For all considering 305-wide tires w/ stock suspension

Discussion in 'Brakes, Wheels and Tires' started by domesticpower, Jun 12, 2019.

  1. domesticpower

    domesticpower Track Addict

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    I had a lot of doubts before pulling the trigger and it seems like I'm not alone judging by the number of wide wheel/tire threads on here and questions I got. Hopefully this thread helps everyone looking to fit something this wide, especially on stock suspension for class or budget. The tires do poke out a bit and I figured rubbing is all but guaranteed at full compression once I saw them on the car... but I couldn't be happier I trusted APEX and those on here who have run it. Here's what you need:

    1. Camber plates: I have MM C/C plates and they are maxed out at -2.3 deg with the stock struts. I have been running them for about 3 years with many track days without issue. APEX recommends at least -3 deg in their fitment guide but I had no choice because I was maxed out.

    2. 1"/25 mm spacer: I have Motorsport-tech 1" spacers and they look like high quality units. There is maybe a 1/4 inch clearance in the back so you can't go any narrower than 25 mm. http://www.motorsport-tech.com/adaptec/car/ford_s and you want Design 2.

    3. Elongated studs: your best bet is to get the FPP hubs with elongated studs instead of reusing the old one. Bearings are consumables anyway so if you're like me and you've been enjoying your car for several years, it might be a good time. They are a bargain considering that they come with ARP elongated studs already pressed in. https://lmr.com/item/M1104A/Ford-Racing-Mustang-Front-Hub-Pair-With-3-Arp-Studs You will need open ended lug nuts which are sold separately.

    4. A good quality 11" wheel: APEX of course! I got square APEX EC-7 19x11 ET52 for rotation, although APEX offers a different offset 19x11 so you don't need a spacer but the spacers will likely pay for themselves quickly in tire life (allowing rotation).

    Here's how the car sits on 305/30/19 RE-71R's all around. I'll post a review of the tires if there is interest, but after a couple of days at the track, I can comfortable say there is no rubbing. The car feels fantastic with this setup. It looks great too... which was a very popular opinion over the weekend.

    Boss 302 Paddock 1.jpg
    Boss 302 Paddock 2.jpg
     
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  2. KRyn

    KRyn TMO Intermediate

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    Thanks for sharing this information and pictures, greatly appreciated. I am still trying to decide between 18" or 19" wheels. The Black Satin EC7s look great on the white Boss 302!
     
  3. JDee

    JDee Ancient Racer

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    Tire review would be cool. Where are you getting the RE71's?
     
  4. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    With respect to that last bit, you might try running the OE closed nuts down over the open-end nuts. You get a somewhat more finished appearance and the stud threads are better protected against the elements. Something like 30 ft*lbs seems to be enough to guarantee they'll stay put and not so much that there's much risk of thread damage.

    Shown on front 18x11 Forgestar wheels that work with no spacer. At offsets up in the +50's, part of the OE nuts sits inside the counterbores of the wheels (looks better). I do remove them and retorque the open-ended nuts before each track event, and replace them afterward. I *might* replace them after retorquing for a wet track day, but I haven't run across that situation since upgrading to the FRPP hubs . . . in the wet a few more in*lbs of rotating wheel mass isn't going to matter.

    Your wheels aren't wide enough - web.jpg


    Norm
     
  5. domesticpower

    domesticpower Track Addict

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    Happy to help! 18 vs 19 is a tough choice. Cons and pros to each but 19 is generally better IMO except for cost, and it was a no brainer for me because I was hitting the limiter in 4th on the old setup (18's) just before braking for one corner on our track.

    Thanks! I agree, it looks great! Those are anthracite, though, for what it's worth. I think it shows the detail/design much better than black (and will hide brake dust better lol).

    Sounds good, will post it. I bought them from a local OK Tire shop that sells a lot of race and time attack tires to competitors here and can typically get them at a good price.

    Thanks Norm, something to consider. I do like the idea of covering up the top of the thread but don't know how much I like double stacking lug nuts. Have you been doing this a while?
     
  6. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    Just on this car and just since replacing the front hubs and rear wheel studs. Maybe two years?

    But I'd do it again if a similar situation came up on a different car.


    Norm
     
  7. blacksheep-1

    blacksheep-1 TMO Addict

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    This is great info, when we run this stuff we throw spacers at it and do whatever we need to in order to make it work, someone taking the time to write it all down and pass it on is really helpful. With regards to the lug nuts, I've taken them in my lathe and cut the tops off so that I can see the how many threads are engaged. Since looks are kind of secondary from my perspective, it doesn't bother me if a few threads are past the end of the nut..in fact it kind of makes me smile.
    These cars need all the rubber they can get, in SCCA T2 they are required to run 275 (even though Camaros with an IRS get a bigger tire) and they are really marginal trying to get them to last for a 40 minute race. I've seen them burned off in a 15 minute practice session. They need at the very least a 295, or better yet a 305.
     
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  8. domesticpower

    domesticpower Track Addict

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    That's good to know. Still don't like the idea of tightening over the lug nuts... but it's tempting to cover the top of the studs. You have to go through a dirt road to get to our track and I really didn't like seeing dust and muck on the studs.

