Close tire sizes interchangeable?
November 15, 2015 1:23 PM Subscribe
Is there a way I can use 205/65 r15 tires on a car that's recommended to have 205/60/r16 tires? The r15 tires are not on rims but I would purchase if needed. I would like to avoid buying a new set of tires if I can, but if it'll damage the car or affect safety in any way then that becomes more important. Thanks in advance!
You are just reverse plus sizing. As long as the rims will clear your brake and suspension components this is usually fine. Most people who aren't pushing their car to the limits won't even be able to notice handling differences.
Brands vary in overall diameter even with the same nominal size so there is an outside chance the tires you have won't work but the tire shop should be able to tell you that if it happens to be the case.
posted by Mitheral at 1:36 PM on November 15, 2015
Brands vary in overall diameter even with the same nominal size so there is an outside chance the tires you have won't work but the tire shop should be able to tell you that if it happens to be the case.
posted by Mitheral at 1:36 PM on November 15, 2015
Is there a way I can use 205/65 r15 tires on a car that's recommended to have 205/60/r16 tires? The r15 tires are not on rims but I would purchase if needed.
This isn't a question that can be answered in the abstract. 15" wheels (rims) might work on your car or they might not, and without knowing the specific year/model/trim of your car, no one here can know this.
But assuming that the answer to that is yes, you will definitely need new wheels/rims. If the car currently has 205/60/r16 tires, that means the wheels are 16" in diameter, while 205/65 r15 tires will only fit on 15" wheels.
posted by Dip Flash at 1:42 PM on November 15, 2015 [1 favorite]
This isn't a question that can be answered in the abstract. 15" wheels (rims) might work on your car or they might not, and without knowing the specific year/model/trim of your car, no one here can know this.
But assuming that the answer to that is yes, you will definitely need new wheels/rims. If the car currently has 205/60/r16 tires, that means the wheels are 16" in diameter, while 205/65 r15 tires will only fit on 15" wheels.
posted by Dip Flash at 1:42 PM on November 15, 2015 [1 favorite]
If your car is supposed to run 205/60/16, the equivalent size is 195/70/15. 205/60/15 will be almost 1% smaller in total diameter and will throw off your speedo and probably affect handling too.
posted by Lame_username at 1:52 PM on November 15, 2015 [1 favorite]
posted by Lame_username at 1:52 PM on November 15, 2015 [1 favorite]
WillTheyFit is a good resource for this type of question, and in this case it looks like you'll be OK.
NB: I used a generic width and offset since you're asking specifically about tire size comparison, but you will have to match the offset (ET) of the stock fitment 16" wheels against the 15"s you will need to avoid affecting clearances and steering handling. However, you need to check the load rating of the existing tires to ensure they're safe for the new car.
posted by a halcyon day at 2:13 PM on November 15, 2015
NB: I used a generic width and offset since you're asking specifically about tire size comparison, but you will have to match the offset (ET) of the stock fitment 16" wheels against the 15"s you will need to avoid affecting clearances and steering handling. However, you need to check the load rating of the existing tires to ensure they're safe for the new car.
posted by a halcyon day at 2:13 PM on November 15, 2015
It really depends on the car. WillTheyFit is a good resource, but some cars cannot handle smaller wheels due to the size of their brakes. Even within a model it varies. My car, for example, has 17" wheels and can handle 16" wheels; the manual transmission version of my car came with exactly the same 17" wheels, but cannot handle anything smaller due to its larger performance-minded brakes.
TireRack is helpful, as are forums specific to your car (search for "winter wheels").
posted by Seeking Direction at 2:28 PM on November 15, 2015
TireRack is helpful, as are forums specific to your car (search for "winter wheels").
posted by Seeking Direction at 2:28 PM on November 15, 2015
The tires ought to work, because they are smaller than the OEM ones overall, but whether the wheels you'd need to purchase in order to use those tires will fit, is hard to answer.
You (or somebody else) needs to take a bare 15" wheel of the kind you plan on buying, and put it on the car and see if it will clear the brakes, etc. I would do it without bothering to mount the tires first, and I'd be sure to test both front and back.
