Tall tire test (taller gearing advantage offset by wider, heavier wheels/tires?)

[mcrews]

Originally Posted by deathtrain

I have used this for a tire calculator

Tire Size Comparison

it will show tire % plus you can compare side by side different tire sizes.

that is a very simple but very cool calculator.

DARIN,
Should we have a section for calculators????

[SentraSE-R]

My three tank average with the new tires is 51.7 mpg. That's a tad better than my lifetime average of 48.8 mpg on this car, and on par with recent prior tanks. The new tires don't seem to be hurting me.

[California98Civic]

Originally Posted by SentraSE-R

My three tank average with the new tires is 51.7 mpg. That's a tad better than my lifetime average of 48.8 mpg on this car, and on par with recent prior tanks. The new tires don't seem to be hurting me.

Cool. Great, fun, swap. We shouldn't forget to enjoy the cars.

[deathtrain]

Originally Posted by mcrews

that is a very simple but very cool calculator.

DARIN,
Should we have a section for calculators????

I think we should.. but this dont take in the weight of the wheel/tire. but like I said I like this one because you can look at a side by side if you where to use the same rim.

[California98Civic]

Yes! I finally found the weight for the crappy Kelly Ultra GT tires I put on my car a few years ago: 19lbs. They are 185/65-R15s. I can switch to Bridgestone EP100s at the larger size of 205/65-R15, get the LRR benefit and a 5% diameter increase while only gaining one pound per tire/wheel, maybe eight pounds total added rotating mass. That change alone could be a 10%+ FE gain on my old car.

[SentraSE-R]

I have to admit, I'm cheap, and one of the underlying reasons for the swap was it was cheap. The wheels cost me $175 for the entire set, and the tires cost less than 10% of their new ($309 each) price, although they still have 70% of their treadwear left. I needed to replace the old tires anyway, so I managed to do it with style, for under $100/tire complete (mounting & balancing included). Best of all, there is no noticeable mpg penalty.

So I'm having fun, looking good, and thumbing my nose at the oil companies. Win, win, win!

[mcrews]

Good mileage & Good Looks...
just like a mod should!!!!(


(you older guys might see the resemblance to a very old cigeratte jingle)

[SentraSE-R]

Time to resurrect this thread. I just bought two used 195/65-15s for $20 each. When I get them mounted next week, I'll be able to test my stock 35 lb. 185/60-15s, my current 47 lb. 205/50-17s, and a lighter 37 lb. 195/65-15 combination. The latter two tire/wheel combos are 5.31% and 4.97% taller than stock, respectively, and have -5.605% and -5.224% rolling circumference differences from stock.

While my mpg has not suffered with the 17" tires, I think that's because my first three tanks with them were on a long road trip. The taller & heavier tires do best under highway conditions where their greater inertia isn't detrimental, and their taller height/taller gearing is beneficial. Also, my AB testing was done under constant speed conditions where the heavier tires' inertia ramp-up isn't measurable.

Using the new tires today under a competition low speed P&G regimen, I was unable to approach the 94.5 mpg I got with the stock tires. In fact, I could only get 70 mpg. I suspect that's because the big, heavy tires need more fuel to come up to speed.

Next week, I plan to do ABCA testing under cruise control and different P&G conditions. I think that testing will be very interesting and educational for me, and probably for all of us.

[CapriRacer]

Originally Posted by SentraSE-R

Time to resurrect this thread........Next week, I plan to do ABCA testing under cruise control and different P&G conditions. I think that testing will be very interesting and educational for me, and probably for all of us.

Just be aware that there are extreme differences in rolling resistance between tires - even of the same size, let alone what the differences in size make. Be careful that you don't draw conclusions without taking into account that there might be severe differences different tires make (meaning make and model of tire).

[SentraSE-R]

Originally Posted by CapriRacer

Just be aware that there are extreme differences in rolling resistance between tires - even of the same size, let alone what the differences in size make. Be careful that you don't draw conclusions without taking into account that there might be severe differences different tires make (meaning make and model of tire).

True, there are dozens and dozens of variables, from manufacturers using the same name on different tires, to them using different compounds on different sizes of the same model. The "new" tires are 8 year old Continentals, sporting an obsolete tread pattern. They're simply cheap test mules which I'll replace with LRR tires if they work well.

On the plus side, I can always fill the worst-testing tires with pure nitrogen, and turn them into the best performing tires .