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  1. #1
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    Default Measuring for Custom Wheels - Advice Requested

    With my widebody going, I went to measure for the new wheels last night. I would like to run a 315 tire on 18x10.5 wheels (square setup) if possible. I'm not opposed to spacers or going after longer studs if needed. Where I'm stuck is at the front. The back should be OK.

    Here is the car being measured, and what I came away with last night.

    Attachment 118523

    Attachment 118524

    Attachment 118525

    Attachment 118526

    I'm right now leaning toward a set of Rovos Pretoria in 18x10.5" (6.7" backspacing +23mm offset) that are made for the SN95 chassis.

    My setup is:
    REAR
    Fox axle housing with 97 GT axles (3/4" wider per side)
    Eibach Sportline lowering springs
    OEM control arms (upper & lower)
    Maier Racing 3" flare

    FRONT
    Fox lower control arm
    94/95 spindle, 97 brake disc & caliper
    Eibach Sportline lowering springs
    Maier Racing 3" flare
    Koni Red strut

    This is going to be 95% street / show car, and maybe a track car a couple times per year to start.
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  2. #2
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    Looks like you have a good handle on it. I like taking an existing setup and plugging it into this calculator: http://www.willtheyfit.com to see how much closer the new setup will be to rubbing. Works pretty good if you have something to start with.

  3. #3
    Moderator wraithracing's Avatar
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    You state that the car is 95% street, with that I assume the wheel tire combo is as much for looks and the "cool" factor as much as anything. I say that with no malice or judgement meant, just trying to determine what the ultimate goal is here.

    The reason I ask is that a 315 on a 10.5 rear wheel is a decent setup, but with the 3" flares you should have plenty of room for more if you wish. So my questions would be : Is this choice for costs?, What you have right now? Just personal choice? Etc.

    I have the Maier 1.5" front fenders and I will be building my own rear flares since I honestly don't want to spend the $$ on flares that don't fit that well and ultimately cost me $1K by the time I ship them. I know with my setup that includes SVO rear brake and axles right now (what I had ready to go ) I can easily fit a 345/30/17 on a pair of Cobra R 10.5 (27mm offset) and fit under a 1.5" flare with plenty of clearance inside. The reason for that setup is once again using what I currently have. Personally I would prefer the 345 on at least an 11" if not 12" wide wheel for better fitment and wider track. For best tire fitment I will probably drop down to a 315 if I stay with the current wheels. I really think you should consider at least an 11" if not 12" wide rear wheel unless there are other constraints such as cost, style, etc. that are more pressing issues.

    Here is a quick look at my 345 on a 10.5 setup with stock quarter. The tire sticks out past the outside of the quarter @ 1-1.25"

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    Here is the setup with a quick copy of the 1.5" front flair to give me an idea of fitment. You can see that using the 345 I will probably have to push the flair out at least another 1/2" to be sure it clears the tire.

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    I will also comment on your front setup. I assume again that the Fox length front control arms are because that is what you had on the car or had available. I would recommend seriously considering at least a pair of OEM SN95 front control arms to widen the front track to help improve not only the handling of the vehicle as that will better match up with your rear track width, but that will also most likely help with front wheel/tire selection. You are most likely going to be severely limited in off the shelf options that will fit up front and yet provide a nice wide setup to fill your front wheel wells.

    With your current setup a 9" front wheel with 24mm offset is about the max you can fit with a stock front fender and not rub on the outside. The 24mm offset is also about the maximum you can run without having strut clearance issues too. Now you have added 3" of additional clearance to the outside. So theoretically adding 3" of wheel (not guaranteeing that is possible just using as an example) You would have a 12" front wheel but you would need an offset of @ -12mm to keep the same @ 6" backspacing (clearance needed for the inside). Needless to say, in my experience that is a tough wheel to find. Obviously you don't need a 12" front wheel, I was just using that as an example if not a bit of an exaggerated one at that.

    If you swap to the SN95 front control arms you will add @ 1" of track width per side that will increase your front grip, reduce understeer, increase corner speed, and will reducing binding in the front suspension if using OEM Ford SN95 ball joints. That will also most likely make more wheel choices available to you due to the difference in offset required to clear the front struts. If you use stock 99-04 OEM control arms you will also gain some additional tire clearance lock to lock due to the slightly different shaped control arm. Obviously you can also consider aftermarket options such as Maximum Motorsports, but since your current setup uses Eibach springs, that would not work as coil overs are required.

