Determining the proper width size of the tire

[WingsofWar]

Originally Posted by fatoni

choosing a wheel size and a tire to match is backward in my opinion. especially when you start playing with diameter sized

your not wrong, sometimes you do need to work backwards (AKA working outside-in). Especially when your building a wheel and tire package from scratch.

For example, on a street car, if your looking at tire with a hard slightly stretched sidewall to fit flush with those fenders, and a contact patch width that clears coils/suspension. You get the best height and width size, and the rest (quality of the tire) is up for personal preference. Then shop for the best width for your wheel then offset then wheel height, (but you have to be careful with the offset because people tend to miscalculate and shit doesn't fit right). I see this method used with lots of tuners, and the STANCE/FLUSH community.

vs

Working inside out, starting from the center of the wheel we consider; Backspacing->Offset->width->height->weight->sidewall height->tire width
(sometimes considering multiple or all at the same time)

[AIRMAX]

My golden rule is +0.5~1Width on Front wheels, +1~1.5 Width on Rear wheels is ideal.

Going +2 needs to be justified... Extra Horse power etc.


Diameter wise, +1 is very common, +2 is again needs to be justified.


I think it will come with 17x7.5 +45 on 215/45 tyres.

Which means 18x8 +37 Front wheels, 18x9 +37 Rear wheels for me! hehe

[Matador]

Originally Posted by WingsofWar

hahah well its not really rocket science. Its pretty simple stuff when you learn and understand all the terminology. You can even learn a lot by tire brochures and reading on tire manufacturing processes.

It starts to get tricky when picking out the perfect motorsports tire. Then you have to consider; type of motorsports(drifting,roadcourse,drag), type of driving style(conservative, aggressive), ambient temp, humidity, elevation, sports compounds (different levels of soft and hardness),

When it comes to real motorsports, refer to my first post in this thread. Otherwise (grassroots, track days), it comes down to;

1- What you are allowed to run (full race compound/slicks, semis, r-compound, street only etc)
2- What are you running on (prepared surface, road course etc)
3- Where/when are you running (hot/dry/cold/wet/ high or low elevation)

Those factors will pretty much determine the compound and tread you select. Then

4- Car type (RWD, AWD, FWD)
5- Car setup and by extension, driving style.

Mostly in that order.

The last two will influence the size you want to run, the pressure you run them at and whether you stagger them or not.

It comes down to how serious you are at what you do, tyre selection can be quite the science depending on what rules you play by. Of course the criteria for the street is a whole different ball game and WoW's previous post pretty much summed it up, though different people have different priorities.

[Random_Art]

Originally Posted by MatadorRacing_F1

When it comes to real motorsports, refer to my first post in this thread. Otherwise (grassroots, track days), it comes down to;

1- What you are allowed to run (full race compound/slicks, semis, r-compound, street only etc)
2- What are you running on (prepared surface, road course etc)
3- Where/when are you running (hot/dry/cold/wet/ high or low elevation)

Those factors will pretty much determine the compound and tread you select. Then

4- Car type (RWD, AWD, FWD)
5- Car setup and by extension, driving style.

Mostly in that order.

The last two will influence the size you want to run, the pressure you run them at and whether you stagger them or not.

It comes down to how serious you are at what you do, tyre selection can be quite the science depending on what rules you play by. Of course the criteria for the street is a whole different ball game and WoW's previous post pretty much summed it up, though different people have different priorities.

That is, of course, if you have the means to be able to justify swapping tires all the time. For me, I'll just stick with a decent summer tire since I won't be tracking it all that often.

[NESW20]

many performance summer tires grip VERY well in the wet. i have a truck for snow/ice. my FT will have summer-only tires.

you absolutely do NOT need all-season tires for rain.

[Mr.Jay]

Originally Posted by AIRMAX

Diameter wise, +1 is very common, +2 is again needs to be justified.

what about -1? Throwing on some 16s on smaller whell less rotational weight?

[Abflug]

17 x 7,5 plus 5 x 114,3 would be great so I can use my oldskool BBS!

[fatoni]

Originally Posted by Mr.Jay

what about -1? Throwing on some 16s on smaller whell less rotational weight?

