Last post on Sep 06, 2008 at 8:12 AM
You are in the Honda Civic GX (natural gas)
What is this discussion about?
Honda Civic, Alternative Fuels, Hybrid Cars
#850 of 1097 Re: Question about 2006 Civic GX Wheel Sizes [99civiccng]
Jul 06, 2007 (11:16 am)
What are the full specs on the tire/wheel sizes of the two vehicles?
For example, my 1991 Dodge came with 195/70-14 tires, but an alternate size listed on the door sticker was 205/60-15 (which of course required new 15 inch wheels). These two tires have the same outside diameter so the speedometer and odometer would read the same.
195/70-14 OD in inches = (195 mm)(1 in/25.4mm)(0.7)(2) + 14 = 24.74 in
205/60-15 OD in inches = (205)(1/25.4)(0.6)(2) + 15 = 24.69 in
The 205 tires are of course 10 mm wider, but the wheel well could accomodate this. It was an officially recognized alternative tire. You would have to check with a Honda dealer to see if the tires from the EX will work on your GX.
#851 of 1097 Re: Question about 2006 Civic GX Wheel Sizes [jim314]
Jul 06, 2007 (12:21 pm)
i'm 99.999% sure you'll be fine. the civics are all essentially the same core cars. any differences are components that are put onto the same scaffold ... aka. all wheels should fit on all versions, all engines would fit in all versions, all seats, transmissions, etc etc.
clearly, once they've slapped in some components, then others no longer make sense (such as gasoline delivery system for a GX) ... but wheels/tires aren't an issue. they would only potentially be an issue if you were getting them from a previous generation Civic or other vehicle ... then those specs are essential to know.
#852 of 1097 Re: Question about 2006 Civic GX Wheel Sizes [epnfrn]
Jul 10, 2007 (2:20 pm)
Thanks to all that responded. I got the EX wheels and tires and mounted them last night. Everything went according to plan!
The ride, to my surprise, is actually SOFTER than with the stock 15" tires!
#853 of 1097 Re: Question about 2006 Civic GX Wheel Sizes [99civiccng]
Jul 10, 2007 (3:35 pm)
Great to hear that you are satisfied. If the wheel sizes are the same as 2007, then the outside diameter of the two tires are different by 0.10 inch, which is negligible as far as the speedometer and odometer readings.
I assume that your new tire/wheels are 205/55-16 89H on 16 x 6.5 inch alloy wheels. The nominal unloaded OD of these is tires is 24.88 inches.
And I assume that the old ones are 195/65-15 89H on 15 x 6 inch steel wheels. The nominal unloaded OD of these is 24.98 inches.
So the new tires are 0.41 % smaller in diameter which is insignificant as far as speedometer and odometer reading, but the larger width and lower profile should give a significantly improved handling, not to mention appearance. Narrow tires on steel wheels are substandard nowadays.
This change could possibly produce a decrease in fuel economy, which might also be negligible, or it might be as much as a 3 or 4 % decrease. Let us know if you find a difference. Of course, you could reverse this difference by driving even a few mph slower on the hwy.
The original tire/wheel combo was probably picked to favor fuel economy and lower price over handling because the GX is mainly sold as a fleet vehicle and a green vehicle. The original tires would have less aerodynamic drag (narrower profile seen from front) and lower rolling resistance due to their being 65 series and maybe the tire model was one of the low rolling resistance models.
What tires/wheels did the owner of the EX change to? What is the maximum inflation pressure of your old and new tires? What pressure do you plan to keep the new tires at? What is the make and model of the old and the new tires? What are you going to do with the old wheels?
#854 of 1097 Maximum GX range?
Jul 18, 2007 (2:51 pm)
OK, so from a good 3600psi overnight fill to bone-dry tank, how many miles can I get out of my 2007 GX? I am thinking 225 miles is about the limit? Anyone have some real-life experiences? Thanks!
#855 of 1097 Re: Maximum GX range? [xpacific]
Jul 18, 2007 (3:25 pm)
From a "fast fill" (regular CNG station) -- where I filled it up 1/2 tank - the max range I've gotten out of my 2006 GX is 221 miles.
If you do an overnight fill, I'd guess you could possibly get another 10 miles out of it, but that would reeaaaaaallly be stretching it.
