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offset question.

Posted: October 28th, 2009, 10:02 am
by MX-3zoom
so i sold my old 17'' rims and dropped my car all the way, looking for new 15's. i've searched in posts, seeing if these would fit.

Size: 2 rims 15x7 with 2.5" Lip, offset is +15

Size: 2 rims 15X8 with 3.5" Lip 0ffset is +0

Bolt Pattern: 4X100 and 4X114.3 (4.5")

Offset: +0 mm




second rims-



Size- 15"x6.5"

Bolt Pattern - 4x100 and 4x114.3
Offset- +40mm



knowing the mx3 stock is 4x100 o.s. 45. will these fit. do i have to roll the fenders? just wanna pick up some rims for summer. fresh paint needs fresh rims :P anyone?

Re: offset question.

Posted: October 28th, 2009, 10:35 am
by wytbishop
Offset is the distance between the plane of the hub and the center line of the wheel. Our stock offset is +45mm. Being positive means that the hub plane is toward the outside of the vehicle. Negative offset is when the plane of the hub is closer to the center of the car than the centerline of the wheel.

As the offset becomes more positive the wheel effectively shifts closer and closer to the car. I would not use a wheel with more than 45mm offset. I’ve read people say that 38mm offset on a 7” wide wheel is perfect for the MX-3.

Keep in mind that if you want a big lip you need to worry about the fender covering the entire wheel.


http://www.1010tires.com/WheelOffsetCalculator.asp" onclick="window.open(this.href);return false;

Re: offset question.

Posted: October 28th, 2009, 11:08 am
by MX-3zoom
bummer.. not a fan of messing with the fenders. so my first set is a nooo... will my second set work? i wanna keep it 15's, 17's are for show, to much road feel for me. http://cgi.ebay.com/ebaymotors/15-Black ... 0416669981 there's the second set. really hope these will work...

Re: offset question.

Posted: October 28th, 2009, 11:53 am
by _-Night-Shade-_
I've got Enkei RSF-2s and they're 17x7 with +40 offset and it's fine.

Re: offset question.

Posted: October 28th, 2009, 12:00 pm
by MX-3zoom
sweeet...wanted to make sure before i buy and can't return. thanks

Re: offset question.

Posted: October 28th, 2009, 12:06 pm
by MX-3zoom
last question...my friend here "MR. HONDA" claims those are not worth the buy, said they are probably cheaply made. and will sooner or later break. which is funny, because i read the rota post earlier, but these are not rota's, thou same in design. can this be true...

Re: offset question.

Posted: October 28th, 2009, 12:28 pm
by wytbishop
awesome tire/wheel calculator compares 2 wheels so you can see the difference betw3een stock and the wheel/tire you want.

http://www.wheelsmaster.com/rt_specs.jsp" onclick="window.open(this.href);return false;

Re: offset question.

Posted: October 28th, 2009, 12:47 pm
by onlytrueromeo
ANother problem w/ messing w/ offset too much aside from fender rolling is the affect on scrub radius.

FWD/Macpherson strut cars are designed w/ slight negative scrub. As you move the tire contact patch center out from the suspension/steering angle of inclination (or w/e its called) you are increasing the scrub. A positive scrub will cause "bump steer" and increased steering effort, neither of which are good. A zero scrub, while leading to straight stability will decrease stability on corners.

Yes, a wider track will increase the cars lateral acceleration abilities, faster turn in and will look cooler, but if proper suspension geometry is not maintained you will get an overall decrease in performance, not to mention wheel bearings will wear faster (though this may not be an issue for some).

Wytbishop had it right, don't go over a 35/38mm offset.


For those of us that are crazy (like myself) I have been reading into scrub and steering angles lately, and trying to decide if it is worth it to modify the suspension in such a way to allow for increased offset while still maintaining negative scrub. This would of course require increased fender flares.

Re: offset question.

Posted: October 28th, 2009, 1:08 pm
by _-Night-Shade-_
wytbishop wrote:awesome tire/wheel calculator compares 2 wheels so you can see the difference betw3een stock and the wheel/tire you want.

http://www.wheelsmaster.com/rt_specs.jsp" onclick="window.open(this.href);return false;
Awesome! Thanks for the link.

...I will have to read about this scrub area thing, I always thought a wider tire is better cause it grips the road more and you will have better handling.

Re: offset question.

Posted: October 28th, 2009, 1:10 pm
by onlytrueromeo
I just posted some more about scrub in my chassis stiffening/handling improvements topic.

I will be researching more into it over the weekend. Can't cut the car apart til I have a garage but I can do lots of reading!

Re: offset question.

Posted: October 28th, 2009, 1:11 pm
by _-Night-Shade-_
onlytrueromeo wrote:I just posted some more about scrub in my chassis stiffening/handling improvements topic.

I will be researching more into it over the weekend. Can't cut the car apart til I have a garage but I can do lots of reading!
Yes I just read it! I see what you mean now, never thought about that. I wonder if 17x7 +40 will made a huge difference. Is there a calculator for the scrub radius much like wytbishop posted for the wheels?

Re: offset question.

Posted: October 28th, 2009, 1:22 pm
by MX-3zoom
onlytrueromeo wrote:ANother problem w/ messing w/ offset too much aside from fender rolling is the affect on scrub radius.

FWD/Macpherson strut cars are designed w/ slight negative scrub. As you move the tire contact patch center out from the suspension/steering angle of inclination (or w/e its called) you are increasing the scrub. A positive scrub will cause "bump steer" and increased steering effort, neither of which are good. A zero scrub, while leading to straight stability will decrease stability on corners.

Yes, a wider track will increase the cars lateral acceleration abilities, faster turn in and will look cooler, but if proper suspension geometry is not maintained you will get an overall decrease in performance, not to mention wheel bearings will wear faster (though this may not be an issue for some).

Wytbishop had it right, don't go over a 35/38mm offset.


For those of us that are crazy (like myself) I have been reading into scrub and steering angles lately, and trying to decide if it is worth it to modify the suspension in such a way to allow for increased offset while still maintaining negative scrub. This would of course require increased fender flares.
i hope +40 isnt pushin it. really really like those

Re: offset question.

Posted: October 28th, 2009, 1:24 pm
by onlytrueromeo
No, scrub is car specific, meaning you can't calculate it from wheel width/diameter like you can w/ the calculator that tells you how much your circumference is changing.

We'd need to measure it, which wouldn't be that hard. Someone w/ a slightly warmer/drier/heated/garaged environment could do it. From there we could figure things out!

Re: offset question.

Posted: October 28th, 2009, 1:28 pm
by onlytrueromeo
The +40's should fit depending on how wide of a tire you go. You can always run a 5mm spacer too, but I don't think you will need it unless you try running 215-225's, which are too wide IMO for a 6.5" wheel.

Keep in mind stock is 45, and every number you go lower moves the tire further towards the outside of the car. when you jump to a wider rim/tire you need a lower offset otherwise it will rub the strut.

Re: offset question.

Posted: October 28th, 2009, 1:33 pm
by MX-3zoom
ill just buy them and work from there. had 17's pretty wide tires, no rub. these's should work....thanks everyone, now im ready to buy :D learned alot today!