# calling all NEB's....verify my wheel calculations please....



## deepblueT (Jan 26, 2008)

I've been doing searches and calculations for days, and have learned alot and been confused all at the same time. i have found equations and calculators that don't quite match up... 

i am selling my current 18x8.5 ET35 rims. i had these on with no spacers. i ran 235/40-18 on all of them.

my new setup that i want. 

want to know if it will work as follows.

front:
18x8 ET35 with a 19mm spacer
Rear:
18x9.5 ET45 with a 18mm adapter

I have H&R springs at 1.5" drop

i will reuse the 235/40-18 on the rear and i am now realizing i will need at least a 225/40-18 on the front. my initial idea was to just reuse all the tires saving cash...but i know that a 235 on a 8" will not look good against the slight stretch of the 235 on the 9.5. 

my question is...this calculator http://www.senebdesign.com/Auto/TT-offsetcalc.htm
tells me i should be good with my sizing, but other equations give me a little different info. 

is the above calculator on the money accurate for a TT? 

in the equations, i used info a gathered from my 18x8.5 not the stock wheels. but if the calculator has exact dimensions from the tt i will follow that result.


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## [email protected] (Jul 1, 2009)

Have you referred to this?

http://senebdesign.com/Auto/TT-offsetcalc.htm


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## deepblueT (Jan 26, 2008)

yeah thats the link i have in my post. i'm wondering how accurate it is. i don't mind a slight poke or stretch as i want the staggard lip look with the wheels i want. just want to know if my spacer/adapter choices are correct. the calculator says it works. anybody used this, bought the setup and have it work perfect? 

thanks.


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## TTC2k5 (May 23, 2008)

as I ran your numbers, it says the rear will be outside the the fender...is that what you want?


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## deepblueT (Jan 26, 2008)

TTC2k5 said:


> as I ran your numbers, it says the rear will be outside the the fender...is that what you want?


see quote below. 



deepblueT said:


> yeah thats the link i have in my post. i'm wondering how accurate it is. *i don't mind a slight poke or stretch as i want the staggard lip look with the wheels i want*. just want to know if my spacer/adapter choices are correct. the calculator says it works. anybody used this, bought the setup and have it work perfect?
> 
> thanks.


i'm more worried about my offset and adapter choices. 1.7mm outside fender is extrememly minimal, and the stretch from the 235 should give me the clearence i need for the fender right? as long as the calculator is accurate i'm happy with that outcome.


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## Forty-six and 2 (Jan 21, 2007)

The calculator was made based off of photos and estimates. I'm sure it's fairly accurate, but if you are counting on a down to the mm prefect fit, I wouldn't put full faith in it.


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## deepblueT (Jan 26, 2008)

i don't need a down to the mm measurement. 

i need to know that the calculator is accurate enough that i will only poke 1.7mm or so past fender... not the 10 mm the equation gives me. i'm gonna go attempt to measure actual measurements seeing as the car is up on stands with no wheels on it.


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## TTC2k5 (May 23, 2008)

deepblueT said:


> ...and the stretch from the 235 should give me the clearence i need for the fender right?


NO! 

the calculator only tells you how far your WHEEL will stick out or stay in. It says nothing about your tires. Notice the calculator is independent of tire. 

So, with your rear wheel, regardless of tires size mounted, you will have 1.7mm wheel sticking out ( per the calculator: OUTSIDE fender ( I read this to be outside the outside of the fender, not outside/past the inner lip of the fender)) plus any wheel/tire that sticks out past the inner lip of the fender, and all is available for crashing/rubbing into your fender upon hard bumps or hard cornering....

again, is that what you what?


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## deepblueT (Jan 26, 2008)

TTC2k5 said:


> NO!
> 
> the calculator only tells you how far your WHEEL will stick out or stay in. It says nothing about your tires. Notice the calculator is independent of tire.
> 
> ...


of course i don't want rubbing or crushing. thats why i want to know how accurate the calculator is. i will put some math down that are actual measurements for my situation. I went out and measured the mounting surface to the fender (audi did us a favor by not having an actual lip, the fender just ends nicely, my eclipse had a 10mm lip that required rolling to fit wide wheels) anyway i measured roughly 96mm from mounting surface to fender.


