Viper STX live axle conversion / Help

[fodio]

The parts just arrived. The first picture shows: 1" x 36" axle, 2 rim halves, sprocket hub and pillow block bearings.


My concern is the lenght of the axle ends if I attached the pillow block bearings directly to the chasis as it is today. Left side will be 7" and rigth side 9.5" from the edge of the chasis to the middle of the wheel. This situation could lead to a bend axle.

Could someone confirm if the axle is strong enough or should I modify the chasis to reduce the length of the axle ends?

 

[landuse]

A 1" axle will be strong enough

 

[Half-breeder]

The axle should be fine... just make sure its centered, as in the frame sets in the middle of the axle. Hope you got some locking collars too.

 

[rmm727]

Let me see if I understand you correctly. You had 4 complete Azusa Tri Stars that are setup for bearings. You bought 1 Tri Star rim for a 1" axle. You're going to mix and match the two types so the inner rim half is keyed to the axle and the outer half has a bearing to slip over the 3/4" threads on your axle?

 

[OzFab]

As long as you don't go driving on some rough trails or jump any kerbs, you should be ok...

My question is why is the axle off centre?

Left side will be 7" and right side 9.5" from the edge of the chasis to the middle of the wheel.

 

[itsid]

the first question that's popping into my mind is..
why did you get a 36" axle and not a 34" or even the 30" axle if the overhang is a concern.

And while I fully agree with what's already said (it shouldn't be a problem on asphalt roads) instead it should at worse provide some rudimentary suspension if you got a flexpruf axle...

But I want to add, that ideally you want the axle supported as close to the wheel as possible! to prevent bending the axle on a rough bump along the way.
(which is where the 30" axle would have been the wisest decision IMHO)

Anyways, that chicken crossed the road I guess, so it's either using what you got and hope there is no hard bump (curb, pothole etc.) that may be bad enough to damage your axle..
or make the decision on either adding axle support frame structures or gettting the shorter axle. *shrugs*

again.. just my humble opinion

'sid

 

[fodio]

Let me see if I understand you correctly. You had 4 complete Azusa Tri Stars that are setup for bearings. You bought 1 Tri Star rim for a 1" axle. You're going to mix and match the two types so the inner rim half is keyed to the axle and the outer half has a bearing to slip over the 3/4" threads on your axle?

Azusa Tri Star rims for live axle are composed by one keyed half and one half with bearing. I'm following Azusa's technical advise, so I bought 2 keyed halves since I already have enough bearing halves.

As long as you don't go driving on some rough trails or jump any kerbs, you should be ok...

My question is why is the axle off centre?

The Viper STX is a rectangular chassis but in the left rear side has a sort of extension to support the engine. The axle will be aligned to the center of the main part of the chassis.

the first question that's popping into my mind is..
why did you get a 36" axle and not a 34" or even the 30" axle if the overhang is a concern.

And while I fully agree with what's already said (it shouldn't be a problem on asphalt roads) instead it should at worse provide some rudimentary suspension if you got a flexpruf axle...

But I want to add, that ideally you want the axle supported as close to the wheel as possible! to prevent bending the axle on a rough bump along the way.
(which is where the 30" axle would have been the wisest decision IMHO)

Anyways, that chicken crossed the road I guess, so it's either using what you got and hope there is no hard bump (curb, pothole etc.) that may be bad enough to damage your axle..
or make the decision on either adding axle support frame structures or gettting the shorter axle. *shrugs*

again.. just my humble opinion

'sid

I understand your point. The rear end is too narrow and I had rolled over twice...a wider axle should prevent roll overs.

My original idea was to modify the rear end of the chassis to make it wider and symmetrical. But before starting the mods, I wanted to have your comments and advice.

Thank you all for your feedback. You helped me to confirm the required mods.

I'll send pictures of the conversion.

 

[OzFab]

The Viper STX is a rectangular chassis but in the left rear side has a sort of extension to support the engine. The axle will be aligned to the center of the main part of the chassis.

My original idea was to modify the rear end of the chassis to make it wider and symmetrical.

Sounds like a plan buuuut,

But before starting the mods, I wanted to have your comments and advice.

to do it properly, you'll need to replace the side rail & the rear crossmember

 

[fodio]

Sounds like a plan buuuut,



to do it properly, you'll need to replace the side rail & the rear crossmember

I'll draw some options for the chassis mods taking your comments into account...

