Upgrade Tire Size 2004 TBird

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krogers

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Sep 10, 2021
Thunderbird Year
2004
I have read that 245/50/17s fit a 2004 TBird and that 235/55/17s also fit. Anyone know if 245/55/17s (wider and taller) will have any clearance issues?
 

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The diameter of factory tire 235-50/17 is 26.3”
When you vary much from that you might get into clearance issues or speedometer changes. When you are shopping tires, click on the specs tab or ask your tire guy. If you decide to change an entire wheel size like I did, you can also change aspect ratio. I went up to 18” and added width with a different aspect ratio. For me, 245-45/18 worked perfectly and was within a tenth the same diameter as factory size so no issues.
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Usually the goal when changing tire sizes is to increase the width without increasing the diameter. The first number is the width in mm. The second number is the ratio of height to width. If you change your rims then that is just an additional variable to the equation. There is a calculator available on the Discount tire website. I explored this last time I changed tires and determined that there was an inch of additional clearance in the front wheel wells of my "03. However, the new size that I calculated was uncommon and expensive so I nixed the idea. I did go with a softer tire from Discount tire that is made by Continental and it really helped my traction and ride over the 11 year old tires that were on it... Those 18's look great !
 
I have seen on other post where people have upgraded their tire size from 235/50/17 to 235/55/17 very successively.
I am planning to do a tire upgrade and was wondering if anyone had gone to 245/55/17 and if there are any problems doing so like wheel well rub?
I am thinking that the "wheel well fill" would probably look a lot better with these bigger tires.
Also is the ride comfort and performance more noticeable running with 245/55/17 ?
Thanks
 
Your Speedometer and odometer will be off by 4% if you do this... It will show that you are going slower and traveling less miles than the actual. The wheel will be 1 inch taller and no wider. If you go to the 245/55/17 the tires will be 1/2 inch wider (add 1/4 inch to each side) and 1.1 inch taller. No interference issues with the suspension. You will notice less torque and acceleration but you will have a higher top speed. I would not expect any noticeable difference in the ride due to the tire size. Any differences I would attribute to the tire construction.

I put 255/45/17 on my car. This decreased the height of the wheel by 0.2 inches. Made the tires almost 1 inch wider but no taller.
 
JohnS said:
Your Speedometer and odometer will be off by 4% if you do this... It will show that you are going slower and traveling less miles than the actual. The wheel will be 1 inch taller and no wider. If you go to the 245/55/17 the tires will be 1/2 inch wider (add 1/4 inch to each side) and 1.1 inch taller. No interference issues with the suspension. You will notice less torque and acceleration but you will have a higher top speed. I would not expect any noticeable difference in the ride due to the tire size. Any differences I would attribute to the tire construction.

I put 255/45/17 on my car. This decreased the height of the wheel by 0.2 inches. Made the tires almost 1 inch wider but no taller.
Click to expand...
You can use an SCT X4 Tuner to change the tire sizes etc. That's what I did on my Mustang,
 
Thank you John S for your input!
Now I am very curious how the 255/45/17 tires would look. Could you send a couple of pics ( maybe straight on and view from back)? I would be deeply appreciated!
Also you can use the Forscan app to adjust for tire size changes! Simply calculate the circumstance of your tire and input it and your all set to go.
I love this site !!
 
@JohnS Did you adjust your speedometer after the size change? I ask because when using the stock size, my 04 speedometer was always 2 mph fast compared to speeds on the GPS app on my phone. I moved up to 235/55/17 and the indicated speed is still just a hair fast, which is OK by me, since it gives me a small safety factor. That 4% error might have made your speedo pretty accurate.

@D'Miles Whatever size you choose, take a hard look at the Michelin CrossClimate series, I put them on my wife's Infiniti and they are great. They were the top-rated all-season tire a year ago, and I caught the $150 rebate for 4 at Costco, so it brought the price in line with other name-brands that had worse performance. This rebate comes around often at the big Tire shops, but if you buy from Costco, be prepared to fight with them over the change in size. I finally had to get Michelin to send me an email saying that the "upsize" was approved. These will be my choice when my Continentals finally wear/age out.
 
WesTxStoner425 said:
@JohnS Did you adjust your speedometer after the size change? I ask because when using the stock size, my 04 speedometer was always 2 mph fast compared to speeds on the GPS app on my phone. I moved up to 235/55/17 and the indicated speed is still just a hair fast, which is OK by me, since it gives me a small safety factor. That 4% error might have made your speedo pretty accurate.

@D'Miles Whatever size you choose, take a hard look at the Michelin CrossClimate series, I put them on my wife's Infiniti and they are great. They were the top-rated all-season tire a year ago, and I caught the $150 rebate for 4 at Costco, so it brought the price in line with other name-brands that had worse performance. This rebate comes around often at the big Tire shops, but if you buy from Costco, be prepared to fight with them over the change in size. I finally had to get Michelin to send me an email saying that the "upsize" was approved. These will be my choice when my Continentals finally wear/age out.
Click to expand...
There was no need for an adjustment because the tire diameter was only 0.5% smaller.
 
Does going to the taller aspect ratio normally make the ride smoother or is the tire brand and model a bigger influencer? Maybe both combined is the way to go for smoothness?
 
krogers said:
I have read that 245/50/17s fit a 2004 TBird and that 235/55/17s also fit. Anyone know if 245/55/17s (wider and taller) will have any clearance issues?
Click to expand...
Back to Krogers original question "Anyone know if 245/55/17 tires will have any clearance issues?"
Has anyone tried this 245/55/17and are there any problems with clearance issues ?
Thanks!
 
D'Miles said:
I have seen on other post where people have upgraded their tire size from 235/50/17 to 235/55/17 very successively.
I am planning to do a tire upgrade and was wondering if anyone had gone to 245/55/17 and if there are any problems doing so like wheel well rub?
I am thinking that the "wheel well fill" would probably look a lot better with these bigger tires.
Also is the ride comfort and performance more noticeable running with 245/55/17 ?
Thanks
Click to expand...
My 2003 has 235/55/17 and no problems. I need new tires and look forward to what people say here.
 
All things being equal if the roads you drive aren’t that good I would not go to a bigger rim / lower sidewall profile because a taller sidewall helps absorb crappy road surfaces
 
I have 245/50/17 on mine and love the look, wider and lower. I had the 235/55/17 and always thought they appeared to tall and narrow, I will see if I can find a good picture and post it.
 
Parkway Thunder said:
I have 245/50/17 on mine and love the look, wider and lower. I had the 235/55/17 and always thought they appeared to tall and narrow, I will see if I can find a good picture and post it.
Click to expand...
A pic of the side view and rear view would be awesome !
thanks !!
 
Thanks for this thread - based on this information I went and bought new tires- 235/55/17 from Discount Tire and boy what an improvement - I tell you what this car drives like a dream— the tires are made by Sentury and they were $91 each.
 
BLUDICE said:
Thanks for this thread - based on this information I went and bought new tires- 235/55/17 from Discount Tire and boy what an improvement - I tell you what this car drives like a dream— the tires are made by Sentury and they were $91 each.
Click to expand...
What brand, model, size did you have before? Do you notice a noise difference?
 
I am looking to upgrade the tire size on my car to fill the wheel wells. Anyone know the max size before wheel scrubbing starts?
 
You can go to the Discount Tire website and they will give acceptable optional tire sizes that will work--need to be cognizant that if you change overall wheel dimensions you will modify your speedometer readings
2002 T-birds can apply 255 45 17--that gives max width dimensions if that's what you're looking for 17" wheel
 
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