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Running wide street tires (305+)

zzyzx

Steve
299
0
For somebody that wants to stay on "street tires", it's a pretty though decision about whether to stay with 19" wheels, or go 18". In 19" there are many more tires available that are > 285.

Which brings me to the BFGoodrich Rival in 315/30-18 for a square setup. That's the widest tire you're gonna find in a competitive street tire in 18".

http://www.tirerack.com/tires/tires.jsp?tireMake=BFGoodrich&tireModel=g-Force+Rival&sidewall=Blackwall&partnum=13WR8GFR&tab=Specs

Debates about a staggered/square setup aside, what are your opinions on whether these would fit on an 18X10 wheel in and offset of +45 or +43?

According to Sam Strano the PF01s will clear with 315 Hoosiers with 5mm spacers up front:

This kit comes with 4 Enkei Racing PF01 wheels, sized 18x10.5" and a pair of H&R 5mm wheel spacers which allow you to fit your S197 Mustang with the same size wheels and tires all around. I'm running this setup on my own car with 315/30-18 Hoosier A6 tires on conventional strut in front.

The wheels are light for the size, coming in at just under 22 pounds per wheel.

I'm not sure what offset those Enkei PF01s are, anybody happen to know?

Steve
 
It "might" be the +15mm offset wheel. I test fit one of my 18 x 10.5 +38mm offset wheels with a 295 R6 and the tire was right up against the strut. I'm not sure about the actual difference on the width between thebHoosier and the 315 tire you are considering, but if it's actually 10mm wider on each side, obviously a 5mm spacer isn't going to do it. It must be the +15 offset. Presumablywith enough camber it clears the fender to the outside.
 

pufferfish

Supporting Vendor
1,094
66
Maryland
as cloud9 illuded to, there are only 2 choices for the 10.5" wide. +25 or +38. i believe strano is running the +38. the net offset with the 5mm spacers would be +33.

hoosiers generally run 10mm narrower than street tires. i only know without a doubt this is the case for 285 and 295, but it stands to reason the wider tires would have the same difference. so, you should really be looking at 305 wide street tires to match what strano did.

i have a set of team dynamics 18x10 with a +35 offset with 285 hoosiers. there is plenty of clearance to the strut. adding 15mm of sidewall to the inside and 15mm to the outside, seems reasonable for how they fit now.

so, i think a 305 street tire on an 18x10.5 +38 with a 5mm spacer would work. the 315 may or may not work depending on the manufacturer's idea of how to measure the tread width. they do vary between most manufacturers.
 

JScheier

Too Hot for the Boss!
I've had both a 305/35 and a 315/35 on all four corners on an 18x10 D-Force with +43 offsets. No issues.

Now, the 295/40 Hoosier on the same wheels is absolutely HUGE and looks like it may rub the outside rear fender (spent an hour making sure the axle was perfectly centered). In that case, a +45 would have worked better in the rear, but then would have been too far inboard to work in the front.
 
JScheier said:
I've had both a 305/35 and a 315/35 on all four corners on an 18x10 D-Force with +43 offsets. No issues.

Now, the 295/40 Hoosier on the same wheels is absolutely HUGE and looks like it may rub the outside rear fender (spent an hour making sure the axle was perfectly centered). In that case, a +45 would have worked better in the rear, but then would have been too far inboard to work in the front.
Are you compensating for something?
 

zzyzx

Steve
299
0
Awesome, thanks for the feedback, guys!

I know I mentioned Stranos 10.5" wheels, but I'll be using 10" wide wheels. Sorry for the confusion on that. I was just using his info as a reference point.

JScheier said:
I've had both a 305/35 and a 315/35 on all four corners on an 18x10 D-Force with +43 offsets. No issues.

Could you tell me what brand/model those 305/315s were? That at least would be another tangible data point as we all know those measurements are pretty inconsistent.

This is great news either way, thanks! It sounds to me like an 18X10 with a +43 or +45 offset can run 315s square using a 5mm spacer up front. Depending of course on how wide the tire runs...

For 305s on an 18" the choices are slim to none. For 19" wheels, there are plenty of good 305/35s available. I run PSS now and in 19" there are as many choices you could ask for really, but for 18" your limited to 285s.
 
zzyzx said:
Awesome, thanks for the feedback, guys!

I know I mentioned Stranos 10.5" wheels, but I'll be using 10" wide wheels. Sorry for the confusion on that. I was just using his info as a reference point.

