I did a lot of measuring of my actual car before I decided on the +45 offset.

I do wish everyone could just standardize on backspace.

If I want 13 inch wide wheels in the rear, what backspace do I want? 7.25 inches

If I want 12.5 inch wide wheels in the front, what backspace do I want? Stil 7.25 inches

So much easier.

Then of course, it is necessary to determine tire clearance, which is another issue.

And some may say "Wait, didn't you mean 7.5 inches?"

No, I find less clearance issues with 7.25 inches, particularly in the rear where the biggest tires live (335/30-18)

Backspace will help you fit wheels to your car, but wont help you fit tires to the car.

Tires center themselves on the wheel, so offset is essential to knowing if the tire will rub to the inside or outside or just clear.

Im using 7.75" backspace, but as you know backspace and offset needs will both vary with static camber and toe settings.

I guess I am missing something, as I don't see how offset helps me know this any more than backspace does.

Pointers?

Oh, yeah. I believe you will understand my point of view on using offset to fit a tire to the car with this example.

An 8" wide wheel with 45 offset places the tire between the suspension and fender in the same location as a 9", 10" or 11" wide wheel.

Your max tire width is the same width on each wheel.

These wheels all have different backspaces.

So for my cars camber and fender roll status I can confidently say that a +45 offset fits the maximum tire (305mm wide so far) no matter the wheel width.

Additionally, offset will help with precision on fitting a tire.
Example, my Forgestar F14 wheels are 11" nominal width (tire bead seat to tire bead seat is 11" wide). They are 12" overall width; however, due to their width and high offset their design encorporates a thicker 5/8" flange on the long unsupported inner barrel lip and only a 3/8" flange on the shorter wheel spoke reinforced outer lip.

Therefore, the "simple" formula of offset equals backspace plus frontspace divided by two minus frontspace does not actually apply.

how many degrees of camber , front and rear, with this new tire set up?

Noticeable better grip with the 305 tires over the 295 tires size ?

Same alignment-
Front= stock alignment capability maxed on negative camber (-2.4deg).
Rear= stock alignment capability maxed on positive camber (-1.2deg).

295s I had and these 305s are two very different types of tire.
These 305s are rain race tires and so work best cold.
Hook 1st gear on the streets which is nuts and so much front grip they need minimal countersteer and its effects are immediate which makes drifting very easy.

Unfortunately, these tires will only last minutes drifting and its easy to overdrive them and get them hot and greasy.

Next tire I want to try is the 315/30-18 Nitto NT01 because its only 25.35" diameter and I have always loved NT01.

One test I read showed the NT01 actually had better initial/cold traction than the new 200utqg Yokohama AO52 (that also comes in wide sizes).

https://titan-7.com/collections/whee...19859667812440

Titan 7 makes an 18x10+50, for those looking for a wheel with high offsets.

SSR Formula Mesh 18/19" brake clearance:

After searching the internet high and low, I have come to the conclusion that this information is not out there.

I've always dreamed of having a set of SSR Mesh, and can finally afford them, so I'm doing research on brake clearance on their new 18" (and maybe 19") versions.

I'm running Project-Mu 4 piston x 4 pad SLIMs (355mm rotors) in front, and Biot OEM caliper extenders out back on 350mm rotors. The brakes look and feel amazing, but leave me with wheel clearance problems. Surprisingly, the problem is mostly in the back!

Does anyone out there have a set of either 18" or 19" SSR Mesh, who can do a couple of measurements for me?? (all on the inside of the rim, where the brakes would be)
Specifically:
1) clear diameter from narrowest point of disk edge (i.e. where the disk face bolts to the rim/lip) across to the same spot on the other side of the wheel
2) backspacing:
a. distance/depth from mounting face to back of disk (standard caliper space measurement)
b. distance/depth from mounting face to back of the rim/lip/disk bolting surface (the part I mentioned above, in point 1)
3) Valvestem protrusion -- if it eats into any of the spaces mentioned above.

THANKS!!

=============
Some ancillary info:

Forgetting about the fronts for a sec, the rear BIOT bridges with OEM calipers are the main problem.

On my SSR Minerva 18" SL disk, the caliper hits the portion of the disk where the disk bolts to the rim -- i.e. the outer loop/circle. It should clear with maybe a 5-10mm spacer, so I think it would clear a 18" LO disk face.

On 18" Work VS-XX O-Disk, the caliper hits the valvestem, but clears the disk and rim. It needs about a 10-15mm spacer to clear the valvestem.
It barely clears the 18" VS-XX A-disk valvestem - by 1mm!!

