Rear diff ratios for big wheels

[j.inniss]

Hi,

Let me start by saying I came across this forum a few days ago and have already found it an invaluable source of information to help me with my project Surf. I live in Barbados in the Caribbean where the roads are small and congested and people drive like idiots. So I decided to sell my A3 in order to get something a little bigger to drive around... I have just bought a 1993 3.0l Surf.

My plan is to build a reliable safe daily driver / weekend off roader / show car out of my Surf. I have started by ordering a 4" Pro Comp Stage 2 lift kit, Steering stabilizer kit, a set of Bushwacker extended flares and a set of 15"x12" American Racing rims. I am also looking a 3" Body lift kit from 4 Crawler and a performance upgrade from Allisport.

My question finally (Sorry for the long post):

I am looking to run either 33" or 35" tires (depending on if I do the body lift). This is going to probably have a serious affect on performance with my current diff ratio. What sort of rear diff ratio should I be looking for if I am running 33s or 35s?

FYI: Current diff ratio I believe is 6.78. This is based on A343F where A= 138mm R&P size, 34= 6.78 R&P ratio and 3=2pinion LSD

[Gizmo]

I cant answer this one myself, but possibly try the american website..I know alot of alterations have been mentioned to brig the ratios down

http://www.yotatech.com/index.php?

Or follow this link http://www.yotatech.com/~corey/portal/portal.htm#
and after scolling down you will see a Tyre and Gear Calculator!!

Regain Performance:
New Tyre Diameter (inches) / Original Tyre Diameter (inches) * Original Axle Ratio = Required Axle Ratio

[suprchrgr]

31 or 33 need 4.88 35 up 5.29 performance products.com

you could do it but clutch and gas mileage down the drain also consider aggressiveness of your tire 33 bfg is close to a 31 swamper im running 33 swampers with 4.88 still crawl and have top end highway

[TonyN]

FYI: Current diff ratio I believe is 6.78. This is based on A343F where A= 138mm R&P size, 34= 6.78 R&P ratio and 3=2pinion LSD

A343F is your transmission code, you want the code next to it for the diffs. It should start with a G---.

We have 33's on our 3.0, while there is a difference in performance, its not that bad in my opinion.

[laser_jock99]

I run on 33's and can't say I noticed much difference either- my Surf is still slow off the line!