break in period? (Full Version)

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break in period?

  

importkiller -> break in period? (5/18/2006 12:22:59 AM)

Will Gas mileage improve once a certain amount of miles are put on the motor? I have 500mi on my h3 (base with 265's) and I'm still only getting around 260 on a full tank. I've read on other forums where people are averaging 350+ miles on a tank, wondering if I will ever see that.

  
skeeet -> RE: break in period? (5/18/2006 1:12:36 AM)

If you are getting 11.3 mpg then something is wrong. I have never seen less then 15 mpg. What is your tire air pressure?
Yes, gas mileage and hp figures usually get better around 5,000 to 10,000 miles. I would try Mobil 1 5-30 for slightly better mileage also. Sure the parking brake is off?[:D]

importkiller -> RE: break in period? (5/18/2006 1:41:58 AM)

Most of my miles are driving in NYC will little to no open highway miles. My last tank was 265mi. and it took 21 gallons, so I got 12.6 mpg. I'll check tire pressure tomorrow, if it's ok and my next tank is the same as my last I'll bring it to the dealer to see whats up.

yes the parking brake is off[sm=goodidea.gif]

importkiller -> RE: break in period? (5/18/2006 1:57:11 AM)

ok, didn't feel like waiting till tomorrow so I just checked air pressure. All 4 tires are at 31 psi. Door sticker says 30 psi but tires say 44 max psi. Should I put a few more pounds in?

Dennis -> RE: break in period? (5/18/2006 8:19:52 AM)

Yes!..inflate your tires to at least 35 psi (cold)..The sticker says 30 becuase that will give you a softer ride, but they fail to mention at that low pressure, the tires will wear out faster and give you poorer gas mileage..don't forget the spare too..as the Tire Pressure Monitor (TPM) also looks at it.

racepet -> RE: break in period? (5/18/2006 11:59:19 AM)

Impy,

I got 10.8 on the first tank, averaging low 13's now mainly LA city driving after 1600 miles. It does not seem to matter if I gun it or drive like Morgan Freeman. Just bumped the tires up to 39psi from 30psi and it looks like I will do about 1 mph better.


Linus Gump -> RE: break in period? (5/18/2006 1:01:04 PM)

I just replaced my tires with a more aggressive tread but stayed with the stock size. At 35 psi the tread centers would be hot after a short freeway drive, or a surface drive across town. Also, if I drove over some dirt on the road, only the center would pick it up. I dropped them to 30 psi and the temp is much cooler and more even across the tread, but now the TPS comes on until the tires warm up. The ply layers are the same bewteen the two tires, so if you do increase your pressure, keep a close eye on tread wear.

racepet -> RE: break in period? (5/18/2006 1:52:23 PM)

Linus what brand did you get? Any pics?[sm=feedback.gif]

Dennis -> RE: break in period? (5/18/2006 2:06:29 PM)

Not to contradict you Linus, but I think you're fooling yourself into thinking they are running cooler at a lower pressure...In fact it probably should actually cause more heat and wear and tear on the tires, becuase of the higher friction factor...Rather than go into the physics of it all, just think about the Firestone dilemma, when they were having the premature blow outs right and left..Come to find out, the final analysis proved that the tires were UNDER inflated and was causing heat build up in the tire, which resulted in tread separation and failure...Any tire maker of credibility will tell you that inflating to the maximum safest tire pressures allowable for a given tire, will give you 3 things;

1. A firmer ride

2. Cooler running tires

3. Longer tread life and more even wear across the tread face.

racepet -> RE: break in period? (5/18/2006 4:16:57 PM)

Dennis,

Not to be contrary[sm=dontgetit.gif] [sm=badbadbad.gif]but if that is true why do the Cup cars on sundays need 3-10 laps to come up to speed based on tire pressure being to low. I have heard DW say the pressures in some cases are in single digits. I used to run BFG AT's at top psi 10 years ago and they ended up looking like a bald guy after 15000 mi, (I did it because I put a lift kit and tires on a manual steering base model).

Dennis -> RE: break in period? (5/18/2006 5:55:09 PM)

No, that's cool...

I don't know the answer to that..maybe something to do with the different types of tires and the way their made..I don't know, but maybe you're right about these kinda of tires..But tread wear rating makes a big difference in how long the tire lasts...Lower the rating, the softer the tire material....But the physical science of heat because of friction is what's baffling me, as why it don't apply in your examples..

I'll be doing a little more research, me thinks..[:D][:D][8|]

Linus Gump -> RE: break in period? (5/18/2006 6:11:55 PM)

I know they are cooler because I put my hand on them as soon as I got home, and the tread center was very warm, bordering on hot. The next day, before I went out, I dropped the pressure down to 30, and drove about the same distance and checked the tires again by placeing my hand back on the tread surface. Not only was the temp more even across the entire tread surface, it was much cooler to the touch. The conditions were about the same for both trips, so the comarison should be fair. The higher temp is probably because that one small strip of tread in the center was doing all of the work for the entire tire.

Linus Gump -> RE: break in period? (5/18/2006 6:27:44 PM)

One thing you have to keep in mind about tires is that the best pressure is one that spreads the weight of the vehicle evenly aross the entire tread surface. The weight of the vehicle will mandate this more then anything, up to the max pressure stated on the side wall. Think of a full size diesel pickup loaded to the max with camping and offroad gear running something like a 14 inch wide swamper. The truck would require a higher pressure in the tires then that same tire on say a lightly loaded old flat fender Jeep. At max pressure, the tire will properly support the max weight printed on the side wall. The Firestone tires were under inflated for thier use. If you run a pressure under the ideal pressure for your vehicle, you will cause under inflation damage to the tire, up to and including Firestone sequals. If you run higher pressure the the ideal pressure, you will cause over inflation problems such as poor tread wear and tire life, including the tire coming apart as well. The construction of the tires also play a role in what pressure to run, but that is harder to read with a stiff multilayer sidewall and tread that doesn't allow for much flex of the tire.

Dennis -> RE: break in period? (5/18/2006 7:11:45 PM)

Allrighty then...[:D]

Listen..I'm open minded...So in the next day or so, I will preform the same experiment as you did Linus and I'll fess up to the results no matter how it turns out..In fact I'll even go more scientific and do it on the same day within the same hour and use a Raytek infrared scanner...in all, to keep all the other variables constant, but only vary the pressure....I'm very curious now...Thanks for the good discussion..What you guys are saying may also makes some sense...

So what is ideal or optimum tire pressures then?..I'm not saying to over inflate like you're suggesting, as this would cause the center of the tread to wear more than the outer edges as you said and I concur..and I'm not saying to undeinflate either, as this will cause the outer edges to wear more than the center tread and also damage the sidewalls...


But in the mean time read this Tire Rack info[sm=smiley2.gif]

[image]http://i16.photobucket.com/albums/b47/Atwater/raytek.jpg[/image]

BlackH3CA -> RE: break in period? (5/18/2006 11:41:51 PM)

Dennis...your desk looks pretty cluttered?

  

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