Better milage and less noise? What's up with that?

[slowzoom]

I have had it with the standard tires, Dunlops... (deadhorse)
Let's face it, they are noisy as all heck, they lasted nothing (I think they even wore-out parked in the garage), and they cost a fortune to replace if you can find them (usually a special order).

Anyway I switched to a larger tire 205-55-16 (vs 195-50-16) Bridgestone Potensa's RE960AS from Sams (paid about $85 per on some special they had) and so far all is good. The larger size just fits and raises the car about 1/2 inch but it is all worth it. The mechanics wouldn't install them untill I signed some disclaimer since they swore it would rub(bang). Well it don't.

The highway noise is now all but gone (incredible). The handling is slightly different but it still feels great. One last benefit to me is the lack of scraping of the front spoiler coming down off my steep driveway. So far I have almost 10k miles on them and no noticable wear (tires are rated at 50k miles life I believe).

The fuel milage, though, is actually slightly better I think. It is tricky to measure since the odometer error is about 5% but the effect is like having a higher gear. i.e. the engine rpm is slower (by about 5%)for the same speed due to the larger diameter tires. I seem to be getting the same miles per tank but again there is a 5% error so I am going farther per tank ...(blah) I think.

To be sure I need to just take a long highway trip which I haven't but was wondering if any of you had real data on this?

 

[HelionTBone]

I have had it with the standard tires, Dunlops... (deadhorse)
Let's face it, they are noisy as all heck, they lasted nothing (I think they even wore-out parked in the garage), and they cost a fortune to replace if you can find them (usually a special order).

Anyway I switched to a larger tire 205-55-16 (vs 195-50-16) Bridgestone Potensa's RE960AS from Sams (paid about $85 per on some special they had) and so far all is good. The larger size just fits and raises the car about 1/2 inch but it is all worth it. The mechanics wouldn't install them untill I signed some disclaimer since they swore it would rub(bang). Well it don't.

The highway noise is now all but gone (incredible). The handling is slightly different but it still feels great. One last benefit to me is the lack of scraping of the front spoiler coming down off my steep driveway. So far I have almost 10k miles on them and no noticable wear (tires are rated at 50k miles life I believe).

The fuel milage, though, is actually slightly better I think. It is tricky to measure since the odometer error is about 5% but the effect is like having a higher gear. i.e. the engine rpm is slower (by about 5%)for the same speed due to the larger diameter tires. I seem to be getting the same miles per tank but again there is a 5% error so I am going farther per tank ...(blah) I think.

To be sure I need to just take a long highway trip which I haven't but was wondering if any of you had real data on this?

I haven't complied any real data on this, but I've also switched to 205-55-16 (Toyo Tourivo from Les Schwab - 80K warranty). Instantly I noticed a huge difference in road noise and comfort. I prefer the look of the car now as well, but I will bet you $$$ that all the modders out there would totally disagree. Oh well, when I'm rolling with my 3 kids in the back I'm not really trying to be cool anyway. (drinks)

 

[aMaff]

People are still running on these tires? Damn... that sucks.

 

[slowzoom]

I agree with the improved look too. The new tires are wider and the little bit more sidewall make the overall size look more appropriate for the car. The original tires, in my opinion, look too small in proportion to the car.

Anyway if anybody else is running larger diameter tires please let us know if they get improved milage. I guess if this is true we could give this info to Obama so he could add that to his energy policy along with more air in our tires.(bike)

 

[bucksatan]

If I take into account that I my odometer now under reads my mileage I get slightly better economy with my new tires. My new kuhmos are slightly louder, but that could be because the dunlops were totally bald when I got rid of them. And yeah, the slightly bigger tires do look a lot better in the wheel wells.

Just remember, your speed-o now under displays your speed. Probably not a whole lot but if the cops in your area are really picky be careful.

 

[mx-p5]

Yeah, people take the car back to the dealer to replace stock with stock.

Dunflops SUCK

And yes, at speed, you're going 3-5 mph faster than you read. Higher the faster you go

 

[slowzoom]

So do you Pro5x2 race your P5 against your wife's P5? (nailbyt)

What tires do you buy?

 

[goodfornothing]

I have Nexen N7000 205/45ZR16 Tires. I get a lot of road noise, if that's what it is lol. Do you guys have any recommendations?

 

[slowzoom]

I like the Bridgestone Potenzas. They ride way better and the noise is much less than the Dunlops. Keep in mind that the P5 is still an econo box in it's heritage so it will not be as quiet as a Caddy or a Buick but before these tires I couldn't drive over 40 without blowing a speaker (band)to drown out the tire noise.

 

[goodfornothing]

Lol that's pretty much how my tires are. I'll check out the Potenzas.

Edit: What's a good size as well?

 

[slowzoom]

To Goodfornothing,

Try the 205-55-16 size. They are probably cheaper, quieter and I think you get better milage too(2thumbs) is the reason for this thread.

I also like the larger look too.(10)

The Potenzas have a 400 threadlife rating which is pretty good compared to others. I don't know what that equates to in actual miles but it is higher than other tires I looked at for the P5.

 

[mx-p5]

So do you Pro5x2 race your P5 against your wife's P5? (nailbyt)

What tires do you buy?

