+38 versus +45 offset???
04-03-02, 05:09 AM
#1
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+38 versus +45 offset???
Guys and gals,
I have "knock-off" Konig Imagine's with a +38 offset front and rear. To make a long story short, my car is almost uncontrollable on uneven road and my tires wear unevenly. If I go to a +45 offset will this make a huge difference or is the variance of +7 not a big deal. If that's the case then something else is wrong with my vehicle.
Your help is appreciated as always.
I have "knock-off" Konig Imagine's with a +38 offset front and rear. To make a long story short, my car is almost uncontrollable on uneven road and my tires wear unevenly. If I go to a +45 offset will this make a huge difference or is the variance of +7 not a big deal. If that's the case then something else is wrong with my vehicle.
Your help is appreciated as always.
04-03-02, 06:22 AM
#2
Lexus Test Driver
I feel your pain...
That's what happens when you go too far past the factory offset. The low profile, wide tire and 18" height are contributing factors. My wheels are 40 offset, and can't stand the way it pulls on worn pavement. Certain tread styles are more or less resistant to this tendancy, so changing tires may help a little, but not cure the symptom.
There is a designed center axis of steering on cars.
What happens is you put the center of the rim out past the steering knuckle. This allows the wheel to put torque on the knuckle which manifests itself as the car veering to one side or the other. Keeping the offset close to the 50mm is a good step towards reducing this tendancy. With the wider tread, lower profile, you'll still get some wander, but it will be reduced.
You should also have your alignment checked although its not likely to change the situation.
That's what happens when you go too far past the factory offset. The low profile, wide tire and 18" height are contributing factors. My wheels are 40 offset, and can't stand the way it pulls on worn pavement. Certain tread styles are more or less resistant to this tendancy, so changing tires may help a little, but not cure the symptom.
There is a designed center axis of steering on cars.
What happens is you put the center of the rim out past the steering knuckle. This allows the wheel to put torque on the knuckle which manifests itself as the car veering to one side or the other. Keeping the offset close to the 50mm is a good step towards reducing this tendancy. With the wider tread, lower profile, you'll still get some wander, but it will be reduced.
You should also have your alignment checked although its not likely to change the situation.
04-03-02, 07:00 AM
#4
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Ok, I am trying to understand offset here and was just wondering if a 47 offset would be fine for 18 inch wheels on my sc300. If the stock is 50 like you say, then will I really feel torque steer and such?
04-03-02, 07:44 AM
#5
Lexus Test Driver
47 would be very close (and a good fitment).
I have a wheel diagram on my site that is for the Supra, but the SC300 has the same suspension geometry and general wheel clearances, etc.
www.datapathusa.com/scott/scott.html.
Its an excel spreadsheet that you can use to approximate good fitments v.s. bad fitments. If you keep that 47 offset, the wheel will have to be pretty wide for the rim to be flush with the fender - (which = good looks). 18x9 fronts and 18x10 rears would be pretty close to perfect on a 47 offset.
What you want is for the rim surface to be flush with the fender, and the offset still high like 47-50. That will give you the best combination of looks and keep your steering in line.
I have a wheel diagram on my site that is for the Supra, but the SC300 has the same suspension geometry and general wheel clearances, etc.
www.datapathusa.com/scott/scott.html.
Its an excel spreadsheet that you can use to approximate good fitments v.s. bad fitments. If you keep that 47 offset, the wheel will have to be pretty wide for the rim to be flush with the fender - (which = good looks). 18x9 fronts and 18x10 rears would be pretty close to perfect on a 47 offset.
What you want is for the rim surface to be flush with the fender, and the offset still high like 47-50. That will give you the best combination of looks and keep your steering in line.
04-03-02, 11:07 AM
#7
Lexus Champion
18x9 +47 sounds great, but will not clear the front suspension upright. Needs to be +40 or lower to physically fit the car.
It's strange, I have always changed the wheels offsets on my cars (to be more 'aggressive'), and have never felt that any of them were darty or dangerous. Typically the newer cars with their more advanced suspension geometries seem less sensitive to wheel offset changes versus cars in the past.
