close to giving up....

[d0sitmatr]

ok, question
got the new tires put on Monday, and while its only been a couple of days, Im wondering now if Falken ZE912's could be considered an LRR tire design ?
since putting the new tires on, my avg has gone up close to 2mpg on the same route and habits I take on a daily basis.
previously, my avg was 29-30 to take my wife to work and come home after (10 mile round trip). now my avg has been hovering around 31-32, same route, same time of day and using the same driving habits Ive been using these past few months.
I have a hard time believing just going with a 205 vs the 215's that were on my car before would have this much affect ?
or is it a combination of things ?

[Varn]

Hi Mike
Are you using the same miles as before. You are loosing about 60 mm per revolution or adding some distance registered to the odometer. It could be half of the 6% that you are noticing.

[d0sitmatr]

same exact distance and everything.
it certainly surprised me, thats for certain.

of course, I wont know if there is any actual increase until I get a couple tanks in, considering my SC might be out of calibration. although someone did tell me how to recalibrate it yesterday, so that will be something I do at my next fill up, and Ill keep my fingers crossed that the numbers Im currently seeing at legit

[RH77]

Brainstorming and Advice:

As a general rule, humidity is good, and heat is bad -- the Weather dictates much of that day's FE result. Some vehicles (rare) like warmer intake temps to dial-down fuel-consumption but most have a sweet spot. Test it out.

Look at oil weights and maybe look into going lighter for those shorter trips.

I can only speak of personal experience and those of what I have learned here:
- It takes time
- Experiment
- Make it Fun
- Look at others' Garage entries for mod ideas

For the long term effort, perhaps setup an SFL meetup. Talking about EcoModding and Driving, in person, works wonders for morale and learning. Ride with a pro driving your own vehicle. Lots of us have met with trusted members and came away with good ideas and camaraderie for the cause.

Last thing -- instant feedback is good, but it's like losing weight. Checking it everyday can be disheartening. Look at longer blocks if frustration weighs on you. Nearly all of us here have been exactly where you are now. It does matter.

Best FE,

RH77

[d0sitmatr]

ok, as a theory, this has been swimming around in my head for a couple days now (this is just a hypothesis):
when I changed tires, I went with 205's all around vs the previous sizes (215 front, 225 rear) due to the rims, the tires are "stretched"
my theory is that the stretching is allowing a more aero face to the oncoming draft, and could possibly allow the wind to completely bypass the rim interior section.
(diagram
\__/

another thought
has anyone tried using motorcycle tires ?
I recently saw a set of 4 trailer rims in a size 17x4, which would be a perfect size for several motorcycle tires Ive used in the past.
granted, I know the cornering would take a hit, even though MC tires are designed for high performance, their structure is also built for leaned cornering. but if you had a vehicle designated strictly as a hwy vehicle...
I got the seed of the idea from an old post I read on here about how skinny tires used to be.
what do you think ?

[Sven7]

Stretched tires, good. Motorcycle tires, bad. I really don't think you want to mess around with bike tires on a car. I'm guessing the contact patch will not be right if you don't lean the tire. If nothing else, find some 145's and throw them on a set of space saver wheels.

[Arragonis]

Agreed - I wouldn't run MC tyres on a car. Tyre size is a compromise though and you wouldn't be able to carry as much speed into bends with something as narrow as a 145 - maybe not as important on a highway vehicle ? I have 155s on a much smaller car (think Metro sized) and know where the limit is - a lot lower than the 205s on my previous TDi.

What pressures are you running the 205s ? I recall from your early post you had a couple quite low which may have caused some of your lower FE numbers in your OP. I run my 155s at 45-50 (max is 55 and from the stealer they were at 35) and that made an immediately noticeable difference in coasting. If you haven't already then go higher. Eventually you may find the ride is more 'crashy' on rougher surfaces at which point you can gradually ease back to where it is OK for you but firmer than before.

I did this on the TDI for 20K miles and didn't see any adverse wear either.

Good luck.

[Frank Lee]

and motorcycle tires have a worse crr than car tires. if anything, motorcycles benefit from running car tires, at least on the back where the handling difference isn't so noticeable.

[d0sitmatr]

good points.
I was thinking more along the lines of the physical shape and how the wind would split around the MC tire vs the flatter car tire. but I do understand what all of you are saying.

Arrogonis, all tires are pressured at 36PSi as I havent had a chance to air them up yet. but when I can, I plan on putting them up to 40psi.

[euromodder]

Originally Posted by d0sitmatr

has anyone tried using motorcycle tires ?

They normally can't handle that much weight.
They wear out fast - even on a motorcycle.
The rounded design concentrates wear in the center - they'd be gone very quickly when mounted on a car.