Auto Fitment Calculator
 

Hi all, I've compiled a ton of information floating around on this forum, and used some of my coding experience to pull together a real-time fitment calculator.

The way it works is, it defaults to the stock tire size, and allows you to compare tires. You can also select front or rear fitment.

http://frsproject.magiclabs.io

Feel free to ask questions.

- 1 pixel equals 1 millimeter.
- 1" drop = 2/5mm offset tuck. (f/r)

*UPDATED*

I have added:
- Verification (FT86 Users can now vote!!!!)
- Fender Gap distance.
- Offset From Flush distance.
- Camber
- Wheel Width
- Graphics!
- Comparison Line
- Ability to view: Wheel, Tire, Hub, or Rotor (more accurate version coming soon..)

I'd appreciate anyone confirming these numbers.

Cool. Good job

AWESOME JOB! Is there any way to include camber in your calculator? That would really complete it.

Thank you!

nice job!

there's one downfall about tire measurements though. a 215 oem tire will have slightly different tread width than a 215 sticky tire. i'm not sure how tire manufacturers choose to measure their tire width.

Thanks guys. There's definitely room for error, so don't take this as the be all end all. It is purely to get an idea of how different tire sizes, offsets, and ride height relate to the fender.

I'd be happy to try and calculate camber, but would need a good technical source on how to calculate it.

Really cool alternative to the miata tire calculator.

Something's wrong. It shows the outside of a 245/40-17 with stock +48 offset being at the same location as the outside of the stock 215/45-17 on +48. The two should be centered, with the 245 having the outer sidewall 15mm further outboard, and the inner sidewall 15mm further inboard.

Should look like this:
http://www.willtheyfit.com/index.php...&Submit=Submit

Thanks for the tip. I did recall this during the coding process, but forgot about it after the fact. I've fixed this.

Kickass :D

You are a genius sire!!!!!

I like it, but it should really have rim width as a factor in there somehow....

also, the fender gap calculation can't be right. I just picked a tire that was 9mm taller in diameter and the fender gap shows 9mm less...shouldn't it be 1/2 that?

Awesome !

I always used http://rimsntires.com/specs.jsp but always wished they had a visual for the specific car's suspension and fender/QP.

My fender gap calculation is strictly vertical gap, it doesn't account from the edge of the tire, as I can't assume what the corner radius of your specific brand of tire is.

Rim width was removed?

Can you add camber to the mix? I feel like that would help.

No, that's not what I mean. Compare a 215/45/17 to a 225/45/17. The diameter of the tire is 625mm vs 634mm, a 9mm difference. Your fender gap calculation shows a change from 54mm to 45mm, also a 9mm difference. But what you aren't factoring in, is that increasing tire height doesn't push it directly closer to the fender. The tire is attached to the car at the hub, and the height change occurs above AND below that. So it would be 4.5mm closer to the fender, the other 4.5mm increase at the bottom would increase ground clearance, not decrease distance to the fender.

Correct. I will adjust this shortly.

Yay I win at math today. :P

Dayam, this is sweet! Added as one of the first links in the Wheel Directory!
http://www.ft86club.com/forums/showthread.php?t=7535

Neat, but without wheel width this tool is very incomplete in showing you changes in fitment as width changes fitment the most drastically.

Oh wow this is pretty awesome stuff!
Thanks a ton for this!

pretty nice tool to have handy since i can't get the miata one to work properly on my firefox.

Pretty cool. Very nice job.

Very nice! Thanks

So this tool assumes that the wheel width is equal to the tire width?

Nice work, in any event, but if you can somehow include wheel width in this, that would make this the mots comprehensive tool available to us. Unfortunately, I'm not sure of the math involved with using wheel width and tire width together to come up with the exact fitments.

I have corrected for this calculation.

this should seriously be stickied

This is awesome. :)

Yes, otherwise he would have to model shapes for tire stretch, which I'm sure is a lot more work.

How accurate is this?

Also can you put in how close it would be to the shock/struts on the inside?

Nice, I wish my math skills were that useful, you should go to MIT....http://www.wildsoundmovies.com/image...ious_jesse.jpg
:thumbup:

Thanks guys. The script assumes an 'appropriate' wheel width, because drawing tire stretch is tricky to do. If there was enough demand, I'd take that challenge on.

As for inside clearance, if someone wants to provide some kind of diagram, or something to work with, I'd be happy to add it in.

Mate I'm not a technical source, but if you know the camber you are targeting it's pretty simple to work out the resultant change of position of the tyre.


x = sin(c) * (D - SH) / 2


Where:

x is change in tyre position
c is camber in degrees
D is diameter of tyre
SH is sidewall height

You could leave the sidewall height out, but it just approximates halfway up the sidewall as the widest point of the tyre.

bumpity..

IMO it's incomplete without wheel width. These numbers arn't the same for a 8" wheel than a 9.5" wheel.

Hi all! I had some time to redesign and add in some key features people have been asking for:

- Camber
- Wheel Width

Enjoy! Maybe this will earn me a sticky now? ha!

I'd still love a way to see how close the wheel would be to hitting the shock/struts or a coilover for those of us who want to run a wide tire out back.