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Hi everyone,

I'm preparing to shed off the winter tires and get into some new summer tires. When I got the winter tires, I didn't care too much on sizing since it was just to not spin out in the snow, and I think I went too large.

Car is a 68 coupe currently running 17x8" 4.5" backspace wheels with 225/55/17 Michelin X-Ice 3 all around. The tires rubbed on large bumps, I rolled the fenders a bit and it's mostly okay. I kept reading 225 width was fine on this setup but now I'm wondering if the X-Ice 3 simply have very wide/bulky shoulders (or maybe snow tires tend to?).

Next, I'm putting the car on coilovers and lowering the suspension. I'd like to tuck a little bit of tire (and not change the wheels, so the 17x8" with 4.5" backspace will have to work somehow). Here is the car on the snow tires before the coilovers:



I have a few questions, please forgive my ignorance:

1. The car originally has F70-14 tires (and people disagree on the modern radial equivalent size). The previous owner ran 205/70/14 on the original GT rims, which seemed undersized to me (25.3" diameter). Photos above have 26.7" diameter tires which is a bit too big in my opinion. What is the "proper" overall diameter for a 68 coupe? The strange thing is, on the 26.7" tires currently, my speedometer perfectly matches my phone speedometer and my GPS (it was off on the smaller tires form the previous owner). This leads me to think 26.7" is not off, but the tires just look huge on the car right now...
2. I figured out that a 205/55/17 on the front might be narrow enough to let me tuck my tires into the fender. If I wanted to stagger the sizes, I could use a 225/50/17 on the rear and have the same exact 25.9" overall diameter on fronts and rears. 25.9" also is sort of in between the previous owner's tires and my current snow tires, which seems like a good size. However, I'm seeing a lot of people run 225/45/17, for which there are a lot more tire choices. But 225/45/17 is a 25" tire, which is even shorter than the previous owner's tires...it seems way too small to me. Any suggestions on tires sizes for 17" wheels that will give me whatever the correct diameter should be and be narrow enough to go into the fenders?
3. What is the easiest/most common way of adding negative camber to the front wheels? I did the Arning/Shelby drop but am looking for a little more static negative camber.
4. Lastly, the car has survived its last winter and will be moving to warmer weather, but with a lot of rain. I am planning on getting Michelin Pilot Sport PS2s as that is what I know, but am curious to hear any recommendations. My biggest concerns are dry/wet grip and dry/wet stopping distance. Stiff sidewalls and good steering response are second. I'm not worried about treadlife or cost, but they do need to be DOT legal. As the same time, this is just a daily driver for the streets so I am also open to a good touring tire. Any suggestions on tires?

Thanks all in advance!
 

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I don't know what you expect, but you're not going to be able to lower that car much with the wrong backspace wheel.

You're going to need at least .25" extra backspace to give you the clearance you what. Going to coilovers won't solve your problems and your wallet will be lighter.
 

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Hi everyone,

I'm preparing to shed off the winter tires and get into some new summer tires. When I got the winter tires, I didn't care too much on sizing since it was just to not spin out in the snow, and I think I went too large.

Car is a 68 coupe currently running 17x8" 4.5" backspace wheels with 225/55/17 Michelin X-Ice 3 all around. The tires rubbed on large bumps, I rolled the fenders a bit and it's mostly okay. I kept reading 225 width was fine on this setup but now I'm wondering if the X-Ice 3 simply have very wide/bulky shoulders (or maybe snow tires tend to?).

Next, I'm putting the car on coilovers and lowering the suspension. I'd like to tuck a little bit of tire (and not change the wheels, so the 17x8" with 4.5" backspace will have to work somehow). Here is the car on the snow tires before the coilovers:



I have a few questions, please forgive my ignorance:

