Torched10 Posted September 1, 2014 Report Share Posted September 1, 2014 Thanks for answer above in why 4 tires vs 2. Now curious how much affect 295 has on Speedo readings Link to comment Share on other sites More sharing options...
Joraft Posted September 1, 2014 Report Share Posted September 1, 2014 Thanks for answer above in why 4 tires vs 2. Now curious how much affect 295 has on Speedo readings Should change the reading by less than 1mph. Link to comment Share on other sites More sharing options...
Torched10 Posted September 1, 2014 Report Share Posted September 1, 2014 Thanks so much. This thread was great think I'll do the 275 k 105y in front and 295 k 105y in back..btw what do you Guys do with the old ones. Ive only got 900 miles on mine Link to comment Share on other sites More sharing options...
billross Posted September 1, 2014 Report Share Posted September 1, 2014 Thanks for answer above in why 4 tires vs 2. Now curious how much affect 295 has on Speedo readings The best way to figure the impact on speedo readings is to find the specs for the stock rear tire to see how many revolutions per mile they do, then find the revolutions per mile spec for the new rear tire. From those numbers you'll be able to determine how many percent fast or slow your speedometer will read. Link to comment Share on other sites More sharing options...
betashave Posted September 2, 2014 Report Share Posted September 2, 2014 Thanks so much. This thread was great think I'll do the 275 k 105y in front and 295 k 105y in back..btw what do you Guys do with the old ones. Ive only got 900 miles on mine Just to be sure, what size tires and rims do you currently have? I couldn't tell in your signature if you have a 2011 or newer Shelby that has the 19" front and 20" rear wheels (which are the wheels the tires mentioned in this thread fit). If you replace your tires and they have most of their tread remaining, list them for sale. Some people like to stick with the stock tires and it the tires you are replacing are stock tires, someone may be looking for replacements if theirs are getting older. Mine are over 3 years old and down to 3/32" tread depth, so I don't want them back. Link to comment Share on other sites More sharing options...
Torched10 Posted September 2, 2014 Report Share Posted September 2, 2014 They are from a 2014 vert. Guess I'll just lost them for local picku here and on Craig's list. Thanks. Bob Link to comment Share on other sites More sharing options...
sparko Posted September 2, 2014 Report Share Posted September 2, 2014 I have 295's 105Y and 275 105 Y and the difference in every way is amazing. The car hooks up well....it handles better....and the ride is smoother. Best of all I will be able to use the car when the temperature goes below 40 degrees.....unlike the GY tires. These tires and the 3.73 rear gears made an amazing difference in my '13 500 Link to comment Share on other sites More sharing options...
Torched10 Posted September 2, 2014 Report Share Posted September 2, 2014 Http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=7 Being an engineer just wanted to calculate the various wheel,/tire heights. Here's a good link the 295 is 28.1 in high and the 285 is 27.8. Accurding to the size the 295 is 11.6 and the 285 is 11.2. The actual Speedo difference of 285 vs 295 is 3%. So at 70 thats 2.1 mph higher sorry to play engineer but that's what I do. Now what I don't know is if the advertised sizes are nominal or actual specs. If the former then it's jump ball Link to comment Share on other sites More sharing options...
betashave Posted September 3, 2014 Report Share Posted September 3, 2014 I have 295's 105Y and 275 105 Y and the difference in every way is amazing. The car hooks up well....it handles better....and the ride is smoother. Best of all I will be able to use the car when the temperature goes below 40 degrees.....unlike the GY tires. These tires and the 3.73 rear gears made an amazing difference in my '13 500 That is great to hear! Still waiting on my tires since I had to change my order. The...wait...is...killing...me... Link to comment Share on other sites More sharing options...
Joraft Posted September 3, 2014 Report Share Posted September 3, 2014 Http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=7 Being an engineer just wanted to calculate the various wheel,/tire heights. Here's a good link the 295 is 28.1 in high and the 285 is 27.8. Accurding to the size the 295 is 11.6 and the 285 is 11.2. The actual Speedo difference of 285 vs 295 is 3%. So at 70 thats 2.1 mph higher sorry to play engineer but that's what I do. Now what I don't know is if the advertised sizes are nominal or actual specs. If the former then it's jump ball According to Michelin their 295 105Y is 28.1" in diameter, and according to Goodyear their 285 F1 is 27.9" in diameter. So you're pretty darn close on the specs. However, my calculations show a .8% difference in size, resulting in a speed of 70.56mph when the speedo shows 70mph. Of course I could be wrong, I think that may have happened at least once before. Link to comment Share on other sites More sharing options...