    Another question I have is in regards to your drawing. The Front diagram appears to show you measuring from the back side of the rotor. I assume that is a mistake as your straight edge in the photo appears to be mounted to the wheel flange of the rotor. Not a big deal, just making sure.

    If it were me, I would seriously consider at least an 11" if not 12" wheel for your setup up front. Not sure those are options depending on your wheel design choices and available offsets/bolt pattens. I also recommend looking into Forge Star wheels http://www.forgestar.com/wheels/collection/ They are a reasonably priced option and a well designed wheel that has a ton of offset and size options that are extremely helpful when doing these type of custom setups. There are more expensive options out there such as CC Wheels http://www.ccwheel.com/ if your budget allows as well as others.
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  4. #4
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    Trey,

    Thanks for the lengthy reply. Let me answer some of your questions. I think this discussion is answering my questions.

    You state that the car is 95% street, with that I assume the wheel tire combo is as much for looks and the "cool" factor as much as anything. I say that with no malice or judgement meant, just trying to determine what the ultimate goal is here.

    Yes, it's more "wow factor" than anything. I want to run in the Optima Series and I want to run some SCCA at some local tracks within a few hours, maybe even a GoodGuys event sometime. But, that will be so limited that I don't feel I should try and build a competitive car for a set of rules I may or may not run. I want this car to be somewhat comfortable, not beating me to pieces at every bump, and I can drive it a few hours if I have the nerve to do it. Cruising around and showing it off are really the main purpose. It won't be competitive against anything and it's meant to be fun to finish and just drive around. That is why I say 95% street.

    The reason I ask is that a 315 on a 10.5 rear wheel is a decent setup, but with the 3" flares you should have plenty of room for more if you wish. So my questions would be : Is this choice for costs?, What you have right now? Just personal choice? Etc.

    Right now I have nothing. No wheels, no tires. I have a set of 4-lug Cobra wheels that are up for sale. The choice is based off what I have seen others running with a similar set-up (I'm not smart enough to brave a new path in this area), and I do have a budget in mind. The Rovos wheels are ~$270 / wheel which is affordable to me. I'm negotiable to a point, but realistic in that I can't afford something 3-piece forged most likely and it needs to be replaceable without selling a kidney. The 315 isn't set in stone, but I have in mind that I want have a square setup for rotational purposes. I'm not opposed to a staggered setup either.

    I have the Maier 1.5" front fenders and I will be building my own rear flares since I honestly don't want to spend the $$ on flares that don't fit that well and ultimately cost me $1K by the time I ship them.

    I know your pain. I think I've finally figured out how to fix mine to my liking.

    I really think you should consider at least an 11" if not 12" wide rear wheel unless there are other constraints such as cost, style, etc. that are more pressing issues.

    Cost is driving the bus right now, and the ability to rotate the wheels (that may be silly considering the car). I'm still trying to figure it out.

    I assume again that the Fox length front control arms are because that is what you had on the car or had available. I would recommend seriously considering at least a pair of OEM SN95 front control arms to widen the front track to help improve not only the handling of the vehicle as that will better match up with your rear track width, but that will also most likely help with front wheel/tire selection. You are most likely going to be severely limited in off the shelf options that will fit up front and yet provide a nice wide setup to fill your front wheel wells.

    I put the front suspension off my wrecked '92 notch on this car (k-member, LCA, springs, struts). The spindles, brakes, and 5-lug hubs are the new pieces in the puzzle, but added for bigger brakes than the Fox pieces and 5-lug wheels. I would like to stay with the Fox LCA for now just to get the car up and running. I'm not opposed to changing eventually, but continually tearing the car down for more parts is starting to put a strain on me. I did have a 9" Cobra R type wheel on the '92 previously (the '80 had the steel OEM wheels until I tore it down). That is why I thought a 10.5 would be able to fit now.

    Another question I have is in regards to your drawing. The Front diagram appears to show you measuring from the back side of the rotor. I assume that is a mistake as your straight edge in the photo appears to be mounted to the wheel flange of the rotor. Not a big deal, just making sure.

