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Discussion Starter · #1 ·
Help needed:
ET Wheel Size- Jeep X J 2000 model - No Lift.

Does someone know all about ET Wheel sizing for an XJ.

What ET wheel size do I need for 17 inch x 9 inch wheel?

1. I need to know the ET size on 17 inch x 9 inch wheels to create a tire center to tire center size measurement of 1470mm to 1490mm maximum.

2. Also what size tires should I fit to the 17 x 9 inch wheels, example ....... 255x17Rx75 ?

My present wheels are 15 inch x 7 inch with a tire centre to tire center measurement size of 1560mm with a 7 inch wide wheel and an ET size of minus -14.

My present tire size is 225x15Rx70.

Looking forward to hearing from anyone that can help on the ET Size and Tire Sizes needed.
Thanks,
Crazyray48
 

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Discussion Starter · #3 ·
Hi There,

yes I didn’t know what ET was until my Jeep Failed it’s Annual ITV/MOT test in Ibiza because the new EU Government Regulations state that on the Jeep XJ the center tire to center tire measurement has to be in line with the Jeeps original build spec of 1473mm.

my wheels which are only 3 years old failed the measurement because the ET is a. Negative minus-14, making the wheels stick out from the body and the center to center size is 1560mm.

Although the Jeep has passed the ITV / MOT for the last 2 years at the very same test centre the Jeep could no long be used on the roads until the wheels had been changed.

so the ET is stamped on the back of the wheels and the negative ET pushes the wheels and a positive ET brings the wheels more under the Jeep for the 1473mm size now required.

it’s a game changer for the Wheel companies who do not know what size ET we JeepXJ owners need.

so I reached out to the Jeep XJ owners with the question, did they know?

I Google “ what is wheel ET “ and there it was but I still need to know the positive ET size I need for 9inch wide wheels and tires?

I hope that there is an ET Guru Genius out there that knows how to work it out?

cheers Crazyray48
 

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OK, so ET is the OFFSET of the wheel mounting surface (WMS) from the centerline of the wheel.. You have -14 which means your wheel mounting surface is "offset" -14mm from the Centerline of the wheel. pushing the wheel away from your axle. Back spacing can and will also move your wheel toward or away from the axle. Do you know what back spacing you have? Do you have wheel spacers? Technically you need to move each tire centerline in 44mm (1560-1473= 87, 87/2=43.5 rounded up to 44mm). You can achieve this with both backspacing and wheel offset. With the centerline of the wheel in the exact same spot you will need +30mm offset. You can use a combination of offset and backspacing to get your centerline within spec. Just be careful of rubbing the control arms.
 

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Discussion Starter · #5 ·
Thank you so much for your help and input on the ET Offset size required for a set of future wheels and tires.

To answer your question on back spacing I have used the wording listed by th Jeep US Technical Department as follows:

axle wheel mounting surface of a Jeeps ( WMS to WMS) is 154.3cm.

Stock wheels is a 15” x7” with 5.25” of backspacing which provides a -1.75” ( -4.45cm) offset of the wheel centreline (WCL) to the WMS.

This offset theoretically reduces the “wheel/tire” centreline from the 154.3cm WMS to 145.4cm WMS.

Any alteration to this offset will impact the Tire Centreline measurement.

If a wider Rim is desired, the additional width will need to be split equally to both the inner and outer dimensions WHILE still maintaining the backspacing offset of 1.75 (. -4.45 CM ) per wheel.

So for Jeep XJ owners to keep that great “Chunky Jeep Look” and to provide a measurement of 1470 mm tire center to tire center by using 9 inch rims.
I very much hopes this Jeep information data helps your calculations?

Thanks again for your brill help!
Crazyray48
 

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Well thats a first for me. Government regulated offsets, wth. I still don't know what you mean by ET, but it sounds like offset.

So let me ask an obvious questoin.......why not get a set of stock factory wheels and put them on for inspection, then take them off and put your other ones back on? Thats what we do in America. Are the police going to pull you over and measure them? Does your Jeep look like an obnoxious monster truck? If the answers are no and no, then just get a cheap set of factory ones and go from there.

They can't fail you for factory wheels. If the vehicle was manufactured with them it has to pass. If they raise hell then tell em to take it up with Jeep.
 

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Discussion Starter · #7 ·
Yes this was the best way you are right.

Jeep owners started buying wheels from the beaker yards with good enough tyres and used them to pass the Annual ITV/MOT.

But after a year from the change in the Regulations to stop Jeeps having Poke the Police knew! .......that all Jeeps must of now been through the Test Center.

If a Jeep was coming down the road with its wheels sticking out beyond the fenders the police knew......

1. The owner had not had his or her Jeep tested and they were on the roads with no ITV/MOT.

result a big fine and the Jeep towed away with a tow charge to the police parking lot.

2. The owner had gone through the ITV/MOT Test Station and this is shown on their cctv cameras that the Jeep was test and passed with the stock wheels, proving that the owner had switch the wheels back to the wide one’s and the Jeep is not legally allowed to use the Jeep on the Roads as the ITV is now void.