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## darrenbyrnes (Jan 4, 2005)

Too much math...

:grinsanta::grinsanta::grinsanta:


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## TTC2k5 (May 23, 2008)

darrenbyrnes said:


> Too much math...
> 
> :grinsanta::grinsanta::grinsanta:


...and not enough :beer::beer::beer::biggrinsanta:


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## Neb (Jan 25, 2005)

I think your fronts will be perfect. although a 235 is a massive tire for that.

I'm not sure about your ets for the rear though. Currently I run a final et of 10 on my 9.5 rears with a 235/35/19 tire. It's perfect in my eyes. But with a thicker tire that isn't running the same amount of stretch it may work better if you aim for et 15-20 total. I NEVER go by those offset calculators to be honest; nor would I put any faith in them either - especially if you're going for a more precise calculation.


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## deepblueT (Jan 26, 2008)

Neb said:


> I think your fronts will be perfect. although a 235 is a massive tire for that.
> 
> I'm not sure about your ets for the rear though. Currently I run a final et of 10 on my 9.5 rears with a 235/35/19 tire. It's perfect in my eyes. But with a thicker tire that isn't running the same amount of stretch it may work better if you aim for et 15-20 total. I NEVER go by those offset calculators to be honest; nor would I put any faith in them either - especially if you're going for a more precise calculation.


yeah i had come to the conclusion that i would have to get a thinner tire for the 8" on the front. 

i also came across another set of wheels i like and they actually will work without adaptors, will just need some spacers to get them perfect. 

fronts are the same 18x8 et 35 
rear's are 18x9 et 38 

they have the staggard lip i want and with a little spacing i can get the look i'm after....looks like i wasted alot of time doing math the last couple days...though i have learned a ton about figuring fitment  

"and learning is half the battle"

thanks


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## [email protected] (Jul 1, 2009)

deepblueT said:


> fronts are the same 18x8 et 35
> rear's are 18x9 et 38


This is a 265 tire on a 9" rim. Final offset is a sizable 30et. But there's quite a bit of room inside the wheel well, so you can get a pretty big tire flush with the fender.


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## deepblueT (Jan 26, 2008)

i am ok with a stretch of my 235's on a 9 or 9.5, its the front wheel i would need a thinner tire. to not look goofy big against the stretched rear...i have yet again changed my mind on wheels...they 
are 18x8.5 35
and 18x9.5 53

all will be 5x112 and the adapters will make up the difference for the position of the wheel. again according to my math. :banghead:

these have a flat face, where i was looking for a staggard lip, but i would have to jump through hoops to make the staggard work...i'm not opposed to that though....just need to make up my [email protected]&#ing mind already.


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## TTC2k5 (May 23, 2008)

deepblueT said:


> i am ok with a stretch of my 235's on a 9 or 9.5, its the front wheel i would need a thinner tire. to not look goofy big against the stretched rear....


I know I'm in the minority on this forum, but if you don't want to look goofy, don't do the stretch on either. 

cheers.


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## deepblueT (Jan 26, 2008)

i'm not a fan of the SUPER stretch either that's why i feel like a rocket scientist for the last 3 days crunching numbers. 

:banghead::screwy::banghead::banghead::what::banghead:


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## TTC2k5 (May 23, 2008)

if you go 235 on the 9.5, you'll probably need 215s on the 8 to even out the stretch-look. 225s on the 8s is OEM and no stretch. 


225-40 on front 8.5s and 255-35 on rear 9.5s will give you the right rolling radius, and the stretch on the both will be near minimal. 215s with 235s will be goofy, IMO.