Cheap steel wheels, of the type frequently used to mount snow tires or on spares, are generally around $45-55 / ea unless you can find used ones (which isn't terribly hard if you search around Craigslist in a major urban area; in a more rural area I'd just go to a pick-n-pull or junkyard and ask, but either way it does imply some legwork), so I would consider whether this plan is really going to save you money. You can always sell the tires on Craigslist yourself and put the money towards buying a new set of tires in the OEM size, which will go on your existing wheels.
posted by Kadin2048 at 5:35 PM on November 15, 2015
You (or somebody else) needs to take a bare 15" wheel of the kind you plan on buying, and put it on the car and see if it will clear the brakes, etc. I would do it without bothering to mount the tires first, and I'd be sure to test both front and back.
Cheap steel wheels, of the type frequently used to mount snow tires or on spares, are generally around $45-55 / ea unless you can find used ones (which isn't terribly hard if you search around Craigslist in a major urban area; in a more rural area I'd just go to a pick-n-pull or junkyard and ask, but either way it does imply some legwork), so I would consider whether this plan is really going to save you money. You can always sell the tires on Craigslist yourself and put the money towards buying a new set of tires in the OEM size, which will go on your existing wheels.
posted by Kadin2048 at 5:35 PM on November 15, 2015
Close tire sizes interchangeable
Um, no. These tyres are not interchangeable, no. For a start, they require different sized wheels, which brings up completely different questions:
1: Can a 15" wheel work on your car? There is no way to know, unless you tell us what car it is. Any answer above that suggests it is ok should be disregarded without explicitly checking with your manufacturer recommendations PLUS the clearance sizes of the particular wheel you end up buying for the car in question.
The tires ought to work, because they are smaller than the OEM ones overall,
This, in particular, is horrible and wildly wrong as an answer (and a justification). There is no way to answer the question with the information provided of whether these tyres will physically fit (with a suitable wheel) and there is more than enough information to make the tyres incompatible unless your car is able to allow for the sizeable difference because:
2: The other question in this is: "Are 205/65 r15 tires interchangeable (ignoring wheel size) with 205/60/r16 tires". No, they're not. The rolling radius (that makes your speedometer calibrated) is likely far enough apart that your car is unable to cope with such a difference. Unless your car has an ecu that is able to make the calibration difference, then these tyres are not only not interchangeable, but incompatible.
So. First things first- check with your manual and see if the speedometer calibration can be set to cope with a 205/65 R15. If not, nothing else matters.
Then, if that is solvable, get a tyre shop to try a 15" wheel of suitable width onto your car and see if it fits. You WILL need to buy a new set of wheels to use these tyres, either way, which just makes it much easier to buy the right tyres.
posted by Brockles at 7:57 PM on November 15, 2015 [1 favorite]
Um, no. These tyres are not interchangeable, no. For a start, they require different sized wheels, which brings up completely different questions:
1: Can a 15" wheel work on your car? There is no way to know, unless you tell us what car it is. Any answer above that suggests it is ok should be disregarded without explicitly checking with your manufacturer recommendations PLUS the clearance sizes of the particular wheel you end up buying for the car in question.
The tires ought to work, because they are smaller than the OEM ones overall,
This, in particular, is horrible and wildly wrong as an answer (and a justification). There is no way to answer the question with the information provided of whether these tyres will physically fit (with a suitable wheel) and there is more than enough information to make the tyres incompatible unless your car is able to allow for the sizeable difference because:
2: The other question in this is: "Are 205/65 r15 tires interchangeable (ignoring wheel size) with 205/60/r16 tires". No, they're not. The rolling radius (that makes your speedometer calibrated) is likely far enough apart that your car is unable to cope with such a difference. Unless your car has an ecu that is able to make the calibration difference, then these tyres are not only not interchangeable, but incompatible.
So. First things first- check with your manual and see if the speedometer calibration can be set to cope with a 205/65 R15. If not, nothing else matters.
Then, if that is solvable, get a tyre shop to try a 15" wheel of suitable width onto your car and see if it fits. You WILL need to buy a new set of wheels to use these tyres, either way, which just makes it much easier to buy the right tyres.
posted by Brockles at 7:57 PM on November 15, 2015 [1 favorite]
Is the load rating compatible? Respectfully; do you know what a load rating is? This stuff can be the difference between recovery from a skid, a sharp manuever to avoid an obstacle, a short stop to avoid an accident; and a sudden blowout due to an improper tire, which means no recovery, no avoidance, and a horrible skid into an accident.
Will the new wheels be able to use the same wheel mounting hardwear that your existing ones do? Will the wheel offset be the same?
