Things to look at when purchasing a tire:
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12-04-2005, 06:16 AM
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Things to look at when purchasing a tire:
Some of you might recognize the info from another area/forum, but since I wrote 90% of it to begin with, I'll just copy and paste to my heart's content:
Tires
1. How far off is a given width/aspect ratio combination going to change the tire circumference from the factory circumference, and how much are you comfortable with? 2%, 5%, 10%, etc. Heck, you could change the effective gear ratio of a Neon with a 3.55 tranny to that of a 3.94 tranny if you really really wanted, but your speedo would be pretty far off... There's a decent variety of 14" tires available, but you broaden that field if you go a little farther outside the norm.
2. Load index-to-sidewall height ratio. By no means is this the be-all-end-all of sidewall stiffness. But generally, the larger the ratio, the stiffer the sidewall. If you plan on doing lots of twistie turnies, a stiffer sidewall is good. If you're more a straight-line person, a softer sidewall is better. Don't just look at aspect ratios - the sidewall on a 185/60 tire is half an inch shorter than the one on a 205/60. Load index is usually lumped with speed rating, like "84W" or "81ZR". The letter is the speed rating - H, V, W or ZR will be more than sufficient, S or lower will not. The load index corresponds to a weight, which you can look up at your leisure on the web.
3. Traction and temperature ratings (UTQG, not customer opinion). Still not as standardized as it should be though. A traction rating of "A" is good. "AA" is better, but you'll have a hard time finding that in a 14" performance tire. A temperature rating of "B" is not something you want to drive on aggressively - it will break down fast...
4. Treadwear ratings. Again, UTQG and not remarkably standardized. The lower the number, the stickier the tire and the shorter the life. Falken Azenis have a treadwear rating of 160 - wicked sticky, buy a new set every year or so. Anything above 400 will last longer, but will heat up fast and get slippery if you are putting them to good use.
5. Tread design. Circumferential grooves do a great job of displacing water. Tires with this design tend to get an "AA" traction rating. Tires without them have a harder time in the rain generally. Keep in mind that this rating is for straight-line braking traction only. Block tread, like what you see on most snow tires, handles better in snow and icy patches. Uneven tread designs tend to be quieter. A more squared shoulder tends to "dig in" on less than favorable roads, and tends to be on tires with a "M+S" designation (Mud and Snow), typically "all-season" tires. A more rounded shoulder makes for more responsive turning, more often on "performance" tires. Smaller blocks/shapes of tread and/or larger space between those blocks/shapes means more tread squirm and more rolling resistance. Just things to look at.
6. Remember, a wider tire does not mean a larger footprint. OK, with a very stiff sidewall, maybe a percent or so. The footprint is wider, but it is also shorter front-to-back as long as the tire pressure is the same (which it should be). Wider tires tend to force you into a lower profile, so they tend to feel better in the turns - it's from the shorter sidewall though, not a bigger footprint. You'll get better performance from a tire designed for your rim width than with a tire that happens to fit (allowable range).
With the huge variety of tires out there, all the media, all the stickers, all your friends' opinions, all the customer opinions, etc., it's hard to make a good decision. You can do your own research and find a tire you are most comfortable with (and many have a 30-day return policy), or you can be like most people, give up on making your own decision, and go with what your friends/heroes/biggest magazine ad says.
Tire Diameter
The first and most obvious thing to consider is the tire diameter. You want to stay fairly close to stock, or you will encounter speedometer and odometer errors. In addition, your wheels/tires act as your final drive ratio. Change the diameter significantly and you change your effective final drive ratio. There is a good tire size calculator on the main page of Neons.org to help you here: Neons.org Tire Size Calculator. Select your desired tire size and see how much speedometer error it generates. Usually anything within about 2 mph will be fine.
But to save time for the lazy folks, some of the closest common replacement tire sizes for Neons are:
195/60-14
205/60-14
195/55-15
205/50-15
215/50-15
205/45-16
215/45-16
205/40-17
215/35-18
Note that some of these are fairly unusual sizes, though, and may have a very small selection of tire brands available. For a good tutorial on what those numbers in a tire size mean, refer to this link: Tire Rack Calculating Tire Dimensions
A common misconception among many enthusiasts is that larger diameter wheels are more likely to rub on a lowered Neon that the stock size. This isn't true, assuming that the correct wheel width and offset are used. A 205/40-17 tire on a 17x7 wheel is almost exactly the same diameter as a stock 185/65-14 tire on the 14x5.5 steel wheel.
