Thread: D2 Diff into a RRC

Originally Posted by Vern

I highly doubt you would break either of those axle combos.
Its a tough call. Some of the way guys treat 30/30 combo on comp rigs running bigger than 37's and generally a cv lets go first. But they are bouncing on the rev limiter.
Not sure how you plan to treat this car you have built though

Sometimes you have to drive hard, but not crazy, I want to do hard tracks and get home, and also dont want to break things going up very steep hills, very dangerous.

Im talking to Jac Mac and Arnold next week so will report back, also speaking to Outcast who are very helpful.

Having read this from go to whoa, I'm still unsure of a couple of things, because too many variables and no confirmed baseline.

So let's establish one, and you can annotate differences, so everything is clear as crystal.

1. Rover housing - RRC / D1
2. ARB / TJM carrier, with 30 spline sun gears
3. Aschcroft crownwheel / pinion set, pegged housing.
4. Housing (standard Rover, not a hi-9?)
5. Axles - not yet defined, but 30/35 sp appears to be desired.
6. CV's are either longfield toyo or ashcroft - not yet defined
7. Drive flanges are matching whatever spline comes out at the end.
8. Spindles - possibly custom to fit larger diameter cv shaft
9. Brakes - not defined.


Despite all the possibilities and permuations / combinations, and your outspoken stated desire to 'build it tough' You still need to design in a point of failure (the engineer in me speaking)...

Why?
Simple: Because if it does happen to break (eventually something will) you want the bit that breaks to be:

a) readily available - i.e. off-the-shelf
b) inexpensive
c) not time consuming or difficult to replace.

Now while I understand all the discussion around the combinations is about bang for buck and seriously tough hardware, I'm not sure that enough thought has gone into those last 3 points.

For this reason alone, I would:

1. concentrate the single point of failure to the drive flange if possible, or the CV at next 'worst case'

2. Use proven redily available parts which do not require any form of modification to any portion of the axle assembly as a whole.

3. try to keep the cost to the minimum.


So that would apparently leave you with some pretty bland offerings -

a) braced rover housing
b) strongest available locking centre - detroit locker, Ashcroft locker, ARB air locker... Eaton e-locker (heard some strange things about warranty with harrop)
c) Hi-tuff axles & MD drive flanges
d) CV - would have to be ashcroft in this instance, unless you want to specify the CV as the break-point, in which case you need some sort of 300M fabricated county-style CV, and stub axles to match.

Or, you can look at something more along the lines of your rear setup, with a hi-9 and all the funky bits, but having to fabricate / modify swivels, hubs to fit the required components.

Personally from the way I'm reading your thoughts in the posts, You're not going to be entirely satisfied unless you've spent an obscene amount of $$$$ on a front end which you're not even going to approach 10% of the design limits with the existing powertrain in the vehicle.

And that's all good - I'm always up for engineeing overkill, I do it myself all the time, but - I am definitely not a fan of setting myself up for additional excessive delay and expense should the subcomponents fail.

So in essence, what I'm saying is that selecting components that are more readily available, which will be more than adequate for the situation and are competitively priced, as well as being of renowned quality - would be the ideal solution.

I'm just not sure that this theory fits with the discussion you've been entertaining.

Personally I can't see a problem with a rover housing, stuffed full of 300M axles, cv's and drive flanges, with a pegged hi-9 or aschcroft geared centre and choose whatever locker best suits your fancy.

Even then, You still have other things to worry about.

But I'd still be building in the single point of failure - aka 'fuse' at the drive flange or CV. because they are easily carried as spares and can be changed over reasonably quickly.

Would be interesting to know if I have misunderstood the underlying philosophy or not. Let me know what you think, or if I am way off-track.

Originally Posted by Mercguy

Having read this from go to whoa, I'm still unsure of a couple of things, because too many variables and no confirmed baseline.

So let's establish one, and you can annotate differences, so everything is clear as crystal.

1. Rover housing - RRC / D1
2. ARB / TJM carrier, with 30 spline sun gears
3. Aschcroft crownwheel / pinion set, pegged housing.
4. Housing (standard Rover, not a hi-9?)
5. Axles - not yet defined, but 30/35 sp appears to be desired.
6. CV's are either longfield toyo or ashcroft - not yet defined
7. Drive flanges are matching whatever spline comes out at the end.
8. Spindles - possibly custom to fit larger diameter cv shaft
9. Brakes - not defined.


