Double Whammy!

[TwisteD90]

I just got few pictures from when I broke the R&P!

[TwisteD90]

More,

[TwisteD90]

Last one!

You can see in the first pic. that I had some air under my tires, look at the tires they look like there are fully inflated (I only had 5 psi).
The second one is when I landed; you can see the rear tire is almost flat.

[DJ Menasco]

Yousef

Although I've never broken a R&P I was wondering how you could have snapped your 4.75's? I was under the impression that the lower ratio of the 4.75's were better suited for rock crawling and would aid you in avoiding such damage?

The only issue that I know of is from a technical standpoint in that the 4.75's are weaker then the taller stock 3.54's. I only ask because I've always read posts on other boards that report broken CV's, R&P's, etc., and it comes off as being a typical faliure. Basically, how much is this due to driver responsiblity and how much is due to equipment?

DJ

[rover4x4]

:eek:

[TwisteD90]

If you noticed most people that broke the 4.75's are running 37" tires and bigger. I think the 4.75's are good up to 35's. Also all the 4.75’s that broke were the rears not front.
Driver / equipment is a tuff question for me. When I blew my 4.75's it was drive error 75% equipment 25%. I wasn't careful and that's why I broke but I also knew that I will break those things one day.

[revor]

From a mechanical standpoint the higher (numerically) the gearset, the weaker it is... This means the pinion gear has fewer teeth, thus less to engage the ring gear... rarely is it a problem of the ring gear but the fact that the pinion is just too small...
An example.. The Rover 4.7 gears have a pinion gear diameter of about 2 5/16" diameter.. the 3.54 gears go about 2 5/8'...
If you want to play with bigger than 35" tires and 4:7 gears with good reliabilty you need to go with a Salisbury... 4.7 Pinion gear= 3 1/8"... At the same measurment.
Sure rock crawling involves a a lot of slow deliberate moves but when you need to get on it and you have sooooo much traction stuff breaks unless it' big... My goal for the perfect "weak Link".......
The Tires are the only acceptable weak link in my book....

[revor]

This is how we fix this...

[revor]

Okay Yousef
You have 'em Post 'em

[TwisteD90]

Those are the pictures that keith sent me.

This is Keith :)

[TwisteD90]

The Slas.

[TwisteD90]

Here you can see we went with disc brakes instead of drums. Disc brakes and calipers were from my D90 and Keith built a bracket to make'em work.

When we were in Moab Keith told me about the sals so while we were there talking about it he told me he will go and drill the hub for 10 bolts but some reason he stayed with 5! Why? :)

[TwisteD90]

Here she is standing on all four :)

[revor]

It is a sweet thing! Almost drop in ... :bling
Anyway the reason I decided against the 10 bolt idea is the actual shear strength of the 5 newly drilled 7/16 threads with proper bolts should easily handle the power of the vehicle. Going to ten just removes a lot of metal that surrounds the outer bearing race and under high torque loading I could see it wallowing out the bored hole that the bearing race sits in... I went for the best compromise that provided the best longeviety.. At least that's the thought.. I have several friends that run circle track cars, both Outlaws, at 650+ HP and modified that hook up their tire with a vengance comming out of the corners... Most run 5. 7/16 hollow drive flange bolts... Yeah they're Titanium but heck they're pushing some power and traction :)

[rover4x4]

Whats the deal with Ti? I know it's strong but my understanding based on pedal bikes is that the stuff is kinda flexy?????

[Buckon37s]

You might want to rethink the 10 bolt idea. Seems to be the last weak link back there.

http://www.pirate4x4.com/forum/showthread.php?s=&threadid=186681

[revor]

Flexi but very resistant to shear

[comac90]

anyone know what they had the 5 bolts torqued to?

don't forget yousef's engine torque is only being multiplied thru the tranny, t-case, and diffs .... he's not running a crawler box. that said, for some applications, 10 bolts would be the way to go. but, for any rover owner running stock tranny and t-case, 5 socket head screw caps are going to be more than ample. also, the sals axles like yousef is getting have a 5 year warranty against breakage. so, even if he found a way to put a Marlin Turbo case on there ;) & broke the flange bolts and axle, his axle shaft is covered.

it would be interesting to multiply out to really see how much torque you could get on an axle with a crawler. anyone know the gear reduction on one? a lot of the ARCA trucks are in the 16k-18k ft-lb range.

as for the Ti bolts....i'm certainly no expert, but a know a little about Ti vs. steel....

you have to look at application. (& i'm speaking in general terms here ... just assume the steel is chromoly and the Ti is 6Al-4V). on a race car (or XC racing mtn bike or road bike for that matter) you're looking to save weight.

take 2 identical bolts .. 1 made of steel, the other Ti. They both have roughly the same strength, but the Ti one is ~1/2 the weight of the steel bolt and has 1/2 the stiffness (the flexiness you mentioned ...& the reason why a lot of Ti bottom brackets creak). in something like a Ti flange bolt on a race car, the performance lost in the 'flex' of the bolt is negligible. the performance gained in weight reduction (especially unsprung rotating weight) is beneficial .... &, as i mentioned, they have the same strength so no worries of breakage, etc. now, also consider that there are some Ti (beta-) alloys that offer more strength than steel at a lower comparable weight. I imagine this is what revor is referring, too.
T

[rover4x4]

:thumbs

[billnsandi]

Looks good Yousef. I am interested to know what the total cost was?

Used Sals axle assembly (I assume)
GBR 35 spline spindle kit with bearings and such
Flanged axles
Spacers for the flanged axles (looks like you would need about 3/4" or so from the pictures if not more)
ARB
R+P with setup
Carrier and Pinion bearings, etc
Custom work for the disc brake calipers

Hope to see ya on the trail soon.

Billster

ps. Does anyone know what a complete Sals/D60 axle assembly weighs?

[WhiteD90]

Yousef-

What is Keith cooking up for you up front, sounds like you are about to chop the front wings by the list of parts you are selling.
How about a shot from the rear at diff level to see what kind of ground clearance you now have.

Tis

PS-When is that east coast trip you are planning?

[revor]

Up Front is a super secret mega strong diff that hasn't been designed to be affordable yet... But we're working on it and it is based on a D60... Sort of a Front Sals on steroids...
Clearance wise it is only an inch lower than the Rover diff... (measured)
To put one of these in a truck would cost in the neighborhood of $2500. Thats's including everything except labor
The big ticket stuff like the locker,axles, and spindles make up for half the cost. Gears are pretty cheap as are bearings.. The housing might be had cheaper... The only custom stuff was the caliper brakets and of course the machine work on the hubs. I ditched the cheesy Sals diff cover in favor of the thicker Ford cover but by the looks of things a guy could put on anything and not worry about clearance at the fuel tank (stock fuel tank). The sals actually has a smaller projection that direction than the Rover diff..

I have been told a complete D60 weighs in the neighborhood of 325 pounds. Either the Rover Diff or the Sals are too heavy!! I'm gonna start working on RC cars from now on...
Funny the older I get the stronger Gravity gets:)

Later
Keith

[TwisteD90]

Bill, Tiz, and David I'm not ignoring you guys but just being a single father for two kids gives me no time to do what I like :(

Anyway, I'll have some pictures soon of what Keith did to my 90.

Later,

[Buckon37s]

No worries, thanks! Man kids:cry