: remove engine support and old axle (interrupted by a football (soccer) match.

 

[fodio]

You did put spacers inside the two side rails, didn't you? If you tighten the bolts as it is, you will crush the tube...

Thanks for the advise. I haven't put spacers yet. My initial plan was to use only flat and pressure washers. The bolts are 1/2".

What kind of spacers should be used? (ie piece of tube)

 

[OzFab]

What kind of spacers should be used? (ie piece of tube)

Yep. 1/2" thick wall pipe will be perfect (pipe is measured by the inside diameter); cut 4 lengths short enough to fit inside the tube, slide them into place & put the bolts through; if you don't want them to move, drill a 1/4" hole adjacent to the bolt hole & weld the spacer to the frame...

A simpler option is to weld on a length of angle & bolt the pillow blocks to it...

 

[fodio]

Yep. 1/2" thick wall pipe will be perfect (pipe is measured by the inside diameter); cut 4 lengths short enough to fit inside the tube, slide them into place & put the bolts through; if you don't want them to move, drill a 1/4" hole adjacent to the bolt hole & weld the spacer to the frame...

A simpler option is to weld on a length of angle & bolt the pillow blocks to it...

The rectangular subframe is already welded. There is no way to place spacers inside, the entry is blocked by the other tube. (Left image)

Could you clarify the angle option? It is to add an angle section to reinforce the tube? (Right image)

 

[OzFab]

No no, weld the angle to the side of the tube with a flat facing away from the tube, then bolt the pillow block to the flat...

Obviously, I have only illustrated one side...

 

[fodio]

No no, weld the angle to the side of the tube with a flat facing away from the tube, then bolt the pillow block to the flat...

Obviously, I have only illustrated one side...

Your concept is clear but I cannot implement it right now (I don't have 1" angle // cannot insert the 1/2" pipe).

The wall of the 1" square tube I'm using is thick enoguh and also I'm using thick flat washers.

I installed the pillow blocks and there is no deformation in the tube. I'll test it, if it fails I'll implement your recomendation.

 

[fodio]

Step 4: remove engine support and old axle (interrupted by a football (soccer) match.

Step 4: completed (BTW my team won 2-0)

Step 5: assembly the axle, pillow blocks, wheel, sprocket and subframe. Verify position in the chassis (this is key for engine position). Subframe not welded yet

 

[fodio]

Step 6: bench testing (rear wheels not touching the ground)
Step 7: subframe welded.
Step 8: brake assembly attached to chassis


Pending: axle locking collars (I forgot to order them), install motor, brake and throttle links.