4x4Wire TrailTalk

"Near enough" ratio for a SAS

Posted By: DamKia

"Near enough" ratio for a SAS - 11/11/10 10:21 AM

http://cars.ebay.com.au/ASHCROFT-4-11-4-...emZ190385281130

Rover front may be worth a look with aftermarket 4.75:1 ratio. Axle assy can be had in about 60" width.

The difference between that and our 4.778 is about 0.6%, basically negligible (ie, on a 30 inch tire about 0.2 inches = not much more than "loading difference" or tire wear) There would be no handling issues associated with the front going marginally faster than the rear on dirt.

Looking at doing a subframe that bolts to the existing upper/lower mounts to mount the spring/shock and Panhard and using the Rover leading arms, or possibly use the existing spring rotated 90 degrees and taken down to the lower part of custom made leading arms utilising leverage for a bit more travel. Chassis end of leading arms would come from a box welded to bottom or side of the chassis.
Posted By: Dryver

Re: "Near enough" ratio for a SAS - 11/11/10 01:16 PM

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The difference between that and our 4.778 is about 0.6%, basically negligible (ie, on a 30 inch tire about 0.2 inches = not much more than "loading difference" or tire wear) There would be no handling issues associated with the front going marginally faster than the rear on dirt.


Actually, the driving distance is about 0.55" (30" x 3.1415 x .58%), or 3.9 more revoutions of the front tires per mile compared to the rear tires. Still probably reasonable on a loose packed surface. I don't think you would want to run this setup on a hard packed or paved surface, though.
Posted By: DamKia

Re: "Near enough" ratio for a SAS - 11/11/10 02:37 PM

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The difference between that and our 4.778 is about 0.6%, basically negligible (ie, on a 30 inch tire about 0.2 inches = not much more than "loading difference" or tire wear) There would be no handling issues associated with the front going marginally faster than the rear on dirt.


Actually, the driving distance is about 0.55" (30" x 3.1415 x .58%), or 3.9 more revoutions of the front tires per mile compared to the rear tires. Still probably reasonable on a loose packed surface. I don't think you would want to run this setup on a hard packed or paved surface, though.


Given that we don;t have a center differential in our Tcase we shouldn't be running 4WD on hard/dry/"sticky" surfaces anyway. My point was that on dirt it won't make the vehicle unstable or undrivable.
Posted By: DEFBOY35

Re: "Near enough" ratio for a SAS - 11/11/10 04:35 PM

my question is if going through all the effort to do the sas, why would you want to have stock gearing? even with 31's the stock gearing is making power suffer.
that being said, the amount of work a sas is, is it worth it if you only plan on stuffing 30 or 31 inch tires under there?
if it is only because you dont want to change the rear axle, i would say the rear axle is the easy part.
either way a cool project none the less.
Posted By: DamKia

Re: "Near enough" ratio for a SAS - 11/12/10 01:16 AM

Looking to do more of a "bolt-on" solution rather than getting too involved with chassis welding. Easier to pass our safety inspections.

The gearing is a fair question, but not having to change both ends will make it easier and cheaper to do.
Posted By: jfrey123

Re: "Near enough" ratio for a SAS - 11/12/10 02:14 AM

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Looking to do more of a "bolt-on" solution rather than getting too involved with chassis welding. Easier to pass our safety inspections.

The gearing is a fair question, but not having to change both ends will make it easier and cheaper to do.



I had similar concerns when I was debating a SAS. I knew that the Sorento gearing in the rear wouldn't match up with other front axles so it was either switch front and rear or switch nothing for me.

So far, I'm choosing nothing. We'll see how long that lasts.
Posted By: 4runnernomore

Re: "Near enough" ratio for a SAS - 11/12/10 07:11 AM

HiDAMKIA

Have you considered the wide axle hilux/4runner axle options.

Here is a link to what I was going to to my sporty with my old 4runner axles.http://www.4x4wire.com/forums/favlinker.php?Cat=0&Entry=24267&F_Board=UBB70&Thread=1029160&partnumber=&postmarker=

Gearing at 5.29 running 32's I worked out to be around the same as running 30's on the Sporties standard gearing. I kick myself now for selling the diffs when I bought the 80 series. I am now selling the 80 and keeping the Sporty.

Cheers, Chris
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