Tire Resizing - in the OTHER direction

[BattleRifleG3]

Hello folks, this is my first post here and from what I read, a break from the usual.

I never thought myself fond of "sporty" cars until I got my Elantra GT 5dr 5spdMT. Formerly a die-hard SUV fan, other areas of practicality prevailed with my current vehicle. I've been happier every day I have it, from packing it full of more than I ever thought it could hold to achieving 40+ mpg consistently on the highway with the cruise locked in at 60mph. It's even done pretty dang well off the paved roads, going about 75% of the places my old Bronco II used to go, and on one or two occasions doing a wee bit better.

From my reading, lots of you folks here like to lower your Elantras for better cornering, lower drag, and other reasons. I have the great fortune of living in western Pennsylvania, and the smoothness of our roads can be... well... lacking. In fact, that's quite an understatement.

So the long and short of it is that I'm looking to raise the wheel diameter for two reasons. 1, to boost ground clearance. 2, to take bumps easier. Kinematics/geometry tells that a larger wheel takes any size of bump more gradually than a smaller one. I'm looking to add as much as possible without changing the mechanics and messing with the best warranty out there.

From some measurements I made, it looks like 205/70-R15 will fit without interfering with the shocks. They would add about an inch to the radius. Biggest I read on the sticky thread was 205/60-R-15, but it didn't seem to indicate that it was borderline on rubbing.

Again, I'm not looking for wider tires, but a larger diameter, and actually thinner width would be better to avoid hydroplaning which happens a lot on my local roads. People at tire stores never manage to comprehend my asking this question, so hopefully I'll find good answers here. I'm still recovering from the day a lady at Firestone seemed incapable of understanding that I wanted LARGER DIAMETER tires for my SUV, she kept repeating the nickle/dime rule like a mantra. Whew... sorry... rant off.

Hope to learn a lot here and contribute what I can. Thanks in advance!

[BlackElantraGT]

I don't think many of us here could help you out since most of us went the opposite route, so I think in the end it might be trial and error for you.

Here's my take on it though. I think that since you're coming from the SUV world, you might be forgetting what the Elantra was designed for, which is basic, normal, everyday driving. If you're taking it places where you used to take your Bronco, this car was never designed to handle that.

What you also have to keep in mind is that with truck/suv suspension, it's designed for a lot of wheel travel, and if your OEM suspension wasn't enough, there are plenty of aftermarket companies that offered off-road suspension parts. If you want to know how to handle bumps, those are the guys to go to. But you won't have any of those products for the Elantra because it's not an off-road vehicle. Also, with many SUV's and trucks, if you changed the size of your wheel diameter, you could easily reprogram it with your new wheel diameter. You won't be able to do that on the Elantra.

I think that if the roads in your area are THAT bad just stick with your stock GT 15" alloys and wheels. They should be more than enough to handle most bumps. Otherwise, I think you'll most likely have major rubbing issues.

[Estopatitiana]

i think you will be alright if you dont get the tires too wide

i have oversized nonlowered tires, 225/45/r17 and they almost never rub

[BlackElantraGT]

He's trying to oversize his wheels in a different way than yours. At 225/45/17, you're 3.1% oversized, which means that when your speed reads 60 mph, you're really going 61.9 mph.

If he were to go 205/70/15, he would be 8.6% oversized, which means that when his speedo reads 60 mph, he's really going 65.2 mph.

That's a HUGE difference.

http://www.miata.net/garage/tirecalc.html

[Hitman]

I ran a 205/65/R15 on the rear for a long while with no rubbing. Maybe a smaller diameter wheel with the same 205 diameter tire would give you that cushion your looking for.

[tharptroy]

The biggest rubbing issues will come from width. my 215/55/16 tires rubbed the fender in the rear. (8.9" section width)

I say give it a shot

[Vampyrate]

sorry for going a bit O/T, but what would the best size be for a more low profile look on the 15" alloys? i know the stock size is 195/60/15 or something like that

[BlackElantraGT]

If you stay with 15's, there's no such thing as a "more low profile" look if you want to keep your overall diameter similiar to stock.