She's got the sportshift auto, but, no performance mods. She just likes it to look pretty and the stereo to sound good

I've got a 5 speed with minor mods(MP3 ecu, magnaflow catback, and Injen SRI-soon to be adding Ractive header).

and i recently cheaped out (VERY VERY VERY VERY BAD DECISCION) and got some cheap crap for my car just so i could throw the Racing harts on.

Spend the money on good tires. Your car will love you for it! Callie's car outcorners me easily now cause she's got good rubber and I have cheap crap

 

[maxchao]

Yea tires do more than people think. I've got yokohama s drive summer tire and I love them, but I might go back to all season next time I change tire because...these yokohamas hold the road too well that I can't break traction to have fun. It's safe though, hard to loose control for sure.

Josh

 

[slowzoom]

She's got the sportshift auto, but, no performance mods. She just likes it to look pretty and the stereo to sound good

I've got a 5 speed with minor mods(MP3 ecu, magnaflow catback, and Injen SRI-soon to be adding Ractive header).

and i recently cheaped out (VERY VERY VERY VERY BAD DECISCION) and got some cheap crap for my car just so i could throw the Racing harts on.

Spend the money on good tires. Your car will love you for it! Callie's car outcorners me easily now cause she's got good rubber and I have cheap crap

So she looks pretty and wins the race??(second)

 

[RatLabGuy]

My suspicion is that the difference is related less to the actual tire size, and more the general design quality of the tire.
The tire size change from 195 50 to 205 55 is only 5%; honestly at 30 mpg you're only talking netting 1.5 mpg at best. However you've also incresed the contact patch on the road (more friction) by 5% so that will be cutting down on the MPG gain substantially. When I switched to my P-Zero Nero's at 205-50 from the stockers (2.5% change), I actually got a slight MPG drop... but the performance was still soooo much better.

I can see the lower highway RPMs being nice, but 5% is small - only from 3500 to 3325, for example.
I'd think the best change for MPGs would be like 195-60, keep it skinny but move all the RPMs down a little.

 

[HelionTBone]

My suspicion is that the difference is related less to the actual tire size, and more the general design quality of the tire.
The tire size change from 195 50 to 205 55 is only 5%; honestly at 30 mpg you're only talking netting 1.5 mpg at best. However you've also incresed the contact patch on the road (more friction) by 5% so that will be cutting down on the MPG gain substantially. When I switched to my P-Zero Nero's at 205-50 from the stockers (2.5% change), I actually got a slight MPG drop... but the performance was still soooo much better.

I can see the lower highway RPMs being nice, but 5% is small - only from 3500 to 3325, for example.
I'd think the best change for MPGs would be like 195-60, keep it skinny but move all the RPMs down a little.

Can't help but agree with that assessment. However, I think its the quality of my tires that have made the most noticeable difference for me. I do like they way they fill the wheel well out though, because I have no intention of lowering.

 

[shadowncs]

I have Nordic Icetrac winter tires 205/55/R16 on my new P5 - that's what the dealer gave me. So I did the math on diameter difference from stock 195/50/R16, for everyone to enjoy

Rims 16'' => 406.4mm in diameter

stock 195/50/R16
195mm width
195*50%= 97.5mm side wall height
total wheel diameter = 406.4mm + 2*97.5mm = 601.4mm (~23.68in)


our 205/55/R16
205mm width
205*55%=112.75mm side wall height
total wheel diameter = 406.4mm + 2*112.75mm = 631.9mm (~24.88in)

so the new wheels are (631.9-601.9)/601.9 = ~5% larger so here is the
speedometer reading vs actual speed
30mph means 31.5mph (actual speed)
60mph means 63mph
40km/h means 42km/h
60km/h means 63km/h
100km/h means 105km/h

not a dramatic difference if you ask me. Just remember to obey the law looking at your dash and you'll move along with the slightly speeding traffic and here is the best part..... your wife will not even notice! haha

 

[slowzoom]

...not a dramatic difference if you ask me.

5% is not significant? If I could package a product that gives you 5% better milage you could make mucho $$$.(dance)

 

[shadowncs]

Interesting you would say that... just yesterday I did my mileage - it boiled down to about 18mpg so it hurts to hear you talking about better mileage. Even after applying the 5% correction.

Now seriously, you will not get better mileage just because tires are bigger. If there is any mileage gain, it would be on the highway only when the RPM would be lower.

As for my bad mileage, it is a combination of daily <3km trips and underinflated tires and lack of tuneup in general, I bought the car 1mo ago so still learning its ways.

 

[HelionTBone]

Interesting you would say that... just yesterday I did my mileage - it boiled down to about 18mpg so it hurts to hear you talking about better mileage. Even after applying the 5% correction.

Now seriously, you will not get better mileage just because tires are bigger. If there is any mileage gain, it would be on the highway only when the RPM would be lower.

As for my bad mileage, it is a combination of daily <3km trips and underinflated tires and lack of tuneup in general, I bought the car 1mo ago so still learning its ways.

I have an automatic and average 27 mpg. The only 2 changes I've made from stock are adding high quality 205-55-16 tires (the quality matters more than the size) and a K&N air filter. I can't tell you which item makes the biggest difference because I did them like 2 or 3 weeks apart.

It should be said, though, that I do about 70% highway (not freeway) driving.