Save yourself a potential disaster; good tires for your existing wheels is the best and safest option.
posted by buzzman at 8:23 PM on November 15, 2015 [1 favorite]
Will the new wheels be able to use the same wheel mounting hardwear that your existing ones do? Will the wheel offset be the same?
Save yourself a potential disaster; good tires for your existing wheels is the best and safest option.
posted by buzzman at 8:23 PM on November 15, 2015 [1 favorite]
Response by poster: Hi everyone, thanks for the answers. The car is a 2015 Mazda 3. I'll have to do some research about the load ratings and call Mazda but it sounds more like I should just get an exact set of tires.
posted by mossicle at 10:20 PM on November 15, 2015 [1 favorite]
posted by mossicle at 10:20 PM on November 15, 2015 [1 favorite]
The load ratings are really not the issue (they're unlikely to be seriously off for a small car like a Mazda3), the physical fit between the wheels and the brakes are. And I doubt that Mazda is going to tell you anything if you call them (a local dealer might, but is more likely in my experience to just try and sell you on some new tires). An independent shop that does tire work is more likely to be helpful and give you an unbiased answer, particularly if they don't sell many tires themselves.
But in general, if you are uncomfortable test-fitting wheels to your car to check for fit, I would probably not go forward with this plan; it's sort of a hacky solution.
posted by Kadin2048 at 7:40 PM on November 16, 2015
But in general, if you are uncomfortable test-fitting wheels to your car to check for fit, I would probably not go forward with this plan; it's sort of a hacky solution.
posted by Kadin2048 at 7:40 PM on November 16, 2015
The load ratings are really not the issue
Load or (more critically) speed ratings are very much an issue. Without knowing what they are, it is impossible to state that they are not relevant. Don't guess or dismiss valid concerns without having the information to ascertain that ratings/sizes are not relevant. Askmefi is for answers, not guessing, even if those answers are 'we can't tell you with what you have given us'.
it sounds more like I should just get an exact set of tires.
This is the correct answer, honestly. There are too many variables and what you (OP) think is 'close' may not at all be the case.
posted by Brockles at 9:03 PM on November 16, 2015
Load or (more critically) speed ratings are very much an issue. Without knowing what they are, it is impossible to state that they are not relevant. Don't guess or dismiss valid concerns without having the information to ascertain that ratings/sizes are not relevant. Askmefi is for answers, not guessing, even if those answers are 'we can't tell you with what you have given us'.
it sounds more like I should just get an exact set of tires.
This is the correct answer, honestly. There are too many variables and what you (OP) think is 'close' may not at all be the case.
posted by Brockles at 9:03 PM on November 16, 2015
Any question can be answered with a useless disclaimer to seek expert advice; as a general rule, I generally give both the asker and future readers the same benefit of the doubt that I'd hope to receive myself, with regard to their intelligence and ability to decide their own level of life / safety / sanity / warranty-voiding risk when taking advice from a bunch of pseudonymous strangers on the Internet. You certainly do not have to in your answers, Brockles, and I realize this is something of a longstanding dispute around here, but that's your choice; do spare me the chiding.
I stand by my earlier answer that the issue that will stop this plan right in its tracks is the physical fit of the 15" wheels on the car (because if the 15" wheel interferes with the brakes, brake lines, ABS sensor wiring, etc., it's Game Over), and moreover the general point, as a sort of rule of thumb, that if you're not comfortable figuring that part out, fudging around with non-OEM tire sizes is perhaps not for you. (Which probably means we're all in agreement in the specific case in point here.) But for someone who is -- which may not be the OP, and that's totally okay, incidentally -- the load and speed ratings, while worth considering, are, if we are talking in practical terms here and not acting like a bunch of Internet Lawyers writing the black-box warning for the inside of a car manual, far less likely to be an issue.
It would be nearly impossible to find 205/65R15 tires -- in the sense that they are not low-aspect tires, nor ancient bias-ply tires, nor trailer tires -- that had such a low load rating that a Mazda3, a car with a curb weight of ~3,000 lbs., would be over the load limit. If you could find some 74 L.I. tires you could do it, but I am skeptical those exist in that sizing in recent manufacture.
Similarly, you'd also be in hen's-teeth territory if you had a 205/65R15 that was less than "S" rated for speed, which at 112MPH max, is still faster than you can legally go anywhere in the US. (And yes, sure, there's a whole tedious argument that one can have over the effect of various speed ratings on handling and cornering, which someone might or might not care about depending on their driving style.)
