Evidentiary standard for tech

[Alaska Mike]

didn't sereis truck run them too...

From TeriAnn's site:

Some ratios:

Stock Series differential ratio - 4.7:1
Stock coiler differential ratio - 3.54:1
Common aftermarket differential ratios for the Rover differential carrier - 4.1:1 and 4.75:1
Standard Series transfer case high range ratio - 1.15:1 (making it an under drive) . Low range varies
Standard Coiler transfer case low range ratio - 3.32:1. The high range varies with the engine used.
Fairy/Superwinch overdrive ratio - 0.78:1
(which coupled with the 1.15:1 Xfer case under drive gives you a 0.90:1 overall ratio through the xfer case)
Roverdrive overdrive ratio - 0.8:1
(which coupled with the 1.15:1 Xfer case under drive gives you a 0.92:1 overall ratio through the xfer case)
Ashcroft high ratio kit high range ratio - 0.87:1 ​

 

[Antichrist]

SIIa

SIII (helical and spur transfer gearbox was standard on 1 Ton)

 

[David Harris]

By making teeth more narrow, you decrease the contact area and actually weaken the gearset. If, as everyone here acknowledges, the weakest point of the Rover differential is the ring and pinion set, why would you want to further weaken it by adding more teeth leading resulting in a greater chance of a shock load being transferred from a pinion, which will always have larger teeth, to the ring gear, which will now have more teeth that will have to have been made smaller and thinner to fit in the same diameter? Your gearing up in the transfer case (lower numbers (1.1 vs. 1.4) makes for higher gearing, or gearing up but Im sure you already knew that) and a substantial gearing down in the ring and pinion will actually result in a WEAKER set up. True strength comes from a ring and pinion size and housing that can suitably support a higher ratio, not just upping the tooth count. Once you go above something like 4.10, you are actually weakening the gearset.

Increasing the number of teeth doesn't necessarily decrease the strength of the gears, since there are now more contact surfaces (not less as you say) to distribute the force, similar to how 24 spline axles are stronger than 10 spline axles. Yes. There does come a point when you are getting into really low ratios, like 4.88 and up, that there may be some weakening depending on the strength of the material involved. However, at this point, it really depends on how you are using it. If you are a rock crawler with big tires and are torching it every time you go out, then you might find strength a problem and want to upgrade the whole unit (Salisbury, etc.), but I really don't think that you would find a problem with most wheeling. I've seen lots of guys running the lower ring and pinions in smaller housings without problems. Anyway, Rob is only talking about going to a mid range set (4.37 to 4.5). I don't think there would be an issue there. As far as the whole mod goes, if the 1.003 gears are available and Rob wants to try it out, then why not? He's not modding your truck and charging you for it. It might be just what he's looking for and then who cares if it's not a common mod?

 

[R_Lefebvre]

Fixed.

You guys are still struggling to come to grips with the fact that there is only a small number of you I don't listen to.

Would you like to see the steel I bought on Friday to build an R380 support bracket to aid in doing my rear main seal? I got the drawing from Antichrist.

Does it interest you at all to know that I had to call Dave Ashcroft this morning to ask about something else, and I ran this idea by him as a by-the-way. He didn't seem to think it was a bad idea at all. The only thing he cautioned is that the 1.003 gearset is an older tooth profile, and thus will whine more than my existing set.

So whom should I be listening to. You? Or the most knowlegable man in Land Rover transmissions?

I am echoing your comment about the "sweet" setup in your head. You want a 1:1 gearset in the transfer case AND 4.5, or higher, in the axles. That is the dumbest "sweet" setup I have ever heard of and here is my evidence as support. In order to gain the gearing that you are looking for, you are looking to increase the number of teeth on the ring and pinion. A jump from 3.54 to 4.5x or higher, will lead to a larger number of teeth and those teeth will then have to be made more narrow (smaller). By making teeth more narrow, you decrease the contact area and actually weaken the gearset. If, as everyone here acknowledges, the weakest point of the Rover differential is the ring and pinion set, why would you want to further weaken it by adding more teeth leading resulting in a greater chance of a shock load being transferred from a pinion, which will always have larger teeth, to the ring gear, which will now have more teeth that will have to have been made smaller and thinner to fit in the same diameter? Your gearing up in the transfer case (lower numbers (1.1 vs. 1.4) makes for higher gearing, or gearing up but Im sure you already knew that) and a substantial gearing down in the ring and pinion will actually result in a WEAKER set up. True strength comes from a ring and pinion size and housing that can suitably support a higher ratio, not just upping the tooth count. Once you go above something like 4.10, you are actually weakening the gearset.

Well, now here's a man who at least presents a thought that is worth considering. And an interesting one at that.

But at the root of it, aren't you suggesting that ALL aftermarket alternate-ratio gearsets are weak and not worth buying? That's a very precarious statement to make. I wonder how that discussion would go if we were to pursue it for a while?

