For FAQ: How to calculate what size spacers YOU need - spacers adapters offset wheels et

[rs4-380]

Lately I've noticed that "what size spacers should I get" have been giving the wheel posts a run for their money. This is annoying for three reasons,

1. like wheels, spacers should be a personal choice as they are mainly a way to alter the appearance of your car (if someone wants to argue about performance benefits, go ahead, but you'll probably get more repsponse from Pontiac owners).

2. Inevitably people never supply, and usually don't know the required information so that someone else can tell you what to buy.

3. Calculating the size spacers you need is easier than installing a euroswitch.

That being said, if you are clueless as to offset, et, wheel sizes, tire sizes and coding and the like, you have some reading to do first. (all the below are in the MKIV FAQ/DIY)

Offset tech
Tire sizing
MKIV Wheel Info

Now, you should be able to fit yourself into one of two categories, you already have in you possession the wheels/tires setup you want to space out, or you don't.

If you have the wheel/tire setup you want to space out
This requires that the tires be mounted on the wheels and the wheels be mounted on the car. First level the car side to side. This can be easily accomplished by just measuring from the ground to the highest point of the fender. Theorectically the car should be even side to side, but they usually aren't. Just jack up the low side in small increments until the measurements on both sides are equal.

Now get a plumb bob (you don't need anything fancier than a string with a nut or washer tied on the end.

Tape the plumb bob to the centerline point of the fender (make good tape choices), wait until it stops swinging, then simply measure from the outer edge of the tire sidewall to the string. Convert this measurement to Millimeters and this is the size spacer you need for the tire to be flush with the fender. If you want to poke or tuck, add or subtract to get the desired width.

dimension a is the required spacer size to get the tires flush

(the above picture is not straight on since the original wheels on my gorgeous model are only 5 inches wide and tuck like no ones business. Therefore you can't see the sidewall from straight on behind as shown below)

If you do not have the wheel tire setup in your possession
You can still calculate what size spacers you need, but I recommend waiting until you get the new setup then following the above directions as that is simpler and more accurate, plus you can fool around with your "A" measurement to visualize what going with larger or smaller spacers will look like.

If can't wait because you are impatient, get out your calculator.

First remove the wheel from one side of the car on the desired end (do front and back separatley). You need to level the car. This can be as above, by measuring from the ground to the highest point of the fender lip and making sure both sides are the same. If they are not, just raise or lower your jack so they are equal. *One thing to note, on the front of the car, especially on lowered cars, because you have an independent suspension you may have to literally put the rotor on the ground to level the car, this is because the suspension is not compressed from the weight of the car. If you need to put the rotor on the ground, just put a block of wood under it, it is ok to let the ground compress the suspension. but make sure the majority of the weight is on the jack.

Now make a plumb bob like above and tape it to the centerline of the fender. When the plumb bob has steadied, measure from the wheel mounting point on the hub (not the brake rotor, where the lug bolts thread in) to the string. Note this dimension.

Because I'm not always a pain in the ass I've gone ahead and done this part for you.
On GTI's/GOLFS the "A" mesurement from hub to fender is

71.4375mm on the front (2 13/16")
and
87.3125mm on the rear (3 7/16")
I am wiling to bet that the front measurement is very close for Jetta's if not identical and the rear is close enough for Jettas if not very close.

*These measurements are only as accurate as the number of beers I drank before doing this, which I can't really remember. It's not my fault if you buy the wrong size spacers.

Now, you want to replicate this distance with your wheel/tire setup in order to get the tire flush with the fender. Again, you can add or subtract to this to achieve a desired poke/tuck look.

To do the calculation you need to know two things. 1, the offset of your wheel in MM (et 42 for example = 42mm) and 2, the width of your wheel OR the width of your tire OR the sidewall width of your tire.
In regards to #2 the best measurement to have is the overall tire width, note this is NOT sidewall width (what is coded in tires sizes). Some people publish tire widths, but most don't. I have seen identically coded tires (205/55/15) vary as much as 3/4 inch in overall width depending on manufacturer and model.
Since overall width is not usually published it is best to use tread width, if you don't even know what size tires you are running you can use wheel width, but usually wheel width will give you low values. *One thing to note, is if you are stretching your tires, you should use rim width NO MATTER WHAT, the whole point of tire stretch is that the wheels are too wide for the tire, so using tire measurements isn't going to give you accurate measurements.

