Finally put a tape measure to my new 245/45/17 S-03's and have a disturbing discovery. Tech data sheet states that thye are 25.7" in diameter, or equivilent to the 225/55/16 Michelin's they replaced - same rolling diameter.

Now for the tale of the tape. The Michelins measure 25.6 (and 12.8 to the center cap of the "Star" on the wheel). the Bridgestones measured 24.6 and 12.3 to the center cap.

1. What gives with the specifications from Bridgestone? I would have gone with the Pilot Sports if I had known this.

2. What impact does this have on my speedometer, wheel bearings, and anything else that might get screwed up?

The tires look and handle great (first 300 miles) but I feel both mislead and potentially headed for other problems by not fitting the correct specification rubber.

HELP get me straight.

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94 E500 (Silver/Black)

Some Michelins, particularly in 225/55/16, tend to bulge a bit, perhaps inflating your reading.

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1988 Mercedes-Benz 260E

MbSteve,
How do the tire heights compare when loaded?
What is ground to star centre distance for both tires, when loaded (ie wheel attached to car). Might want to do this with comparable tires on opposing sides?
farrukh

Sorry this is off topic but I was wondering if you would part with one of your TDMA digital motorola phones for an E500. I would have emailed you but there was no email listed.

Sorry Erase - I have not been in town for awhile and find myself a little behind in responding. I do not have a digital TDMA so I'm afraid I cannot help you out.

Have a great weekend.

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94 E500 (Silver/Black)

Steve,

The published specs for tires are essentially approximations. A given tire size (i.e., 245/45/17) is approved by the mfr to fit on a range of wheel sizes (i.e., 7.5-9.0 inches). When the tire is mounted on the narrowest wheel, the dimensions (and circumference) will be different than when on the widest. Usually the specs indicate the "measuring" wheel used to generate the numbers. I think they measure new tires and do not account for wear, which can make a pretty big difference from new to worn out. Also, the specs are different for rolling circumference and static circumference, just an FYI.

As to what problems it will cause, basically NONE except your speedometer & odometer may be a few percent off (smaller tire means speedo & odo read faster/higher than actual). No big deal at all.

BTW, I sent you a private message regarding your question on "LTD" spring part numbers...


Regards,

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Dave
Boise, ID
Check out my website photos, documents, and movies!

Thanks for the tire sizing info, it explains the appearant panick I suffered. The optomistic speedo will probably serve as a built in traffic citation reducer .

I repsonded to you e-mail - look forward to hearing back.

Steve

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94 E500 (Silver/Black)