Torched10 Posted September 3, 2014 Report Share Posted September 3, 2014 The only variable in calculating circumference is the change in radius. Which is a function of the changing width ie 295 vs 285. That's the 3%. Of course if their actual tire wall sizes are different then there'd be a diffrence from my theoretical number.btw I was trying to figure out the 101 and 105 terms. I'll bet it's the tire is 5% wider / higher than nominal. Link to comment Share on other sites More sharing options...
billross Posted September 3, 2014 Report Share Posted September 3, 2014 That's why I'd be looking at the revolutions per mile specs instead of the diameter/circumference specs. Comparing the revs per mile for the two different tires should give a solid measure of impact on the speedo reading. I also have MPSS tires on my wish list just as soon as the Goodyears wear out. My biggest complaint about the Goodyears is how much sand and gravel they pick up and throw against the car. Link to comment Share on other sites More sharing options...
betashave Posted September 3, 2014 Report Share Posted September 3, 2014 My biggest complaint about the Goodyears is how much sand and gravel they pick up and throw against the car. That is indeed very annoying! Have you every checked the rocker panels for all the excess gravel caught up in there? I did once and couldn't believe how much gravel poured out of there. I will say that over time this effect of picking up sand and gravel seems to have diminished, but only because the traction is nearly gone on these things. Link to comment Share on other sites More sharing options...
betashave Posted September 3, 2014 Report Share Posted September 3, 2014 The only variable in calculating circumference is the change in radius. Which is a function of the changing width ie 295 vs 285. That's the 3%. Of course if their actual tire wall sizes are different then there'd be a diffrence from my theoretical number.btw I was trying to figure out the 101 and 105 terms. I'll bet it's the tire is 5% wider / higher than nominal. I myself am no engineer, so there is a high likelihood that I have no idea what I'm talking about here. But I'm not sure calculating this based on theoretical 295 vs 285 sizes gives a real world result when you are comparing across brands, even within the same brand. It seems almost like how HDTV's have gone to a "class" of size, e.g., a 52" class tv may not truly measure 52" diagonally. A 295 Michelin tire is not necessarily the same size as a 295 GY, or another Michelin for that matter. As for what 101 and 105 means in terms of the size of the tire, I'm not sure, and I'm not sure if there is any true correlation. All I know is that 101Y and 105Y are indicators of load rating of the tire. Link to comment Share on other sites More sharing options...
Torched10 Posted September 3, 2014 Report Share Posted September 3, 2014 Got one last question the Michelin site says the tire is not designed to drive in near freezing conditions. The gy tires aren't supposed to be driven under ,40. So are they both not supposed to be driven under 40. Is there something documenting their lie temp performance Link to comment Share on other sites More sharing options...
betashave Posted September 3, 2014 Report Share Posted September 3, 2014 Got one last question the Michelin site says the tire is not designed to drive in near freezing conditions. The gy tires aren't supposed to be driven under ,40. So are they both not supposed to be driven under 40. Is there something documenting their lie temp performance I don't know the specifics, but I do know these particular tires are "summer tires." Michelin also offers "all-season" tires in the MPSS line, I believe in these same sizes. Being in Texas and also having a Tacoma 4x4 as my second vehicle, summer tires are what I prefer for my Shelby. Link to comment Share on other sites More sharing options...
Joraft Posted September 3, 2014 Report Share Posted September 3, 2014 ... I'm not sure calculating this based on theoretical 295 vs 285 sizes gives a real world result when you are comparing across brands, even within the same brand. It seems almost like how HDTV's have gone to a "class" of size, e.g., a 52" class tv may not truly measure 52" diagonally. A 295 Michelin tire is not necessarily the same size as a 295 GY, or another Michelin for that matter. As I said earlier, I got my specs directly from the respective manufacturers, and on the specific tires in question. Link to comment Share on other sites More sharing options...