Could you tell me what brand/model those 305/315s were? That at least would be another tangible data point as we all know those measurements are pretty inconsistent.

This is great news either way, thanks! It sounds to me like an 18X10 with a +43 or +45 offset can run 315s square using a 5mm spacer up front. Depending of course on how wide the tire runs...

For 305s on an 18" the choices are slim to none. For 19" wheels, there are plenty of good 305/35s available. I run PSS now and in 19" there are as many choices you could ask for really, but for 18" your limited to 285s.
While you can put a 315 on a 10" wheel, there aren't many/any that are recommended for that size wheel. The downside is the contact patch rolls up to meet the narrower wheel so I'm not sure you gain anything by going wider than the suggested tire size for a given wheel. John's running slicks and they fit differently (no sidewall bulge to protect rim) than a DOT street tire. Always a good idea to check the mfrs recommended wheel size on that. Just my $0.02
 

pufferfish

Supporting Vendor
1,094
66
Maryland
305 is the max i would suggest for a 10" wheel for track driving. the wider tire will roll over in a turn, which will effect your clearances and handling characteristics. if you are just interested in street driving, go for the 315. i run a 285 on my stock 9" wide on the street (which would equal running a 315 on a 10" wheel) and while it does look a bit silly bulging out from the rim, it works just fine.
 

JScheier

Too Hot for the Boss!
zzyzx said:
Could you tell me what brand/model those 305/315s were? That at least would be another tangible data point as we all know those measurements are pretty inconsistent.

Hoosier or continental. Sidewalls are different, but some run larger than others.

This is great news either way, thanks! It sounds to me like an 18X10 with a +43 or +45 offset can run 315s square using a 5mm spacer up front. Depending of course on how wide the tire runs...
+43 is probably the best size to run all around and be able to rotate. the +45, albeit only 2mm, really can affect the front wheel to strut clearance. Nothing a small spacer can't take care of. Just be aware.

For 305s on an 18" the choices are slim to none. For 19" wheels, there are plenty of good 305/35s available. I run PSS now and in 19" there are as many choices you could ask for really, but for 18" your limited to 285s.
The 285 Hankook RS3s on the 18x10s didn't look that bad (other than being short). I ran those many times.
 
Well, I can tell you that my +42 ET 18x10 F14s shod w/ 295/40 Hoosier R6s fit, but just barely. They are quite massive for a 295 section tire, with a lot of sidewall.

With, say, -2 or -2.5 deg of camber the fronts should be fine. There is maybe 1/4 or 3/8" clearance between the sidewall and the sway bar link upper bolt with no camber. However, with some neg camber I imagine that will be reduced, thus will need to cut off the hex end of the link bolt to provide for adequate clearance.

Out back the sidewalls stick out slightly, even with a centered axle. I am hoping the .8" lowering in the rear from the Steeda Boss springs being installed today won't present a problem because of this.
 

JScheier

Too Hot for the Boss!
dabossinne said:
Well, I can tell you that my +42 ET 18x10 F14s shod w/ 295/40 Hoosier R6s fit, but just barely. They are quite massive for a 295 section tire, with a lot of sidewall.

With, say, -2 or -2.5 deg of camber the fronts should be fine. There is maybe 1/4 or 3/8" clearance between the sidewall and the sway bar link upper bolt with no camber. However, with some neg camber I imagine that will be reduced, thus will need to cut off the hex end of the link bolt to provide for adequate clearance.

Yeah, the fronts are fine for me (significantly lowered on AST 4100s with mucho negative camber)

Out back the sidewalls stick out slightly, even with a centered axle. I am hoping the .8" lowering in the rear from the Steeda Boss springs being installed today won't present a problem because of this.
I've got two fingers between the tire and the fender. My spring rates are high (200#) and my ride height is low... looking at video / stills from PPIR, I 'think' I should have enough clearance, but it may be close. I may have to raise the rear of the car a touch. Too bad the tires were so damn cheap :)
 
I'm running 295/40/18's on the 302r 18x10 wheels and the M-18000-C struts. I found that the front sway bar end link bolt was too close to the sidewall of the tire and cut and ground them down. Also, I experienced some slight rubbing on the brake ducts.

Will be testing this configuration on track this weekend.

Zero chance I can run a 10.5 or 11" rim or more than a 295 tire though up front. No strut clearance.
 

zzyzx

Steve
299
0
Just wanted to jot down my thoughts on what's the "competitive" street tires combos that are available, ignoring anything narrower than a 285 which IMO is just not enough tire.

