I need help with some measurements....

[court65]

I have a 2K2 NEON with stock 15x6 185/60/15 with 35mm offset, how do you figure out backspace?

I am planning on getting some Rota Subzero's which are 18x7.5 with a +45 or +48 offset with 225/40/18 rear and 215/35/18 front or just 215/35/18's all around. How would I calculate how big the wheel spacers will need to be to clear the extra backspace, fit the extra offset and if that extra clearance would make the tires rub against stock fenders or any part of the car?

If this could be tested on a 2k2 Neon or calculated using a 2k2 Neon specs that would really be a great help.

[Cy@tirerack]

I deleted my previous post and your answer because I my previous post had some confusing information.

Please refer to the below diagram for an explantion of offset:

http://www.tirerack.com/a.jsp?a=DY2&...ech/offset.htm

Backspace is the distance from the mounting surface of the rim to the back of the rim flange so for your stock rim backspace = 1/2 the rim width + offset + the width of the rim width flange. In the case of your stock rim backspacing in mm = 3" x 25.4mm (25.4mm per inch), + 35mm + .5" x 25.4mm = 123.9 mm equivalent to 4.88 inches.

In order to calculate spacer size and/or whether you will have rubbing on the fenders, we have to make certain assumptions that you must confirm by either measuring yourself or by checking what other Neon owners have down in trying to runnng similar size wheels and/or tires.

Assumming that largest combo we've test fit for your car, 205/40-17 on 38mm 7.5" wheel is the widest combination that fills the max amount of space to the outside and inside without rubbing then by going to a 45mm 7.5" 215/35-18 combo you need an 8.27mm spacer (closest readily available spacer is 10mm) to clear the inside (base on Yokohama Parada Spec 2 tire).

With a 10mm spacer you're effectively running a 38 mm offset wheel. We guarantee fitment on a 7.5" wide 35mm 205/40-17 combination which has a section width of 8.4" and tread width of 7.7" which means you would have 3mm or .12" additional clearance with a 38 mm offset wheel which should allow for a 215/35-18 tire having a section width of 8.5" and a section width of 7.6" because both the added tread width and section width should be within .12 inches.

Since the above is based on certain assumptions, I would recommend double checking with Neon portion of this site and/or Neon specific sites.

[email protected]

[court65]

So your pretty much saying that a 18x7.5 with 42-48mm offset could fit with the right spacers without rubbing? and what if I opt'd to drop the car to give a nice fender gap fill? will there be probs?

[Cy@tirerack]

18x7.5 with 42-48mm offset with appropriate spacers probably would fit but double check with Neon section of this site or a site like neons.org to see what people have run into when runnning this set-up.

If you lower the car, then obviously less clearance more possibility of rubbing.

[court65]

Hey thanx for the continuos help, ill get back with the results and post them for all to see......