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M2 flare kit - advice for wheel fitment

maestromaestro

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#1
Soooo.... I am planning on getting the M2 flare kit (whenever it is going to appear on our shores) and cutting the fenders. Anybody with a knowledge what's the widest rim/tire combo I can fit and, most importantly, that would clear the calipers?

An important info here: I have converted to 4x100 bolting pattern and am running 16" x 7" rims with a +40 offset on a Wilwood BBK. This "just clears" the calipers, so much so that I have to put the balancing weights closer to the inside of the rim. My preference would be to keep the 16" or even step down to 15", if that makes any sense or provides a combination of dimensions for which tires are available. To that end, I suppose a more accurate question would be - what is the widest tire/rim combo for which tires don't cost $250 a pop...

Please share your experience or suggestions!
 


RubenZZZ

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#2
Soooo.... I am planning on getting the M2 flare kit (whenever it is going to appear on our shores) and cutting the fenders. Anybody with a knowledge what's the widest rim/tire combo I can fit and, most importantly, that would clear the calipers?

An important info here: I have converted to 4x100 bolting pattern and am running 16" x 7" rims with a +40 offset on a Wilwood BBK. This "just clears" the calipers, so much so that I have to put the balancing weights closer to the inside of the rim. My preference would be to keep the 16" or even step down to 15", if that makes any sense or provides a combination of dimensions for which tires are available. To that end, I suppose a more accurate question would be - what is the widest tire/rim combo for which tires don't cost $250 a pop...

Please share your experience or suggestions!
Step up to 17x9 and you can probably stuff some 235 or 245s under there. You can pick up all season tires for less than $100 each.

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maestromaestro

maestromaestro

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Thread Starter #3
Step up to 17x9 and you can probably stuff some 235 or 245s under there. You can pick up all season tires for less than $100 each.

Sent from my LGLS992 using Tapatalk
According to the "experts" at NTB, you can throw on 245s on 7" rims... I doubt that it would be a good idea. Again, my preference would be not to increase the wheel size to 17". Maybe even go down to 15s... I am wondering if I were to use say, a 9" rim on a 16" rim, how do I figure out what offset I need, given that I have a 40 mm offset on a 7" rim.[dunno]
 


jeffreylyon

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According to the "experts" at NTB, you can throw on 245s on 7" rims... I doubt that it would be a good idea. Again, my preference would be not to increase the wheel size to 17". Maybe even go down to 15s... I am wondering if I were to use say, a 9" rim on a 16" rim, how do I figure out what offset I need, given that I have a 40 mm offset on a 7" rim.[dunno]
7" -> 8" width will add 12.7 (1" = 25.4mm / 2) of width on both sides of the wheel. ET40 -> ET27 will set the wheel so that all of the additional wheel width will be on the outboard side of the mounting surface (brake rotor). I run 17x8 ET45 with no fitment issues with 205/40, slight rub with 215/45. I plan to run M2 flares over 17x9 ET45 with 24mm spacers, making them ET21.

Does anyone know how much addition clearance the M2 flares promise?

BTW: These guys: www.uswheeladapters.com make really nice spacers. I had them cut a set for me with the bore adapter machined in.
 


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maestromaestro

maestromaestro

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Thread Starter #5
7" -> 8" width will add 12.7 (1" = 25.4mm / 2) of width on both sides of the wheel. ET40 -> ET27 will set the wheel so that all of the additional wheel width will be on the outboard side of the mounting surface (brake rotor). I run 17x8 ET45 with no fitment issues with 205/40, slight rub with 215/45. I plan to run M2 flares over 17x9 ET45 with 24mm spacers, making them ET21.

Does anyone know how much addition clearance the M2 flares promise?

BTW: These guys: www.uswheeladapters.com make really nice spacers. I had them cut a set for me with the bore adapter machined in.
I used one of these nifty online calculators to play with the sizes. It looks like I'd need a rather massive offset to clear the calipers - or will have to use spacers, potentially use long studs.
The car has been lowered 1", so that's another dimension that I need to watch out for - as the 255 will be taller than the OEM by 0.75", thus eating the clearance by a 1.75" combined.

Does anybody have any numbers for the distances between the OEM wheel and the fender wall on the top? For that matter, the other two - between the inner sidewall and the suspension and frame?
Would like to avoid futzing with calipers under the car... [hihi]
 


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maestromaestro

maestromaestro

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Thread Starter #6
I plan to run M2 flares over 17x9 ET45 with 24mm spacers, making them ET21.
A 24 mm spacer - is it not too much? Do you have enough thread left in the stud? I figured that the offset (or a combo of the offset and the spacer) would have to be about 59 mm, if I go to 255s (54 mm if 245s). So, with a 24 mm spacer, I could use an ET30 or ET25. But - would long studs be needed? (Again, too lazy to go actually measure)...
 


RubenZZZ

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A 24 mm spacer - is it not too much? Do you have enough thread left in the stud? I figured that the offset (or a combo of the offset and the spacer) would have to be about 59 mm, if I go to 255s (54 mm if 245s). So, with a 24 mm spacer, I could use an ET30 or ET25. But - would long studs be needed? (Again, too lazy to go actually measure)...
24mm is nearly 25mm, which is a common 1" spacer adapter: you bolt the spacer to your hub, then bolt the wheel to the spacer.

