AndrewL

Hi, I have a stock 2017 Ecoboost and am wondering what modifications I can make to make the ride less bumpy.

1) Can I get a tire sidewall bigger than what 235/55/17 offers?
2) What tire make/model can give me the quietest smoothest ride?
3) Does tire width matter for ride bumpiness?
4) Any suspension mods I can do to make the stock even softer?

Fully expecting a lot of hate but I commute 2 hours a day on crappy freeways so hopefully there will be some good advice out there!

Thanks all

Bert

I think you are on the right track by starting with the tires, they can probably make the biggest difference.

Yes you can go to a taller tire with more sidewall. I think you can increase the overall diameter of the tires by an inch or more without running into any clearance problems. Pretty sure Ford still designs these cars with enough clearance for tire chains. Be aware that if you go to a larger diameter tire, you will be going faster than the speedometer says, unless you recallibrate the speedometer.

I would look at Tire Rack to research quiet and smooth riding tires.

Width probably does affect bumpiness a little but I don't think I would go narrower than 235. I'm thinking 235/60-17 would be a good size to look at.

I don't think there are any softer springs available for these cars, but I could be wrong. Changing the struts and shocks might "improve" the ride, but you don't want to go with less damping because then it will get bouncy.

AndrewL

Thanks Bert, that is super useful!

My current stock tires are 235/50/R18. I would love to try 235/60/17, does anyone know if that would fit on my 2017 ecoboost car?

Curious because I don't see that wheel dimension option in this webpage: https://www.americanmuscle.com/tire-sizes-for-s550.html

laserred38

Air suspension.

Evil_Capri

Threads merged. No need for 2 threads . . .

Bert

I thought you said in your first post that you have 235/55-17. That's why I suggested 235/60-17 as a small jump up in sidewall. But I knew those numbers didn't feel right . . .

I assume you understand that 18 and 17 are the wheel diameter, so to go to 17" you would need new wheels and tires. I don't know if the S550 offers 17" wheels or if there would be any clearance problems; I assumed 17 was OK because I thought you said that's what you have.

American Muscle only offers "standard" sizes, and you are talking about "going off the reservation" with a non-standard size. You want a taller sidewall, which is the opposite of what most people do, so I guess that's why AM does not offer it.

If I was in your situation, first I would decide if I want to pay for new wheels. If yes, then I would investigate whether 17" wheels are available to fit my car. Then I would look at tires on Tire Rack to investigate the different sizes available.

And also hopefully find a way to confirm that the larger diameter tires will clear with no issues. Like I said earlier, I'm pretty sure that Ford still designs these cars with plenty of extra clearance, but i would want to check that before buying tires.

wanted33

Andrew, one of the easiest ways is to check your tire pressure. Our '18 had 35 lbs psi in all 4 tires when we got it home. Check yours, if that where your's is take it down to 32. That will help you a lot, and won't hurt tires in any way. It helped ours. Manufacturers are recommending 35 lbs simple to get a minute amount more of gas mileage to help with the CAFE rules.

AndrewL

Thanks wanted33! I will definitely lower the tires psi.

Bert, apologies for the confusion, I'm definitely interested in getting new wheels and I see on tire rack and American Muscle that 17" are possible. I'm just wondering if what is listed on American Muscle is the largest sidewall possible (https://www.americanmuscle.com/tire-sizes-for-s550.html). I'm definitely interested in going off the reservation and even seeing if 16" wheels are possible, but want to make sure I don't break the car. Has anyone out there had experienced with large tires on an S550?

Laserred38 - Will air suspension actually make things softer than my stock suspension? I read that I could make it ride taller but that extra pressure would actually make the car ride harsher.

wanted33

Andrew, if you decided to order anything from American Muscle give them a call first. Tell them you are a member of the forum, and that you would like to get a discount code. It will save you 6% on all purchases.

Bert

I think I would stick with 17", I think 16" would create clearance problems with the brakes and is just plain too small, LOL

I didn't look at the AM link, but I believe the answer is yes, you can go to higher sidewall than they offer. They are probably sticking with the original outer tire diameter. I am not sure on the S550, but on earlier years you could safely go at least 1" larger outer diameter than original; original was 27.2" so 1" larger was about 28" OD

AndrewL

Thanks Bert! Has anyone tried a 235/60-17 on an S550? It fits but it has a diameter greater than the 3% of variance rule of thumb, so I'm not sure if it will damage anything else in the car.

Many thanks to anyone who can opine on this.

David Young

Many years ago, I had a 300Z and wanted wider tires on the rear. I 'didn't' go one size smaller on the second set of numbers for the tire size. The new tires looked good but it screwed up my handling and most of all my rear end gear ratio. It made my car a 'slug', so after a few months I got rid of it .

The Mustang isn't a luxury, soft and smooth riding car. I never has been. "In my opinion", your going to mess up your Mustang

AndrewL

Great thanks!

Does anyone have experience installing air suspension on their cars? Are they able to make the air suspension ride smoother than the stock suspension?

Thanks in advance!

laserred38

Yes I installed my own, and the range of ride on Air Ride's shocks is pillow soft Mercedes to full on race car. The front struts have 30 options for stiffness and the rear shocks have 15. Then you can set the static height as well, like coilovers. So it all depends on how you set it up.

15BluStang

Get Steeda's Comfort Suspension Kit. It has progressive springs so if you are cruising, you get a nice comfortable ride. When you hit bumps, you do not get the initial hard thump. Then when you drive aggressively, the car is much more planted. I was taking 35 mph turns at 60 and there was no lean. When I exit the place were I live and need to turn quickly, the back end does not lose grip as easily. This is easily the best (and favorite) mod I have made to my Mustang.