4.1 ratio diff matched with 4.11 ratio...

[el_freddo]

G'day - this could be a stupid question from a crazy Aussie, but here goes anyway:

 

If I was going to drop a 4.10:1 ratio rear diff into my subi with a 4.111:1 front ratio what would be the consequences of this on the viscous centre diff?

 

Got an idea in my head that I want to do on the cheap if possible - I really don't want to buy a new R&P set if possible, but I also really don't want to destroy my centre diff.

 

I know the ratios are close, but are they close enough not to do damage?

 

Cheers

 

Bennie

[1 Lucky Texan]

I have no experience but, when these type issues come up, I often wonder if there's a way to compensate with different tire sizes on front vs rear axle.

 

maybe not practical for many people but, just a mental exercise hah!

[Gloyale]

Not sure about damaging anything.

 

With that setup you'd have a slight rear power bias......might be good for drifting:brow:

 

Perhaps run some slightly worn down tires on the back, and brand new up front?

[presslab]

Subaru once specified a maximum difference of 1/4" in tire rolling circumference. Although they also supplied a doughnut spare that violates that.

 

Anyway the difference of 4.1 and 4.111 is 0.27%. 1/4" on a 205/50-15 tire for example is 0.35%. I think you will be just fine, just be sure to rotate the tires as scheduled.

[el_freddo]

Ok, I'm not keen on running the different ratios, even if it is a tiny bit out. Through some other questions else where on the web I've found that I can get the 4.111:1 at a reasonable price - last time I checked it was two or three times the current amount.

 

Plan is to fit another vehicle's diff to the rear of my subi and run an air locker - this way I can still safely use my AWD in the snow/really slippery conditions without the rear end sliding out as it would with a welded or auto locker.

 

Cheers

 

Bennie