If you plan on using wheel width convert it to millimeters. Now you have your tire/wheel width and the wheel offset. The rest is just math.

Take the tire or wheel width measurement and divide it in half. Subtract the offset from this figure. Subtract the resulting value from the appropriate hub-fender measurement above, and that is the size spacer you need in order to be flush, again, you can vary this to achieve a desired look.

Example. Montreal I rim et42, 205/55/16 tire

(205 / 2) - 42 = 60.5

71 - 60.5 = 10.5
So 10mm Spacers would get me flush in front

87 - 60.5 = 26.5
and 25mm Spacers would get me flush in the back

Things to remember in either case

1. 1 inch = 25.4mm http://www.onlineconversion.com
2. 5mm is only 1/5 of an inch, going down 5mm in spacer size may save you a bunch of money without seriously affecting whether you are "flush" or not
3. If the number you get after calculating your offset - wheel/tire width is LARGER than the hub - fender measurement you are going to poke no matter what. Spacers only extend your wheel and tire out, they can't subtract width. You need to do that with offset.
4. Along with #2, you do not need to hit the values EXACTLY, depending on drop, 15mm inside the finder can look "flush".

If people want to post pictures from straight on (front or rear) with the appropriate values as a reference go ahead, but make sure you include OFFSET, TIRE WIDTH/TREAD WIDTH/WHEEL WIDTH, and any SPACER size if applicable. Alternatively, you could just figure out your hub to sidewall width and give that to us instead (WIDTH/2 - OFFSET + SPACER). The good thing about giving the hub - sidewall value is that is doesn't matter what size wheel tire or spacer you have. A hub -sidewall width of 85MM should look the same no matter what wheels tires or spacers you are using (factoring in of course the error caused by tire/tread width and that it is on the same end of the car).

[Chacolla]

awesome...good post

[2002GTI]

Wouldnt it be best to measure from the inner fender lip as to not rub?

[rs4-380]

Quote, originally posted by 2002GTI »

Wouldnt it be best to measure from the inner fender lip as to not rub?

Good point, however, A, it's hard to tape your plumb bob there, B, thats not really "flush", C, if you are worried about rubbing just measure the width of the lip and subtract that from your hub - fender measurement.

[RavinJetta]

Very nice post.

[abydielsgli]

Quote, originally posted by RavinJetta »

Very nice post.

true
but also remember people. the wider the spacer the easier it is for the lug bolts to brake

[2002GTI]

Quote, originally posted by rs4-380 »

Good point, however, A, it's hard to tape your plumb bob there, B, thats not really "flush", C, if you are worried about rubbing just measure the width of the lip and subtract that from your hub - fender measurement.

Yea it is hard to tape, but I just held it there. The reason why I mentioned that is when I did the measurements for the Kinesis wheels they instructed me to take the measurement from the inside lip as to not rub, just food for thought. Nice write up.

[manasteel]

Ok lemme do a quick check on this for a 9in wide rear wheel I want

9inx25.4mm= 228.6mm

228.6mm/2= 114.5mm

114.5mm-87mm=27.3mm

so ideally a +27.3mm offset on a 9in wide wheel would flush out the rears?

so lets see with a 10in wide shall we

10inx25.4= 254mm

254mm/2= 127mm

127mm-87mm= +40mm offset for flush rear! should i worry about rear clearance if I'm running 12in rear rotors with stock calipers?


Modified by manasteel at 10:52 PM 3-13-2005

[rs4-380]

Quote, originally posted by manasteel »

rotors with stock calipers?

You shouldn't have any problems with the stock caliper but it totally depends on the wheel.

