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Author Topic: Does running different rolling diameter wheel harm 4wd?  (Read 1001 times)

DeadBroke

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Does running different rolling diameter wheel harm 4wd?
« on: June 07, 2016, 10:42:36 PM »
So I've just picked myself up a 2.5L Stagea the other day, and I've decided  may as well use the mags off my skidder while that's in hibernation (if you could  call it that). And I noticed that my front wheels have a slightly smaller rolling radius than my rear wheel. Will bolting these wheels on bad for the 4wd transmission in anyway? Will it make it handle funny in the wet? Will it put strain on the box? I see this car has a 4wd switch that makes it 50/50 front and back I believe, but with it off. I'm told the car constantly runs an Atessa system similar to the Skylines. Still not quite sure what that is. Anyone shed some light? Thanks.

westybob

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Re: Does running different rolling diameter wheel harm 4wd?
« Reply #1 on: June 08, 2016, 08:52:19 AM »
Yes it will harm the attessa to run different rolling diameters front and rear. And no turning the switch on will not help. It locks the system into 50/50 front and rear (for getting out of a boggy paddock or up a boat ramp) but it reverts to the normal computer control above about 20 km/hr. You will notice unwanted vibrations and harshness.

DeadBroke

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Re: Does running different rolling diameter wheel harm 4wd?
« Reply #2 on: June 08, 2016, 07:49:27 PM »
Well I'm definitely not thinking of running it in 50/50. Wow does it actually harm in in normal attessa mode? I was under the impression that the front wheels only kick in when the back breaks traction. Any downsides if you remove the 4wd fuse? I'm considering that.

westybob

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Re: Does running different rolling diameter wheel harm 4wd?
« Reply #3 on: June 09, 2016, 01:07:33 PM »
The Attessa in the Stagea normally runs about 95% rear 5% front until the computer tells it otherwise. So there is a constant pressure on the clutch packs which will burn out if abused. The R32 attessa is different and you can just pull the fuse to run in RWD. There is a complicated procedure for running in 2WD for say a 2WD dyno but it needs to be gone through every time you start the car so if you really want to run different wheel sizes your best bet is to pull the front driveshaft. There are just 4 bolts and the driveshaft pulls out of the transfer case. There is no downside to this procedure (other than the loss of AWD) and it is easily reversible if and when you get same sized wheels/tyres.

DeadBroke

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Re: Does running different rolling diameter wheel harm 4wd?
« Reply #4 on: June 09, 2016, 08:31:33 PM »
True. Thanks for the info mate. Looks like I'll stick to the stock wheels until I get a matching pair of tyres.