    Yes, a mistake. I was doing a lot of other stuff while I was measuring (filming for YouTube and answering DMs). I put the line in the wrong place, and of course with pen you can't erase it.

    If it were me, I would seriously consider at least an 11" if not 12" wheel for your setup up front. Not sure those are options depending on your wheel design choices and available offsets/bolt pattens. I also recommend looking into Forge Star wheels or CC Wheels if your budget allows as well as others.

    I am still figuring it out. I started thinking about the 18" w/ 315 tire so long ago, I'm probably being bullheaded about it. I'll do what makes it work in the long-term. I put up a post on Instagram earlier today tagging a lot of wheel and tire companies looking for suggestions from their catalog. I added the pictures that I posted here, so they can see the same info (and mistakes!) that you did. Someone may have something they want to see on the car, and I'll go from there. I may just order a set for the rear at first that will work, then fit them on the front to gauge how close they are.
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  5. #5
    Moderator wraithracing's Avatar
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    Yes, it's more "wow factor" than anything. I want to run in the Optima Series and I want to run some SCCA at some local tracks within a few hours, maybe even a GoodGuys event sometime. But, that will be so limited that I don't feel I should try and build a competitive car for a set of rules I may or may not run. I want this car to be somewhat comfortable, not beating me to pieces at every bump, and I can drive it a few hours if I have the nerve to do it. Cruising around and showing it off are really the main purpose. It won't be competitive against anything and it's meant to be fun to finish and just drive around. That is why I say 95% street.

    If you are seriously considering running Optima Series, SCCA, etc. then I would advise that you at least be aware of the rule package that you might be subject too. I understand that you don’t want to add a huge cost to the build for something that may or may not ever happen. I would just hate for you to build the car, then have the chance to run one of the events/series you desire only to have to make costly changes to the vehicle to be allowed/legal/etc. At least know what the rules are and then determine if that fits into your build/budget before making what could be costly mistakes.
    Somewhat comfortable is a relative term, so I will leave that up to your decisions and choices as to what exactly that is or is not!

    Right now I have nothing. No wheels, no tires. I have a set of 4-lug Cobra wheels that are up for sale. The choice is based off what I have seen others running with a similar set-up (I'm not smart enough to brave a new path in this area), and I do have a budget in mind. The Rovos wheels are ~$270 / wheel which is affordable to me. I'm negotiable to a point, but realistic in that I can't afford something 3-piece forged most likely and it needs to be replaceable without selling a kidney. The 315 isn't set in stone, but I have in mind that I want have a square setup for rotational purposes. I'm not opposed to a staggered setup either.

    I understand the budget constraints and that is why I suggest Forgestar wheels. They are a bit more expensive than your current $270, but depending on style, size, and color options they can be purchased from several vendors in the @ $350/wheel range. So definitely more money, but not $1K/wheel kind of money. They may also allow you to get a better fit to your setup than any off the shelf wheels without option offset can too. Nothing wrong with the 315 size, they are affordable and work just fine. Although again depending on your wheel size, etc. You might want to at least look at larger sizes to really fill up the wheel wells.

    I know your pain. I think I've finally figured out how to fix mine to my liking.

    I have had the front fenders for probably 15 years now. They are actually the original fenders off Mike Maiers C Prepared Yellow Mustang when he converted it to the Aero body style. Surprising still how much work they will need to look “right” to me. Due to the same budget issues you have is the reason for my own fabrication of rear flares.


    Cost is driving the bus right now, and the ability to rotate the wheels (that may be silly considering the car). I'm still trying to figure it out.

    If you can work a combination that allows wheel/tire rotations that is great, especially for a street car. Not sure that will work considering your desires for the large wheel/tire combo and the stock style front suspension. I am not saying it’s impossible, but you definitely have some work ahead to sort it all out.

    I put the front suspension off my wrecked '92 notch on this car (k-member, LCA, springs, struts). The spindles, brakes, and 5-lug hubs are the new pieces in the puzzle, but added for bigger brakes than the Fox pieces and 5-lug wheels. I would like to stay with the Fox LCA for now just to get the car up and running. I'm not opposed to changing eventually, but continually tearing the car down for more parts is starting to put a strain on me. I did have a 9" Cobra R type wheel on the '92 previously (the '80 had the steel OEM wheels until I tore it down). That is why I thought a 10.5 would be able to fit now.

