Offset Gurus.....

[JRTurbo909]

I have decided to make somewhat of a change on my original plans for my car. I am doing a roadrace set-up primarily and I want the widest wheels i can possibly fit on it. I bought some Jun over fenders and I believe these extend the fender about 30mm. At least thats what they say on Jspec.com. Does any one have the actual measurements of these?

Anyways, I am buying some 15 or 16 inch road race wheels that I can get in any size or offset. Whats the widest I could go and what offset would be good to get this FLUSH. I know exactly what I am doin in terms of a set-up, so I just need u guys to help me with the right sizes and offsets for a 10in or 9.5in wheel. Thanks.

Shah

[nightwalker]

This is a 15x7 +10. Tires are a 195/55/15. Just a little bit-o- stretch. Camber is -1.25. The front, you can't see the tire because it's a -3 camber. So if you want those fenders, add 30mm to the offset. If you want a wider wheel, 8inch? configure that into it as well. I forget how many millimeters in an inch.
http://www.imagestation.com/picture/sraid102/p95580369e3a6b5460305a1246ff184ea/f9b76480.jpg.orig.jpg

[DuffMan]

S13 or S14, what, if any coilovers.

You need to provide a lot more information in order to get a answer thats actually meaningful.

[adey]

I'm pretty sure you can fit 15*8.5 +/-0 with 205/60/15 with little problem... I imagine you could probably fit a 16*9 +/-0 with 225/50/16 quite easily if you wanted to, too. It would certainly be tight, but doable!

[DuffMan]

You could fit a 10 or 10.5 inch wheel in front with 275 tires and clear coilovers if you wanted to with 30mm wider fenders. +4 or lower offset. On a S13.

[nokeone]

This is a 15x7 +10. Tires are a 195/55/15. Just a little bit-o- stretch. Camber is -1.25. The front, you can't see the tire because it's a -3 camber. So if you want those fenders, add 30mm to the offset. If you want a wider wheel, 8inch? configure that into it as well. I forget how many millimeters in an inch.
http://www.imagestation.com/picture/sraid102/p95580369e3a6b5460305a1246ff184ea/f9b76480.jpg.orig.jpg


http://www.imagestation.com/picture/sraid102/p95580369e3a6b5460305a1246ff184ea/f9b76480.jpg

[DoriftoSlut]

You could fit a 10 or 10.5 inch wheel in front with 275 tires and clear coilovers if you wanted to with 30mm wider fenders. +4 or lower offset. On a S13.
Duffman, how do you propose to turn? Your wheels would hit either: TC rod, fame, fender, or LCA. OR all of those... And don't you scream bloody murder ranting about bump steer and shit when I talk about 9J +10 wheels?

[LanceS13]

Duffman, how do you propose to turn? Your wheels would hit either: TC rod, fame, fender, or LCA. OR all of those... And don't you scream bloody murder ranting about bump steer and shit when I talk about 9J +10 wheels?

No they wouldn't. The inside of the tire wouldn't be any closer than any other narrower wheel/tire. It'll rub the strut long before it hits any of those components. With the right offset, the wheels/tire would just extend outboard, so the only clearance problem is the fenders, which are already taken care of in this case from the sound of it.
I know it's not a 240, but similar size and I *think* DSM's have front McPherson struts like we do...kinda nuts: http://www.wincom.net/trog/newimages/2002_cartitle.jpg
I believe those are 17x9.5 +12 w/ 275/40/17 tires.

[DuffMan]

Duffman, how do you propose to turn? Your wheels would hit either: TC rod, fame, fender, or LCA. OR all of those... And don't you scream bloody murder ranting about bump steer and shit when I talk about 9J +10 wheels?

Turning is overrated.

Actually, I dont think they would hit anything with the wide fenders. He asked what is the widest you could run, not what he should run. If you were going to actually do this, S14 front suspension swap would make decent handling and 10 inch wide wheels within the realm of possibility.

[driftingpanda]

Actually, I dont think they would hit anything with the wide fenders.

Duffman, even if he had NO fenders, when turning, the high scrub radius of the wheels/tires will definately rub some, if not all, of the items doriftoslut mentioned. with a 10.5 wide wheel, 275 wide tire, and +4 or lower offset, you're looking at nearly 20% loss of your steering capabilities due to obstruction. although it would decrease the scrub radius somewhat, the same thing is still very likely to occur even with s14 front suspension, since your firewall, tc rod, and inner fender aren't gonna move anywhere. nonetheless, you are 100% correct that it is possible to "run" these specs.