Joraft Posted September 3, 2014 Report Share Posted September 3, 2014 That's why I'd be looking at the revolutions per mile specs instead of the diameter/circumference specs. Comparing the revs per mile for the two different tires should give a solid measure of impact on the speedo reading ... Goodyear says 766 revs per mile for the 285 F1. Michelin says 740 revs per mile for the 295 MPSS. Link to comment Share on other sites More sharing options...
Torched10 Posted September 3, 2014 Report Share Posted September 3, 2014 Ok. 766/740 is 3.5% which is what i calculated.so at 70 your really going 72.5 Link to comment Share on other sites More sharing options...
1TUF14SHELBY Posted September 3, 2014 Report Share Posted September 3, 2014 I have the Michelin 295's and GPS'd them last summer against my speedometer on the car and they almost are identical. Real world difference is not 2.5mph unless stock speedo is off to begin with. Link to comment Share on other sites More sharing options...
Joraft Posted September 3, 2014 Report Share Posted September 3, 2014 Ok. 766/740 is 3.5% which is what i calculated.so at 70 your really going 72.5 It would certainly seem so. Enter the tire specs at Tire Size Comparer, and you come up with a different answer. Either way, I'm thinking it's too little to worry about. Link to comment Share on other sites More sharing options...
Torched10 Posted September 4, 2014 Report Share Posted September 4, 2014 As we used to say its close enough for government work. Just trying. To exercise my retired mind.now that I have over 900 miles I'm pushing it more and slipping more. Need to get tires Link to comment Share on other sites More sharing options...
Joraft Posted September 4, 2014 Report Share Posted September 4, 2014 ... Need to get tires Me too, and I'm working on the exact same swap as you, only my 295s will be going on 11" wide wheels. I'm also working on a gear change, so a speedo adjustment will be a must for me. Link to comment Share on other sites More sharing options...
03reptile Posted September 4, 2014 Report Share Posted September 4, 2014 I don't know the specifics, but I do know these particular tires are "summer tires." Michelin also offers "all-season" tires in the MPSS line, I believe in these same sizes. Being in Texas and also having a Tacoma 4x4 as my second vehicle, summer tires are what I prefer for my Shelby. The Michelin PSS AS/3 is the all season tire for our cars. They are available in stock size for front and rear, but not a 295 for the rear. I'll be buying the all seasons as I drive the car in winter when roads are clear and dry. Link to comment Share on other sites More sharing options...
betashave Posted September 5, 2014 Report Share Posted September 5, 2014 The Michelin PSS AS/3 is the all season tire for our cars. They are available in stock size for front and rear, but not a 295 for the rear. I'll be buying the all seasons as I drive the car in winter when roads are clear and dry. Ah, my bad. I guess that somehow makes sense. FINALLY getting mine installed tomorrow! Link to comment Share on other sites More sharing options...
betashave Posted September 7, 2014 Report Share Posted September 7, 2014 It wasn't without some drama (one of the tires was "missing" so I had to make two trips to Discount Tire on Friday), but it's done! Link to comment Share on other sites More sharing options...
Torched10 Posted September 7, 2014 Report Share Posted September 7, 2014 Thats my color !!! what were the final sizes and price of you dont mind telling me.they look great esp the rears. Dont look big .can you tell the difference in traction Link to comment Share on other sites More sharing options...
betashave Posted September 7, 2014 Report Share Posted September 7, 2014 Thats my color !!! what were the final sizes and price of you dont mind telling me.they look great esp the rears. Dont look big .can you tell the difference in tractionThanks. The tires and prices were: Fronts: 275/40ZR19XL 105Y $290 each Rears: 295/35ZR20XL 105Y (FER) $393 each Total was $1,577.34 installed, with tax, out the door. I haven't had the chance to test out traction yet. Haven't even got it out on the freeway, just the drive home on neighborhood streets. But the ride did seem very nice! Link to comment Share on other sites More sharing options...
21chip Posted September 7, 2014 Report Share Posted September 7, 2014 I went with the Nitto 315/35/20 for my 14 GT500 and love them. Stock rims. Link to comment Share on other sites More sharing options...
svtmattUT Posted September 17, 2014 Report Share Posted September 17, 2014 If you actually want to put the power down. Toyo R888 is the only way to go. Have them on mine and they are awesome. they are much better than nitto 555R and last long not to mention they make the correct size. Almost no wheel spin and it's got exhaust, intake, and tune. Link to comment Share on other sites More sharing options...
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