A big Fine is issued and the Jeep towed with a tow charge and storage charge until the fine is paid.

so it’s all about Fines.

The Government is desperate for money and are using every method that they can come up with to create revenue by using Fines, seriously in every way that they can.

so I need to know if any one has tried fitting 17 inch x 9 inch wheels on a Jeep XJ?

If they have:
a) what offset did they use, was it a big one like an offset ET of 44. ?

b) what tire size worked for them, 245,255,265 x 60, 70, 75 ?

c) and big question, what is the tire to tire center measurement, was it 1470mm.

The ITV/MOT Center said because we have passed your Jeep twice before with the wheels you presently have on the Jeep we will let you go up to 1490mm, tire center to tire center.

so I need some help from the Guys who really know there Offset Sizing on a Jeep XJ to provide us with a 1470mm to 1490 mm and to keep that great Chunky Jeep look.

Thank you for your help.
 

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9" wheels are two inches wider than stock wheels. Tucking an extra two inches inside your fenderwells and maintaining a reasonable turning radius just isn't going to be possible. You'll rub on everything. What do your laws say about adding wider fenderflares? A set of Bushwackers or Notch Customs or whatever would cover your tires without issue.
 

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Discussion Starter · #9 ·
Hi There,

on the increase from 7 inch to 9 inch Jeep say “ If a wider rim is desired, the additional width will need to be split equally to both inner and outer dimensions “
The big question is the new Center tire to centre tire measurement, it cannot be more than the 1473mm being the original build size.

As you can see from an earlier post it is said that the Off Set needs to be 44mm which would require a + 30mm Off Set using the back spacing.

so I am desperate to see if any one has fitted the 9 inch rim using 17 inch wheels and to see if they can put a tape measure over the rear/front to check the Tire Center line to tire center line and does to match the calculation of 1473mm and what Wheel Off set was used?

The new regulations are a Total Game Changer
 

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Regulations, where at?
 

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That is the first I have heard of those regs.
 

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Discussion Starter · #13 ·
Yes, What’s worse for me is that the current wheels are only 3 years old and for the 2 years before the same ITV/ MOT Test Center had passed the Jeep with these same wheels on!

The present wheels are 15 x 7 with a minus - 14 ET Offset running 225 x 15R x 70 tires, but puts the tire center line to tire center line out to 1560mm and the new regs say that you have to be as per the build spec of no more than 1473mm and they sent me copies of the Jeeps Chrysler Documents

I would like something like the Fuel Wheels!

so if anyone is running 17 inch or 18 inch what Offset did you buy and what’s your Center Line measurement 58 inches (1470mm) ?
 

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I am still a little confused what you really need. I searched and at one vendor there is 57 wheels 17X9 with 0 offset. How much do you need again from center?
 

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Discussion Starter · #15 ·
The Wheel Offset size needed is to create a measurement of 1473mm from the center of the tire to the Center of the opposite tire on the same axle.
Thanks to the Brilliant reply from Gluckmysock - Super Modenator.
He worked out that technically I need to move each tire center line in 44 mm.
With the Center at the same spot he believes I will need a plus +30 mm offset wheel.
This information was brilliant so now I need to find out if there is anyone running this Wheel and Tire set up on their Jeep without an issue of rubbing.

No wheel supplier has been able to tell me what wheel size I need for the 1473mm because this has never been needed to be known before.

But we do now for the Exported Jeeps to the EU Jeep community.

Thanks to everyone for their help to crack this one!
 

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The number I came up with needs to take into consideration both back spacing and wheel offset.
 

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Discussion Starter · #18 ·
Hi

I sent a copy of the back spacing that Jeep sent to me from the Jeep Customer Care Center.

Was this Jeep Data sent by Customer Care any good on the back spacing information to check that the calculation at +30 mm. Off set is okay.

what do you think?

As a matter of interest Jeeps Customer Care could not come up with a Number for the Wheel Off-Set needed or even to make a Calculation, not helpful Jeep!

They offered to take a look when the wheels had been fitted by me taking the Jeep to their Jeep Dealership, good of them but!

But as I need to buy wheels and tires first to go their route for the Dealer to take a look at 2,000 USD + shipping this is not totally helpful.

So if there is anyone out there that has fitted 17 inch or 18 inch Wheels it would be great to hear from them to see if their wheels are + 30mm and also the tire size they fitted to check that they are not getting any rubbing, with no lift.

Once we have cracked this one I can let other Jeep owners know the Off-Set information to get there Jeeps back on the road again because a lot of Guys are putting their Jeeps up for scrap/ braking because they don’t know what to do and do not want to buy and go back to the thin 1990”s style thin wheels.

Thanks again for your help very much appreciated.
 

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Can you give me a link to the wheels you are interested in, or a website. I will do some research and see if I can get some numbers from them.
 

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Discussion Starter · #20 ·
The style of wheels I have had an interest in are:
Bolt 114.3
Fuel D560 Vapour Matte
Fuel D546 Assault Matte
XD 851 Monster 3
XD 129 Hole Shot

On some of the wheels offer a 34mm Off Set but a back spacing is to high at 6.09.

Hope this helps with my thoughts.
Cheers.
 
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