JRTurbo909, IMHO, if you're serious about a roadrace setup, you should focus more on scrub radius, jacking forces, camber limits, wheel/tire weight, and contact patch shift, rather than just width and flush-ness. but, if you're just looking for the widest wheel that's flush with your wide fenders, you'd have almost 11 to 12 inches to work with. (stock strut to fender distance is about 10", with your 30mm fender and possible coilovers, distance adds up to about 11"-12", depending on your camber.) just measure from your coilover to the fender lip, (this equals to the widest width wheel/tire possible), divide that measurement by two, and subtract the horizontal (normal) distance from your hub mounting face to the edge of your coilover (this is the offset). give yourself a 5mm "safety margin", and you should have a good general idea of what fits and what doesn't. camber does wonders with wheel fitment, so don't forget to factor that in. hope that wasn't too confusing...

danny

[DuffMan]

Maybe myself, and LanceS13 are missing something here, but I still dont see it. The axis of rotation isnt the center of the tire, its the line passing through the upper strut mount and ball joint of the control arm. Relitive to that axis, the tire/wheel is "expanding" outward. Theres nothing out there but fender.

[driftingpanda]

Maybe myself, and LanceS13 are missing something here, but I still dont see it. The axis of rotation isnt the center of the tire, its the line passing through the upper strut mount and ball joint of the control arm. Relitive to that axis, the tire/wheel is "expanding" outward. Theres nothing out there but fender.

the outward 'expansion' as you call it, will cause the outer edge of the wheel to move away from the steering axis of the front suspension. the distance from the center of the contact patch (ie center of tire), to the center of the steering axis, is called scrub radius. with wider wheels/tires, and/or low positive offset (or even negative offset), the scrub radius increases. now, imagine if you will, a big ass wheel/tire that's very far away from the steering axis (aka kingpin rotational axis). when these wheels are steered, there will be a lot of front/back movement (as opposed to just pivoting), which will force the tire to contact the INNER fender, also known as wheel wells. there are some pinch welded sections of the inner fender that can be hammered down for more clearence, but even then there isn't enough room for such a wide wheel with such a low offset. doriftoslut's shetty car experiences this with mere 17x9" wheels, super stretched tires, stock fenders, and +5 offset (IIRC). i don't know what else i can say to clarify that... should i draw a picture?

danny

[driftingpanda]

here you go... i feel kinda lifeless/pathetic, so this better help someone!

danny

[nokeone]

hahaha...nice drawing...actually really helped in understanding...:D

[LanceS13]

I know what you're talking about, but I still don't see where the suspension components would come into play...just the fender and inner fender. Even you're drawing shows the inside of the bigger wheel/tire is further away from where the suspension pieces would be than the smaller wheel/tire.

I dunno...I'm not gonna say it'll work b/c I've never seen it done.

[DoriftoSlut]

Danny, dont make fun of my car!!! Just cause it sucks and has been stuck at your house for 3 weeks with us working on it every damned day!!!! Oh and the front wheels Offset are +10 cause i'm "only" running a 20mm spacer. +10 on stock, rolled and ever slightly pulled fenders... Shit, you were there for the fender rolling aka "heating and beating".

Nice drawring btw. You should also go to art center. Hahaha. I keeed I keeeed.

[DoriftoSlut]

In theory, things work out much differently than planned. Once you actually have a big wide low wheel in there and see where it rubs and bangs you will understand. And aftermarket TC rods are HUGE. With an increased steering angle it is very possible you can hit those without a low enough offset. Fine. But when you go reaaaly wide and need that low enough offset to clear you inner suspension bits, your scrub radius increases, and your tire starts rubbing shit near its outer edge.

Not to sound elitest or any shit liek that, but if you could see it first hand and sit there with your car and see what hits your tire and shit you would understand. I didn't think it was possible until i got home from the track and I had bright silver polished patches on various suspension bits and the INNER lip of my wheel was scraped to high hell.

[adey]

FWIW my experiences are as doriftoslut and driftingpanda explain it... I have rubbed 3 parts of my front wheel wells so far: my ('outer') fender, my inner fender and the "firewall" side, all "just" running 205/55/15 on 15*7 +2 wheels with between 2 and 3 degrees of negative camber.

