Kia Forum banner

1 - 19 of 19 Posts

·
Registered
2012 Rio LX 2012 Soul+ 2.o
Joined
·
61 Posts
Discussion Starter #1
Hey Folks,

I am considering a change in wheels/tires and realize I am clueless about, well a lot of things.

So, here are my questions:

What range of variance is there when it comes to selecting a rim that will fit my car, not interfere with calipers etc?

If I was to upsize the wheel by an inch, can I downsize the tire (external dia.) by an inch and end up with the same OD?

Can I do the same w/ 2"?

If not, how can I tell my cars computer that the perimeter of the tire has changed and all of the readouts will be off as a result?

Oh, and do you think a bronzy wheel would look good on my black car or would I look to much like I am trying to be a wrx?

Thx in advance for any and all knowledge and/or opinion.
 

·
Registered
2012 Rio LX 2012 Soul+ 2.o
Joined
·
61 Posts
Discussion Starter #3
Thank you for the valuable resource. So, are we stuck with having to apply a multiplier to all of our readings? Is there no way to "tell" the computer that a change has been made?
 

·
Registered
Cerato S Hatch Auto
Joined
·
1,236 Posts
Various models of the Rio come with 15", 16" or 17" wheels, with increasingly lower profiles, so that the overall diameter is about the same. A quick calculation puts the nominal ODs for the Rio as: 621, 620 and 616mm. The maths for this is so basic that there's hardly a need for a "tool"; although I will add that the effective (rolling) diameter is about 97% of the nominal OD.

If you go outside the recommended tyre sizes for any particular wheel, you will only get to about 3% difference in OD before you run into clearance difficulties, and at 3%, that's hardly worth worrying about for the speedo/odo calibration.

Alloy wheels are mostly cosmetic and add little value to the car, either for handling or resale, IMHO.
 

·
Registered
2012 Rio LX 2012 Soul+ 2.o
Joined
·
61 Posts
Discussion Starter #7
Thank you guys for the info and perspective. Yes, the move would be primarily cosmetic. A nice set of alloys may be also a bit easier to clean, again cosmetic. But then again, cosmetics was a primary driver in my selection of the Rio over the accent.
 

·
Registered
Cerato S Hatch Auto
Joined
·
1,236 Posts
Thank you guys for the info and perspective. Yes, the move would be primarily cosmetic. A nice set of alloys may be also a bit easier to clean, again cosmetic. But then again, cosmetics was a primary driver in my selection of the Rio over the accent.
I always thought alloys were harder to clean. The steels on a couple of our cars have plastic wheel covers that aren't too ugly and only need a quick wash (but don't look at the wheel underneath!).

I like the look of the more conservative alloys, but they do have to be kept clean to look the part. Also, if your car isn't garaged, rainwater splashing onto the disk rotors tends to leave unsightly rust rash if you have alloys. Steel + cover protects the rotors.
 

·
Registered
2012 Rio LX 2012 Soul+ 2.o
Joined
·
61 Posts
Discussion Starter #10
We don't get an excessive amount of rain here (just east of San Francisco) so I am not too worried about the rust, but I would still consider painting the calipers. Again there is a delicate balance between painting for protection and pretending I have Brembos. Perhaps a black in lieu of red . . . David Scott that wheel would easily be in my top 3 . . might have to sit on a site that fakes em in to get a feeling of the look.
 

·
Registered
Kia Rio 2012 UB/EX 1.4 CDRI 90 Premium 5-door
Joined
·
2 Posts
Hello,

I am french and i have already thought about buying news wheels for my Rio 2012 EX(UB) 5-door 1.4l CRDI 90

Entraxe = 4x100 (number of holes and distance between two consecutive holes)
Alésage (bore diameter) = 54,06 millimeters
Offset between ET36 (steel rim) and Offset = ET43 (alloy rim)
Rim width = 5.5 inches (LX) or 6.0 inches (EX) (i don't know for SX)
Authorized rim diameters = 14-15-16-17 inches
Dimensions tyres (near tyre inflation pressure details of the front driver door) :
175/70-R14 or 185/65-R15 or 195/55-R16 or 205/45-R17

I hope this can help you.

Best regards,

Azuriad
 

·
Registered
'13 Rio5 LX Manual, '15 ZX14R, Honda VFR800, Ducati 748, '87 Buick Grand National, '13 Subaru BRZ
Joined
·
101 Posts
This tread got me thinking about my speedometer/odometer accuracy. At 60mph on my speedometer, my GPS says 57. So every hour that I drive (at 60mph on my speedometer) I lose 3 miles on my odometer. That's about 5%. So it looks like I'll be cheated out of 5,000 miles of my 100,000 mile waranty... The odometer will say 100,000 but I will have actually traveled only 95,000. Did I do the math wrong??? If I'm right, my MPG is also less by 5% than I thought.

I think it would be better to install tires that have a larger OD to correct the inaccuracy.
 