Out of curiosity, did any Rovers ever come stock with 1.003's? I'd never heard of these gears until I they were mentioned here and then saw them on Ashcroft's site.

Dave said early RRC's with a 3 speed auto ran them. We never got it in NA.

As a Jeep owner, I spent quite a bit of time there years ago, until the signal to noise ratio got too high. There's a lot of buggy-fueled, "who is more hardcore" chest thumping over there. Just not my scene. I'll still browse a bit from time to time to find a specific bit of data, because there's a lot of good tech on that site if you look for it.

I could see that. Generally it's way too hard core for me. But it's nice to see some of the work people do, and they aren't stuck in some kind of purist mindset.

 

[Viggen]

Anyway, Rob is only talking about going to a mid range set (4.37 to 4.5). I don't think there would be an issue there. As far as the whole mod goes, if the 1.003 gears are available and Rob wants to try it out, then why not? He's not modding your truck and charging you for it. It might be just what he's looking for and then who cares if it's not a common mod?

Of course hes not. Id never gear up the strong side, transfer case, to gear down the weak side, the diffs. I, and many others, just dont see the point to doing it. The issue is the fervent affirmation that this is an idea that has never been done before. The other issue is that this gearing set up of his is "progress" in the Rover world. Thats just ridiculous. Progress is actual innovation, not a rehash of higher gearing in one place that will require ridiculously low gearing in another.

Increasing the number of teeth doesn't necessarily decrease the strength of the gears, since there are now more contact surfaces (not less as you say) to distribute the force, similar to how 24 spline axles are stronger than 10 spline axles.

Splines and teeth are different things and even with axles, size equals strength. I can take a 10 spline and then put 24 on it and increase strength. There would be NO increase in strength if I took that 10 spline and put 35 on it as I am, like gearing, putting more ridges in that same small place.

But at the root of it, aren't you suggesting that ALL aftermarket alternate-ratio gearsets are weak and not worth buying? That's a very precarious statement to make. I wonder how that discussion would go if we were to pursue it for a while?

No, if you read the statement I said that a certain gearing set up with newer gears that will use better metallurgy and design will increase in strength versus the stock set BUT its hard to get past the fact that jamming more teeth onto the same amount of space isnt going to decrease strength. I hate rock crawling but if youre looking for pieces that need strength, youll notice that they are running low gearing in the axles BUT are using axles that start on the small end for them, which is the big end for us, the D60. Bigger ring gears and pinions allow for lower ratios without sacrificing strength. If low gearing is the goal, just go switchable underdrive rather than having to screw with regearing 3 areas.

 

[David Harris]

Increasing the number of teeth doesn't necessarily decrease the strength of the gears, since there are now more contact surfaces (not less as you say) to distribute the force, similar to how 24 spline axles are stronger than 10 spline axles.

I should qualify this by saying that the numerically higher the ratio, the more teeth in the ring, and the fewer in the pinion. Also, the teeth in the ring have to become thicker to contact the fewer number of teeth in the pinion. So, ultimately the ring becomes stronger and the pinion weaker. I know the strength trade off is a matter of debate. Please correct me if I am wrong about this.

 

[David Harris]

But it's nice to see some of the work people do, and they aren't stuck in some kind of purist mindset.

I agree. One of the cool things about the 4x4 and car hobby in general is that it's a forum for individual expression. It's actually a very creative process which allows wide scope to innovate and try new things for different uses. We don't all want to drive around in the same trucks do we, ones which correspond to the same doctrinal paradigm?

 

[David Harris]

If low gearing is the goal, just go switchable underdrive rather than having to screw with regearing 3 areas.

True. Underdrive gets you into the super low crawling range real quick, but a factor to consider here is that your torque multiplication becomes so great that it becomes extremely easy to twist/break even the strongest driveshafts, gears, lockers and axles when you put so much gearing at the transfer case. On the other side of the coin, putting the gearing at the axle itself actually decreases the load on the driveshaft and everything in front of it.

 

[R_Lefebvre]

The issue is the fervent affirmation that this is an idea that has never been done before.

But which is it?

I for one have never seen a 1.1 lt230 tcase. The 1.2's are as tall as I have seen. The old lt95 came in a 1.1.

I mean ****, what's a guy to think? One experienced guy saying he's never seen it before, and another saying it's been done many times.

And whatever happened to this?

Good point. I would do the 3rd members before a transfer case. Lower gears in the axles give you better OVERALL reduction whereas, unless youre going to put an underdrive, youre not going to see any offroad benefits when in low whereas the gearset will give you the road gearing youre looking for AND a better ratio off road.

Did you come upon this weak ring gear theory just recently, or are you just jumping on the bashing bandwagon with the cool kids?

 

[Viggen]

Did you come upon this weak ring gear theory just recently, or are you just jumping on the bashing bandwagon with the cool kids?

No, this was with a realistic regear of 4.10 rather than a more work, and probably cost, intensive process of regearing the transfer case with 1.4:1. Now, the situation has morphed to 4.5x in the axle and 1:1 in the transfer case. Completely different.