Despite all the possibilities and permuations / combinations, and your outspoken stated desire to 'build it tough' You still need to design in a point of failure (the engineer in me speaking)...

Why?
Simple: Because if it does happen to break (eventually something will) you want the bit that breaks to be:

a) readily available - i.e. off-the-shelf
b) inexpensive
c) not time consuming or difficult to replace.

Now while I understand all the discussion around the combinations is about bang for buck and seriously tough hardware, I'm not sure that enough thought has gone into those last 3 points.

For this reason alone, I would:

1. concentrate the single point of failure to the drive flange if possible, or the CV at next 'worst case'

2. Use proven redily available parts which do not require any form of modification to any portion of the axle assembly as a whole.

3. try to keep the cost to the minimum.


So that would apparently leave you with some pretty bland offerings -

a) braced rover housing
b) strongest available locking centre - detroit locker, Ashcroft locker, ARB air locker... Eaton e-locker (heard some strange things about warranty with harrop)
c) Hi-tuff axles & MD drive flanges
d) CV - would have to be ashcroft in this instance, unless you want to specify the CV as the break-point, in which case you need some sort of 300M fabricated county-style CV, and stub axles to match.

Or, you can look at something more along the lines of your rear setup, with a hi-9 and all the funky bits, but having to fabricate / modify swivels, hubs to fit the required components.

Personally from the way I'm reading your thoughts in the posts, You're not going to be entirely satisfied unless you've spent an obscene amount of $$$$ on a front end which you're not even going to approach 10% of the design limits with the existing powertrain in the vehicle.

And that's all good - I'm always up for engineeing overkill, I do it myself all the time, but - I am definitely not a fan of setting myself up for additional excessive delay and expense should the subcomponents fail.

So in essence, what I'm saying is that selecting components that are more readily available, which will be more than adequate for the situation and are competitively priced, as well as being of renowned quality - would be the ideal solution.

I'm just not sure that this theory fits with the discussion you've been entertaining.

Personally I can't see a problem with a rover housing, stuffed full of 300M axles, cv's and drive flanges, with a pegged hi-9 or aschcroft geared centre and choose whatever locker best suits your fancy.

Even then, You still have other things to worry about.

But I'd still be building in the single point of failure - aka 'fuse' at the drive flange or CV. because they are easily carried as spares and can be changed over reasonably quickly.

Would be interesting to know if I have misunderstood the underlying philosophy or not. Let me know what you think, or if I am way off-track.

Hi,

Thanks for your well thought out and helpfull reply.

As said previosly this is where i'm at..

"At this stage its looking like the following in the stock RRC front housing

Off the shelf 30 spline side gears on an ARB or TJM prolocker and pegged Ashcroft CW&P
30spline Hi Tough Axles
30/30 Toyota longfeilds
30spline 10bolt Hi Tough Flanges

Other option is to use a 9" 31 or 35 spline centre in the rover housing (can be done) then go to 30spline on the outer, i just dont think going to the 9 on the front will be needed over all the 30spline gear as above"

The rest of the truck and driveline are very strong.

Meeting with a few shops this week


Have also addressed the weak link argument previously, I preffer to build my trucks strong enough to handle my driving style, and if something does go i will uprade it not replace it.

I really dont understand what you mean by the 10% comment or the I wont be satisfied until i spend big dollars comment??

This is being done because its needed and I dont intend on wasting money, just spending what i have to, to get the job done right.

30 Spline in a Rover coiler housing is not something new, its just not available anymore off the shelf as a kit anymore, its relatively easy if you use a shop that has done it before and know where to source the components from.

Will report back

What I implied by the 10% comment was the intention to build something that is absurdly strong, which (let's face it will cost an arm and two legs) will at the end of the day have a 90% reserve capacity of tensile / fatigue / compression strength. All this 'unused potential' which loosely translates to 'overspend' or as some would say 'unnecessary waste of funds'.
That is not to say it is not fit for purpose, but rather is wildly superfluous to requirements.

I had this huge long-winded reply, which I just cut, because I can probably do a better job without going into detail.

I fully understand what you want. My only query in the previous post, was 'so many available options' but 'at what real cost' and just how much of a safety margin do they provide for that cost.

And, is the additional work required, to make a set of huge axles fit, worth the expense? a pair of 24 spline 300M treated axles are incredibly strong.

