Sidewall height???

[CnP]

I've searched thru a lot of threads/posts about tires and tire sizes and I might have missed something but I have not seen anyone really question the possible safety issue in going to a taller sidewall. It seems that several people have gone to a 235/55-17 instead of the oem size of 235/50-17. I can understand a more comfortable ride with a slightly taller sidewall but there are some tire dealers that will tell you that there could be a possible safety issue since the diameter of a 235/55-17 is almost an inch more (27.17 vs 26.25). Wouldn't this have an effect on the brakes???

[Lonestar]

Re: Sidewall height???

Assumption…. You are replacing a 235X50X17 V rated tire with a 255X55X17. No danger at all and virtually no adverse effects. If you laid into a corner at a very high rate of speed with the 50 series and immediately put a set of the same brand & model in a 55 series and laid into the same corner you might feel slightly more give and sway. Now, if you replaced that 235X50X17 V rated tire with a 255X55X17 S rated tire and did the same test then the result might surprise you as to how much give you would feel. Might as well drive a mini van.

[CnP]

Re: Sidewall height???

Yes, your assumption is correct (I think, LOL) - but doesn't the overall diameter of the tire have an effect on braking - particularly when you go to a tire that has a bigger diameter? I was trying to compare a 235/55 x 17 Michelin Primacy MXV4 to a 235/50 x 17 Bridgestone Turanza Serenity. It doesn't seem that Michelin has our oem size in that particular tire and I am leaning towards the Michelin.

I am not planning on driving the car like a sports car - it's a cruiser - so I am not even thinking about driving it like I stole it. Been there done that (and had fun) with other cars that were meant to go fast.

[bronzebird]

Re: Sidewall height???

Craig:

I think we have enough people who have gone to the 55's and put substantial miles on them, that any such braking problems would show up.

I have been running that size for over 20,000 miles now and I am not easy on a car. My ceramic pads were put on at the same time as I went with the new tires and they still spec out with lots of pad left.

Other folks have put many more miles on this size tire than I have and we haven't heard of any braking issues.... or any issues, for that matter.

Bronzebird

[CnP]

Re: Sidewall height???

Thanks guys. I would have thought that if anyone knew of any issues it would have been posted in this forum. I just can't understand why some companies feel they have to report that the sky might be falling if someone sneezes wrong. If you know what I mean. Classic example would be the 1010tires web site. If you enter the OEM tire size for the retro T'bird and then enter 235/55x17 size on their tire size calculator you will see what I mean.
Thanks again.

[Lonestar]

Re: Sidewall height???

You need not be concerned with braking issues IMHO. It is not like you are putting on a 78 series tire and thus if you brake hard you fold the tire folds under the rim.

I ran a set of Bridgestone Serenity’s on my Thunderbird for a while and I think they exceeded the OEM tire in every dimension. Plus, if you try you can usually get a Bridgestone Tire Store to deal with you on price.

The Michelin Primacy is an excellent rated tire and comes in 4 flavors – MXV4, MXM4, Pilot Primacy, and Primacy HP. The later two are summer tires. The MXM4, Pilot Primacy, and Primacy HP do not come in 235X50X17 but do come in 245X45X17 which is virtually the same dia. As the 235. The MXV4 that you can get in a 255X55X17 is basically for sedans and mini vans and is not a V or higher rated tire.

If you are looking at Michelins then take a gander at the Pilot A/S Plus.

[Leroy]

Re: Sidewall height???

I believe a bigger sidewall will also effect your speedometer readings slightly. Leroy

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[steelblue5505]

Re: Sidewall height???

I'm going to jump in here & tell you about my thoughts on my new Michellin Pilot Plus A/S tires. Another member recently asked me about them knowing that I put them on a few months ago. Here is a copy of the reply I gave to him.

You asked about my new tires and rightfully so since it was with some of your input that led me to these tires. I really like them, very much. We have had some real crappy weather with the horrid white shit on the ground as well as many mornings with black ice. These new Pilot Sport A/S Plus are real grippers. It was difficult to get them to break loose and put the Bird into auto traction control. The old OEM Pilots went into auto traction control with just the lightest touch to the pedal. The same can be said about Plus's ability to grip during a hard break.
They are excellent.
Before the weather changed to winter and we still had warm days I found the tires performance on cornering like a sharp right off of a hyway onto another where no actual speed reduction was necessary the tires do not have a "going soft" feel. They take this type of cornering great, the same is to be said for going into hyway curves. I for one do not like to take the curves at their posted yellow cautionary speeds. If I'm cruising along and a curve comes up posted at less than what I'm cruising at I do not break, I do ease up and head into the curve. These Pilots take these types of curves extremely well.
So I guess if you are somewhat of an aggressive driver, which I suppose I appear to be, you too will enjoy these Pilots. If you are not you may be spending your money on too much tire.
The Pilots do not make road noise and as new tires, certainly give a smooth ride. Ride smoothness is tough to evaluate when going from a worn set of tires to brand new ones. New always seems quiet.
The tread looks aggresive, lots of tread out to the edges, but this is what gives this tire its performance along with its wear ability. The Pilots have a 45K tread wear warranty. They are directional so it is important that during a tire rotation that it is done properly.
Well, that was the long version. The short is that I really do like them and would have to tell you that if you too purchase them you will not be disappointed.
take care

And there you have it.

[bronzebird]

Re: Sidewall height???

I believe a bigger sidewall will also effect your speedometer readings slightly. Leroy

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Leroy:

Actually the 55's correct the speedometer error. The 50's on my car never matched up with the speed showing on my GPS. As David A and I have both discovered since we put the 55's on the car, the speedometer and the GPS now show exactly the same speed over the road.

That is one factor that leads us to believe that this is the size designed to be in the car from the start.

Bronzebird

[CnP]

Re: Sidewall height???

Ok............. so............... Michelin it is and it will be a 235/55 x 17. My question to those that are recommending the Pilot Sport A/S Plus is........... are they worth the extra $140.00 over the Primacy MXV4? Tire Rack rates them slighty less (very slightly) in the categories of road noise, ride comfort and also light snow. Yes, unfortunately the car will be driven in light snow if I have to take it out and the wife has the other car. I mean WOW - the ratings on these 2 tires are so close to one another that I am trying to justify in my mind spending the extra money.

[Lonestar]

Re: Sidewall height???

Primacys are classified as "Grand Touring" and the Pilot A/S Plus are classified as "Ultra High Performace Grand touring" for whatever that is worth.

If Thunderbirds were built assuming 235X55X17 tires then with 70 MPH showing on the speedo the GPS would say you are traveling at 67.62 MPH. With my cruise set at 75 my Garmin says I am going 76 - at least it did on my trip to Choo Choo.

[bronzebird]

Re: Sidewall height???

If Thunderbirds were built assuming 235X55X17 tires then with 70 MPH showing on the speedo the GPS would say you are traveling at 67.62 MPH. With my cruise set at 75 my Garmin says I am going 76 - at least it did on my trip to Choo Choo.[/quote]



Yeah, bit it is downhill all the way from Tennessee to Texas. GPS doesn't account for terrain. lol

Bronzebird

[WLW]

Re: Sidewall height???

Both sizes are available from Goodyear in the Response Edge - I like 'em on the Jag & it carries the same rim size as the Bird. And they're made in USA. WLW