    I completely understand your situation and I struggle with the same on my multiple projects at this point. I still believe a pair of SN95 front control arms may be a better option and ultimately make some of your plans work out better, but . . . I get it. I would recommend crunching some numbers and at least looking at the option of the control arm swap. If you can find some at a local junk yard in decent shape you can often pick them up for $100-$150 for the pair. IF you have to put ball joints in them, then order a pair from Maximum Motorsports at <$60 each, so for around $250 you might be able to save some $$ on wheel/tire combo depending on how everything sorts out.

    Yes, a mistake. I was doing a lot of other stuff while I was measuring (filming for YouTube and answering DMs). I put the line in the wrong place, and of course with pen you can't erase it.

    Again, I completely understand and wasn’t calling you out, just wanted to make sure of the measurements.


    I am still figuring it out. I started thinking about the 18" w/ 315 tire so long ago, I'm probably being bullheaded about it. I'll do what makes it work in the long-term. I put up a post on Instagram earlier today tagging a lot of wheel and tire companies looking for suggestions from their catalog. I added the pictures that I posted here, so they can see the same info (and mistakes!) that you did. Someone may have something they want to see on the car, and I'll go from there. I may just order a set for the rear at first that will work, then fit them on the front to gauge how close they are.

    I am not running the same combo as you are, but I might have time this weekend to do a test fit on my Road Racer to show the fitment of a 17X10.5 (27mm offset) fits up front with the flares, etc. That may at least save you some time and $$. I will see what I can do, the wife and kids are out of town this weekend, so I just might be able to get it done.
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  6. #6
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    If you are seriously considering running Optima Series, SCCA, etc. then I would advise that you at least be aware of the rule package that you might be subject to.

    I've read the Optima 2018 rules. Haven't gotten to the SCCA rules yet. On my to do list. I need some tow points, plus all the personal safety gear for Optima. SCCA who knows. Agreed on the "read the rules first" piece. I probably won't run it this year due to the extra costs for gear.

    I understand the budget constraints and that is why I suggest Forgestar wheels. They are a bit more expensive than your current $270, but depending on style, size, and color options they can be purchased from several vendors in the @ $350/wheel range.

    I put some feelers out today. I'll keep looking. They are included in the brands I messaged.

    I have had the front fenders for probably 15 years now. They are actually the original fenders off Mike Maiers C Prepared Yellow Mustang when he converted it to the Aero body style. Surprising still how much work they will need to look “right” to me.

    If they fit like my "new" ones do, I'm not surprised at all. I'll have mine wrapped up soon enough to my liking and be on to the next piece of the puzzle.

    If you can work a combination that allows wheel/tire rotations that is great, especially for a street car. Not sure that will work considering your desires for the large wheel/tire combo and the stock style front suspension. I am not saying it’s impossible, but you definitely have some work ahead to sort it all out. I completely understand your situation and I struggle with the same on my multiple projects at this point. I still believe a pair of SN95 front control arms may be a better option and ultimately make some of your plans work out better, but . . . I get it. I would recommend crunching some numbers and at least looking at the option of the control arm swap.

    The dilemma I have with this is the "crunch the numbers". I dont know where to start to prove they are a better choice long-term, or that I can work with I have right now in the Fox LCA and replace them later with over the Winter with SN95 pieces. I don't want to buy things twice necessarily, but don't want to keep refining a build to the point of never finishing it either. I will most likely just show and drive the car to town and back this year and not race it anywhere. There would be so much to do to make it capable and legal that I may never get there.

    I am not running the same combo as you are, but I might have time this weekend to do a test fit on my Road Racer to show the fitment of a 17X10.5 (27mm offset) fits up front with the flares, etc. That may at least save you some time and $$.

    Thanks in advance if you can get to it. It would be nice to see what it does look like.
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  7. #7
    Moderator wraithracing's Avatar
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    The dilemma I have with this is the "crunch the numbers". I dont know where to start to prove they are a better choice long-term, or that I can work with I have right now in the Fox LCA and replace them later with over the Winter with SN95 pieces. I don't want to buy things twice necessarily, but don't want to keep refining a build to the point of never finishing it either. I will most likely just show and drive the car to town and back this year and not race it anywhere. There would be so much to do to make it capable and legal that I may never get there.