I think what you're trying to ask is what are the biggest tires you can fit to get the most tire contact patch from 15's, while still keep a similar overall diameter.

theoretically, 215/55/15 would be the closest to stock diameter, but there's no such thing as that tire size.

your next best size would probably be 205/60/15, which would give you 2% increase in diameter. 225/55/15 is 2.2% larger than stock diameter, but you might have some rubbing issues not to mention a VERY small selection of tires to choose from.

If you want that smaller sidewall look and are willing to have a smaller diameter than stock, then you can go with 205/55/15 which is -1.4% or you can try 225/50/15, which is -1.5%, but depending on your offset you might rub against the lip of your wheel well.

[Vampyrate]

not really, i want the tire to look closer to the rim... less sidewall sort of look for a "low profile" look

as far as i know, 195 is teh smallest that i can find

[BlackElantraGT]

So basically you want your car to look like those lowriders bouncing on wheels way too small.

It's pretty simple thinking. Think of your tire as a circle. If the size of your rims do not change, then there's no way for you to have a low profile look unless you changed the diameter of that circle. The smaller you make that circle, the more your car will look like those lowriders, except now your car will look super GAY because

1) It's a Hyundai Elantra, not a '64 Impala
2) You don't have a hydraulic or air suspension to lower and raise your car closer to the ground.

[Vampyrate]

i am going for springs soon to drop the car and want to avoid air ride while i go to school in the mtns. but thanks for the info... i had an idea that it would look stupid on anything less than a 16" rim.

[BattleRifleG3]

I considered going smaller wheel diameter with bigger tires. I may yet, but I'm seeing what I can do with stock rims. I had considered getting an extra set of rims as cheap as I can, basically to have different tools for different uses.

I certainly wouldn't be expecting an Elantra to be an off-road machine, its abilities on the unpaved are icing on the cake. Tell you what though, if they made an Elantra with AWD and a little more clearance, basically the Subaru Outback treatment, I'd be in heaven. The Tuscon/Sportage that are supposedly based on the Elantra are just too big to compare, and with the fuel economy of the Sportage I looked at, might as well get a truck based SUV.

But back to the topic, I really appreciate all your experiences with what tire sizes do and don't rub. I had earlier thrown together an Excel spreadsheet and compared those sizes to others, and of course realize that not all makes of tire have exactly the same dimensions for a given size, so that would go into the margin for error.

I have a couple 205/70-R15 tires and am debating on whether it's worth trying them out since I already have them. On the other hand, if 205/65-R15 is known to be an ok call, it might be a good one for now. I need new tires anyway, never thought I would at 20k miles, but I figure if I go through a few generations of tires I'll have time to go up a size at a time and see how much room each ones give. My front tires are near bald and I don't peel out except accidentally on occasion. Having near zero traction on wet pavement made me take a closer look.

Don't think I'll need anything over 205mm width, whatever the case. 205/75-R15 is a common size that I'm sure is too big. I'll let you guys know what I do and how it turns out. I can't stress enough how bad the roads are around here. And then there are driveways...

[robs02elantra]

I have 195/65-R15 tires on my car. They were on sale and I was poor when I got them. I drive some unpaved roads, and I can't imagine that you would want to go any larger than what I have on my car. It's just fine for me, very comfortable for some of the places I drive.

Look into it if you're going for new tires. I know it doesn't seem as drastic a change from stock, but it feels a world of difference to me.

