New tires = poor fuel economy?

Taskmaster · 02-26-2016, 07:57 PM

Quote:

Originally Posted by Eagle1oh7

Misread that!

Are you driving more aggressively?

Not at all.

X-M · 02-26-2016, 08:13 PM

Stickier tires will affect the acceleration on a car. It slows down the acceleration, but your trade off is not slipping at the rear wheels, hence why drag cars run slicks on the back and regular tires up front. Mpg is at its worst during acceleration, since the tires are stickier the car needs to put more power down to get the car moving, and keep the car going in straight without losing speed. The tradeoff for that is shorter stopping distance and better handling.

chris82 · 02-27-2016, 03:19 PM

FWIW I've never dropped below 28-30 mpg (highest I've gotten) on pure highway driving on any tires I've used whether RFT, summer, or winter tires, apex, stock, or any other aftermarket wheels.

Taskmaster · 02-27-2016, 03:22 PM

Quote:

Originally Posted by chris82

FWIW I've never dropped below 28-30 mpg (highest I've gotten) on pure highway driving on any tires I've used whether RFT, summer, or winter tires, apex, stock, or any other aftermarket wheels.

Any change because of the rubber or wheels? I don't get it...

Taskmaster · 02-27-2016, 07:21 PM

I don't think it's just the tires or wheels at all, I think there is something wrong with the car. The redline is now 6500RPM for some reason, on cold starts the car starts HARD, and the car stumbles at low RPM in high load. Going to pull some shadow codes...right after I buy a new cable.

Three_thirty_I · 02-27-2016, 07:38 PM

Hope it's nothing serious! Let us know what you find.

larrysing · 04-01-2016, 09:00 AM

In general, new tires decrease the MPG for a short period. They are softer, they have the most rubber and weight they are EVER going to have. They should break in and be fine, depending on if they are the "right" tire for good MPG on your car. You can reduce overall MPG by buying the "wrong" tire.

I had a Camry hybrid, and when I replaced the LRR tires with a non-LRR set, we lost 7 MPG, from 34 MPG down to 27 MPG.

Taskmaster · 04-01-2016, 11:46 AM

Problem ia the valvetronic sensor is failing.

Three_thirty_I · 04-01-2016, 08:34 PM

Quote:

Originally Posted by TheAxiom

Problem ia the valvetronic sensor is failing.

What makes you suspect this? Symptoms, errors?

Taskmaster · 04-02-2016, 09:48 AM

Quote:

Originally Posted by Three_thirty_I

What makes you suspect this? Symptoms, errors?

Codes (shadow codes) and random judders, 6500rev limit, etc.

Three_thirty_I · 04-02-2016, 11:31 AM

Quote:

Originally Posted by TheAxiom

Codes (shadow codes) and random judders, 6500rev limit, etc.

Ah, was curious, these things don't always throw codes.

Fundguy1 · 04-02-2016, 11:36 AM

More sticky tires. Big drop though. I'm getting mid 20s with my car on 19" 235 and 275 Michelin pss.

Taskmaster · 04-02-2016, 11:42 AM

Quote:

Originally Posted by Fundguy1

More sticky tires. Big drop though. I'm getting mid 20s with my car on 19" 235 and 275 Michelin pss.

I had 19s on before (with V12s) 235/265 and the fuel economy was better. It just so happened that the sensor failed with the wheel and tire change.

Fundguy1 · 04-02-2016, 11:44 AM

How's the mpg now?

Taskmaster · 04-02-2016, 09:09 PM

Quote:

Originally Posted by Fundguy1

How's the mpg now?

Piss poor still, like mid to high 20s on my communte when I used to hit 30s.

I need to fix the valvetronic sensor, but it's a really cumbersome job.

Fundguy1 · 04-02-2016, 09:11 PM

So unreliable those 328s.

Taskmaster · 04-02-2016, 09:34 PM

Quote:

Originally Posted by Fundguy1

So unreliable those 328s.

Pretty much. The good news is, this is as bad as it gets.

Torobimmer · 04-03-2016, 03:48 PM

Quote:

Originally Posted by Ruddigger

The most I ever got was 24.5 with everything bone stock. How do people get such high mpg?!

same here. I get 24.5 mpg on manual transmission. 50/50 highway/street travel.

currently it dropped to 23.7 or 23.5 perhaps because its getting warmer in my area.

Taskmaster · 04-04-2016, 11:45 AM

Quote:

Originally Posted by tororosso1

same here. I get 24.5 mpg on manual transmission. 50/50 highway/street travel.

currently it dropped to 23.7 or 23.5 perhaps because its getting warmer in my area.

There ia something going on here for sure. I was doing 80-85mph and the readout said 32-34mpg with cruise control, and then the car surged for no reason and that dropped to 26-27mpg.

Then, a small jump in partial throttle acceleration made the readout just drop to 6mpg, like the car was just dumping fuel.

Need to get this fixed, car drives pretty crappy right now.