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## deepblueT (Jan 26, 2008)

TTC2k5 said:


> if you go 235 on the 9.5, you'll probably need 215s on the 8 to even out the stretch-look. 225s on the 8s is OEM and no stretch.
> 
> 
> 225-40 on front 8.5s and 255-35 on rear 9.5s will give you the right rolling radius, and the stretch on the both will be near minimal. 215s with 235s will be goofy, IMO.


so i ended up buying a set that will be 

18x8 et 35 5x100
18x9 et 38 5x100

I will calculate spacers when they get here and i can hang the wheels and measure, i landed on these based on the staggard lip look that i like. I will also figure out what tires i will need for the front when they arrive. i'm confident the 235 will work fine on the 9" rears. according to the tire calcs. if i get 215/45/18 for front i would be within .82% of rears. well under the 3.00% everybody talks about.


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## TTC2k5 (May 23, 2008)

Those are the same size as my wheels and I'm running 235-40s and 265-35s. Also, no spacers.




























I went with a little larger rubber for a couple of reasons:

1. extra rubber (height) will offset any rough-ride associated with 18s versus standard 17s.
2. extra rubber (height) will provide a little more protection of rims against pot hole damage
3. extra rubber (width) will provide a little more protection from kurb rash.
4. mo rubber looks better than less rubber.

cheers.


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## Neb (Jan 25, 2005)

deepblueT said:


> so i ended up buying a set that will be
> 
> 18x8 et 35 5x100
> 18x9 et 38 5x100
> ...


Why wouldn't you just go 215/40/18 all around? I ran this exact setup with my Super RS's as well as my last set of Rays wheels. You don't get stretch on the front but it doesn't look as beefy as what you're planning on running.


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## deepblueT (Jan 26, 2008)

TTC2k5 said:


> Those are the same size as my wheels and I'm running 235-40s and 265-35s. Also, no spacers.
> 
> 
> 
> ...


this is no longer my daily driver so alot of the "real world" driving conditions will be avoided/removed, It most likely will never be parked on a curb. and where i go the roads are actually pretty good.


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## deepblueT (Jan 26, 2008)

Neb said:


> Why wouldn't you just go 215/40/18 all around? I ran this exact setup with my Super RS's as well as my last set of Rays wheels. You don't get stretch on the front but it doesn't look as beefy as what you're planning on running.


i was trying to keep the tires as close to the same size as possible, i thought thats what the name of the game was... a 215/40 against a 235/40 is a 2.5% difference...i just feel better with the .82% difference. but like i said...when my wheels arrive i will have the rears mounted and see what i'm looking at then i will make a decision.


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## dogger (Jul 29, 2005)

A 215 on a 8" wheel is not going to have much stretch if any. I run a 215 on 8.5" and the stretch is nice and not too excessive. A 235 on a 9.5" will have quite a bit of stretch. I'm running a 225 on a 9.5" in the rear and it has a lot of stretch. Unfortunately the tires I wanted don't come in a 235. Personally I think a 235 is ideal for a 9.5" wheel. 

Your rears should sit nice with that spacing and offset. Not too much poke.

My rear final offset rear is et15 and it pokes quite a bit.


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## Neb (Jan 25, 2005)

deepblueT said:


> i was trying to keep the tires as close to the same size as possible, i thought thats what the name of the game was... a 215/40 against a 235/40 is a 2.5% difference...i just feel better with the .82% difference. but like i said...when my wheels arrive i will have the rears mounted and see what i'm looking at then i will make a decision.


No i mean run a 215/40/18 on the front AND back.

Will look like this:


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## deepblueT (Jan 26, 2008)

because i have a ton of life still in my 235's and don't wanna spend the money for all new tires.... i'm willing to get some used 215's to get close to what i have left on the 235's
it does look good though, i also don't think i will end up with that much poke in the rear, so i won't need that much stretch.


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## dogger (Jul 29, 2005)

Why not sell the 235's? If they have enough tread left you should be able to get decent money for them.


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## deepblueT (Jan 26, 2008)

dogger said:


> Why not sell the 235's? If they have enough tread left you should be able to get decent money for them.


because they are the best tires i have ever had!!!.... dunlop direzza star spec!
they don't make those in 215/40 or 215/45 plus selling is not guarenteed to happen fast.