+1 on -1 although i think 17 is okay. it was sad to see what 18s on the elise when they first came over simply because theylook cool. i have a feeling that 16s might be too tough to shop for because of brake clearance i dont really know how the tire selection is for 16s. seems to be that 15s and 17s are where the coolest street sizes are

[Dave-ROR]

For 16s, the most perfect match in overall diameter is 245/45/16. Assuming they fit that'd be great... assuming you want to run R comps since that's all that's available in that size.

For a more reasonable 225/50/16, which is .3" total diameter larger than 215/45/17s you can get all of the normal suspects in the extreme summer category (RE11, XS, AD08, Star Specs and RS-3) plus a large selection of R comps.

I'd likely run 16s and either 225/50 or 245/45 if they fit for track use without a doubt. I doubt this car will have large enough brakes to prohibit the use of most 16" wheels.

For the street, in terms of pricing (TR)you can get (225/50/16 for 16" vs stock 215/45/17 for 17"):
Star Specs: 16"=$133, 17"=$144
AD08: 16"=$164, 17"=$172
RE11: 16"=$178, 17"=$199
RS-3: 16"=$102, 17"=$129
XS: 16"=$121, 17"=$128

So for the most part, there's not a great amount of difference there either way except for the RE11 and RS-3, $21/tire for the RE11 and $27 for the RS-3. I'd likely run the stock wheels on the street and 16s on the track/autocross (assuming R comps, I wouldn't want to go up in overall diameter to stick with street tires, the gearing change will more than offset anything else IMO - and there are no new/good R comps in the stock size) $40 or so extra for each set of tires is going to be cheaper than 2 sets of 16"s for a long time....

Now assuming you don't mind spending money.. if they'll fit 245/40/17s are only .1" overall diameter larger.. and all the tires are available in that size (extreme performance and r comps).. RE11s are only $244 each... AD08s my current favorite tire is $204 each.. ouch..

Now 235/40/17s will actually let you reduce the overall diameter by .5" (making for shorter overall gearing) and while tire selection isn't as good... you can get RE11s for $224, AD08s for $189 and Star Specs for $162. Better than 245/40/17s but worse than the OEM sizes price wise. Also the new gForce R1 is available in that 235/40/17 for $255 for those who want a R comp...

Load ratings change depending on the size selected and if lower than OEM could be a potentially dangerous setup, so check all that before making decisions on tire/size selections.

[Alfie]

I just remembered if the rim is sold as 17 x 8 (which is what I want), the rim width is really 1 inch wider from bead to bead. That seems plenty wide for this car!
MY 2 Favs right now: SUMMER / WINTER

[Racecomp Engineering]

I always see people go on and on about fitting wide tires.....just to throw crappy all-seasons on the car. Compound is much more important than tire width. I'll take a 215 good summer tire before a 255 all season.

Hopefully some cheap used takeoff subaru wheels fit for use as winter wheels. Maybe make a coffee table for the wheels i'm not using.

- Andrew

[oneday]

Originally Posted by Racecomp Engineering

I always see people go on and on about fitting wide tires.....just to throw crappy all-seasons on the car. Compound is much more important than tire width. I'll take a 215 good summer tire before a 255 all season.

Hopefully some cheap used takeoff subaru wheels fit for use as winter wheels. Maybe make a coffee table for the wheels i'm not using.

- Andrew

Glad I'm not the only one!

[Dave-ROR]

Originally Posted by Racecomp Engineering

I always see people go on and on about fitting wide tires.....just to throw crappy all-seasons on the car. Compound is much more important than tire width. I'll take a 215 good summer tire before a 255 all season.

Hopefully some cheap used takeoff subaru wheels fit for use as winter wheels. Maybe make a coffee table for the wheels i'm not using.

- Andrew

Agreed. Hence all the tires I mentioned in my post :P

[SHINCHU86]

Originally Posted by n2oinferno

235... on a 10.5" wheel.

You laugh, but I guarantee some people will do it.

thats what i had on the rear of my silvia.

i think i would run 17x8/9 with 225/235 on the FR-S with as much offset as i could get under the stock fenders.