94marcus · 04-05-2016, 10:42 PM

axiom out here fishing for rep

Torobimmer · 04-10-2016, 03:16 AM

Quote:

Originally Posted by TheAxiom

There ia something going on here for sure. I was doing 80-85mph and the readout said 32-34mpg with cruise control, and then the car surged for no reason and that dropped to 26-27mpg.

Then, a small jump in partial throttle acceleration made the readout just drop to 6mpg, like the car was just dumping fuel.

Need to get this fixed, car drives pretty crappy right now.

I think i figured it out the significant drop from 24.5 to currently 22.2 mpg.
I switched from 17 to 19" wheels and added a front lip (which added 3 inches of frontal surface area under the front bumper) due to increasing drag and weight of bigger wheels+tires my fuel economy dropped 2.3 mpg on 50/50 highway/street usage.

I can deal with the penalty of fuel efficiency vs aesthetics
the car gets more head turns now days.

02-26-2016, 08:13 PM	#24
X-M Enlisted Member 11 Rep 39 Posts Drives: 2012 E92 328i xDrive Join Date: Jul 2015 Location: Long Island, NY iTrader: (0)	Stickier tires will affect the acceleration on a car. It slows down the acceleration, but your trade off is not slipping at the rear wheels, hence why drag cars run slicks on the back and regular tires up front. Mpg is at its worst during acceleration, since the tires are stickier the car needs to put more power down to get the car moving, and keep the car going in straight without losing speed. The tradeoff for that is shorter stopping distance and better handling. Last edited by X-M; 02-26-2016 at 08:14 PM.. Reason: grammar
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02-27-2016, 03:19 PM	#25
chris82 Brigadier General 827 Rep 3,856 Posts Drives: 128i Join Date: Aug 2012 Location: NY NY iTrader: (8) Garage List 2009 BMW 128i [9.80]	FWIW I've never dropped below 28-30 mpg (highest I've gotten) on pure highway driving on any tires I've used whether RFT, summer, or winter tires, apex, stock, or any other aftermarket wheels.
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02-27-2016, 07:21 PM	#27
Taskmaster Banned 2465 Rep 9,004 Posts Drives: M235i 6MT / E92 328 Msport 6MT Join Date: Nov 2013 Location: Florida iTrader: (6)	I don't think it's just the tires or wheels at all, I think there is something wrong with the car. The redline is now 6500RPM for some reason, on cold starts the car starts HARD, and the car stumbles at low RPM in high load. Going to pull some shadow codes...right after I buy a new cable.
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02-27-2016, 07:38 PM	#28
Three_thirty_I Lieutenant Colonel 200 Rep 1,834 Posts Drives: '05 E90 330i Manual Join Date: Aug 2010 Location: Cape Town, South Africa iTrader: (0) Garage List 2005 BMW E90 330i [0.00]	Hope it's nothing serious! Let us know what you find. __________________ BMW E90 330i (M) '05 (His) \| (Hers) BMW E46 320i f/l (M) '03
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04-01-2016, 09:00 AM	#29
larrysing First Lieutenant 95 Rep 308 Posts Drives: 2011 335d M-Sport, Nav/Blinds Join Date: Feb 2016 Location: Arlington, TX iTrader: (0) Garage List 2011 BMW 335d [0.00]	In general, new tires decrease the MPG for a short period. They are softer, they have the most rubber and weight they are EVER going to have. They should break in and be fine, depending on if they are the "right" tire for good MPG on your car. You can reduce overall MPG by buying the "wrong" tire. I had a Camry hybrid, and when I replaced the LRR tires with a non-LRR set, we lost 7 MPG, from 34 MPG down to 27 MPG.
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04-01-2016, 11:46 AM	#30
Taskmaster Banned 2465 Rep 9,004 Posts Drives: M235i 6MT / E92 328 Msport 6MT Join Date: Nov 2013 Location: Florida iTrader: (6)	Problem ia the valvetronic sensor is failing.
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04-02-2016, 11:36 AM	#34
Fundguy1 Major General 2032 Rep 8,339 Posts Drives: 335 e93 Join Date: Aug 2014 Location: Orlando, fl iTrader: (0)	More sticky tires. Big drop though. I'm getting mid 20s with my car on 19" 235 and 275 Michelin pss.
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04-02-2016, 11:44 AM	#36
Fundguy1 Major General 2032 Rep 8,339 Posts Drives: 335 e93 Join Date: Aug 2014 Location: Orlando, fl iTrader: (0)	How's the mpg now?
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04-02-2016, 09:11 PM	#38
Fundguy1 Major General 2032 Rep 8,339 Posts Drives: 335 e93 Join Date: Aug 2014 Location: Orlando, fl iTrader: (0)	So unreliable those 328s.
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04-05-2016, 10:42 PM	#42
94marcus Private First Class 16 Rep 145 Posts Drives: 09 328i 6MT Join Date: Jun 2014 Location: san diego iTrader: (0)	axiom out here fishing for rep __________________ Charcoal Delete // K&N Drop In // Cyba Air Scoops // OEM SSK // AA Stage 2 Tune // BC Coils // Apex Arc-8 18X9.5 255/35/18 //
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