But, the SSR Mesh are not Minervas, nor are they VS-XX so I need to check if anyone here has real experience, or a rim that they can measure. :D


Tags: ssr, mesh, minerva, vsxx, wheels

With respect to the guidance above, is it plausible that narrower (within mfg spec range) than common tires would provide a bit more wiggle room? Considering this setup:
F: 18x9.5 +43 245/35/18
R: 18x10 +31 255/35/18

Thanks!

Sorry, ended up selling the wheels/tires before ever mounting. 🤦

pictures?

Wow, this thread is a real eye opener. Wish it was around when I made my wheel choices many years ago.
F 9.5 x 18 50 offset R 10.5 x 18 50 offset Went with 255-35-18 and 275-35-18 tires, didn't want the shorter
285-30-18 in the rear. It was ok as I only had about 340 rwhp but now have gone single and need more rear wheel
traction. I am now thinking of going 295-30-18 rears thanks to BLUE TII pushing the envelope in sizing. Now
don't know what to do with the fronts. Stay with 255-35-18 or go to 285-30-18, want to stay at or under 25" front
height. The 255 on 9.5 wheel is a nice fittment but would be much narrower than the 295 on the rear, would be a
lot of stagger. The 285 on front would better for stagger but 285 on a 9.5 wheel is a little "poochy", although still the
minimum recommended wheel size for that tire size. What do you all think would be the better front choice on a
street driven car driven in dry only? Might have to mix tire brands for those fittments. Want extreme perf summer tires.

I don't think there's any real good solutions for your tire sizing dilemma unless you were to order new wheels like these which an accommodate a square 285 setup. You can go wider up front but then diameter becomes an issue. Your other option is to just get stickier tires. How much power are you putting down now? Still rotary? I think for a street car you're fine with the staggered setup. Seems like you need more straight line grip.

Titan7 T-R10 18x10 +50 5x114.3 Matte Black (set of four)

Taller, skinnier tire will have more straight line traction than shorter wider tire so just keep the 275/35-18 size you have in the rear and go with a stickier tire.

Wide tires horizontal contact patch is for lateral traction (cornering), tall skinny tire vertical contact patch is for longitudinal traction (accel and decel).

Thanks for the replies. Would my 275-35-18 Bridgestone SO-3 give more acceleration traction than a 295-30-18 Yok A052? What tire would be the stickiest say in 70-80 +- degrees weather without heating them up like track lapping would do? I wouldn't be doing a burnout everytime I wanted to jump on it. Running 450-500 rwhp depending on boost setting.

These look good for longitudinal grip.

https://m.tirerack.com/tires/descrip...um=735WR8RT660

I believe the A052 will provide more traction than the S03 because they are a sticky 200utqg race tire.

Then the next step beyond performance tires is DOT drag radials that have a soft sidewall and compromise cornering further for the sake of straight line traction. I have used MT ET Street radials.

It seems the high horsepower Mustang, Camaro, and Hellcat guys swear by the Toyo R888R for straightline hook.

My experience is Maxxis RC1, R888, R888R, NT01 all hook as well or even slightly better than the current crop of 200utqg street race tires.
The Maxis work cold (without a burnout,) but dont have tread pattern, the R888s and NT01s want some heat.

So does this Enkei setup from first post fit without modified(rolled) fenders or crazy camber?

For those running 9.5 F and 10.5 R, please post up tire and offset pic/specs please.

275/35/18 Bridgestone RE71R on 18x10 +50 square
https://cimg2.ibsrv.net/gimg/www.rx7...fbc1e416c9.jpg

So I have glanced at this thread off and on for years. Each time I think I understand and think I will have a decent set up I find myself questioning. With my car finally going to the shop for the build it is time to pull the trigger on tires.

I have Volk RE 30s
Front 17x8.5 +40 Thinking 245/40
Rear 17x9.5 +42 Thinking 265/35

Is it advised to go wider?

Alos what tire options are currently available for a street/track tire. Over the years they have been tires that have come and gone that I see people like. Just want to see what is advised now.

Thanks for the input.

Might as well run the same 17x9.5 +42 front and rear- there is no meed to build more understeer into the chassis.

You dont "need" a wider wheel and tire if your not competing in timed events- just more $ for tires.

some of the same old street and track tires are still loved by enthusiasts such as NT01, R888/R888R and there is a rash of new 200utqg tires that are just as fast.

budget.
Federal 595 RS-R and RS-RR are by far cheapest and perform decent.
Nankang CR1/S or AR1 are pretty good price and a bit faster.
NT01/R888 are decent price.

the fastest 200utqg tires are $$$ necause racers have to use them to fit their class and tire rack typically buys all 9f tje good ones and controls the price.