 

[R_Lefebvre]

True. Underdrive gets you into the super low crawling range real quick, but a factor to consider here is that your torque multiplication becomes so great that it becomes extremely easy to twist/break even the strongest driveshafts, gears, lockers and axles when you put so much gearing at the transfer case.

Somewhat true. But it can be easier on things in some instances. It really depends a lot on the driver. I want lower crawl ratio so that I can be easier on the powertrain. Not harder. Lower gearing allows less clutch burn. Or, less need to drop the clutch hard and shock the transmission to get over a rock. Just let out the clutch, and let it walk over.

Now if a tire is wedged in a crevase, you'll just snap something. Or if you're beating your truck on an obstacle, hopping the axles, the inertia from the flywheel being multiplied through such a low range... yeah, that's gonna break something too.

 

[R_Lefebvre]

No, this was with a realistic regear of 4.10 rather than a more work, and probably cost, intensive process of regearing the transfer case with 1.4:1. Now, the situation has morphed to 4.5x in the axle and 1:1 in the transfer case. Completely different.

Who's talking 4.5? I never did. I said 4.11 or 4.37.

 

[David Harris]

Somewhat true. But it can be easier on things in some instances. It really depends a lot on the driver. I want lower crawl ratio so that I can be easier on the powertrain. Not harder. Lower gearing allows less clutch burn. Or, less need to drop the clutch hard and shock the transmission to get over a rock. Just let out the clutch, and let it walk over.

Now if a tire is wedged in a crevase, you'll just snap something. Or if you're beating your truck on an obstacle, hopping the axles, the inertia from the flywheel being multiplied through such a low range... yeah, that's gonna break something too.

I agree. The lower gearing will take stress off of the powertrain. I was just referring the the ultra low effect of an aftermarket underdrive at the transfer case. (100:1 or so), putting huge stress on the rest of the drive down to the axles. With an underdrive, you would really have to be careful about how much throttle you use and when. I see no problem with the principle of what you are suggesting on a 1:1 in the TC and a mid range r&p in the axle. It makes sense because you are now moving more gearing to the low range, while the high range will stay the same. This is the way almost all 4x4's are, so I can't see why you are getting so much resistance on this. The LR axles are more than strong enough to take what amounts to a mild mod altogether.

 

[Maryland 110]

But which is it?



I mean ****, what's a guy to think? One experienced guy saying he's never seen it before, and another saying it's been done many times.

And whatever happened to this ?

As I said I had a 1.1 tcase in a 110 with a 4 liter toyota diesel with stock diffs. Ie enough torque to pull away in 1st and not stall but the effect on the axle shafts was intense- the splines literaly had acute 30 degree bends/twists after 8 mos in the truck. I was running 285's so a 33.25 tire. The gear box was a 4 spd so thats why the tall gearing- so the diesel wasn't over revving @ 70 mph. 4.75 gears would have limited my top speed to about 50 to stay in that diesels happy range. I have of course seen the 1.1 gear sets for sale for lt230's, what I was saying is I have never seen anyone running one. I have had about 100 defenders pass through my hands- most of them imported from different corners of the world and 90% or more had 1.4 tcases. The idea you are so agressively defending may work-but it also means the most modification- both a different t case and all new gear sets and presumably lockers while you are in there to have it all make sense. ie-$3000-$4000 minimum investiture is far more than many Disco's owners total investiture in their rigs. Since it works on a gearing calculator but no one is running it (qualify:that I know of )so is somewhat of an expensive gamble.
I'm not "bashing you" as you say above. For me one of the things thats neat about these trucks is how capable they are in stock form- more so the tdi defenders than the computer controlled efi disco's and rangies. I'm someone who has been driving these trucks off road for 30 some odd years (with a reputation for attempting/doing some reckless obstacles). I started with series trucks with 33.12.5.15 McCrearys in the 70's and went through the V8 thing with Range Rovers in the 80's and 90's and went defender a while ago. I have a v8 110, a tdi 110, and a tdi 130 right now. I drive a 300 tdi 130 as my daily driver-still on 33's 30 years later (I think the 255.85 or 285.75's are the ideal rover sizes-again my opinion based on well over 750,000 miles behind the wheel). Gearing is and always has been a compromise. I have had the transfer case out of the 130 4 times so far this year. Its not a job I enjoy so I take each change very seriously. You feel strongly about what you are saying- make the swap and show these guys it works. Otherwise just agree to disagree like gentlemen. You all seem to agree the personal attacks are uncalled for but then revert to it. This isn't disco web and it would be nice if WE keep it that way.

On a possitive note anyone else watch Scott Brady's Moab trip through the 39yr snow storm on Dangerous Drives on the Speed Channel ?

 

[David Harris]

I have had the transfer case out of the 130 4 times so far this year. Its not a job I enjoy so I take each change very seriously.

Do you mind sharing your experiences with the tc changes? What kind of changes did you make and why?