    I guess my main point was to consider additional options that although at first may seem to be more $$ in the long run may be the cheaper/better option. If you are pretty well set on the wheel choice, then most likely you are going to need to run somewhere around 35- 40mm spacer to clear the strut with your current offset and tire. That number could change a bit ether way, but that should get you pretty close. You will want to press out your current wheel studs and install ARP longer wheel studs (3.5" overall 2.5" threaded) The spacer would just slide over the studs and be held in place by the wheel and wheel nuts. Make sure to buy a quality hubcentric spacer such as the ones sold by Maximum Motorsports.

    I would recommend checking out this thread on CC.com Rob's setup has a lot of similarities to what you and I both want to do and he has sorted out some of the same issues you and I both will face. I won't guarantee its a perfect match, but can probably help you with some of your ideas and decisions.

    http://www.corner-carvers.com/forums...t=maier+racing
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  8. #8
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    I guess my main point was to consider additional options that although at first may seem to be more $$ in the long run may be the cheaper/better option. If you are pretty well set on the wheel choice, then most likely you are going to need to run somewhere around 35- 40mm spacer to clear the strut with your current offset and tire.

    I sat and thought about it last night and talked to a couple people off Instagram after reading your initial response. Since I don't have anything bought at this point, I see no reason to be stuck on anything. Looks and function are my main points of focus, and they are not exclusive from each other. I am probably not driving this car more than a few thousand miles in a year, so the thought of rotating the tires probably isn't going to be enough to justify a square setup. I did a pro vs. con on both, and really can't find enough reason to go with a square setup over a staggered set.

    Assuming I go staggered, that makes it easier for the rear. I will find what works / fits without going crazy. 315s are reasonably priced and I say that with tongue in cheek. I haven't looked at what a 335 costs. If it's like the 315s, there are only a few tires available in the market that aren't complete race tires.

    Staggered may make it easier for the front also. I'm not excited about using a spacer unless I have to. The question I would then have is, can I buy a wheel to continue to use the Fox LCA for now without the spacer and longer studs? And with that wheel, would it later be advantageous and/or feasible to switch to the SN95 LCA if I decide to get more into track / handling driving?


    I would recommend checking out this thread on CC.com Rob's setup has a lot of similarities to what you and I both want to do and he has sorted out some of the same issues you and I both will face. I won't guarantee its a perfect match, but can probably help you with some of your ideas and decisions.

    I have read the thread before looking for answers on the fenders and if my poor fit was exclusive to my set or just the way they are. I will go through it again for the suspension setup.

    Maybe Jack Hidley will jump in with his opinion on the subject. if not, I'll PM him. He's been a great resource on the build so far.
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  9. #9
    Moderator wraithracing's Avatar
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    I agree that if like many play toys your tires will probably dry rot before you wear them out (well at least the front that is! ) Rotating is great for the daily driver that sees 10K miles plus a year. A play toy/cruiser/show car that only sees a couple thousand will not see a huge benefit to being able to rotate. Always a good thing when possible, but probably not a huge benefit overall.

    You are going to be at $350-$450 in the tire size range you are looking at depending brand, type, and final size chosen. Definitely not cheap tires, but we pay to play.

    Just playing with the numbers and not actually mocking a wheel/tire combo up you are most likely going to need @ 5mm to a Zero Offset 10.5" wheel with a 315 on it in order to clear the strut. I can't guarantee that is absolutely correct again, just playing with a simulator and the numbers. You are going to need generally 6" of backspacing to clear the strut all things remaining the same. Not sure what is out there with those type of specs that meet your needs, but that at least gives you an idea. Obviously if you change wheel tire/tire size all those numbers will change again.

    You might be able to find a wheel that has an offset closer to what you need and be able to run a smaller spacer to make everything work. Nothing wrong with spacers to fine tune the setup. You just want to make sure the spacer is made out of quality material, hubcentric, and that you have long enough wheel studs to get full engagement of the wheel nuts when installed.

