Wheel/size/offset and tire/size/profile...can be confusing.

[Shrikecorp]

I've been sort of compiling and validating some combinations. Criteria: avoiding poke, trying to find ways to improve on the stock look without compromising performance too much, etc. Seems like an okay start, might be cool if we could add to it (original in Excel has formulas and all that bit.) Thoughts?



Corrected/updated:


Link to editable Google Sheet. Add your own, etc. Play nice. Wheel Tire Options

• Added columns for AWD/RWD and lowered or not.

Seriously nifty comprehensive calculator linked by @YOWStinger : Rim & Tire Size Calculator. Custom Offsets

 

[Manaz]

For tyre sizes and trying to keep to stock-ish rolling diameters (to avoid Speedo inaccuracy, or to avoid issues with AWD and mismatched sizes), there are a number of tyre size calculators online that can help. The miata.net site has one that has been my go-to for years - it's basic but it works (There are others out there that graphically show the differences, etc).

Tire size calculator

 

[Logic717]

Great post, thanks for sharing this!

I've been sort of compiling and validating some combinations. Criteria: avoiding poke, trying to find ways to improve on the stock look without compromising performance too much, etc. Seems like an okay start, might be cool if we could add to it (original in Excel has formulas and all that bit.) Thoughts?

View attachment 23854

nks f

 

[Shrikecorp]

For tyre sizes and trying to keep to stock-ish rolling diameters (to avoid Speedo inaccuracy, or to avoid issues with AWD and mismatched sizes), there are a number of tyre size calculators online that can help. The miata.net site has one that has been my go-to for years - it's basic but it works (There are others out there that graphically show the differences, etc).

Tire size calculator

Indeed, that's what the Excel formulas are based on. I do find significant discrepancies between calculated values and actual diameters at times. Michelin appears to be more consistent than others (I'm looking at you, Pirelli).

 

[YOWStinger]

If I may suggest, staggered 20 option B is

Front 20x8.5+30 245/35r20
Rear 20x10+40 285/30r20

This is the suggested TSW wheel size, I'm still working on validating +40 in the front which may not work depending on the shape of the spoke.+40 was used on the Federation Stinger on the front with TSW Sprints.

 

[Shrikecorp]

If I may suggest, staggered 20 option B is

Front 20x8.5+30 245/35r20
Rear 20x10+40 285/30r20

This is the suggested TSW wheel size, I'm still working on validating +40 in the front which may not work depending on the shape of the spoke.+40 was used on the Federation Stinger on the front with TSW Sprints.

Excellent input. It'd be great to see living documents for quantitative information (perhaps fuel mixing, etc.., as well), updated by site members. Searching is tricky with terms repeated thousands of times. I'll integrate this data when I'm back to a PC.

 

[Kamauxx]

I've been sort of compiling and validating some combinations. Criteria: avoiding poke, trying to find ways to improve on the stock look without compromising performance too much, etc. Seems like an okay start, might be cool if we could add to it (original in Excel has formulas and all that bit.) Thoughts?

View attachment 23854

20a wouldn't work. The rear tire would be way too small compared to the front. Since that looks like the specs from my car you probably meant to put 285/30 vice 285/25.

A 285/25/20 mixed with 245/35/20 would look like this:

 

[Andimal]

I have a square set up - 19x9.5+25 and 255/35/19 tires. AWD on Eibach springs. Tight fit in the front, but perfect, not issues.

 

[Shrikecorp]

20a wouldn't work. The rear tire would be way too small compared to the front. Since that looks like the specs from my car you probably meant to put 285/30 vice 285/25.

A 285/25/20 mixed with 245/35/20 would look like this:

View attachment 23870

Thanks! I see my formula for calc diameter for 20A was borked, now corrected in Excel file. And it now aligns with the results you got from the TireSize calculator. The mix I was going for was 245/30 20 and 285/25 20, trying to stay very close to stock diameter, which gets us this...just .2"/0.8% difference, pretty close to the stock 26 and 26.1:



What's yours exactly, offsets and all?

 

[Shrikecorp]

I have a square set up - 19x9.5+25 and 255/35/19 tires. AWD on Eibach springs. Tight fit in the front, but perfect, not issues.

Added in

 

[MisterMac]

I have a square set up - 19x9.5+25 and 255/35/19 tires. AWD on Eibach springs. Tight fit in the front, but perfect, not issues.

FYI, This set-up results in 1/2 inch of poke front and an inch in the rear..

 

[Shrikecorp]

Excellent input. It'd be great to see living documents for quantitative information (perhaps fuel mixing, etc.., as well), updated by site members. Searching is tricky with terms repeated thousands of times. I'll integrate this data when I'm back to a PC.

Added in

 

[Tobstertx3]

Another option for you which is my current 20” staggered setup

Front 20x9+35mm 235x35
Rear 20x10+40mm 275x30

 

[Shrikecorp]

Another option for you which is my current 20” staggered setup

Front 20x9 235x35
Rear 20x10 275x30



View attachment 23905

Any poke?

 

[YOWStinger]

Front 20x9 235x35
Rear 20x10 275x30

What offsets?

 

[Shrikecorp]

Here we go. Posting this here, and I'll add the original post. Link to Google Sheet, open to edit for all who have the link. Add yours if you like, etc. Play nice. Wheel Tire Options

 

[Shrikecorp]

What offsets?

Indeed, I should note that accuracy for @Kamauxx and @Tobstertx3 configs are pending offset data.

 

[brancky3]

Added mine.
19x8.5 +32 // 255/35/19
19x10 +47 // 295/30/19

They are 0.05" apart in circumference

 

[YOWStinger]

Also, I might suggest using this as the calculator going forward, which allows you to enter all of the specs including offset, tire size, and calculate fender and wheel clearance, etc. I should measure up what the stock fender clearance is.

E.g. Rim & Tire Size Calculator. Custom Offsets

 

[Shrikecorp]

Also, I might suggest using this as the calculator going forward, which allows you to enter all of the specs including offset, tire size, and calculate fender and wheel clearance, etc. I should measure up what the stock fender clearance is.

E.g. Rim & Tire Size Calculator. Custom Offsets

That's excellent, really nice find ...if we get the fender and suspension clearances, I can probably extrapolate the formulas from the results and incorporate into the sheet as well. That'd be great.