First, let's talk tires. I think the following list sums "likely candidates" that come in appropriate sizes. I've listed these in groups in terms of dry grip as "A", "B" or "C", the "A" group being the best:

1. BFGoodrich g-Force Rival (A)
2. Michelin Pilot Super Sport (A)
3. Hankook RS-3 (B)
4. Dunlop Direzza ZII (A)
5. Bridgestone RE-11 (C)
6. Kumho Ecsta XS (C)
7. Yokohama ADVAN Neova AD08 (A)

From this list of tires that by-and-large have a history of being competitive, I'd remove the AD08 due to it's heat-cycling longevity issue. The compound dies off far to quickly considering the price, even though they stick like glue out of the box. The rest are known to both take heat relatively well and provide decent wear.

Now, let's looks at viable fitments (numbers refer to list above):

18" wheels

1. 295/35, 315/30, 335/30 (Rear possibly)
2. 285/35
3. 285/35
4. 285/30
5. N/A
6. 315/30
7. 285/30, 295/30

19" wheels

1. N/A
2. 285/35, 295/30, 295/35, 305/30, 325/30 (Rear possibly)
3. 305/30
4. N/A
5. 285/35, 305/30
6. 285/35
7. 295/30, 305/30

The list above should be pretty eye opening. The Rival (1) clearly has the most options for those running 18" wheels, whereas the PSS (2) has the most options for 19" wheels.

So, that leaves us with the following:

18" wheels, with BFGoodrich g-Force Rival

1. 295/35 Front & Rear
2. 295/35 Front, 315/30 Rear
3. 315/30 Front & Rear
4. 315/30 Front, 335/30 Rear

(Option #4 sure does look tempting...)

19" wheels, with Michelin Pilot Super Sport

1. 285/35 Front & Rear
2. 285/35 Front, 295/35 Rear
3. 295/30 Front & Rear
4. 295/35 Front & Rear
5. 295/35 Front, 305/30 Rear
6. 295/30 Front, 305/30 Rear
7. 305/30 Front & Rear
8. 305/30 Front, 325/30 Rear

NOTE: Avoid the PSS in 295/35-19. It's a BMW spec tire and because of this it's a $100 premium per tire.

Now, if we assume that our wheels are 10" wide, the ideal square setup for 18" would be option #1, and for 19" it would be option #7. The difference between these two is that the 19" option yields more contact patch and a better diameter. The PSS in 305/30-19 has a 26.3" diameter whereas the Rival in 295/35-18 has a 26.1" diameter. Considering how close that is, it's obvious the sidewall on the PSS is quite a bit shorter.

The bottom line though - or brass tax - is that any 19" option is going to cost significantly more in the long run. The tires cost more (recurring cost), and the wheels cost more (initial outlay).
 
Good analysis! Personally, I'd go with the BFG Rival in a 295/35-18 square setup. Going bigger you might be taking some chances on clearance issues, but guys are running the big steam rollers, so you might be fine. Nothing ventured, nothing gained, right? Anyway, the new Rival tire sure seems to offer quite a lot of bang for the buck. Either way, you can't go wrong. Let us know what you decide!
 
Good list Steve and the Rival's will be my next track tire (I drive my car to the track) and I might just order a set now. But I'm not sure why you want such a wide tire for the street. It would seem a 295 or 305 would be sufficient and minimize any rubbing issues.
 
zzyzx said:
4. 315/30 Front, 335/30 Rear

(Option #4 sure does look tempting...)

If you decide to try this, I would be really interested in the results. Specifically wheel offsets, widths, clearance, modifications, you know, the minor details. :)
I am looking to squeeze some serious tire under the Boss this summer so I would be very interested in any info on that combo. I grow tired of my Hockey pucks.
 
Has anyone tried toyo r888s in 305/35/18 up front? It's a good tire to drive to the track to and should be stickier than the tires mentioned.
 
neema said:
Has anyone tried toyo r888s in 305/35/18 up front? It's a good tire to drive to the track to and should be stickier than the tires mentioned.
I did on an Enkei PF01 18 x 10.5 +38mm offset and the tire's right up against the strut. Maybe with the +47 offset or a spacer.
 
cloud9 said:
I did on an Enkei PF01 18 x 10.5 +38mm offset and the tire's right up against the strut. Maybe with the +47 offset or a spacer.

+47 would make it worse if it's already on the strut, no? Adding a spacer should help move the tire away though. regardless, I'm diving in (using 18x10.5 +38). I'll report back with results
 

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