But.... (as I wrote in my absurdly longwinded reply) If you have done the math, and you know what your max tq figures are in low and high range and at peak tq rpm, do they fall well within the material specifications for each component in the drivetrain? and are your tyre diameters also taken into account?

I wrote a physics paper in my other reply. I'll try not to crap on about it. I'll just ask if you have calculated those figures or not. If you have, you can very easily and clearly determine what axle spec, diameter and material, spline count etc is req'd. same for cw&p, locker, cv/s etc..... So you can factor in the cost versus safety margin you require.

My only concern was that potentially your combination of parts may not all be within the same margin of overhead, and could possibly leave you with a weak point, that may become the failure point - if - the safety margin is not 'enough'

Anyway, it sounds like you are on a path where you can choose from a selection of reliable commercially available parts which will provide you with the strength and reliability you need.

Let us know how it pans out. I'll be interested in how the build progresses. I had a desire for a hi-9 purely for the raised pinion, to provide better driveshaft angles, but the costs are prohibitive for a single net gain in my case.

In yours, I think you have more to gain with a carefully well-matched specification which has a reasonable margin of 'safety' above the max tq figure of your drivetrain.

Originally Posted by Mercguy

What I implied by the 10% comment was the intention to build something that is absurdly strong, which (let's face it will cost an arm and two legs) will at the end of the day have a 90% reserve capacity of tensile / fatigue / compression strength. All this 'unused potential' which loosely translates to 'overspend' or as some would say 'unnecessary waste of funds'.
That is not to say it is not fit for purpose, but rather is wildly superfluous to requirements.

I had this huge long-winded reply, which I just cut, because I can probably do a better job without going into detail.

I fully understand what you want. My only query in the previous post, was 'so many available options' but 'at what real cost' and just how much of a safety margin do they provide for that cost.

And, is the additional work required, to make a set of huge axles fit, worth the expense? a pair of 24 spline 300M treated axles are incredibly strong.

But.... (as I wrote in my absurdly longwinded reply) If you have done the math, and you know what your max tq figures are in low and high range and at peak tq rpm, do they fall well within the material specifications for each component in the drivetrain? and are your tyre diameters also taken into account?

I wrote a physics paper in my other reply. I'll try not to crap on about it. I'll just ask if you have calculated those figures or not. If you have, you can very easily and clearly determine what axle spec, diameter and material, spline count etc is req'd. same for cw&p, locker, cv/s etc..... So you can factor in the cost versus safety margin you require.

My only concern was that potentially your combination of parts may not all be within the same margin of overhead, and could possibly leave you with a weak point, that may become the failure point - if - the safety margin is not 'enough'

Anyway, it sounds like you are on a path where you can choose from a selection of reliable commercially available parts which will provide you with the strength and reliability you need.

Let us know how it pans out. I'll be interested in how the build progresses. I had a desire for a hi-9 purely for the raised pinion, to provide better driveshaft angles, but the costs are prohibitive for a single net gain in my case.

In yours, I think you have more to gain with a carefully well-matched specification which has a reasonable margin of 'safety' above the max tq figure of your drivetrain.

Your last paragraph is pretty close. Make everything as strong as possible negating the need for any weak points. Really dont want to snap a stub or anything for that matter half way up a steep rocky high country hill!

Whilst I appreciate your input and also whilst your 10% comment may be true driving up a driveway, its way off in this application and its uses but lets not get into that.

This thread is designed to find a good solution to match a front coiler Rover or D2 housing to the strength of a 30/31 or 35spline Rear (I have 35spline rear diff to Drive Flange).

I highly recommend the LRA TruHi9 rear, if you are going to keep your Rangie for a long time, do it when you can.


To be honest I dont think this is reinventing the wheel too much, 30spline front has been done many times, A pegged rover diff with 30spline not so much or a front 9 in a rover coiler housing with 31/30 or 35/30 also not common, but still all things have been done if not in the same combo seperatly in some form.

Will let all know how I go this week

Would be intersted to hear from anyone who has, or has info on putting a Ford 9" into a complete rover coiler housing, force 9 style. Not half a 9 housing/half rover housing but a full rover housing. I have been told it can be done but only one ive seen is the Force 9.

Reason im interested is the front with an LSA and long travel etc doesnt have as much space like the rear so we may "have" to keep the housing 100% Rover Coiler.

Originally Posted by blackrangie

LSA

I think "LSA" is a key word here.

Originally Posted by Slunnie

I think "LSA" is a key word here.

Haha