We do this on Vipers, Ferrari F360s & F550s, Porsche Turbos, etc., and have never had as much as a negative comment. In my little dream world, I would build a bunch of (for example) 18x8.5 wheels with varying offsets and equip them all with identical tires for some instrumented testing & evaluation (on the same exact car).
On my '85 MR2, when I put the stock wheels back on, the steeering feels 'slow' at low speeds, but my 17" HRE's are stable as can be on the freeway and have Viper-like grip in the corners with 225/35zr17 front and 245/35zr17 rear.
It's strange, I have always changed the wheels offsets on my cars (to be more 'aggressive'), and have never felt that any of them were darty or dangerous. Typically the newer cars with their more advanced suspension geometries seem less sensitive to wheel offset changes versus cars in the past.
We do this on Vipers, Ferrari F360s & F550s, Porsche Turbos, etc., and have never had as much as a negative comment. In my little dream world, I would build a bunch of (for example) 18x8.5 wheels with varying offsets and equip them all with identical tires for some instrumented testing & evaluation (on the same exact car).
On my '85 MR2, when I put the stock wheels back on, the steeering feels 'slow' at low speeds, but my 17" HRE's are stable as can be on the freeway and have Viper-like grip in the corners with 225/35zr17 front and 245/35zr17 rear.
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04-03-02, 12:25 PM
#8
Lexus Champion
I have +38 all around, the car has a big problem with the steering wheel torquing on uneven or crowned surfaces, especially when braking, it's unsafe, the car wants to change lanes sometimes. We've discussed this before Scott, not long ago. I told them I wanted anything in the mid 40's for my offset, later, when I realize the problem, I check the offset and they're 38mm front and rear, but the wheel shop, Precision Installations, NY's only certified Volk and RH dealer, said there was nothing they could do, that they've never heard of offset creating this problem, they called the manufacturer, who told me that they never heard of that either. I explained to them that anything that altered the track of the vehicle that much could affect suspension geometry, but they still wouldn't admit to a poor fitment. It's OK, if I don't get my hands around his neck (can't get him alone for even a minute), then i'll get my lawyer's hand around his b@lls.
P.S. - I'll do an alignment and see if it helps. Hoops, what tyres are you using? Have you aligned it?
P.S. - I'll do an alignment and see if it helps. Hoops, what tyres are you using? Have you aligned it?
Last edited by Lex Luthor; 04-03-02 at 12:28 PM.
04-03-02, 02:07 PM
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I'm runnin' Bridgestone Potenza's SO3's which are the creme de la creme of tires IMO.
The tires were purchased less than a month ago and I had them aligned at the time. Also, this is my 2nd set. The first pair were totally chewed up in about 60 days. They were replaced free of charge by Kost Tire. I know it isn't the tire though because I have to "fight" the car to keep it straight on uneven pavement. Also, when I brake I get some serious pulsing and pulling to one side. And last but not least, I have significant tire warble which is getting louder.
This is the reason I'm lookin' to drop abouit $3k on new rims. If i'm wasting my time than I will keep the cash and buy my wife them ugly *** pots and pans she wants.
wtf is going on?
Emerald, ALL Konig's are knockoffs. The Imagine is a knock off of the Rezax II by Work. Here's the REAL deal. Nasty!!
Rezax II
The tires were purchased less than a month ago and I had them aligned at the time. Also, this is my 2nd set. The first pair were totally chewed up in about 60 days. They were replaced free of charge by Kost Tire. I know it isn't the tire though because I have to "fight" the car to keep it straight on uneven pavement. Also, when I brake I get some serious pulsing and pulling to one side. And last but not least, I have significant tire warble which is getting louder.
This is the reason I'm lookin' to drop abouit $3k on new rims. If i'm wasting my time than I will keep the cash and buy my wife them ugly *** pots and pans she wants.
wtf is going on?
Emerald, ALL Konig's are knockoffs. The Imagine is a knock off of the Rezax II by Work. Here's the REAL deal. Nasty!!
Rezax II
Last edited by hoops_24; 04-03-02 at 02:38 PM.
04-04-02, 01:09 AM
#11
Lexus Fanatic
Just a though but what about the fact that with these new wheels, you're also putting on low profile tires. They have much less sidewall and that, to me, seems like it would cause your tires to "hook and stay" in the grooves (less "flexability" in the sidewalls)...