 

[rmm727]

Azusa Tri Star rims for live axle are composed by one keyed half and one half with bearing. I'm following Azusa's technical advise, so I bought 2 keyed halves since I already have enough bearing halves.

Didn't know both sides of the rim weren't keyed. Learn something new every day.

 

[fodio]

Didn't know both sides of the rim weren't keyed. Learn something new every day.

Part numbers for live axle:
With Steel Insert-1" to 3/4" Step, 1/4" Keyway 1117
Half With Steel Insert 1" ID, 1/4" Keyway 8009
Half With 3/4" Bore 8011

1117 is composed of one 8011 and one 8009.

 

[fodio]

The drawings show the original asymetric rear end (left one) and my proposal to make it symetrical (on the right).

The idea is to add a 24"x10"x1" rectangular frame to install the pillow block bearings that support the 1"x36" axle. This will reduce the overhang.

I'll also move the engine from the left side to the center of the chassis.

All your comments will be appreciated.

 

[Half-breeder]

I more than understand the widening of stance for a stabler base! I can see that working well, but... remember that sprockets and brakes take up space, be sure to leave yourself room for sprocket/brakes and 'possible' alterations for the future if need be(larger diameter sprocket/breaks). If you set the axle clearance at a distance that only 1 type of gearing can be achieved, then for future tense, if youre wanting to gain torque(by gearing), a JS unit will have to be implemented... and those are always annoying! The main reasoning for down gearing in the future... what if you get a larger tire/wheel? A probable gearing change 'may' be wise/needed. My previous setup was set in stone, asfar as gearing, due to clearance(9T-45T), I literally only had a matter of a few cm's between the gears teeth from contacting each other(but I never had/have plans on slowing her down via that drive setup).

IMO... Im hoping that your wheel tracking will be overlapping still(rear wheel path overlaps front wheel path going straight). If the track of the rear is 'too' far out from the track of the front, steering could become 'laboriously' difficult(may have to slow way down... just to turn... like a 3 wheeler).

 

[fodio]

I ... remember that sprockets and brakes take up space, be sure to leave yourself room for sprocket/brakes and 'possible' alterations for the future

Thanks! I'll double check the 10" dimension planning for the future.

IMO... Im hoping that your wheel tracking will be overlapping still...

There will be just 0.75" overlap in each side since it was wider in the front. What is the minimum recommended overlap? Once assembled I'll test it and can perform a mod in the front end if required.

 

[OzFab]

You already have an intermediate crossmember, why would you not simply extend off that?

Remember, KISS

Using the intermediate, you can repurpose most of the existing material (rear axle becomes the new rear crossmember, existing crossmember becomes the new right side support...), then mount the new axle where the existing one sits...

 

[fodio]

You already have an intermediate crossmember...

I already have enough 1" square tube and want to minimize welds on structural parts.

Using the intermediate, you can repurpose most of the existing material ...

I'll use most of the removed material.

 

[OzFab]

I already have enough 1" square tube and want to minimize welds on structural parts.

I can understand that but, I'd rather make a few more cuts & have a better chance of the frame holding together, rather than adding to an existing length & having the join break...

Sometimes, a little extra work can be the difference between life & death...

 

[fodio]

I can understand that but, I'd rather make a few more cuts & have a better chance of the frame holding together, rather than adding to an existing length & having the join break...

I'm confused now. I don't plan to extend any segment existing by welding material using just the section as point of contact (ie make a 12" segment by joining an 8" and a 4" segments)

My idea is to build a brand new 24"x10"x1" rectangle, pillow block bearing will be attached to the 10" segments.

The rectangle will be welded to the chassis with at least 4 points of contact (could be more depending on the position).

Could you please clarify?

 

[OzFab]

Well, now that you have...

I was unaware you were adding a whole new subframe (my first question is why?) I was referring to modifying the existing frame...

with Tihm (half_breeder) 10" is not enough, that's the basis of my suggestions...

 

[fodio]

I was unaware you were adding a whole new subframe (my first question is why?) I was referring to modifying the existing frame....

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.

with Tihm (half_breeder) 10" is not enough, that's the basis of my suggestions...

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!