This is not to say that load rating or speed rating are not an issue at all, but compared to the rather nonnegotiable issue of physical fit, both are -- after taking into consideration the realistic minimum values likely to be found on a modern passenger-car tire, and also that if you're running a different tire size than OEM, you are already stepping outside the manufacturer-approved mainstream -- the sort of things that reasonable people could disagree on the pros and cons of running on a small car, and therefore something of an exercise for the (sober, consenting, adult) reader.
posted by Kadin2048 at 8:53 PM on November 17, 2015 [1 favorite]
I stand by my earlier answer that the issue that will stop this plan right in its tracks is the physical fit of the 15" wheels on the car (because if the 15" wheel interferes with the brakes, brake lines, ABS sensor wiring, etc., it's Game Over), and moreover the general point, as a sort of rule of thumb, that if you're not comfortable figuring that part out, fudging around with non-OEM tire sizes is perhaps not for you. (Which probably means we're all in agreement in the specific case in point here.) But for someone who is -- which may not be the OP, and that's totally okay, incidentally -- the load and speed ratings, while worth considering, are, if we are talking in practical terms here and not acting like a bunch of Internet Lawyers writing the black-box warning for the inside of a car manual, far less likely to be an issue.
It would be nearly impossible to find 205/65R15 tires -- in the sense that they are not low-aspect tires, nor ancient bias-ply tires, nor trailer tires -- that had such a low load rating that a Mazda3, a car with a curb weight of ~3,000 lbs., would be over the load limit. If you could find some 74 L.I. tires you could do it, but I am skeptical those exist in that sizing in recent manufacture.
Similarly, you'd also be in hen's-teeth territory if you had a 205/65R15 that was less than "S" rated for speed, which at 112MPH max, is still faster than you can legally go anywhere in the US. (And yes, sure, there's a whole tedious argument that one can have over the effect of various speed ratings on handling and cornering, which someone might or might not care about depending on their driving style.)
This is not to say that load rating or speed rating are not an issue at all, but compared to the rather nonnegotiable issue of physical fit, both are -- after taking into consideration the realistic minimum values likely to be found on a modern passenger-car tire, and also that if you're running a different tire size than OEM, you are already stepping outside the manufacturer-approved mainstream -- the sort of things that reasonable people could disagree on the pros and cons of running on a small car, and therefore something of an exercise for the (sober, consenting, adult) reader.
posted by Kadin2048 at 8:53 PM on November 17, 2015 [1 favorite]
I stand by my earlier answer that the issue that will stop this plan right in its tracks is the physical fit of the 15" wheels on the car (because if the 15" wheel interferes with the brakes, brake lines, ABS sensor wiring, etc., it's Game Over)
And I completely agree with that. And have said so. Unfortunately for this position, 15" wheels are available on that car, so you can't dismiss all other parameters because the base assumption that they won't matter is removed. If the tyres WILL physically fit, then the other parameters are greater in importance.
But sweeping statements such as 'the tyres should work because the size is smaller' (even ignoring the wheel size) is entirely misleading (and factually wrong) unless the asker/reader understand the process in at least a token depth. There is no evidence to suggest that is the case (quite the opposite) in this question. Also, the next reader may know even less and (entirely not deliberately, I suspect) your words here could be read as 'only the size and whether they physically fit is important'. I don't think you genuinely meant that, but it's misleading and dangerous to leave it as a viable interpretation, in my opinion.
Additionally - 'load ratings are not the issue' is equally misleading unless someone already knows how to consider load ratings or even what they are for. If you and I were discussing it, I'd be happy using the same kind of blanket dismissive tone of important parameters that you are using, but in a forum where you cannot know what the reader understands, then I think it is irresponsible to give them a 'minor' and dismissive focus when they are at least as important as the tyre size itself. Something the OP clearly didn't understand (or equally and perhaps more charitably - didn't clearly state they DID understand) or they'd have quoted speed and load ratings of the two tyres in the beginning when asking about equivalency.
the load and speed ratings, while worth considering, are, if we are talking in practical terms here and not acting like a bunch of Internet Lawyers writing the black-box warning for the inside of a car manual, far less likely to be an issue.