Wheel Size
Wheel size is generally specified by diameter and width. For instance, if you see a 17x7 wheel advertised, it is 17 inches in diameter and 7 inches wide. Diameter and width are both measured at the bead mounting surface, rather than the outside edges of the rim. Most typical Neon owners will be looking for wheels between 14 and 18 inches in diameter and between 6 and 7.5 inches wide. Anything beyond these limits is getting pretty extreme and may run into clearance problems.
Bolt Pattern
This one is fairly obvious, but also frequently overlooked. The bolt pattern on the wheel must match the bolt pattern on your Neon, or there's no way your nice new wheels are going to go on the car. Most 1st generation Neons and all 2nd generation Neons have a 5x100 bolt pattern. This simply means that they have 5 lugs arranged in a 100mm diameter circle. Some 1995 Neons have a 4x100 bolt pattern instead. The vast majority of aftermarket wheels with 5 hole patterns will either be 5x100 or 5x114.3. A number of wheels actually have a dual bolt pattern to fit both 5x100 and 5x114.4 applications.
Offset
The final factor to consider is wheel offset. Offset is the difference between the center line of the wheel and the mounting surface. For a more detailed description of offset, refer to this link: Tire Rack Wheel Tech Offset
The main reason to be concerned about offset is because it is one of the major factors that determines backspacing. Backspacing is the amount that the tire extends inboard from the mounting surface on the hub. 1st generation Neons generally can only tolerate 6 inches of backspacing before you start to run into clearance issues with the rear torsion struts. 2nd generation Neons can tolerate a little more backspacing, but if you try to keep it under 6 inches, you'll always be safe. Also, going with a smaller offset number is usually better than a bigger one. Neons have 40mm offset on all of the stock wheels. Going with anything higher than 40mm means that you are making the track of the car narrower by moving the tires further inboard. Smaller offset numbers make the track wider by moving the tires outboard. As a general rule for any reasonable size wheels for a Neon, you want to keep the offset in the 35mm to 42mm range.
Putting it all together
So the big question remains, how do we calculate backspacing for a particular wheel/tire combo. Lets run the numbers with a couple of typical wheel/tire upgrades for Neons.
Case 1: 15x7 inch Kosei K1 Racing wheels with 205/50-15 Bridgestone Potenza S-03 tires
The first thing we need to do is determine the exact dimensions of the tires. Tire Rack has an excellent Specs section for each tire they carry that gives all of the dimensional information we're looking for. The tables show that our tire has an overall "section" width of 8.4 inches when mounted on a 6.5 inch wide wheel. However, we plan to mount it on a 7 inch wide wheel. The rule of thumb is that every half inch difference in wheel width changes the tire width by 0.2 inches. So in this case, our tire will be 8.6 inches wide. Now all we need is the wheel offset to calculate the backspacing. Offsets aren't always shown on the web sites, but you can always call a wheel vendor to get that information. In this case, our wheel has a 38mm offset.
To calculate the backspacing, we divide the tire section width by 2 (since the tire will always be centered on the wheel) and add the offset. Of course, the wheel width is in inches and the offset is in mm, so we need to do a little converting:
Backspace = (8.6 / 2) + (38 / 25.4) = 5.8 inches
Our calculation show that this wheel/tire combo will work fine, but is getting pretty close. We wouldn't want to go any wider on the tires or any more offset on the wheels, or we would probably rub in back.
Case 2: 17x7.5 inch Rota Subzero wheels with 205/40-17 Kumho Ecsta 712 tires
These wheels are actually designed for a Subaru and have a fairly high offset (45mm), but would look really good on a Neon as well. But before we spend $900 or so on wheels and tires, let's make sure they'll work on our car.
From Tire Rack again, the section width of the tires is 8.6 inches on a 7.5 inch wide wheel. That's the size we plan to run, so we don't need to adjust anything. Therefor,
Backspace = (8.6 / 2) + (45 / 25.4) = 6.07 inches
Oops -- that's more than the 6 inches of backspace we want to run, so chances are pretty good that we are going to have rubbing issues in the back.
However, all is not lost. We just need a way to get a little more clearance in back. If we really have our heart set on these wheels (because they're cheap and very light), there are two possible solutions to the offset problem. The first is to run spacers in back. Since we're only a tiny bit over the 6 inch backspacing limit, we could probably run a 1/4 inch spacer and be fine. 1/4 inch = 6.4mm, so that changes our effective offset to 38.6mm, which we know is fine. Anything thicker than that, and we will need longer wheel studs, though. The other solution is to get a set of modified rear torsion struts. The 2nd generation torsion struts actually have an S-bend in them to give the wheels a little more clearance in back. How much? Dunno, lend me your car for a couple of days...