Unfortunately, unlike dorifto and drifting, I lack the intellectual capacity to understand why.

[driftingpanda]

my mistake! i didn't notice doriftoslut's mention of LCA. the LCA on doriftoslut's car doesn't hit anything other than the dirt at buttonwillow (heh). the TC rod, however, extends towards front of the car at an angle smaller than the largest possible steering angle, thus making it possible for a high scrub radiused tire to rub it. no more pictures from me. go take a look under your car, cut out some cardboard circles to illustrate wheel size/offset, and just play around. apparently, cardboard circles can be much more convincing than i ever will be. adey, you shouldn't be saying such nonsense, you are so capable (just look at your perfect grammar, proper punctuation, and respectable user name!)

danny

[JRTurbo909]

Well, sorry guys for not explaining it futher. I was in a rush when I wrote that so I forgot to mention some things. The car is an S13 with tien coilovers. I also have all the basic suspension pieces (tension rod, tie rod, various other braces). I was just trying to get somewhat of a feel for all this and see what kind of experiences you guys had. Thanks for all the info, it really helps.

So I plan on doing some measuring and what not, but based on the scrub raduis, and the suspension components rubbing, what do you guys think would be a safe or optimal setup. I want the widest wheel that will aid in my handling, not something that will hinder it. What do u guys think bout the width for the front and rear to give maximum grip?

[DuffMan]

You could probably contact the frame inside the fender. I'll give you that. It doesnt really matter though for race car. Drifting with full lock counter steer, I'm sure you could wreck a wheel or tire. But on a fast course I really doubt it would happen. Race cars with widebody fenders are set up like this all the time. If the lose control of the car, they can cut a tire. Just pit and get a new one.

Contacting the suspension parts I still dont get. Do you have a steering rack mod done to your car to increase max turning lock? My wheels and tires are right against the Tein HE springs. I dont see how a wheel/tire that has 2 more inches outward from the suspension would be any different in terms of susepsnion clearance.

As to what tire you should run, I dont really know. Though I am assuming if you were really serious about wheel to wheel track racing, you'd be at the track trying different setups instead of asking us. Other peoples opinions of what works for their car isnt a substitute for real word experience with your own car.

[JRTurbo909]

Though I am assuming if you were really serious about wheel to wheel track racing, you'd be at the track trying different setups instead of asking us. Other peoples opinions of what works for their car isnt a substitute for real word experience with your own car.


Oh i agree entirely. I just wanted to know what kinds of setups people have tried before and their experiences on them. We all need to have at least a starting point and I am just trying to get an idea on where that is for me.


Shah

[DoriftoSlut]

offsetsaside, many people who i respect as grip drivers with their 240s reccomend 8 inch wheel with 225 tires, or 9 inch with 235/ 245s.

Duffman... steering angle? tie rod spacer will do that, wich I currently do not have on my car cause i am lazy and need to buy them already. Many people i know have them and have more problems than i do.

Again, like I said, theorize and calculate all you want, but until it happens to you, i guess you may never know... I don't know how else to put it. I'm not making shit up.

[DuffMan]

offsetsaside, many people who i respect as grip drivers with their 240s reccomend 8 inch wheel with 225 tires, or 9 inch with 235/ 245s.

Out of curiosity, are they running street tires or r compound?

Again, like I said, theorize and calculate all you want, but until it happens to you, i guess you may never know... I don't know how else to put it. I'm not making shit up.

Well I'm not saying you're lying I just dont really understand how if it is happening, running wider or narrower wheels would make it any different.

[VersionS13]

Anyone ever try 16x8 -10 offset on the rear of an S13?

[DuffMan]

That wont fit without an assload of camber.

[VersionS13]

That wont fit without an assload of camber.
How bad do you think that would stick out? About an inch or 2?

[SimpleS14]

Is this a good size for a S14....

17x8.5, +22, with 215/40/17 tires ?

[pruto]

Is this a good size for a S14....

17x8.5, +22, with 215/40/17 tires ?

are you talking about flushness? the 215/40 will be a bit of stretch and small for a s14,
for flushness it depends on camber. I have 17x8.5 +35 with 245/40/17 up front, with like 2 degrees of camber currently. I'm guessin' it needs a 15mm spacer and fender rollin' for it to be completely flush, but i'm not that anal. :fruit:

nice drawing danny. :cool:

[SimpleS14]

ah yes....I was just guessing on tire size....