I've had cars with larger diameter wheels that were the same offset (as stock) with only a small increase in tire width (but a big decrease in sidewall height and it did the same thing...never to the point where it was "dangerous" though..
Even with my current setup on my GS, (20x8.5 +38 F and 20x9.5 +37 rear) it does sometimes "hook" into odd contours of some roads but again, never to the point where I felt it was "dangerous"...
Maybe you guys just have weak arms!!
I've had cars with larger diameter wheels that were the same offset (as stock) with only a small increase in tire width (but a big decrease in sidewall height and it did the same thing...never to the point where it was "dangerous" though..
Even with my current setup on my GS, (20x8.5 +38 F and 20x9.5 +37 rear) it does sometimes "hook" into odd contours of some roads but again, never to the point where I felt it was "dangerous"...
Maybe you guys just have weak arms!!
04-04-02, 06:21 AM
#12
Lexus Test Driver
I didn't get to test two identical tires, but he's what I had to test:
Setup #1. ---Taken from wife's car.
Lexus GS400 front rims 17x8 with Lexus offset (i think its around +50mm) and Michelin pilot sports up front 235/45/17. ---This setup yielded very little dartiness and tendancy to track and pull the wheel on worn roads.
Setup #2
Monsoon front rims 17x8 with +40mm offset and Dunlop SP5000 sports up front. ---This setup has horrible tendancy to wander everywhere despite being the same width, same category of tire, etc.
BTW---- has anyone driven a slammed honda with deep dish spindle wheels sticking out 6" from the side of the car? Its the same effect, only not as pronounced...
Setup #1. ---Taken from wife's car.
Lexus GS400 front rims 17x8 with Lexus offset (i think its around +50mm) and Michelin pilot sports up front 235/45/17. ---This setup yielded very little dartiness and tendancy to track and pull the wheel on worn roads.
Setup #2
Monsoon front rims 17x8 with +40mm offset and Dunlop SP5000 sports up front. ---This setup has horrible tendancy to wander everywhere despite being the same width, same category of tire, etc.
BTW---- has anyone driven a slammed honda with deep dish spindle wheels sticking out 6" from the side of the car? Its the same effect, only not as pronounced...
Last edited by SC300T; 04-04-02 at 06:23 AM.
04-04-02, 06:36 AM
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I've got two sets of rims.
Original 16 inch by 7 with 50mm offset 225 tyres
BBS forged 18 inch rims front offset 38mm, rear is 42mm offset.
Both sets were shocking on the car until a factory spec wheel alignment. This improved the car out of sight. The standard rims were perfect, the 18's were much better.
The 18's had worn front tyres (scrubbing on outside).
New generation Kuhmo 712 Ecstas on the front fixed the 18's.
In my case the alignment made the biggest difference.
Tyres made a huge difference on the 18's.
Offset had no negative effects.
The car steers and handles better with the 18's. No tramlining, no pulling over uneven surfaces - effortless to drive.
Some tyres tramline worse than others.
The Soarer needs a four wheel laser alignment to get it singing. Before an alignment my car was darting all over the road.
Alignment and tyres have a far greater effect on the handling than offset. Technical Books reference rear wheel drive cars get better turn in reducing the offset.
Original 16 inch by 7 with 50mm offset 225 tyres
BBS forged 18 inch rims front offset 38mm, rear is 42mm offset.
Both sets were shocking on the car until a factory spec wheel alignment. This improved the car out of sight. The standard rims were perfect, the 18's were much better.
The 18's had worn front tyres (scrubbing on outside).
New generation Kuhmo 712 Ecstas on the front fixed the 18's.
In my case the alignment made the biggest difference.
Tyres made a huge difference on the 18's.
Offset had no negative effects.
The car steers and handles better with the 18's. No tramlining, no pulling over uneven surfaces - effortless to drive.
Some tyres tramline worse than others.
The Soarer needs a four wheel laser alignment to get it singing. Before an alignment my car was darting all over the road.
Alignment and tyres have a far greater effect on the handling than offset. Technical Books reference rear wheel drive cars get better turn in reducing the offset.