New (to me) VX wheels w/ tires

[first350]

I bought a set of VX rims and new tires for my civic this past week...

New tires: 155/80/13
OE tire size: 165/70/R13

1) more narrow
Pro: less rolling resistance (better FE)
Con: less traction
2) taller tire
Pro:higher final gear ratio (better FE)
Con: Speedometer will read 7% lower than actual, more sidewall flex during cornering
3) lighter wheels
Pro:less rotating/moving mass (better FE)
Con: costs more than steel rims, Al alloys are more prone to damage.
4) higher tire pressure (50 PSI cold)*
Pro:lower rolling resistance (better FE), longer life
Con:more noise/vibration
*tire specs: Max tire pressure (cold): 44 psi, Max Load: 963 lbs.
...since I'm no where near the max load, I'll probably run the tires around 50 PSI...this should also help w/ FE by reducing rolling resistance.



I got the wheels for $200 and the tires for $130 (tirerack.com)...I spend around $200/tire for my 350Z - I love the civic !

2 of the new civic tires are as wide as 1 of my 350Z tires!!!:icon17:


here's the tires mounted:


*if you're in the Seattle area, check out:
http://www.tightntidyracing.com/Tire_Services.html
$50 for 4 wheels mounted/balanced.
These guys are great - they do it out of their garage as a side business...they're super knowledgeable, nice people, and very fast autoXer's...plus their prices can't be beat!

[Danronian]

I love the cheapness of VX tires.

I just installed some 155 80s as my winter tires on my winter set of VXs. I love the wheels. Only would part with them for some 14 in HXs which I think look a bit better.

[204snic]

Nice deal on the VX wheels! Does the new tire size throw your spedometer off a little? So you got a FE car (civic) and JFF car (Just For Fun, 350Z). Nice!! I wish my other half would let me do that. She doesn't thing a 2,500 car would last to long. But, I especially like the eg hatches. Definitely on my want list of cars to have.

[first350]

Originally Posted by 204snic

Does the new tire size throw your spedometer off a little? So you got a FE car (civic) and JFF car (Just For Fun, 350Z). Nice!! I wish my other half would let me do that. She doesn't thing a 2,500 car would last to long. But, I especially like the eg hatches. Definitely on my want list of cars to have.

yeah, the difference will be:

New tires: 155/80/13 --> sidewall thickness = 124mm
OE tire size: 165/70/R13--> sidewall thickness = 115.5mm

124/115.5 = 1.07...so my speedo will be reading 7% lower than my actual speed.


I'm enjoying having 2 cars...1 for commuting, and 1 for autoX/Track and relieving stress !

[FritzR]

yeah, the difference will be:

New tires: 155/80/13 --> sidewall thickness = 124mm
OE tire size: 165/70/R13--> sidewall thickness = 115.5mm


Don't think so. You have to go with the overall tire height not the sidewall as that's what effect RPM of the tire


Tire Size Comparison

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
155/80-13 4.9in 11.4in 22.8in 71.5in 886 0.0%
165/70-13 4.5in 11.0in 22.1in 69.4in 913 -2.9%


from
http://www.miata.net/cgi-bin/tirescgi

[first350]

Originally Posted by FritzR

Don't think so. You have to go with the overall tire height not the sidewall as that's what effect RPM of the tire


Tire Size Comparison

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
155/80-13 4.9in 11.4in 22.8in 71.5in 886 0.0%
165/70-13 4.5in 11.0in 22.1in 69.4in 913 -2.9%


from
http://www.miata.net/cgi-bin/tirescgi

lol...thnx for the catch - guess my brain wasn't working this morning. (seems like ever since from graduating w/ an engineering degree, I know less and less math )

[FritzR]

No big deal. I did the same thing with my CRX tires. I thought for a minute I would have to correct my gaslog. Just wish I could get some 135/90-13

[brucepick]

Check out this calculator I just discovered today.
http://ejelta.com/tiresize/index.html?ws15=1&tiresize=185%2F80%2F14&minwidth= &maxwidth=&minratio=&maxratio=&minwheel=&maxwheel= &maxdelta=10

After you enter your OEM or other "base" size, it lets you see other sizes and exactly how close they match your OEM overall diameter. Same rim or other rim diameters. Should be ideal for those contemplating tire size changes.