[bigmak]

Quote, originally posted by 2002GTI »

Wouldnt it be best to measure from the inner fender lip as to not rub?

dont forget that tires are not square. they have enough of a curve that the measuring location would not make any difference really in the rubbing issue.

[CapeGLS]

The rear axle on a MK4 has 2 different "sizes" I believe the passenger side sits further inside the fender than the drivers side...
This is a good writeup though!

[GTIk2to]

I'm confused .. can someone please help me out?

So according to this calculation for my rear monte carlo wheels, I would need:

7 x 25.4 mm = 177.8 mm

177.8 mm / 2 = 88.9 mm

88.9 - 38 offset = 50.9 mm

87.3 - 50.9 mm = 36.4 mm spacer needed?

If this is the case, then why are there so many ppl on here who say that 20 mm is the max you can go on rear stock monte rims before you experience rubbing?? What am I doing wrong in my calculation? HELP !!! thanks,

[manasteel]

[Kahnjr321]

Quote, originally posted by GTIk2to »

I'm confused .. can someone please help me out? So according to this calculation for my rear monte carlo wheels, I would need: 7 x 25.4 mm = 177.8 mm 177.8 mm / 2 = 88.9 mm 88.9 - 38 offset = 50.9 mm 87.3 - 50.9 mm = 36.4 mm spacer needed? If this is the case, then why are there so many ppl on here who say that 20 mm is the max you can go on rear stock monte rims before you experience rubbing?? What am I doing wrong in my calculation? HELP !!! thanks,

You are using the wrong first number measure the width of the tire -- not the rim UNLESS you are using stretched tires.

I'll pretend you have 225mm tires -- which isn't the true width -- but we'll give it a shot.

225/2 = 112.5 - 38 = 74.5

87.3125 - 74.5 = 12.812 so depending on how much you are lowered I think 15 mm would bring you quite flush.

Substitute in the correct tire width -- measure not from the side of the tire and you should be okay.


Modified by Kahnjr321 at 7:25 PM 4-5-2005

[manasteel]

yea so it would depend on the wheel face too, whether the concave is deep or shallow

[rushbone]

Great post
However i have BBS RK's Silver painted the rims are 7 inches wide and the ET 48. I tried putting them on last night at work but when i did the wheel goes in too deep therefore it slightly touches the brake caliper. I was devastated because i was really looking forward in putting them on. So now I need spacers so how would i calculate the spacers that i need for these wheels considering that i want to lower my car in the future.
I used the formula that you have I have 215/45/17 (7Jx17h2 ET 48) does that mean i need 11.5 mm spacers in the front and 27.5 mm in the back and if so how long the bolts are supposed to be and i can't determine what is the seat on my rims as well I thought it was conical but I also thought that the stock bolts were conical as well not the ball seat.
Well i would love to hear back from you because I really want to put these rims on as soon as possible.
Thanks

[burtondk12]

[GTIaintNOgOlF]

i have the 20th stock rims and wheels.....so i shud just go with 15mm in back and 10mm in front?

[jason.smeall]

also looking for help my gti vr6 is lowered 1.5 inches and has 15" DE wheels with 205/50/15 rubber what is the largest i can go without rubbing

[E36toGTI]

I'm sorry I still don't understand this...when would you need spaces...are they required for example to lower your car...what exactly is the purpose of them...

[vwjettamk4]

To space out your wheels from the hub, to give you that wide euro stance

[Illuminati63]

I ordered a pair of 5mm spacers. im wondering if: i shoudl have gone bigger, i want it to look good,subtle and clean on a stock car. will i run into any problems when installing (rubbing etc).

i have a completely stock 2003 GTI on stock 17's

also ive been looking in the DIY for how to install these and i cant coe up with anything. Can anybody send me a link?


Modified by Illuminati63 at 10:42 AM 8-22-2007

[the_journalist]

Quote, originally posted by Illuminati63 »

I ordered a pair of 5mm spacers. im wondering if: i shoudl have gone bigger, i want it to look good,subtle and clean on a stock car. will i run into any problems when installing (rubbing etc). i have a completely stock 2003 GTI on stock 17's

With those wheels you can easily go with 10mm in front and 20mm in the rear. However, if you're running stock suspension still, it will just accentuate the wheel gap.