    Glad to hear! I am hoping it does help someone on the fence and worried about rubbing. Agree on the studs, I like the look of them sticking out... lol. Just don't like dirt on the threads if I have to rotate at the track and take lug nuts on/off.

    That's very frustrating... I wonder why the Camaro's are allowed to run wider? I'm not very familiar with SCCA rules up here north of the border.
     
  9. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    The outer nuts are only there for thread protection, so they only need to be tightened enough to keep from falling off, basically only a little more than 'snug' seems to be enough. I doubt that clamp load is much affected, and you would remove them as part of checking the torque on the "main" nuts as part of pre-event prep anyway.


    Norm
     
  10. TymeSlayer

    TymeSlayer Tramps like us, Baby we were born to run...

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    I'm running pretty much the same set-up as @domesticpower but was able to pinch out -2.6 camber out of my MM CC plates with Koni Sports and OP 25mm spacer up front. This leaves me with about 4mm clearance. Right now I have 305/30/19 on my EC7s with the same size RE71s on the Apex's SM-10s in the wings. Same FRPP front hub and ARP studs out back and doing both autoX and track work I have had zero issues and no rubbing. I have no vision of banging doors and stayed with 19 inch wheels because have a huge range of rubber just wasn't that important to me. Plus with the T Springs and the car lowered, it helps a smidge when loading it up on the trailer. (I still have to inflate the tires occasionally to prevent from the front splitter from catching even with the long Race Ramps) I'll share a picture when I get a chance but the look from the front on the 19x11 looks pretty much like DPs.
     
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  11. 12WhiteBoss302

    12WhiteBoss302 TMO Beginner

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    Wow I did not know they would fit with the stock suspension. Thanks for this info! How big of a spacer do you need on the rear to make this work?
     
  12. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    On the rear . . . you might need 3mm or possibly you won't need any spacer at all with +52 offset 11" wide wheels. Less spacer/need for spacer with 19's than 18's, too. But you might want to trim the shock boot.


    Norm
     
  13. TymeSlayer

    TymeSlayer Tramps like us, Baby we were born to run...

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    No spacer on the rear. Talk to the good folks at Apex. They'll help settle any concerns.
     
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  14. domesticpower

    domesticpower Track Addict

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    It's a great setup! I'm looking at suspension next. Those tires in that size are really taxing the stock suspension. Very glad to hear about more camber, I have been counting on more with aftermarket struts. -2.6 would be nice step up, especially with springs/dampers (or coils if budget allows).

    You're welcome! I have no spacer in the back. It's basically flush with the fender so a spacer with ET52 offset might actually cause rubbing. Only need a spacer in the front. APEX fitment guide says that some people need to trim the rear shock boot like Norm said so I'm sure some have run into the issue, just something to keep an eye on.
     
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  15. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    You'll want to keep the OE 'divorced' spring-shock setup on the rear (I think there are height adjusters for this). Otherwise the spring will eat into the room you want for the tire.

    As my car sits right now, there's quite a bit of clearance on the inside for the rear tires (no spacer). 305/30's on 11" wheels are only about half an inch wider (1/4" inside, 1/4" outside) than these 285/35's on 11's, not almost 3/4" like the size number suggests. IIRC, the wheel offset is slightly more + than +52. Though as the suspension drops into 'droop', the clearance to the shock does tighten up a bit.

    2853518 on 11 shock clearance web.jpg


    Norm
     
  16. domesticpower

    domesticpower Track Addict

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    Thanks Norm. That makes a lot of sense, I didn't think of that. Wonder what the guys with coil overs are doing with this size wheel/tire combination. I'd certainly like to have an excuse to avoid coils for budget lol but springs and dampers will put me up two classes, whether they are the cheapest non-adjustable I can find or a proper setup costing several grand so might as well have adjustability to dial in the car.
     
  17. rwleonard

    rwleonard TMO Intermediate

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    Griggs and Cortex offer kits for their rear CO's to allow for 315's, but it involves even more money and welding, I believe.
     
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  18. neema

    neema TMO Race

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    On the Cortex setup it's only a nominal amount more to use 315s in the back. Been a while since I ordered mine. No welding needed on their setup. All bolt on stuff.

    That said I still ended up going divorced springs and conventional shocks in the back (Cortex uses adapters and eye-eye shocks) for more room.
     
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  19. docs302

    docs302 TMO Race

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    I have the Cortex JRi rear coilovers and run Apex 18x11's with 315's. I ended up doing the Vorshlag-recommended removal of the bump stop plate that sticks out and often makes contact with the tire. But I did run with that set-up with the plate in and did not have contact. It was a few hours of work with a spot weld drill bit, grinder and primer but I'm glad I did it. I feel pretty confident now that 315's are no issue and 335's are an option as Vorshlag has demonstrated but I'm not planning that route anyway.
     
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  20. Stangra

    Stangra TMO Intermediate

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    Cortex Koni coilovers , Nitto NT01 305/35-18 square, Enkei PF01 18x10.5+47

    No wheel spacers

    20180718_091540_HDR - Copy (2).jpg
    20190512_184151_AA.jpg
    20180723_082344_HDR A.jpg
     
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