Low Profile Tires Limit Lowering Car?

[EsGeht]

To the best of my knowledge, the car is at factory height. I have factory adjustable spring plates with new bushings ready to install, and plan to replace front bushings as well. I'd like to lower it a bit for a better look, but I've complicated things by running 225/50/15s in the rear and unfortunately, by mistake, 205/50/15s in front. I meant to get 205/55 fronts in order to match the rears, and I don't like the looks of the fronts at all, but I'm stuck with them for the time being. How much do low profile tires limit attempts to lower the vehicle ride height? I assume there must be some limitations over 60 or 65 series tires because the vehicle itself is already lowered due to the lower profile tires.

[Chuck Miller]

Mike,

Got kind’a short-circuited once I scrolled down and saw your car……

Not sure how to answer your questions…

- Looks like your car is SC flared with 15” by 8’s on the back and 7’s on the front (or maybe 7’s on around)
- You can keep lowering the car until it starts almost riding on the 50 series tires.
- You can also lower your car on 60’s until they start doing the same as well… but the car will be slightly higher.
- Both above strategies will compromise the handling greatly.
- Do you want to run 55’s all around?
- Do you want to switch to 60’s ?

What I’ve found that works best for looks and ride with your combo (my combo as well) are 205x60’s on 7’s in front and 215x60’s on 8’s or 7’s in back.
Unfortunately tire companies stopped making ‘ultra high performance’ tires in that size years ago… (i.e. Yokohama AVS Intermediates)

If you don’t have the need for super performance tires, companies still make tires in that size. (BTW- 215x60 is the same diameter as the stock 185x70)

If you want super performance tires you need to go 205x50’s, 205x55’s or 225x50’s… (the 205x55 is the same diameter as the 225x50) I used to run 205x50's in front on the track and ALWAYS thought they looked short.

It all kind’a depends on what you want to do with the car… and I guess, how you want it to look.

FWIW,
I’ve done two things:
- Completely stopped trying to find ultra performance 15” road tires and switched to TOYO RA1 DOT track tires. (I have 2 sets of tires and wheels, one for track and one for street)
(I was getting about 7000 on the rears with Bridgestone S-03 road tires… and I get about 4500 with RA-1’s street driving)
- AND, I switched to 225x50’s on 7’s and 8’s all around……… (Thought I was going to lose some crispness on ‘turn in’, and found I gained) I now realize I should have done this 15 years ago.

Not sure if any of this helps………… sorry

Cheers

[kenikh]

I had this issue on my car, a '69S w/ RS flares and 7s/8s. 205/55/15s and 225/50/15s really limited ground clearance on the car when lowered to stance that had the fender lips flush with the top of the tire. As you know - it sucks.

I ended up bagging these tires during my resoration back to narrow body, even though you can fit these same tires on a narrow body with 7R offset wheels. Instead, I went with 195/65/15 and 215/60/15 tires.

225/50s and 205/55s have a 4.4" sidewall height
215/60s and 195/65s have a 4.9" sidewall height (205/60 has the same sidewall height, BTW)
205/50, on the other hand has a 4" sidewall height. Yikes.

Also realize that there is some variance in overall tire height due to tread design and depth. I have seen one set of 205/50s with terribly low height, while another set was more akin to the 205/55. It pays to compare in person.

Keeping the suspension at the same height, I gained just enough ground clearance to pass over every speed bump and driveway I used to hit prior.

The other x-factor in lowering is sway bar mount geometry on the a-arms. If you go too low, the sway bar mounts bind, so you need to turn the mounts 90 degrees to compensate. Additionally, you may need to trim the snubber rubbers for additional clearance or you'll bottom out on the rubber, which makes for a very, very jarring rid.

[Chuck Miller]

Kenik had a MUCH better handle on your questions Mike ..... sorry, didn't get it....... please excuse my ramblings........

Cheers

[EsGeht]

Thanks, guys. For now, I'm staying with the tires I have, I just would like to lower it a bit. I'd like to bring the rear down so there is no space showing above the tire, but I'm afraid that would leave the front, when brought down the same amount, too low for ground clearance on a street car. Those are Bridgestone S0-3's on 7's and 8's with RS flares. Just checked ride height at fender lips and they are 24 1/4 front and rear except for the front right, which is 24 1/2. (looks like I'm in for some adjustment just to get that rf corner at the same height as the others) Not sure how much lower I should go than that on a street car. Based on yor figures, Kenik, with 205/50/15's in front, I'm already nearly a full inch lower (ride height) than 185/70's. I guess to get that really good looking stance I'd need to have taller profile tires stuffed up into the wheelwells in order to maintain some reasonable ground clearance, as opposed to low profiles that lose ground clearance just by their size alone.

[EsGeht]

For example, I'd like to lower it about like this car (love the color, flares, RS touring trim) Chuck, are those 50 or 55 series tires in front? From what you say in the post where I got this pic, you're at 23.5 in the rear, so I could go down .75 in back. Just not sure about the front.

[kenikh]

I guess to get that really good looking stance I'd need to have taller profile tires stuffed up into the wheelwells in order to maintain some reasonable ground clearance, as opposed to low profiles that lose ground clearance just by their size alone.

This is my experience for sure.

Chuck's car, IIRC rund 225/50s at all 4 corners.

Also, be aware of rear clearance, too. My car when is was low on 225/50s dragged the trans and engine case on the speedbumps at the Flamngo Hotel in Santa Rosa, during Treffen a few years back. It wasn't fun trying to take every speedbump at 45 degree angles!

[Chuck Miller]

Mike,

I think that's an earlier pic... for sure those are my racing wheels, but I think I was still on 205x50's in the front.

Have plenty of pics with the 'new set-up' w/225's all around... will post later

Kenik is right........ EVERY driveway, bump, and slow dip was a problem... especially with the 205's in front. The 225's in front help... and also the new stiffer suspension.

Also, my car has had rolled inner front fender lips (from about 10:00 to 2:00oclock) for most of its life.

Have the tires you REALLY want on the car when you do your set-up, you'll/they'll set the ride height first then the balance and alignment...... take your time.

Cheers

[Shaun 69 E]

I just got my car set up, I hope this helps.

Tires are SO3s on 7x15 cookie cutters all around

Front
205/55
24.2 ride height
-1.2 camber


Rear
225/50
23.8 ride height
-1.7 camber

Rear fender well lips were ground down and rolled up.

I don't have any rubbing in the rear.

[kenikh]

WTH are you still finding S03s??? IIIRC they are out of production in 15".

BTW, the car looks SICK, Shaun.