[Vampyrate]

rob im with you on that buddy ^

i got a set of walmart Douglas GT-H 195/65r-15 and only cost me 200 for everything (mount balance and all) and i rode them hard for the amount of miles they were on the car, and still looked and performed like brand new tires on my sedan.

i got them in august of 05 (when i first got down to school, just barely had tread left enough to make it to walmart) and they lasted until my accident and appeared to still have at least 90% tread left (i had 78k on the odo when i got to school and the car totalled at 99k on the odo, almost 100k)

[Kenshin]

OT - Vamp, I'm getting a set of 205-55-15's mounted here in a couple of days (or weeks, depending on when my fed. tax return finally shows up...) I'm getting a decent deal on a set of Goodyear Eagle GT-HR's in that size, and it won't throw off the speedo drastically, and at least it'll throw it off in the safe direction, so I figured I'd go for it. I'll let you know what I think of them once I get them on. They should look nice and handle a bit better than stock, too. :cool:

[Daan]

BattleRifle- I may be reading your post wrong, but if you were just looking to get tires with taller sidewalls, you can get 14" wheels and go up a size (185/70-14 vs. 185/60-15) I'm assuming you have an XD Elantra with 15" wheels. If you have an older-style Elantra, I have the J2-style Elantra (2000). I replaced the 14" stockers with 15" off an XD, so they're an inch taller than what was on already. I get no rubbing or other driveability issues.

[quickfingerz]

I'd be worried about when the car is fully turned and you were to go over a bump that it might hit the front fender. That would be what I'd worry about most. How much clearance do you have when fully turned? (you'll measure this from any point on the fender straight down to the tire) You're actual clearance should be whatever you measured minus 3.5 inches.

[BattleRifleG3]

I have measured clearances when fully turned but that 3.5" margin for wheel travel on bumps is exactly what I needed to know. Thanks a bunch!

And basically to clarify it is the total wheel diameter that I'm looking to increase. Smaller rims with taller sidewalls is an option with its own set of tradeoffs, but either way my goal is to have the largest diameter wheels feasible without rubbing.

[BattleRifleG3]

Alrighty, time for an update - I went to Sears and got 4 new tires in 205/65-R15. Thanks very much to everyone here for the advice. Currently I'm really glad I picked that size. Here are a few details about my experience.

1. So far everything's fine on clearance issues. One of the first things I did was cut as hard as I could in an empty lot. No troubles at all. Cutting hard at higher speeds over large bumps - that will come later. The wheels do seem to fill the wheel wells more. But I've always thought Hyundai wheels were undersized anyway. So now it just looks a wee bit more like, say, a Chevy Cavalier.

2. Handling - I've never gotten a clear answer on what exactly handling is and what makes good and bad handling, but basically it does handle different. I feel the body banking more when I go around a curve. Being used to SUVs, this is nothing unfamiliar. A Nissan Xterra does this rather artfully, the Hyundai Elantra does it modestly but gracefully. The ride does feel slightly higher, which it is, which basically causes me to turn more carefully by reflex. While it does feel a little wierd cornering, the tires I chose - Falkens - certainly deliver lateral traction. So I think the new tires gave me a net gain due to their design that offset what I lost by going to the bigger size.

3. Power and speed - The difference in radius and therefore everything else relating to speed and acceleration is higher by 5.28%. That means that in a given gear I have that much less acceleration, that the speedometer reads that much lower, and that I have to apply the brakes that much harder. Brake life will likely be proportionally shorter - but if you want a real bad example of that, check out the Hummer H2. Now a key point on lower acceleration - note that I said "in a given gear". All that this ultimately does is change the gear ratios by - you guessed it - 5.28%. So I basically adjust my shifting that much later. I find when shifting by feel and evaluating speed by sight that it gives me the most power at different speeds from before - higher speeds in a given gear. So instead of going into 4th gear at 38mph, I'd go closer to 40mph on a given grade. The only real differences in acceleration are starting off and in the highest gear. 4th gear is suddenly a lot more comfortable on the 4 lane highway with traffic lights. I'll be able to see how it does in the higher speeds on the way to work tommorrow and how it does on moderate cruising tommorrow evening.