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## deepblueT (Jan 26, 2008)

dogger said:


> Why not sell the 235's? If they have enough tread left you should be able to get decent money for them.


because they are the best tires i have ever had.... dunlop direzza star spec!
they don't make those in 215/40 or 215/45 only 225/45 plus selling is not guarenteed to happen fast.


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## deepblueT (Jan 26, 2008)

so these finally showed up yesterday.

sizes:
front 5x100 18x8 et 35 i will add a 18mm spacer to get flush
rear 5x112 18x9 et32 these will require a 15mm adapter obviously.

still need tires for the fronts. will start looking for them today.


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## TTC2k5 (May 23, 2008)

nIce looking wheels. 


Have you actually mounted them and measured for the proper size spacer or just winging it with the 15s and 18s?


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## Forty-six and 2 (Jan 21, 2007)

Nice!! I have been waiting for an update on these.:thumbup:


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## deepblueT (Jan 26, 2008)

the 15mm adapters are the smallest (safe) minimal thickness i can use for the rear. the front i may wait to measure. i did hang the front wheel, but the car is on stands with no wheels so i can't get the suspension compressed enough to get a solid measurement. i will wait till the tires are mounted, put them on, and drop the car to see about spacers, i'm pretty confident that 18mm will work best. 

wheels are Rohana RL-06


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## nilreb (Mar 17, 2012)

rims: 
18x8 + 35 offset 

tires:
225 40 18


front is
19.35mm INSIDE fender

rear is
25.35mm INSIDE fender

Isn't this almost flush? Do i need spacers?


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## deepblueT (Jan 26, 2008)

some more pics...

hung one on the front to see caliper fitment, and the black against my dark blue.


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## Converted2VW (Apr 8, 2009)

Those look nice! Can't wait to see them on.


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## Krissrock (Sep 10, 2005)

looks good with the orange calipers.


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## deepblueT (Jan 26, 2008)

Converted2VW said:


> Those look nice! Can't wait to see them on.


speaking of seeing them on... what about the P2's?


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## deepblueT (Jan 26, 2008)

had the rear tires mounted on the wheels today ( i have a connection at a BMW dealer in allentown, half price) should have the new front tires in early next week and will have them mouned, looks like i should be rolling before March is over


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## Krissrock (Sep 10, 2005)

deepblueT said:


> had the rear tires mounted on the wheels today



without any scratches to that finish?


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## deepblueT (Jan 26, 2008)

Krissrock said:


> without any scratches to that finish?


mounted from the back 

also they have a newer machine. no calmps...

the wheel is held down on a rubber pad with a cone that goes through the center bore...nothing ever touches the face or out rim of the wheel. balancing is done holding the wheel with the bolt pattern (he asked what it was so he could use the correct clamp)

:thumbup::thumbup:


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## Krissrock (Sep 10, 2005)

awww man!! where is this? 

finding to mount tires properly is so freakin hard!!


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## deepblueT (Jan 26, 2008)

Krissrock said:


> awww man!! where is this?
> 
> finding to mount tires properly is so freakin hard!!



Allentown, pa. Its daniels BMW its right at 22 and 309


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## deepblueT (Jan 26, 2008)

for those that may have missed the update....

http://forums.fourtitude.com/showthread.php?6000981-Finally-some-pics-of-the-new-wheel-setup.


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## deepblueT (Jan 26, 2008)

so the used front tires i bought are $hit. looked fine off the wheels, when mounted and inflated, they have dryrot all over the place. needles to say they don't hold air. i have bought another set for the front and will have them mounted early next week. this weekend i have to finally do the rear diff. fluid, i had to order a 17mm allen wrench for the fill plug in the rear diff. who designed that to be behind that bracket? hopefully i'll be able to go for a drive next weekend. the first one since mid Oct. 2012.


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## TTC2k5 (May 23, 2008)

deepblueT said:


> so the used front tires i bought are $hit. looked fine off the wheels....


That sucks...but you never know with used tires. I gave away my last set rather than sell them. They had tread, but were old. If they failed to hold air for the new owner, at least he had zero invested...othere than mounting fees.

cheers.


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