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Diff width advice


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#1 123OUC

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Posted 08 May 2022 - 11:43 AM

I'm after some advice on choosing the wheel offset to match diff width for my UC hatch.
I am looking at running a convo pro 8" rear rim with 4.5" backspace.
I planning on a 235 or 245 tyre depending on which will fit and want to know how much I will need to shorten the diff to suit.
Guards are rolled but no tubs.
Cheers

Edited by 123OUC, 08 May 2022 - 11:43 AM.


#2 Cook

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Posted 08 May 2022 - 12:33 PM

Hi Dave.  I can't give an accurate answer but to give you some idea, I am running 17 X 8s with 4.25"  backspace (145/40 tyres) with a 9" diff and from memory the diff length from wheel to wheel was 1400mm.  That is with guards rolled but not tubbed.  I bought the wheels first and sat them in place and got the diff made to suit and that is what I would recommend.  Also consider what brakes/suspension you are proposing to use for checking clearances. Cheers Ron.  



#3 123OUC

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Posted 08 May 2022 - 12:34 PM

thanks mate



#4 Bigfella237

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Posted 08 May 2022 - 08:11 PM

Just be aware of your minimum and maximum rear track measurements as well. I think all states (and the NCOP) allow up to +25mm over standard but you are not allowed to go under the standard track width at all.

 

So it you shorten the diff, then get defected for the 8" wheels, it may not be legal to bolt stockie rims back on because they may come in under the standard track width.

 

Your mileage may vary of course and a lot depends on the cop/inspector/mechanic/engineer you get and how knowledgeable/strict they are.






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