1. The car originally has F70-14 tires (and people disagree on the modern radial equivalent size). The previous owner ran 205/70/14 on the original GT rims, which seemed undersized to me (25.3" diameter). Photos above have 26.7" diameter tires which is a bit too big in my opinion. What is the "proper" overall diameter for a 68 coupe? The strange thing is, on the 26.7" tires currently, my speedometer perfectly matches my phone speedometer and my GPS (it was off on the smaller tires form the previous owner). This leads me to think 26.7" is not off, but the tires just look huge on the car right now...
2. I figured out that a 205/55/17 on the front might be narrow enough to let me tuck my tires into the fender. If I wanted to stagger the sizes, I could use a 225/50/17 on the rear and have the same exact 25.9" overall diameter on fronts and rears. 25.9" also is sort of in between the previous owner's tires and my current snow tires, which seems like a good size. However, I'm seeing a lot of people run 225/45/17, for which there are a lot more tire choices. But 225/45/17 is a 25" tire, which is even shorter than the previous owner's tires...it seems way too small to me. Any suggestions on tires sizes for 17" wheels that will give me whatever the correct diameter should be and be narrow enough to go into the fenders?
3. What is the easiest/most common way of adding negative camber to the front wheels? I did the Arning/Shelby drop but am looking for a little more static negative camber.
4. Lastly, the car has survived its last winter and will be moving to warmer weather, but with a lot of rain. I am planning on getting Michelin Pilot Sport PS2s as that is what I know, but am curious to hear any recommendations. My biggest concerns are dry/wet grip and dry/wet stopping distance. Stiff sidewalls and good steering response are second. I'm not worried about treadlife or cost, but they do need to be DOT legal. As the same time, this is just a daily driver for the streets so I am also open to a good touring tire. Any suggestions on tires?

Thanks all in advance!
So, I have a 68 coupe as well, with 17” wheels. I’ll do my best to answer your questions

1. Cant answer what the “proper” diameter is for this car. But I will say the tires you have now (225/55) are way to tall. My calibrated eye says 25-26” is about good.

2. As Happystang stated, you’re not going to get anything to tuck in without the correct backspace/offset. Yes, a narrower/shorter tire will help with fender clearance, but knowing what look you want, the current backspace you have isn’t going to work. Lowering the car will make a shorter tire look correct. With the tallish stance you have now, a taller tire fills the wheelwell out better. Lower ride height, a shorter tire is ok. A 17x8 with 4.75” bs, and a 225/45 or 235/45 tire would lok spot on. On my car, I have a 17x7 with a 205/50 tire. 3.75” bs, which equates to the same “front spacing” (that is, from the mounting flange to front side of wheel) as a 17x8 with 4.75” bs. I promise the math checks out. Anyhow, with that wheel tire combo, it just BARELY sits inside the fender. Looking at your car l, I would say you may be in the same boat as I. On the rear of my car, I have 17x8 with 4.5” bs, with 255/40 tires. Real close to the fenders, but it clears. I should also mention all my fenders are rolled.

3. For more camber, adjust the lower control arm eccentric outward. Moving the whole arm outward will increase negative camber. Easy peasy.

4. Cant help you there bud. Kudos to you for driving your car in all weather. I’m going to be changing tires pretty soon, and am thinking about the Falken Azenis 615k+ tires, which are summer tires. Maybe I should drive in inclement weather hmmmmmmm

Hope that helps a bit. Attached a few pics of how my car sits today.




Sent from my iPhone using Tapatalk
 

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17x8 on all 4 corners. I want to say 5” bs but could totally be 4.75”bs, I’ve had them on for a very long time and don’t really remember. 255/55-17 rear and 225/45 front and obviously lowered front and rear. Rear fenders are rolled but I still get a little bit of rubbing over bumps if I have four people in the car.
FFC45A11-99CD-4A5C-A7B9-AC1D70769B77.jpeg
 

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Whichever size you pick,.I just got a message from tirerack.com about a Pirelli rebate. You can get some nice Nero GTs, 220TW i think, and others for ~$110 each:)
They haven't had a Michelin rebate for a long while so I would expect one to come out before much longer.
 

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Discussion Starter #9
Thanks everyone for the replies and help! Does anyone have a pic of a 67-68 with 225/45/17 tires?

So, I have a 68 coupe as well, with 17” wheels. I’ll do my best to answer your questions

1. Cant answer what the “proper” diameter is for this car. But I will say the tires you have now (225/55) are way to tall. My calibrated eye says 25-26” is about good.

2. As Happystang stated, you’re not going to get anything to tuck in without the correct backspace/offset. Yes, a narrower/shorter tire will help with fender clearance, but knowing what look you want, the current backspace you have isn’t going to work. Lowering the car will make a shorter tire look correct. With the tallish stance you have now, a taller tire fills the wheelwell out better. Lower ride height, a shorter tire is ok. A 17x8 with 4.75” bs, and a 225/45 or 235/45 tire would lok spot on. On my car, I have a 17x7 with a 205/50 tire. 3.75” bs, which equates to the same “front spacing” (that is, from the mounting flange to front side of wheel) as a 17x8 with 4.75” bs. I promise the math checks out. Anyhow, with that wheel tire combo, it just BARELY sits inside the fender. Looking at your car l, I would say you may be in the same boat as I. On the rear of my car, I have 17x8 with 4.5” bs, with 255/40 tires. Real close to the fenders, but it clears. I should also mention all my fenders are rolled.