A 1" spacer kicks out even the most sunken-in factory wheels way out.

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OP
maestromaestro

maestromaestro

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Thread Starter #9
You also dont seem to understand how offsets work.

Check out this link.

https://tiresize.com/wheel-offset-calculator/

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Are you talking to me?

I used the very calculator. So, I think I have a good grasp of the concept. Without spacer, I'd need ET55. With a 25 mm one, ET30.

Love your sandwich, by the way.
 


jeffreylyon

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Are you talking to me?

I used the very calculator. So, I think I have a good grasp of the concept. Without spacer, I'd need ET55. With a 25 mm one, ET30.

Love your sandwich, by the way.
You've got it backwards - a spacer will reduce ET, not increase it. A smaller ET places the wheel farther out.
 


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maestromaestro

maestromaestro

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Thread Starter #11
You've got it backwards - a spacer will reduce ET, not increase it. A smaller ET places the wheel farther out.
How is what I said is backwards? If I need a wheel with a 55 mm offset, I can get the same accomplished with a 25 mm spacer and a wheel with a 30 mm offset, for the same size rim. That's what the Tiresize.com graphics indicate anyway. Having said this, the sign of the offset (positive or negative) is important when you say "reduce".

My plan is to go with a 9" wide rim, vs. the 7" that I have currently. So, the new offset is = (9-7)*25/2 + 40 (where 40 is the offset of the current wheel in mm) =65 mm This results in a net (almost) zero outward shift. Any "deficit" due to the new wheel having a smaller offset (good luck finding the 65 mm offset wheel) is made up by a spacer. So, if I use a 25 mm spacer, I could use a 40 mm offset wheel. These are all, by the way, negative offsets.

Still backwards?
 


RubenZZZ

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How is what I said is backwards? If I need a wheel with a 55 mm offset, I can get the same accomplished with a 25 mm spacer and a wheel with a 30 mm offset.

?

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Negative ghostrider.


Adding a 25mm spacer to 30 offset wheel makes the total offset 5.



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maestromaestro

maestromaestro

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Thread Starter #13
This picture is actually confusing - they are not actually showing the offset dimension. This one does: Capture.PNG
 


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maestromaestro

maestromaestro

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Thread Starter #14
We are all on the same page. Thanks for the inputs, fellas - sometimes the best advice is to go research.
 


jeffreylyon

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How is what I said is backwards? If I need a wheel with a 55 mm offset, I can get the same accomplished with a 25 mm spacer and a wheel with a 30 mm offset, for the same size rim. That's what the Tiresize.com graphics indicate anyway. Having said this, the sign of the offset (positive or negative) is important when you say "reduce".
A ET30 wheel with a 25mm spacer will result in a ET5 (30 - 25) wheel. A spacer reduces ET.

My plan is to go with a 9" wide rim, vs. the 7" that I have currently. So, the new offset is = (9-7)*25/2 + 40 (where 40 is the offset of the current wheel in mm) =65 mm This results in a net (almost) zero outward shift. Any "deficit" due to the new wheel having a smaller offset (good luck finding the 65 mm offset wheel) is made up by a spacer. So, if I use a 25 mm spacer, I could use a 40 mm offset wheel. These are all, by the way, negative offsets.
Still backwards?
7" -> 9" wheel results in 25mm (25.4) more wheel on the inside *and* the outside if the two wheels have the same ET. To ensure that the inside edge of the 9" wheel is at the same spot as the 7" wheel, you'll need a 25mm spacer, assuming that both wheels have the same offset (ET).

Your math is a little circular: (((9 - 7) * 25) / 2) = 25mm, the same 25mm that I spoke of above. If your current 7" wheels are ET40, then a 9" wheel with an effective ET15 (40 - 25) will place the inside edge at the same place at the 7" ET40. One way to get ET15 is to buy an ET40 wheel and use a 25mm spacer.
 


OP
maestromaestro

maestromaestro

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Thread Starter #16
We are in sync. See below. Essentially, if I were to move from an OEM size to the 255s (which you can put on a 9-10" rim), I'd need a 15-16 mm POSITIVE offset (ET15).
 


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RubenZZZ

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#17
We are in sync. See below. Essentially, if I were to move from an OEM size to the 255s (which you can put on a 9-10" rim), I'd need a 15-16 mm POSITIVE offset (ET15).
Thats a slick calculator. Link to site or app?


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maestromaestro

maestromaestro

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Thread Starter #20
Be careful using tools like these; actual tire dimensions vary quit a bit from their spec. size.
Understood. They provide explanations; this is from their site:

"Wheel width will effect the tire width by 1/10" on each side for ever 1/2" change in wheel width. This is a small concern unless you plan on running wheel widths that are well outside the manufacturer's recommended range. If you plan on stretching the tires, or running wheel widths that are wider than the width of the tire then you will need to keep in mind that the visualizer is showing tire position not wheel position. In this case the wheel may be closer/further than the calculated distances of key measurements."
 


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