Offsets

nderryking · Post by **nderryking** » Tue Dec 23, 2003 12:28 am

Can anyone give me information on correct offsets for aftermarket wheels for a Daewoo Lanos? What will work, what won't? I see 40mm and 45mm offsets, but I'm not sure what to get.

Post by **PrecisionBoost** » Tue Dec 23, 2003 1:09 am

Ok.... I'm not 100% sure about this but my calculations match what I was told by someone else so I think they are correct.

I found the offset on my stock 185/60/14 rims to be 49.5mm

My rim was 163mm wide so the centerline is at 81.5mm
The backspacing I measured was 131mm
From this the distance from the mounting surface to the centerline is 49.5mm = the stock offset

I was also told by someone else that the stock offset was + 49mm

Given that less offset moves the outside edge of the rim towards the street your 45mm offset wheels will stick out a little more than stock.

Less offset than stock can cause problems with wheel bearings and the way in which the car tracks around a corner (can become unstable in rare cases)

So try to get as close to +49mm offset as possible to ensure that your car will handle good.

I can't remember what I was told.... I think 3mm or 4mm is still ok but after 5mm of difference the steering wheel pulls left or right when going over ridges in the road.

Who knows 40mm or 42mm might be usable on a Daewoo.... I think it depends primarily on the suspension/steering geometry

What offset is everyone's rims?????

nderryking · Post by **nderryking** » Tue Dec 23, 2003 3:25 am

I just checked www.tirerack.com and all their wheels that fit a 2000 Lanos range from +35 to +38 offset. Now I'm not sure what to think.

Goldenboy · Post by **Goldenboy** » Tue Dec 23, 2003 3:05 pm

I have a 40 mm offset on mine...before I did the suspension it was pulling to left and rigth. But after the suspension job all was fine

Mat

Post by **PrecisionBoost** » Tue Dec 23, 2003 11:18 pm

Since there isn't much support for the Lanos/Nubria I searched for factory offset on an Astra MKII which uses the exact same wheels (and suspension as our Lanos)

As I suspected I found 5 or 6 pages that listed the OEM offset as 49mm.

I did however see a pile of Astras with offsets between 38mm and 49mm and even one that had an offset of 10mm! (wheels stuck out about 2" outside of the wheel well)

Needless to say I think the best way to find out about offset is to see what everyone has and how their cars are with that particular offset.

I also know what your talking about with the small offsets on the Tire Rack wheels but if you go up to 17" most of the offsets are 42mm to 45mm and if you hit 18" they are also up in the 45mm range.

So Mat aka "Goldenboy" has a 40mm offset which means his offset is off by 9mm which is only about 3/8".

Post by **PrecisionBoost** » Tue Dec 23, 2003 11:36 pm

I've been looking at some nice 17" rims with a 42mm offset or the same rims in 18" with a 45mm offset.

I need much wider tires to hold down the extra power my 2.0L Turbo engine will be putting out so I'd like to go with 225/35/18 which have a diameter of 24.3" vs the stock 22.7" diameter.

Alternatively if I go with 17" rims I was looking at 235/40/17 (24.5" Diam) or 245/40/17 (24.8" diam)

Pirelli P7000 and Goodyear Eagle F1 Gs-D3 tires also come in a 245/35/17 but I'm somewhat inclined to stay with my favorite brand (Bridgestone)

So with a wider tire I will definitly have to do some changes in offset to clear the inner wheel well ( outer wheel well is easier to change)

Post by **Efratech** » Wed Dec 24, 2003 6:24 am

but why not better try 17" with nittos 555 or toyo proxies? at least on the front, or maybe for track days 16" with semi-slicks

Post by **PrecisionBoost** » Wed Dec 24, 2003 7:49 am

I've been doing more research on offsets and how they change the way the car handles.

First off I had a diagram from one of my research sites but Yahoo Photos area is down right now so I can't post it quite yet.

Basicly there is something called a King Pin Inclination ( call it KPI )

Imagine drawing a line through the upper and lower ball joints in your suspension all the way to the ground.

This line should ideally hit the ground and exactly intersect the centerline of your tire to give the perfect balance in steering.

Any offset from this is called King Pin Offset ( call it KPO)

The larger the KPO the more leverage the wheel puts on the suspension.

So as KPO increases force from uneven surfaces,bumps and ruts will make it much harder to keep the steering wheel straight.

KPO also naturally adds postive camber on the outer wheel when the body roll increases during cornering.

Limited Slip differencials combined with a large KPO make steering even worse. (not sure why)

Although ideally the KPO should be zero ( KPI line intersects wheel centerline) many race cars have a very high KPO because it creates a much wider stance and helps with cornering.

Fortunatly for these drivers the race track is much smoother than the street so they don't see ill effects from hitting potholes.

So all and all you can decrease the offset as much as you feel like but it will start to affect your ability to keep the car in a straight line when you hit bumps or ruts in the road.

I personally find the Lanos steering very light so I wouldn't mind changing the offset a little so that I feel the road a little more.

As well this extra leverage will wear out suspension components quicker but how quickly depends upon your driving style and the local road conditons.

Post by **PrecisionBoost** » Mon Dec 29, 2003 12:18 am

Finally got a chance to show the diagram of the King Pin offset....

http://ca.f1.pg.photos.yahoo.com/ph/erf ... ingpin.jpg