I'm not that anal about flushness, just wanted to know if I would have any issues with an offset and width such at that. BTW...that's a funny sig you have there pruto.

[pruto]

ah yes....I was just guessing on tire size....

I'm not that anal about flushness, just wanted to know if I would have any issues with an offset and width such at that. BTW...that's a funny sig you have there pruto.

thanks, Pluto rocks, i let him drive my car when i'm tired or drunk =)

irc Sam from jspec recommended 235/45/17s for my front wheels. You might want lower profile for better cornering or lower width for better steering response/feel or just to fit crazy offset wheels. But a combo of both means smaller tire size. I'm sure someone else can give you better advice. I'm not sure why i went with such big ass rubber up front, it grips like a mo fo but doesn't have the right feel to it sometimes.

17x8.5 +22 will fit great and will clear coilovers

[DoriftoSlut]

215/40/17 is fine for front. I use it because I am running a lot of caster, and it lower the front of my car, making my CG lower. The 215/40.17 on a 9 inch has much mroe clearance than i did with 215/45 or 225/45/17 up front. I like it alot.

Do not run 215/40/17 in ther ear though. It si quite a bit smaller overall diameter than stock so if ran int eh rear you speed reading would be way off, PLUS, you don't need such a small tire. Rear has plenty more room for clearance and it looks really ugly with such small overall diameter back there anyways.

[SimpleS14]

cool...thanks for the info guys...

I have one more newbish question..

say my rims are 17x7, +35, tires 225/45/17....is it a bad idea to get longer studs (60mm) and 10mm spacers? I'm curious to know if that will greatly affect ride and handling.

[adey]

running a 10mm spacer won't hurt anything noticably as long as the wheels are properly torqued down. You probably don't even need extended studs to run a 10mm spacer (it's recommended you have 8 full turns of a lugnut, though this can be flexible)... but if you insist on longer studs, 50mm will do just fine too. (Incase you can't find 60s.) On S13, stock stud length was ~42mm.

Keep in mind that 225/45/17 is both taller than stock, and will give you noticable "mush" in steering (and everything, really) response as well as an ugly bulge in the sidewall. That means speedo readings that are lower than acual, as well as poorer cornering performance. You will, however, gain (marginally) gas mileage and ride comfort.

[DuffMan]

You probably don't even need extended studs to run a 10mm spacer

:smash:

...................

[adey]

Whaat, whaaaaaat?? I've done 9mm (3*3mm) without any sort of ill effects... of course it's not ideal, but I don't think it's so bad on a street driven car!

[SimpleS14]

My car will be street driven, however...I tend to have spirted runs on some backroads once in awhile.

[hybrid_eg]

I have an S13 stock body, TEIN HE's (will roll fenders front and rear) and if needed cut along the lip (inside once the fender is rolled) to minimize any potential rubbing.

Wheels are 16x8 +0 offset, most importanly with what tire size will they fit? I know i will need neg camber up front of course, and rear as well (need to by rear adj. cntrl arms)

Thanks all.

[SimpleS14]

ok...since this thread have been dugged up I have another question...

will I have any issues with 17*8.5 +30 in the front and 17*9.5 +30 in the rear?


oh yea...I thought this offset calculator for anyone that wants to check it out..
http://toy4two.home.mindspring.com/offset.html

[VersionS13]

ok...since this thread have been dugged up I have another question...

will I have any issues with 17*8.5 +30 in the front and 17*9.5 +30 in the rear?


oh yea...I thought this offset calculator for anyone that wants to check it out..
http://toy4two.home.mindspring.com/offset.html
I have the same question about 17x8.5 and 17.9.5, but for a S13. I'm trying to figure out which offset I will need to go with to clear Z brakes and Tein Flex coilovers on stock fenders, for now anyway

[ryan hagen]

[QUOTE=adey
Keep in mind that 225/45/17 is both taller than stock, and will give you noticable "mush" in steering (and everything, really) response as well as an ugly bulge in the sidewall. That means speedo readings that are lower than acual, as well as poorer cornering performance. You will, however, gain (marginally) gas mileage and ride comfort.[/QUOTE]


i ran a 17 by 7 with a 225-40 and there is pretty much flushness, slight buldge but not bad at all, look alot better than steched and the handleing was hard.....

[adey]

To that I'd say I suggest you hold your judgement until you've tried driving a car with slightly stretched rather than slightly bulged tires... you'll notice a difference, I guarantee it!