Tires
1. How far off is a given width/aspect ratio combination going to change the tire circumference from the factory circumference, and how much are you comfortable with? 2%, 5%, 10%, etc. Heck, you could change the effective gear ratio of a Neon with a 3.55 tranny to that of a 3.94 tranny if you really really wanted, but your speedo would be pretty far off... There's a decent variety of 14" tires available, but you broaden that field if you go a little farther outside the norm.
2. Load index-to-sidewall height ratio. By no means is this the be-all-end-all of sidewall stiffness. But generally, the larger the ratio, the stiffer the sidewall. If you plan on doing lots of twistie turnies, a stiffer sidewall is good. If you're more a straight-line person, a softer sidewall is better. Don't just look at aspect ratios - the sidewall on a 185/60 tire is half an inch shorter than the one on a 205/60. Load index is usually lumped with speed rating, like "84W" or "81ZR". The letter is the speed rating - H, V, W or ZR will be more than sufficient, S or lower will not. The load index corresponds to a weight, which you can look up at your leisure on the web.
3. Traction and temperature ratings (UTQG, not customer opinion). Still not as standardized as it should be though. A traction rating of "A" is good. "AA" is better, but you'll have a hard time finding that in a 14" performance tire. A temperature rating of "B" is not something you want to drive on aggressively - it will break down fast...
4. Treadwear ratings. Again, UTQG and not remarkably standardized. The lower the number, the stickier the tire and the shorter the life. Falken Azenis have a treadwear rating of 160 - wicked sticky, buy a new set every year or so. Anything above 400 will last longer, but will heat up fast and get slippery if you are putting them to good use.
5. Tread design. Circumferential grooves do a great job of displacing water. Tires with this design tend to get an "AA" traction rating. Tires without them have a harder time in the rain generally. Keep in mind that this rating is for straight-line braking traction only. Block tread, like what you see on most snow tires, handles better in snow and icy patches. Uneven tread designs tend to be quieter. A more squared shoulder tends to "dig in" on less than favorable roads, and tends to be on tires with a "M+S" designation (Mud and Snow), typically "all-season" tires. A more rounded shoulder makes for more responsive turning, more often on "performance" tires. Smaller blocks/shapes of tread and/or larger space between those blocks/shapes means more tread squirm and more rolling resistance. Just things to look at.
6. Remember, a wider tire does not mean a larger footprint. OK, with a very stiff sidewall, maybe a percent or so. The footprint is wider, but it is also shorter front-to-back as long as the tire pressure is the same (which it should be). Wider tires tend to force you into a lower profile, so they tend to feel better in the turns - it's from the shorter sidewall though, not a bigger footprint. You'll get better performance from a tire designed for your rim width than with a tire that happens to fit (allowable range).
With the huge variety of tires out there, all the media, all the stickers, all your friends' opinions, all the customer opinions, etc., it's hard to make a good decision. You can do your own research and find a tire you are most comfortable with (and many have a 30-day return policy), or you can be like most people, give up on making your own decision, and go with what your friends/heroes/biggest magazine ad says.
Tire Diameter
The first and most obvious thing to consider is the tire diameter. You want to stay fairly close to stock, or you will encounter speedometer and odometer errors. In addition, your wheels/tires act as your final drive ratio. Change the diameter significantly and you change your effective final drive ratio. There is a good tire size calculator on the main page of Neons.org to help you here: Neons.org Tire Size Calculator. Select your desired tire size and see how much speedometer error it generates. Usually anything within about 2 mph will be fine.
But to save time for the lazy folks, some of the closest common replacement tire sizes for Neons are:
195/60-14
205/60-14
195/55-15
205/50-15
215/50-15
205/45-16
215/45-16
205/40-17
215/35-18
Note that some of these are fairly unusual sizes, though, and may have a very small selection of tire brands available. For a good tutorial on what those numbers in a tire size mean, refer to this link: Tire Rack Calculating Tire Dimensions
A common misconception among many enthusiasts is that larger diameter wheels are more likely to rub on a lowered Neon that the stock size. This isn't true, assuming that the correct wheel width and offset are used. A 205/40-17 tire on a 17x7 wheel is almost exactly the same diameter as a stock 185/65-14 tire on the 14x5.5 steel wheel.
Wheel Size
Wheel size is generally specified by diameter and width. For instance, if you see a 17x7 wheel advertised, it is 17 inches in diameter and 7 inches wide. Diameter and width are both measured at the bead mounting surface, rather than the outside edges of the rim. Most typical Neon owners will be looking for wheels between 14 and 18 inches in diameter and between 6 and 7.5 inches wide. Anything beyond these limits is getting pretty extreme and may run into clearance problems.