    Most likely you could use the same wheels if you switched to longer control arms at a later date. The longer control arms will widen the track so that allows you to maximize your grip. The longer control arms will also generally give you a better camber curve as well as allowing for more negative camber which will help handling too. You may have to tweak or adjust your spacers if used as the longer control arms will move the wheel outboard to the fender.
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  10. #10

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    Cannan,

    I would start by looking at how the car will be used.

    With a 315 tire of even reasonable softness, the car is going to have a lot of grip for cornering, braking and accelerating. Assuming that you plan on using this grip during an autocross, the dive, roll and squat is going to be ridiculous with the springs that are currently on the car. At an absolute minimum, I would increase the rate of the springs and keep them conventionally located (on the control arms). The biggest issue with this is that to get enough stiffness to keep the dive, roll and squat in check, the ride quality is going to suffer. If you installed coilovers on both ends of the car, you could keep the chassis motions in check and still have decent ride quality. It is important to consider this now, as coilovers in the front suspension have clearance issue implications to the wheels and tires. Even if you don't install them now, you need to make sure that there is room for them in the future.

    This is really the proper procedure when any car is designed. Start with the wheel and tire dimensions as well as the tire brand and model as these things determine the total grip available. The total grip available along with the car's weight and weight distribution determines the forces that the suspension must deal with. This then determines spring rates, swaybar sizes and damping.

    Unless you are trying to get a particular wheel look, I think using custom wheels is a huge waste of money. S197 Mustangs use wheels with a large backspacing. They are available in a very wide selection of widths. You will save a lot of money by selecting a wheel for this chassis and then installing the correct wheel spacers at each end of the car to optimize back spacing. When in doubt, always, always get a wheel with more back spacing then you think you might need. It is trivial to move the wheel outboard. It is impossible to move the wheel inboard if there is a problem.

    I have seen a number of people purchase very expensive custom wheels only to discover slight mistakes in their assumptions or calculations in the correct back spacing. This is a very expensive mistake.

    I would really finish the suspension first, before committing to wheels and tires. Using SN95 FCAs in the front is a good idea. It will give the car a better bumpsteer curve and less lateral tire scrub. Used SN95 FCAs are cheap and have much better ball joints then your current FCAs have in them. These changes improve the handling in a way in which no amount of tire grip can. I would also update the front spindles to 1994-95 models at the same time, although this isn't absolutely necessary and could be done later.

    I realize that you may not want to hear some of the information that I've posted, but I'm very confident that you will be much happier in the long term with the car and it won't be that much more expensive, if at all, than what you have planned.
    Jack Hidley
    Maximum Motorsports Tech Support

  11. #11

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    A couple other things.

    Once you've decided on the suspension.

    Avoid staggered wheels and tires. It makes the car handle worse and the tires can't be rotated so you lose life from them.

    This is yet another advantage to using wheels with extra back spacing. If the optimum front and rear wheels need different back spacing, then you just install a thinner wheel spacer at the end of the car which needs more back spacing. This way you can rotate the tires and wheels, yet have the optimum back spacing at each end of the car.

    Forget offset specifications for the wheel. They are nearly useless for your design procedure. Only look at back spacing. You can use this to calculate Stickout.

    Advertised wheel width = Back spacing + Stickout - 1"

    This way of looking at the wheel and tire package makes it trivial to look at your sketch to determine what the optimum wheel specifications are.
    Jack Hidley
    Maximum Motorsports Tech Support

  12. #12
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    Jack,

    Thanks for the honest opinion. That's the exact reason I'm glad you and Trey are offering better advice than I know on the subject. The first thing you mentioned is about how the car will be used. 95% street, meaning driven to car shows and meets. Some highway, but more 50/50 highway to street split. Maybe an autocross every year, but little track time to start. I don't plan to do more than show and drive the car in 2018 (no autocross, Optima, drag race, etc.). If that changes in the future, I understand that it can or will drive more changes to perform better. Based on both responses from Trey and yourself, I *think* this is the best course of action for me right now to get the car done for 2018 and get some miles on it to sort out the initial build. Do you agree?

