Replacement tires 2004 Bird

4PacificBird

4PacificBird

Active Member
Last seen
Joined
Sep 9, 2017
Thunderbird Year
2004
Recommendations for tires and for spare...
 
I bought a set of Toyo white sidewall tires for my 03 Bird. I got them on line and drop shipped to my local Ford dealer for installation. I bought them from a now defunct website.
 
I put BF Goodrich G-Force Sport Comp 2s (blackwall, black lettering) on my 2003. Excellent traction, high speed rating, attractive tread, and design reduces the chance of hydroplaning. It is a summer sport tire, but also comes in an all season style.
 
I have a 2005 and upon purchase last summer put on Continental Pure Contact, 96V. Paid $720 installed.
I've used these tires on our Audi A6 and they handle great and are quiet on both cars.
 
I just picked up my 2004, and the selling dealer had installed new Yokohama Avid ENVigor tires. I can’t say I would recommend these as they seem to produce a lot of road noise. I don’t really have anything to compare it to, but I’d be curious to hear what others say about road noise in their Thunderbirds.
 
I'm debating whether to upsize a little to 235/55/R17 or 245/50/R17. I think I read on here that they work ok on the original rim. Not sure who would install off size tire though. Appreciate the comments!
 
I changed the wheels on my 2003 to 18s, and the Goodrich tires I put on are 235/45s. That put my circumference within a tenth of an inch of the original combination. I like the shorter sidewall, and it gives a firmer feel on turns, better handling. May be a bit stiff if you like a softer ride.
 
Thank you...I'll check that combo out.
 
I like the look of the 18 inch wheels. Bigger, but not ridiculous. I bought my TBird in 2015, and the previous owner had scraped one of the original chrome wheels, so I just decided to get new ones. Pacer Silhouettes, chrome finish, perfect offset and fitment.
 

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I was checking my tires last year and noticed they were nine year old Michelin Pilot HXMXM4 with plenty of tread left on them. Since I only drive my 2004 about 3,000 miles a year I was never going to wear them out. My daily driver is a 2016 Fusion with exactly the same tire size (235/50-17) and had Michelin Energy Saver AS tires with only 18,000 miles on them. So I switched them out and the 2004 runs quiet with good handling on the Energy tires and I can wear out the nine year old tires in a year or two on my Fusion.
 
I'm thinking about an upsize to a 225/55/17 tire if I can find a retailer to put them on. Any thoughts about the size change??
 
I'm thinking about an upsize to a 225/55/17 tire if I can find a retailer to put them on. Any thoughts about the size change??

OEM tire circumference for the 235/50/17 is 26.59 inches.
Using a 225/55/17 gives you a circumference of 27.10 inches, about 1/2 inch larger. This will affect your speedometer, because it is calibrated for the OEM circumference.
Going to a 245/45/17 only gives you a circumference of 26, which also is over a half inch smaller.
The circumference formula is:
Tread width in mm/24.5 × % × 2 + wheel diameter.
 
Appreciate the info.....
Ok, I shouldn't try to multitask AND write long answers on my phone. I goofed on the equation so here are the correct numbers:
235/50/17
235÷25.4 = 9.25 x .50 = 4.624 x 2 = 9.25 + 17 = 26.25 inch diameter

225/55/17
225÷25.4 = 8.86 x .55 = 4.873 × 2 = 9.75 + 17 = 26.75 inch diameter
Results are the same. The 225/55 is 1/2 inch larger in diameter which would affect your speedometer accuracy.
I prefer the wider tread (235mm vs 225mm) for road contact and handling
The 10 mm difference is about 4/10 inch
 
I recently replaced the tires on my '02 T'Bird - nothing wrong with the Michelins on it except they were old. I went with Pirelli P7's in the 245/50R17 size. They are 1/2 inch taller, and 1/2 inch wider than stock, fit the original wheels just fine, and fit nicely in the fenderwells. The slightly larger diameter corrected my speedo at 70 mph - it now reads 70 when I'm doing 70 according to my GPS (the factory speedo calibration reads about 2mph fast, reading 70 when I was really only doing 68). The Pirelli's were rated higher than Michelins on the Tire Rack website. I am very pleased with my new tires. I also replaced my OE Firestone spare with the factory replacement Maxxis Temporary Spare tire.
 
A 245/50 tire is wider AND taller than a 235/50. Don't know what formula you used to determine that the diameter was the same, but, if you run the numbers in the formulas posted above, you will find the 245/50 to be about 4/10ths of an inch taller than a 235/50 - very close to 1/2 inch by my calculations.
 
With your 50's it's a 1.5% diameter increase or .9 mph speedo reading increase at 60 mph, that changes your actual speed .9 mph increase at 60 mph speedo indication (60.9). Whereas the 55's give a 3.5% speed increase of 2.1 mph at a speedo reading 60 mph (62.1). 1.5% is pretty much the difference between new and used tires. My Tbird speedo indication to actual driving speed is far closer to a 3.5% over reading then 1.5%. Taking the tire wear factor into consideration your 245/50/17's have netted you a slightly marginal speed increase over your speedo indication. Math 101.
 
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