·
Registered
Cerato S Hatch Auto
Joined
·
1,236 Posts
This tread got me thinking about my speedometer/odometer accuracy. At 60mph on my speedometer, my GPS says 57. So every hour that I drive (at 60mph on my speedometer) I lose 3 miles on my odometer. That's about 5%. So it looks like I'll be cheated out of 5,000 miles of my 100,000 mile waranty... The odometer will say 100,000 but I will have actually traveled only 95,000. Did I do the math wrong??? If I'm right, my MPG is also less by 5% than I thought.

I think it would be better to install tires that have a larger OD to correct the inaccuracy.
You can't use the speedo calibration to make assumptions about the odometer. Usually the speedo reads a bit high (like yours), while the odometer is more accurate. Test your odometer against the GPS next time you go on a trip; set a destination and compare the odometer vs. distance to destination. On a recent trip, GPS distance was 711 km, odometer was 709 km.

On two of my cars, the speedo is about 5% high, while the odometer shows 99.9% and 99.7% (as above) of the actual distance. These figures are for new tyres; you will get about 1% increase over the life of the tyre, so don't sweat over small differences.

The Cerato speedo is only 2% high but the odometer is 97.7% actual (i.e. I'm getting more miles on the warranty!). Our model has 15" wheels which are a bit larger OD (1.5%) than the 17". I assume they don't use a different calibration for the two models, so the gauges are a bit out.
 

·
Registered
2013 Rio SX Hatchback
Joined
·
417 Posts
Why do you assume that the GPS speed is accurate and it must be the speedometer that is wrong? Is it not possible that the GPS speeds are not as accurate as the speedometer in your car??
 

·
Registered
Cerato S Hatch Auto
Joined
·
1,236 Posts
Why do you assume that the GPS speed is accurate and it must be the speedometer that is wrong? Is it not possible that the GPS speeds are not as accurate as the speedometer in your car?
This has been covered before. GPS is accurate, and it's easily checked with a stopwatch against measured distances. We have 5km test zones for this purpose, and a close relative who is a road engineer assures me that they are accurate. I can think of at least 3 survey methods which would locate the test zones (including intermediate markers) to within ±1 metre. Certainly, the intermediate kilometer posts are consistent with the overall 5km distance.

The speed reading on the GPS is derived from a constantly-updated series of readings from the satellites (including Doppler data), NOT from a simplistic point-to-point calculation, as some people assume.

Old-style speedometers were electro-mechanical and a bit unreliable. Modern speedos are electronic and usually calibrated to be slightly optimistic in my experience. Many countries mandate speedos that do not read less than the actual speed, so manufacturers bump them up a bit to be sure.
 

·
Registered
2013 Rio SX Hatchback
Joined
·
417 Posts
Cuda, Thanks for that answer. Thanks for realizing that my question was not meant to be argumentative but was a genuine question. After I read my question I realized that it could be taken the wrong way.
 

·
Registered
Cerato S Hatch Auto
Joined
·
1,236 Posts
Cuda, Thanks for that answer. Thanks for realizing that my question was not meant to be argumentative but was a genuine question. After I read my question I realized that it could be taken the wrong way.
I always assume that questions are genuine. Anyhow, trolls are usually put off by a "complete" answer. :)

For more reading, see the following thread relevant to the marine application:
Accuracy of GPS Receiver Speed Measurements - Moderated Discussion Areas

I once happened to mention to a guy at a tyre place that I calibrated my speedo using GPS, and he completely rubbished me and went on and on about GPS not being accurate because:

1. GPS only takes a fix every 100 metres and that could be out by 20 metres at least.
2. It's impossible to drive a completely straight line.
3. What about hills?

I dealt with No. 1 in my original answer. Weaving down the road and deviating 2 metres for every kilometre (a fairly gross driving error) would only add 2 metres to a journey of 1000 km. Hills aren't likely to effect the calibration, although you'd need to be on a 10 degree slope for there to be any possibility of "cosine" error.

BTW, I'm just in the process of fitting a speedo to my push bike. Not sure if I'll check it with GPS, maybe just adjust the wheel circumference parameter. :lol:
 

·
Registered
2013 Kia Rio 5 SX UVO, 2012 Cadillac Escalade Ultra Luxury
Joined
·
116 Posts
This has been covered before. GPS is accurate, and it's easily checked with a stopwatch against measured distances. We have 5km test zones for this purpose, and a close relative who is a road engineer assures me that they are accurate. I can think of at least 3 survey methods which would locate the test zones (including intermediate markers) to within ±1 metre. Certainly, the intermediate kilometer posts are consistent with the overall 5km distance.

The speed reading on the GPS is derived from a constantly-updated series of readings from the satellites (including Doppler data), NOT from a simplistic point-to-point calculation, as some people assume.

Old-style speedometers were electro-mechanical and a bit unreliable. Modern speedos are electronic and usually calibrated to be slightly optimistic in my experience. Many countries mandate speedos that do not read less than the actual speed, so manufacturers bump them up a bit to be sure.
Does GPS take into account any elevation changes? For example, point A to B lets say is 50 km, but if you are travelling up and down on hills, it would theoretically read more, as there was a greater distance travelled, although the linear distance is the same. With that being said, I would take the odometer over a GPS. UNLESS the GPS can account for that……
 
1 - 19 of 19 Posts
Top