[Illuminati63]

well see i have a small problem with going 20mm, one i dont want to do alot to my car until its mine. second, because my dad still owns it he is against me modifying it heavily. so i dont want the excessive stance because i think it would look ugly on a stock car. which is why i went with the 5mm. ill take before and after pics to show today but can someone with a pretty much stock exterior show me the 10mm? thanks


Modified by Illuminati63 at 10:58 AM 8-22-2007

[skatingzooyork]

Quote, originally posted by Illuminati63 »

well see i have a small problem wiht going 20mm, one i dont want to do alot to my car till its mine. second, because my dad still owns he he is against me modifying it heavily. so i dont want the excessive stance because i think it would look ugly on a stock car. which is why i went with the 5mm. ill take before and after pics to show today but can someone with a pretty much stock exterior show me the 10mm? thanks

Just search a little man, you will find tons of people running 10/20mm spacers w/ stock wheels and height. It does look better and remember, a 5mm spacer is just 3/16s of an inch so it's going to be very mild.

[YNotBoost1]

First off, this is a very informative write up which increased my understanding of wheel offset and spacing.

I'm trying to figure out what size spacers I would need for the "flush" look. Here are my wheel specs and calculations.

H&R/Billstein sports 1.5" drop
19 x 8 et35 w(235/35/19 pilot sports ps2)

235/2 = 117.5 - 35 = 82.5

87.3125 - 82.5 = 4.81 (so a 5mm spacer in the rear)

71.4375 - 82.5 = -11(apprx front) Does this mean the front will poke?

[VR]

was this measurement taken from the inside of the fenders or the outer edge? I plugged in 225 and ET of 35 and I came up with 6.5 F and 9.5 R. This seems very mild to what I have seen around. I was thinking if you measured to the inside of the fender this would make more sense, measuring front the outside could add a few MM.

[Gakka]

Edit for noobness: My ass is blind.



Modified by Gakka at 11:07 PM 3-16-2008

[VR]

Quote, originally posted by Gakka »

busted pics?

look at the original post date

[brandomos]

I know this is an old post but I'm buying some sawblades this weekend. I just want to make sure I have the calcs correct.

wheel = 56mm offset

f 215mm wide/2 = 107 - 56 = 51 , 71 - 51 = 20mm

r 241mm wide/2 =120 - 56 = 64 , 87 - 56 = 23mm

So what I gather is I need 20mm adaptors front and back and should be fine BUT I saw two seprate guys saying f1.3' and r1.5" for these wheels. Would that just be personal preferance? Thanks for you help.

[Kelevra85]

havin some trouble figuring out what size i need..
Stock VR6 gli w/ monte carlos
i'm about to Purchase a Koni Coilovers
what size spacers would i need to flush up

[Navydub]

Best...Post....EVAR

[Bora Jon]

Great post, this answered all of my questions without starting another thread on offset. Thanks!

[02jettamatt]

ok im editing cause im a nub and didnt read the whole post, so lemme put my math in...

Jetta
Aristo's 18x7.5
225/40/18
et 35

F 225/2= 112.5.. 112.5-35=77.5.. 71-77.5 and i get negative 6.5mm? lol?

R 225/2=112.5.. 112.5-35=77.t.. 77.5-87= 9.5mm?

the rears seem to be ok but -6.5mm in the front?


Modified by 02jettamatt at 9:38 AM 5-2-2009

[tlj 3]

Ok need some help guys I got some bbs ck's rthey are 18x7.5 with 42mm offset and are 5x114.3. I found 2 adapters 25mm and 31mm with the 25mm I would have a 17mm offset and with the 31mm I would have a 11mm offset. I plan on running 225/40/18 Please help me out and tell me what adapter I should get I dont want any rubbing or poking I want the rims to sit flush . Will the 31mm make them poke out front? Which ones should I get?