The increased ride height will hurt the fuel economy a little, but with an increase of only about 1%, I don't think it'll be all that much (though for hard to explain reasons I do think it'll be more than 1%). Also, of course, the mpg meter will read lower than it really is because it thinks I'm going 5.28% shorter of a distance than I really am. So I'm going to guess that I'll be reading 10% fewer mpg, only half of which will be accurate.

Time will tell. But all in all I'd say it's a success for what I had in mind. I realize that it's not for everyone, but if anyone was wondering if it would work, so far so good. Part of me would really like to see how it would do with similar diameter tires on larger rims. Perhaps when my ships come in. For now I'm happy with what I have.

[evan938]

your gear ratio is the same. your tire size is 5.3% different. ive been to PA MANY times and i still can not see why you feel the need to put huge tires like that on. i go out there on 205/55 and 215/50s (even smaller) and have never had any sort of problem. 15s have so much tire it really takes a lot to damage them. i can understand you wanting to put maybe a 215/55/17 if you had 17s, to give some more cushion for the wheel, but for 15s, its not necessary. youve already got like 4.5" of sidewall with stock size tires

[BattleRifleG3]

Ok, perhaps gear ratio was the wrong term. You could say the net ratio between engine torque and linear acceleration.

I've been very happy with how my Elantra did before it had the new tires, but there is a such thing as more, which is what I'm going for. The Elantra is a great car in many ways, I'm just looking to bring out its strengths as an efficient, conservative country road car when most folks bring out its strengths as a fast handling street car.

[Leviathant]

your gear ratio is the same. your tire size is 5.3% different. ive been to PA MANY times and i still can not see why you feel the need to put huge tires like that on.

PA is a pretty big state with a lot of variety, going from Erie to Philadelphia. Big tires would be good in the ghettolicious disrepaired streets of Philthadelphia, as well as in the mountain "roads" of Tioga county. Whilethere are certainly a lot of nice roads, there's also a lot of roads where big tires would be a nice thing to have.

[evan938]

PA is a pretty big state with a lot of variety, going from Erie to Philadelphia. Big tires would be good in the ghettolicious disrepaired streets of Philthadelphia, as well as in the mountain "roads" of Tioga county. Whilethere are certainly a lot of nice roads, there's also a lot of roads where big tires would be a nice thing to have.

honestly, in the 16 or so states ive been to, the only other state with worse roads ive been to is MI. pittsburgh is a close 2nd to the ****tiest roads ive ever been on

[OPZ]

Evan, pittsburghs roads are a BLESSING compared to butlers. I understand where he's coming from, and I honestly think its cool that he's doing that. But seriously, if you get outta the "major PA cities" and into the mountain regions...well ****, the roads are horrid. Why else do truckers consider PA to have the worst roads ever.

Oh, and the elantra's are fun to offroad/slight mudding while avoiding deep puddles so as not to hydrolock.

[BattleRifleG3]

Just did my daily commute in the rain with no troubles at all. Had to get used to the new acceleration levels in the different gears, but all went well. Think I still need to give my tires a little more pressure.

[only1db]

4th gear at 38mph!!! sheesh...thats pushing it dont you think??

i'm with evan on this...with my 40 profile with 17's and my teins i have driven on some pretty ****ty roads...and i have had no issues...but through philly and p burg...even harrisburg has some crap roads....and have you been to the poconos....dont think you western boys have it the worst...come around my way....

its called the POTHOLE state for a reason...

[Vampyrate]

its called the POTHOLE state for a reason...
its a central migration point for hippies?

[BattleRifleG3]

4th gear at 38mph!!! sheesh...thats pushing it dont you think??

In which direction? I'd go higher or lower depending on the grade of the road and the acceleration I desire.

Seriously though, this totally seems like a matter of preference. I was told on another thread that my 0-60 speed would go up by a significant fraction of a second. Now I do think 0-60 speed is cool, but that's not what's most important to me. The ability to more easily cover bad roads is more useful. Not that I can't handle them already, but that this will do it better, and that the tradeoffs are reasonable.