#856 of 1097 Re: Question about 2006 Civic GX Wheel Sizes [jim314]
Jul 18, 2007 (3:30 pm)
I've had about a week of the new tires under my belt now and I can't see any perceptible decrease in fuel economy. It's about the same.
The tires are actually 205/60-16 89H Hankook Optomo tires - which actually have good reviews over Tire Rack.
They are 5mm larger in height (no clearance issues, btw), so I've calculated a 3% difference in actual speed vs. speed shown on speedo (i.e., speed shown on speedo is now 3% LOWER than actual speed).
I've kept the tire pressure 36psi all around and the ride is a vast improvement over the stock tires - torque steer has been greatly diminished.
I have no idea what the guy with the EX did for tires - the car wasn't there when I bought them
As for mine? I figure I can eBay the wheel covers and then give away the tires/steel rims to a recycling center -- I don't think they have much value.
#857 of 1097 GX Rear Speaker Installation - any reason why not?
Jul 18, 2007 (3:32 pm)
I'm thinking about a DIY rear spear install on the rear shelf of my 06 GX but want to proceed with caution. Looking at the trunk, where the CNG tank is, I believe I can fit speakers in the stock location w/o much headache. But am wondering if there was any "real" reason Honda didn't do this for any of the CNG models it has produced (98-00/01-05/06-07). Is there chance of an electrical spark from the speaker wire? If so, it seems odd because there is other electrical running near the tank...
Thoughts? Anyone attempt something like this (i.e. not a surface mount solution)?
#858 of 1097 Re: GX Rear Speaker Installation - any reason why not? [99civiccng]
Jul 18, 2007 (5:18 pm)
to DIY speaker -- nope, you will NOT be able to fit rear speakers there. i have a 2006 that i completely stripped out so that I could see how much room there was ... answer, about an inch. i've never heard of a decent speaker 1" deep, which means you'll have to custom fabricate some type of enclosure to raise the height up. my advice to you is put a nice amp in the trunk, and get nice component speakers for up front. after many many hours of thinking about rear speakers, i just don't think there is a reasonable solution. if you find one, let me know!
to 2007 tank capacity -- on my 2006, i regularly get 250-260mi on a fast-fill tank. and this is in the bay area, which i would suggest means part city/ part highway due to the traffic. even after 254mi, i can only jam in 6.593GGE ... suggesting i might have eaked out a little more (though i was NOT going to try!!) i don't have personal experience with a slow fill, but as others have suggested, you can likely get even more miles.
#859 of 1097 Re: Question about 2006 Civic GX Wheel Sizes [99civiccng]
Jul 18, 2007 (5:53 pm)
I calc the same 3% change (2.8%) in speedo and odo readings as you did. With the new tires if the odo says a trip was 100 mi, it was actually 103 mi (102.8 mi), and if your speedo reads 70 mph then the actual speed is 72 mph.
At a true speed of 70 mph your speedo will read 68 mph and your engine rpms will be 3 % lower than with the OE tires at the same true speed. This should lower true fuel consumption per unit distance (i.e. increase true mpg) cruising on level ground at legal speeds. You have in effect raised the gearing by 3%.
Unloaded diameter* of 205/60-16 is 25.69 inches. If the the OE tire was 195/65-15 (dia 24.98 in), then to get the correct values you would multiply the speedo and odo readings by 25.69/24.98 = 1.03 (1.028).
*(205mm)(1in/25.4mm)(0.60)(2) + 16in = 25.685 inch
If the OE tire was 195/65-15, then the dia of the new tire is larger by 0.71 inch (or 18 mm) and the radius would be larger by 9 mm. So with the new tires you get 9mm more ground clearance and the top of the vehicle is 9 mm higher above the road. This will increase your aerodynamic drag by a probably negligible amount. But if you use the same hwy cruise setting in mph reading on the speedo as you did with the OE tires, you will actually be driving 2.8% faster and so you would increase the aerodynamic part of the fuel consumption per mile by a factor of 1.028^2 = 1.057. That is, the fuel use per mile could increase by close to 5.7% because you are actually driving faster and the aerodynamic effect on fuel consumed per unit distance travelled is proportional to the speed squared.