I don't accept this hand-wavy stuff. People need to have all the information and it is not 'Lawyer ass covering' as you are implying to make sure that people know ALL the critical parameters for making an equivalency decision. Load and speed ratings are safety critical, even if a different parameter already precludes them needing to be considered in this particular example when the comparison is complete. Primarily because it hasn't been established yet that physical constraints are preventing the 15" tyres and wheels from being fitted. 2015 Mazda 3's are capable of being fitted with 15" wheels, which a few seconds of research will get you, in which case physical tyre (external) size, load rating and speed rating are far, far more important than wheel size because the 15" issue is potentially moot.
t would be nearly impossible to find 205/65R15 tires ....that had such a low load rating that a Mazda3, a car with a curb weight of ~3,000 lbs
You may know that and I may know that, but it is a big, big assumption. The risks from finding some weird chinese knock off tyres with a low speed rating for cheap is real, however small, and to dismiss something so important because you're 'pretty sure you won't find any that are a problem' is not a good answer. These are tyres. They can kill people if they are wrong. It is far better to be safe (with the spec) than sorry.
Also, it doesn't matter that they are 15" tyres, to some extent, because they are the wrong outer diameter anyway. THAT precludes them entirely being fitted, to me, but you can't make that judgement call. Without enough information, some readers may think it is 'close enough' for their own application and ignore other issues because someone dismissed them as unimportant compared to just size from a position of seemingly being knowledgable.
posted by Brockles at 8:24 AM on November 19, 2015
And I completely agree with that. And have said so. Unfortunately for this position, 15" wheels are available on that car, so you can't dismiss all other parameters because the base assumption that they won't matter is removed. If the tyres WILL physically fit, then the other parameters are greater in importance.
But sweeping statements such as 'the tyres should work because the size is smaller' (even ignoring the wheel size) is entirely misleading (and factually wrong) unless the asker/reader understand the process in at least a token depth. There is no evidence to suggest that is the case (quite the opposite) in this question. Also, the next reader may know even less and (entirely not deliberately, I suspect) your words here could be read as 'only the size and whether they physically fit is important'. I don't think you genuinely meant that, but it's misleading and dangerous to leave it as a viable interpretation, in my opinion.
Additionally - 'load ratings are not the issue' is equally misleading unless someone already knows how to consider load ratings or even what they are for. If you and I were discussing it, I'd be happy using the same kind of blanket dismissive tone of important parameters that you are using, but in a forum where you cannot know what the reader understands, then I think it is irresponsible to give them a 'minor' and dismissive focus when they are at least as important as the tyre size itself. Something the OP clearly didn't understand (or equally and perhaps more charitably - didn't clearly state they DID understand) or they'd have quoted speed and load ratings of the two tyres in the beginning when asking about equivalency.
the load and speed ratings, while worth considering, are, if we are talking in practical terms here and not acting like a bunch of Internet Lawyers writing the black-box warning for the inside of a car manual, far less likely to be an issue.
I don't accept this hand-wavy stuff. People need to have all the information and it is not 'Lawyer ass covering' as you are implying to make sure that people know ALL the critical parameters for making an equivalency decision. Load and speed ratings are safety critical, even if a different parameter already precludes them needing to be considered in this particular example when the comparison is complete. Primarily because it hasn't been established yet that physical constraints are preventing the 15" tyres and wheels from being fitted. 2015 Mazda 3's are capable of being fitted with 15" wheels, which a few seconds of research will get you, in which case physical tyre (external) size, load rating and speed rating are far, far more important than wheel size because the 15" issue is potentially moot.
t would be nearly impossible to find 205/65R15 tires ....that had such a low load rating that a Mazda3, a car with a curb weight of ~3,000 lbs
You may know that and I may know that, but it is a big, big assumption. The risks from finding some weird chinese knock off tyres with a low speed rating for cheap is real, however small, and to dismiss something so important because you're 'pretty sure you won't find any that are a problem' is not a good answer. These are tyres. They can kill people if they are wrong. It is far better to be safe (with the spec) than sorry.
Also, it doesn't matter that they are 15" tyres, to some extent, because they are the wrong outer diameter anyway. THAT precludes them entirely being fitted, to me, but you can't make that judgement call. Without enough information, some readers may think it is 'close enough' for their own application and ignore other issues because someone dismissed them as unimportant compared to just size from a position of seemingly being knowledgable.
posted by Brockles at 8:24 AM on November 19, 2015
This thread is closed to new comments.
posted by GhostintheMachine at 1:31 PM on November 15, 2015 [1 favorite]