I look at it this way - I think we can agree that the Elantra has power to spare and excellent cornering. Some see it and say "Cool, that means I can accelerate faster, and trim my air resistance and improve cornering even more by lowering my car." Others see it and say "Cool, that means I can go up a couple tire sizes and add well over half an inch of ground clearance and still accelerate and corner just fine, and have an easier time with bumps and potholes and nonexistent driveways."

Seriously guys - I'd do that to a Mustang if I had one. Roll your eyes and laugh all you like. I'm happy with my car, and hope you're as happy with yours.

[Mad_Hatter]

honestly, in the 16 or so states ive been to, the only other state with worse roads ive been to is MI.

Represent for the sh*ttiest roads in the US of A...but in our defense, our road commision can hold up a mean shovel.
-bill

[Kenshin]

I'm glad to hear that everything's working properly with the new tires. Not too many people will likely need to go this route, but it's good information to have on the forum nonetheless. For those (like you) that live where the roads are truly craptastic, it's good to know that they can go with a slightly larger tire on the stock rims without messing anything up.

OT - Vamp, I just got my 205-55-15's installed a week ago, and man, what a difference in handling. The wider footprint and (slightly) shorter sidewall make a huge difference in the level of control and stability, and they look nice, too. Not as hot as 50 series tires on 16's would, but hey, I'm too broke to buy rims. :rolleyes: They also had the opposite effect I was expecting on ride quality. The car is actually MUCH less harsh feeling over bumps now than it was with the stock michelins on it. And SOOOO much quieter! :cool:

[BattleRifleG3]

I'm guessing that the improvement in bump handling may be related to the larger air volume inside. A bump of the same size would cause a lower specific volume change (that's volume per unit mass, mass being constant within a tire) which would result in a lower reaction force due to pressure. My tires having the same width and an even higher volume (well over 6/5 of your volume) should do about that much better.

Your option sounds great for those who want more bump forgiveness while keeping below the stock tire diameter, as well as all the handling advantages you noted.

I'm going to measure the clearances to see if my next tires (60k+ miles from now) could afford to be any bigger. 205/70-R15s may still work, someday, probably a few years from now. I wonder how many of us will be around this forum then to find out.

[BattleRifleG3]

Latest report - I inflated the front tires to max pressure yesterday and the rear tires just short of that. Ride instantly felt a great deal stiffer. Felt bumps harder too, but no different than before. And the vehicle looked and felt taller for it.

Then I drove a section of highway I do once or twice a week that typically gives me my best mileage over a long distance and is more or less friendly to a slow driver in the right lane. When using the cruise at 60mph the whole way, I used to get about 40mph, when down around 52mph or so I would get a little over 45. This time I was probably doing about 58 or so (with the speedometer reading about 55), and the mpg read 39, and this included one stop (which some of the other times didn't.) Multiply by 1.0528 and that's 41mpg.

So surprisingly the fuel economy seems to be about the same, or only slightly lower. I would attribute that to having a lower engine speed with a better fuel economy that offsets the greater drag due to increased height. The flipside is that I won't be able to cruise as slowly as before, as the corresponding engine speed will be lower than desireable, and the torque required by the larger wheels even higher. So whereas on some occasions I would go down to 50mph, I'll probably want to keep at 55 (reading, not actual speed) or higher if I'm going to lock the cruise in 5th gear for a long trip that includes hills. If I have to go slower due to weather or curves, I'll have to drop to 4th gear at the expense of fuel (not a bad trade).

One area where mileage is way down is in city driving. I'm getting 25 where I used to get 28 or so. That's probably due to having to use the clutch more when starting out, and my having not yet adjusted to the different ratios.

I haven't really taken it up to high speed to see how it accelerates at the higher end of the range, but at rush hour highway speeds (70-80mph) it's done as well as it ever did. Again, I'd attribute this to the engine turning at a lower RPM for the same speed.

So here's an interesting observation - If anyone wanted to increase external wheel diameter ONLY to improve fuel economy, they could use larger wheels and then lower their car.