Bolt Pattern
This one is fairly obvious, but also frequently overlooked. The bolt pattern on the wheel must match the bolt pattern on your Neon, or there's no way your nice new wheels are going to go on the car. Most 1st generation Neons and all 2nd generation Neons have a 5x100 bolt pattern. This simply means that they have 5 lugs arranged in a 100mm diameter circle. Some 1995 Neons have a 4x100 bolt pattern instead. The vast majority of aftermarket wheels with 5 hole patterns will either be 5x100 or 5x114.3. A number of wheels actually have a dual bolt pattern to fit both 5x100 and 5x114.4 applications.
Offset
The final factor to consider is wheel offset. Offset is the difference between the center line of the wheel and the mounting surface. For a more detailed description of offset, refer to this link: Tire Rack Wheel Tech Offset
The main reason to be concerned about offset is because it is one of the major factors that determines backspacing. Backspacing is the amount that the tire extends inboard from the mounting surface on the hub. 1st generation Neons generally can only tolerate 6 inches of backspacing before you start to run into clearance issues with the rear torsion struts. 2nd generation Neons can tolerate a little more backspacing, but if you try to keep it under 6 inches, you'll always be safe. Also, going with a smaller offset number is usually better than a bigger one. Neons have 40mm offset on all of the stock wheels. Going with anything higher than 40mm means that you are making the track of the car narrower by moving the tires further inboard. Smaller offset numbers make the track wider by moving the tires outboard. As a general rule for any reasonable size wheels for a Neon, you want to keep the offset in the 35mm to 42mm range.
Putting it all together
So the big question remains, how do we calculate backspacing for a particular wheel/tire combo. Lets run the numbers with a couple of typical wheel/tire upgrades for Neons.
Case 1: 15x7 inch Kosei K1 Racing wheels with 205/50-15 Bridgestone Potenza S-03 tires
The first thing we need to do is determine the exact dimensions of the tires. Tire Rack has an excellent Specs section for each tire they carry that gives all of the dimensional information we're looking for. The tables show that our tire has an overall "section" width of 8.4 inches when mounted on a 6.5 inch wide wheel. However, we plan to mount it on a 7 inch wide wheel. The rule of thumb is that every half inch difference in wheel width changes the tire width by 0.2 inches. So in this case, our tire will be 8.6 inches wide. Now all we need is the wheel offset to calculate the backspacing. Offsets aren't always shown on the web sites, but you can always call a wheel vendor to get that information. In this case, our wheel has a 38mm offset.
To calculate the backspacing, we divide the tire section width by 2 (since the tire will always be centered on the wheel) and add the offset. Of course, the wheel width is in inches and the offset is in mm, so we need to do a little converting:
Backspace = (8.6 / 2) + (38 / 25.4) = 5.8 inches
Our calculation show that this wheel/tire combo will work fine, but is getting pretty close. We wouldn't want to go any wider on the tires or any more offset on the wheels, or we would probably rub in back.
Case 2: 17x7.5 inch Rota Subzero wheels with 205/40-17 Kumho Ecsta 712 tires
These wheels are actually designed for a Subaru and have a fairly high offset (45mm), but would look really good on a Neon as well. But before we spend $900 or so on wheels and tires, let's make sure they'll work on our car.
From Tire Rack again, the section width of the tires is 8.6 inches on a 7.5 inch wide wheel. That's the size we plan to run, so we don't need to adjust anything. Therefor,
Backspace = (8.6 / 2) + (45 / 25.4) = 6.07 inches
Oops -- that's more than the 6 inches of backspace we want to run, so chances are pretty good that we are going to have rubbing issues in the back.
However, all is not lost. We just need a way to get a little more clearance in back. If we really have our heart set on these wheels (because they're cheap and very light), there are two possible solutions to the offset problem. The first is to run spacers in back. Since we're only a tiny bit over the 6 inch backspacing limit, we could probably run a 1/4 inch spacer and be fine. 1/4 inch = 6.4mm, so that changes our effective offset to 38.6mm, which we know is fine. Anything thicker than that, and we will need longer wheel studs, though. The other solution is to get a set of modified rear torsion struts. The 2nd generation torsion struts actually have an S-bend in them to give the wheels a little more clearance in back. How much? Dunno, lend me your car for a couple of days...
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RE: Things to look at when purchasing a tire:
ORIGINAL: RadarLove
215/35-18
215/35-18