    Wheels:
    Rovos Pretoria (based on SN95 fitment and lower cost of entry). Still not sure yet of brand/style, but I think the size is correct for what I need.
    size: 18x10.5 backspace: 6.7" offset listed as +23mm (0.9")
    I believe I can use these on front and back and adjust with spacers as you mentioned.
    I will most likely order one pair initially for the rears and test fit the front before ordering a second set since they are off the shelf parts.

    Tires:
    I had the BF Goodrich Rival S, Falken Azenis RT615K+, or Pirelli P Zero Rosso in mind. I don't see anything with a higher UTQG wear rating in that size.
    Size : 315/30-18

    Suspension:
    1. For 2018 I can leave alone, but know that I can't beat on the car through corners without it fighting back.
    2. Next Winter I have the choice of higher spring rates and harsher ride or going full coilovers on each end to drive harder in 2019.
    - Change the front LCA to SN95 parts, keep the 94/95 spindles I have now (add new balljoints and bushings if LCA are used, maybe new otherwise).

    Priority 1 - What do I need to do to finish with minimal changes from today's setup to drive the car around in 2018?
    Priority 2 - What do I need to consider for next Winter to drive the car harder in 2019?

    Two cars that I'm watching are Joe Ayad in Washington and Gregg Biddlingmeier in Arizona to understand what they are doing and using. You probably know them well since they are MM supported cars. They've been thankfully answering some questions on their cars.

    Thanks for the help and advice!

  13. #13
    FEP Super Member erratic50's Avatar
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    One thing - if you do it the way others have done it inside the wells and also leverage your flares, then sky is the limit on rear tire size. Here's some 315/25/17's going on to a stock foxbody after some minor tweaking of the inner wheelwell structure. No tubs!

    http://www.mustangandfords.com/how-t...ustang-wheels/

    Good luck!

  14. #14

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    I would:

    Install 1999-2004 FCAs. These have a different shape than the 1994-98 models, so you will get more steering lock without rubbing. Don't change the ball joints in them unless you know they are damaged. They should move freely by hand. If you want better handling, change the bushings to polyurethane or Delrin.

    With the above FCAs, you will need to use SN95 inner and outer tie rods.

    You will also need to install an SN95 front swaybar as the endlink holes in the SN95 FCAs are wider apart. I would use a 1994-98 Mustang GT unit. This is 30mm hollow. It is the largest bar used on an SN95 Mustang . You will need to buy some other parts to mount the swaybar on your car as the SN95 swaybars mount under the frame rail instead of inboard of it.

    http://www.maximummotorsports.com/Fr...4-04-P442.aspx

    http://www.maximummotorsports.com/Un...0-mm-P438.aspx

    The first product linked above can be bolted or welded to the bottom of the frame rail. Then the bushings in the second link can be used to mount the swaybar to it.

    I think 10.5" wheels with a 6.7" back spacing will fit fine at both ends of the car. Try to use the minimum thickness wheel spacers in the front. This will minimize the scrub radius.
    Jack Hidley
    Maximum Motorsports Tech Support

  15. #15
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    Thanks for the great advice Jack. I'll get everything ordered up and continue on with this adventure. I'll get some miles on the car this year and then we can decide on springs next Winter. I looked at the spring and coilover options on the MM site. If the Konis I have are still good another year, I may just go with springs. I am skeptical they will last another year, so I may just look at a package box and we can talk about the differences. I appreciate your knowledge!
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    '86 Hatchback V6 / Auto Restomod (For Sale)

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    Jack,

    I had someone ask about updating the K-member to a 94+ K-member (which is wider?) to match the 99-04 LCA. You never mentioned it, so I fgured it's not needed. Is that something I should look at doing?
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  17. #17

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    Cannan,

    The extra width in the SN95 Mustangs is from the FCAs, not the k-member, sort of. For Fox Mustangs, there are about five different k-members which all have different FCA pivot hole locations. The SN95 Mustangs only have two different k-members with different pivot hole locations. The pivot holes on the SN95 k-members are about at the same width apart of the narrowest Fox k-member pivot holes are.

    You can't install an SN95 k-member in your car without some modifications. The 1994-95 k-member might weigh less than the k-member that is currently in the car. If you are going to the work of changing the k-member, I would install one with modified geometry so that you get better handling, steering, etc.
    Jack Hidley
    Maximum Motorsports Tech Support

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