I took a wee bit of time today checking clearances, but the light wasn't great. So far though I'm very glad I went with this size and no larger. I'll have to take some measurements and crank some real numbers to see if my original idea of 205/70-R15 would have worked, but it looks like there's a chance it wouldn't, and I'd be in bad shape for it. The places where it looks closest are at the front and rear of the wheel wells. It looks like there's plenty of space above in the wheel well (more than the 3.5" listed above) but it's the spring that would get in the way if anything did.

So a great big THANK YOU to everyone here who gave me very helpful numbers to work with. I went with the biggest size that anyone here had tried thus far and it looks like it may really be the limit, but entirely suitable as well.

[only1db]

air pressure in our cars is supposed to be 30psi...the most you would want to go is probably about 38-40psi...this is the range that i have mine at...any higher and you risk wearing out the tires down the center of the tire...

i used to do this for the longest time and never knew why...(thanks swortham) but those tires had a 50psi max...i usually had it at 50 or 55...and it was way too much! my new falkens i have down to that mark mentioned above and i have great traction and the wear should be very even...

more power to ya for trying for gas milage...but i'm not that kind of guy...my foot has lead in it and always has...and for sure will always!

[BattleRifleG3]

There are two pressure ratings I saw on the tire, one for regular inflation and one for some sort of test strength. I saw the larger one and thought "50 psi, what the heck?" but then read more of the writing that went along with it and I saw that it was some sort of test rating, not the maximum inflatable pressure. I think it may have been what the car could sustain if say you put them on a truck and then put an elephant in the bed. There was a weight that came with it, somewhere in the teens of hundreds of pounds, which is roughly half the weight of an Elantra. On an Elantra, they'd never go more than 3/5 that load (on the front, 2/5 on the back assuming a 60/40 front/rear balance.)

I inflated my front tires as close to 40psi as I could estimate, and the rear two are probably 38psi.

I have already noticed the difference in clearance. There's a parking lot at a post office that has what they think are speed bumps, but no... they seem to be "truck only" bumps on each entrance to the customer parking lot. No matter how slowly I took them, and I really mean slowly, I had to use the clutch in first gear to creep over them and brake all the way down the other side, but I still scraped bottom - I was not pleased at all. I consider a stock Elantra to have pretty nice clearance, better than an early '90s Dodge Caravan. Now with my oversized tires I clear them abrasion free using the same care. Also pulled my front lip entirely over a curb in a parking spot today (no I wasn't on the sidewalk.)

Still need to do some measurements, but I think we have a winner.

Oh, and regarding gas mileage, I think that's the beauty of an Elantra. With milder speeds and minimal speed changes, you can get an absolutely remarkable fuel economy from a car its size with its size and power of engine. But when you need/want to, it has all the power you need, which you will pay for in fuel, but that's thermodynamics. I can drive to work at high rush hour speeds and get 27mpg highway, and I can take road trips at a leisurely pace and score over 40mpg. Whatever your choice at the time, you can make it and the Elantra will deliver.

Geez, they should be paying me for this. ;)

[BattleRifleG3]

An update on my experience with the new tires - fuel economy seems to be noticeably lower in stop and go travel, as well as higher highway speeds, ie 65+. I would attribute these to the greater difficulty starting from a stop and to the increased wind resistance, respectively. The fuel economy is the same 45mpg when driven about 55mph. It may be more than just the added height, there may be the development of different wind flow patterns with the new profile. So this is NOT a modification to do if you want better mileage, but if you drive at the right speeds you will at least get the same mileage as you did before. If you do want to gear up, I would suggest lowering your car to standard height after putting the larger tires on.

On the size and space left, I would say pretty confidently that these tires are the absolute maximum size usable on a stock Elantra XD. That's 205/65-R15. I cannot fit my pinky finger in the space between the tire and strut. I think I found a winner and really lucked out, thanks to help from the guys here.