A Focus-friendly tire diameter chart

[cobratt]

I agree great post, but I have to pose a question. If you were to run the 205/55/16 on OEM rims would there be any rub with strut or.???
If anyone has tryed this please let me know. Thanks
Bill

[John B]

What size are you OEM rims? 15 x 7 or 16 x7 or ???

[boalie]

here is a program that might help out...

http://www.bigcustomwheels.com/rt_specs.jsp

[John B]

That is da bomb ^

[2006 ST2]

Anyone ever considered some 225/35R18's (instead of the normal 215/35R18)? According to The Tire Rack, they are only just a hair larger in diameter (24.2 to 24.3 inches) and about 3/4 inch wider tread width than the stock 205/50R16's on my '06 ST. I'll bet they'd work just fine with some 18x7.5" wheels on a moderate drop. Any thoughts? Add it to the list?

Comparing apples to apples, what is the BEST wheel and tire SIZE for autocrossing and/or road racing? This assumes that money is not an issue, tire width is limited to a 225 for class reasons, being used on an "ideal" suspension setup, and taking into consideration availability issues. I guess in my mind, it boils down to 215/40R17, 215/35R18, or 225/35R18 if they'll fit.

I really like those Falken RT-615's, but in cross-referencing from the list, they are only available in 215/40R17 and 215/45R17. Should I stick with the 17" Falkens that are so highly recommended? What would you get if money were not an issue? I want maximum lateral traction and lightness.

[John B]

Originally Posted by 2006 ST2

Anyone ever considered some 225/35R18's (instead of the normal 215/35R18)? According to The Tire Rack, they are only just a hair larger in diameter (24.2 to 24.3 inches) and about 3/4 inch wider tread width than the stock 205/50R16's on my '06 ST. I'll bet they'd work just fine with some 18x7.5" wheels on a moderate drop. Any thoughts? Add it to the list?

Comparing apples to apples, what is the BEST wheel and tire SIZE for autocrossing and/or road racing? This assumes that money is not an issue, tire width is limited to a 225 for class reasons, being used on an "ideal" suspension setup, and taking into consideration availability issues. I guess in my mind, it boils down to 215/40R17, 215/35R18, or 225/35R18 if they'll fit.

I really like those Falken RT-615's, but in cross-referencing from the list, they are only available in 215/40R17 and 215/45R17. Should I stick with the 17" Falkens that are so highly recommended? What would you get if money were not an issue? I want maximum lateral traction and lightness.

WELCOME TO THE JET!!!

We've talked about this alot and for auto-x, 16" is the biggest diameter you want to go because of inertia moment (rotational mass).

Me personally, I went with 205/50r15 because of better gearing and superlight (OZ Ultraleggera 11.5lbs) wheels and also because I have teeny tiny ZX3 brakes and not SVT brakes. The fact that Falken RT-615 come in that size is a bonus.

BTW, I have pictures showing that these wheels fit over SVT brakes (barely).

I would not recommend autocrossing or road racing a Focus on 17" or 18" wheels. I think the aspect ratio is too small. I used to run 225/45r17 and 215/40r17 and there is just too little sidewall to do anything but slip 'n' slide.

No offense, but if you showed up to a road race or an autocross on 18" wheels, I would think you were a poser.

Let's face it, if money was REALLY no object, would we be racing foci?

[Auto-X-ZTS]

Originally Posted by 2006 ST2

I want maximum lateral traction and lightness.

225/45-15, or if bigger brakes are a concern, 225/45-16 or 215/45-16. The smaller wheels will be lighter than the bigger wheels and more imprtantly as JB said, the moment of inertia will be closer to the axis of rotation. In an ideal world, you want the smallest diameter wheel that clears your brakes that comes in a width to support the widest tire (or in this case a 225), of the correct diameter, that fits your car. The tire should be between around 23 to 24" on a Focus, give-or-take a fraction.

[2006 ST2]

Whoot!... it worked! Thanks guys, thats exactly the information I was hoping to have added to this post (I was testing the foci's community knowledge). I hope you don't mind my beating around the bush and loaded questions to get a real world admission of truth. hahaha!!

I love this board already!

[v8FociDreams]

new poster here......looking to change my 195/60/15's to 205/60/15. I would think I should have plenty of room, but don't see it listed on the chart...should I go for it or will they rub the fenderwells???

Has anyone tried this??

[John B]

What brand are you trying in a 205/60r15?

[Reza]

205/60/15 is 24.7" tall 195/60/16 is 24.2" tall they should work fine but Why not the OE size?

[v8FociDreams]

well i was looking at a set of tiger paws for $125 the guy said they were almost new in the bigger size. My car is really squirrely in the corners and if it's wet, forget about it, so I was kicking around ideas with my ridiculously tight budget.

Found my friends and family card from Firestone and will be getting a set tomorrow for 10% above cost so I will be sticking to the OEM size at 195/60/15

4 tires out the door with road hazard for $223
Only $23 over budget. Good times

http://www.firestonecompleteautocare...iew.do?tire=96

[greentengu]

Okay, this one is actually for the mods: has anyone actually "cleaned this thread up" yet? I'm really not sure; I've read it, and when I click on it, I get one initial set of tire values, but then, going page by page, I find other, updated tire revs per mile, etc. values, people talking about getting out various forms of computers and calculators and "getting back to [us]"--and apparently notnot getting back to us, as well as all sorts of conflicting information.

While I know that the previous authors have gone back and updated their postings, I'm not completely sure that these postings, some from quite some time ago, are one-hundred percent "the be-all, end all of tire size friendly charts". Is there one, actual, definitive chart we can all follow? Or are we doomed to try to discern the truth, Davinci Code style, from a multitude of seemingly conflicting sources?