3. For more camber, adjust the lower control arm eccentric outward. Moving the whole arm outward will increase negative camber. Easy peasy.

4. Cant help you there bud. Kudos to you for driving your car in all weather. I’m going to be changing tires pretty soon, and am thinking about the Falken Azenis 615k+ tires, which are summer tires. Maybe I should drive in inclement weather hmmmmmmm

Hope that helps a bit. Attached a few pics of how my car sits today.
[
Thank you, that's super helpful! I guess maybe to be safe I should look into a new set of wheels... your car looks great and I'd love to have that same setup. I don't know if I could really fit a 255 on the rear...the 225s on their now are getting close. Time to go shop for some wheels and take more measurements...
 

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A 225/45/17 tire would look even more ridiculous on a 67/68 than my 65. You need rims/wheels with the proper backspace to accomplish your goals. I currently run cheapo 17 x 8 4.81 backspace Torque Thrust II rims/wheels on my 65 and they rubbed on the rears until some massaging. You should be able to run a larger tire with no problem with the proper backspacing.

745712
 

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A 225/45/17 tire would look even more ridiculous on a 67/68 than my 65. You need rims/wheels with the proper backspace to accomplish your goals. I currently run cheapo 17 x 8 4.81 backspace Torque Thrust II rims/wheels on my 65 and they rubbed on the rears until some massaging. You should be able to run a larger tire with no problem with the proper backspacing.

View attachment 745712
Looks good to me , I'm biased I guess
 

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Discussion Starter #12
I would buy new rims in a better offset if I could find a style I liked...there just don't seem to be that many choices in the sizes for our cars...
 

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3. What is the easiest/most common way of adding negative camber to the front wheels? I did the Arning/Shelby drop but am looking for a little more static negative camber.
You could install a UCA that is shorter than stock. Street or Track says a 245/45/17 tire can be installed up front on our 66 (with a rolled fender lip). They don't mention back spacing but I think the 68 has more clearance so maybe it can be done without rolling the fender lip on that nice High Country.
 

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Thanks everyone for the replies and help! Does anyone have a pic of a 67-68 with 225/45/17 tires?


[
Thank you, that's super helpful! I guess maybe to be safe I should look into a new set of wheels... your car looks great and I'd love to have that same setup. I don't know if I could really fit a 255 on the rear...the 225s on their now are getting close. Time to go shop for some wheels and take more measurements...

No problemo! Glad to be useful!

I do however think you can fit those 255s in the rear. I don’t have anything special as far as rear suspension (leafs in the standard location and a panhard bar), so I see no reason why it would not fit for yours with a little fender rolling. The 225s you have now are very tall and bulbous. A shorter, less bulbous sidewall would work. Go for it!


Sent from my iPhone using Tapatalk
 

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Discussion Starter #15
No problemo! Glad to be useful!

I do however think you can fit those 255s in the rear. I don’t have anything special as far as rear suspension (leafs in the standard location and a panhard bar), so I see no reason why it would not fit for yours with a little fender rolling. The 225s you have now are very tall and bulbous. A shorter, less bulbous sidewall would work. Go for it!


Sent from my iPhone using Tapatalk
I am beginning to really wonder if my snow tires are just abnormally fat/wide despite being 225's. My latest thinking was going for a 205/50/17 front and a 225/45/17 rear (not sure if the rear being 0.1" shorter is a problem). I'm also a little unsure about mounting a 205 tire on an 8" wheel and how stretched that might look.
 

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I watched as the tire guy had a hell of a tough time mounting a 205/70 on my 7"-14 wheel. I think a 17x8 would be even harder.
 

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17x8 on all 4 corners. I want to say 5” bs but could totally be 4.75”bs, I’ve had them on for a very long time and don’t really remember. 255/55-17 rear and 225/45 front and obviously lowered front and rear. Rear fenders are rolled but I still get a little bit of rubbing over bumps if I have four people in the car. View attachment 745617
Jamesgang, can you post some additional pictures of your car showing the wheels and tires? I am considering putting 255's on the rear of my 66 fb.
 
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