Not trying to be a horse's ass here, but the "search" function is all but useless in this thread, as it reveals several points of (amazingly done) information when I point my browser here.


--Scott

[John B]

Scott, what are you looking to do with said tires? Street/Strip/Track?

[greentengu]

Thank you for asking! That'd be "street" for now, but a visit this past Friday and a talk with the owner of Phoenix Racing to put on my tires has gotten me thinking about buying a Focus with my brother and going to racing school for an SCCA license [sic]. No joke: good or bad, win or lose, spending hours at this shop, talking to the incredibly enthusiastic owner, then to my brother about his "strip" (e.g. pre-marriage, pre-children tubbed out '72 Nova) days, has me thinking...where do I go from here? If I actually move and do "track days" (I realize there's the Auto-x forums...) where's a good place to start?.... answer: tires! (illogical, maybe?)

Nowadays, I put about/over 25,000 miles of "spirited driving" per year commuting on my car, and I chew through tires like a piranha chewing through an Amazon frog's leg. I am forever researching combinations of tire/wheels to increase performance (in summer, when I do not commute as much) and mileage (fall, spring, winter: during the school year). I have three sets of rims (two stock 16" and one aftermarket 15" set) and am fascinated, but not conversant in, the language of calculations regarding tire use. Thus, even though I put on so many miles on my tires, I am still (!) trying to learn (web searches, tire rack browsing notwithstanding) all I can about those critical things that keep my car attached to terra firma--I'm nothing but the most ignorant of students when it comes to tis topic, and want firm, solid, concrete information regarding it from experts who have real-world, quantified experience with this subject.

In other words, I'm a college professor who teaches English research writing re: primary/authoritative sources vs. secondary/questionable sources, and as such, I also know when I'm CLEARLY "out of my league". In this sense, I like to have "primary/fully authoritative sources" for everything I do so I don't make an uninformed decision about something that could seriously effect my life [tire grip in rain, etc.], bank account [price/cost/wear ratings] and, to be truthful, ego [grip, winning/losing if I ever do get to track my car or another car we purchase]. Thus, my question here--reading the various awesomely arranged tables/charts is like having three incredibly authoritative, highly respected sources, all saying nearly the same thing, but just being "off" by the slightest amount....and this then confuses my febrile brain.

In other words, I tend to take things I read here as "gospel", but there are no fewer than three "authoritative sources of foci" weighing in on this topic, so I am wondering if this was all settled. I can of course modify tire ratios, etc. with my XCal2 (haven't done so yet, but could, as I understand), but I'd enjoy a definitive breakdown for peace of mind nonetheless. For instance. I was wondering why, besides perhaps rules by sanctioning bodies, some Auto-crosssers attest to the effectiveness of the 205/50/15 tires, and whether this would be a practical tire for the street vis-a-vis rotations per mile, etc.--then saw the postings here regarding wheel/tire size in inches. Yet, for a "street" application, with three possible charts to go on, I'm unclear as to exactly what route I should follow. I'm assuming (ass/u/me) that a trip to the auto-x forums would help, no?

Anyway, in the end, sorry if I'm writing too much--I'm just very enthusiastic, and respect so much the opinions and experience of those who take the time to post these charts, I want to know if they've reached a concensus.

Cheers,

--Scott

[John B]

Thank God for you, Scott. Finally, a noob that can spell AND has good grammar!

I would not run 205/50r15 on the street simply for the fact that you have a supercharger (among other mods). Lots of non-SVT Auto-xers run this size in STS because we opt to change the gearing. I think with all the HP you have, coupled with a smaller overall diameter tire, you will be spinning them too much.

As far a good overall street tire...there's hundreds of choices. I have tried Kumho 712, Nokian, and Yokohama and they all perform fine in all season spirited driving.

A trip to the Auto-X forums is going to give you lots of food for thought.

[greentengu]

Thank you for the compliments re: spelling and grammar. It always irks me when I see people posting--on any forum--who have limited knowledge of how to take the time to write replies and questions in simple, standard English. It's disheartening to see the language I teach mangled, twisted, abbreviated, skewed and bastardized in posts, and I sigh a deep sigh whenever I read a post that runs like this: "s0 i wuz at the trak An i saw smoke from my car can U tell wats up with my car now!!! plz let me no wut is teh thing prolly wrong." ...

Okay, rant over, I shall calm down and respond calmly and appropriately.

I'll take your advice regarding running 205/50/15's. It's fascinating and exciting to delve deeply into learning all I can about the "main" element of a pleasurable driving experience: the tires, wheels, and brakes that keep me planted to the ground.

I am looking forward to reading the auto-x forums and ingesting great quantities of "food".

Lastly, I'll just say: I am the biggest car noob/student on Earth, and proud of it! The day I stop being a noob is the day I stop caring about cars.

Cheers,

Scott

[TurboST]

Might think about adding 225/50R16 to the list. No rub experienced, as of yet on my stock-suspension '06 ST w/ stock wheels.

http://forums.focaljet.com/tire-rack...0r16s-fit.html

[OmniFocus]

They're a little unfriendly from a diameter (24.86") standpoint, but otherwise they'd be good. A 7" wheel would likely cause rub.

[TurboST]

Agreed... but that was one of the specific reasons I chose them (for the slightly larger diameter). My car makes so much power, I was borderline considering a steeper ratio anyway. I can "almost" use 1st gear now. Plus, better mileage. I believe a 7" wheel could be used with a 40-45 mm offset. I vote for the size to be added (with special caution.)

[Pach]

Great Info

[method213]

Would 205/60/15 work with a 40 off set wheel? 15x6.5? i believe or would 215/60/15 work better?

[method213]

^^oh yeah with a drop??