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11 December 2010 #1
Dave T. Super Moderator
- Join Date
- 03 Aug 2010
- Location
- near Seattle, Washington
- Posts
- 1,515
- Saab(s)
- 1999 9-3SE (2013-2015), 2005 9-3 (2005-2013), 1990 900 (1990-2003)
tires do make a difference in fuel economy: my own experience
I've long heard that car company select tires with fuel consumption as a factor. After all, governments measure what Americans call "gas mileage". In the 80's, Saab used Pirelli P8 tires and mentioned about fuel economy as a factor.
Immediately after changing to snow tires from summer tires 3 weeks ago, I noticed better gas mileage. Looking back at my fuel records, this seems to be the case every year.
Most of the year, I use Goodyear Eagle F1 Asymmetric tires (235/45R17). Snow tires aren't the most economical but my Bridgestone Blizzak WS60 tires are better than the summer Goodyears. They are also narrower at 215/55R16. The diameter is the same. The weather is also similar before and after the change. My guess is that I get up to 2 mpg better gas mileage with snow tires.
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12 December 2010 #2
- Join Date
- 30 Jul 2010
- Location
- Vancouver, British Columbia, CANADA
- Posts
- 711
- Saab(s)
- 2006 9-3 2.0T SportCombi "Mattie"; On SAABatical: 1993 9000 CSE 2.3T "Matilda"
After switching to my snows (Nokian Hakka 4's) from my Bridgestone RE950s last month, I too notice a slight 5-10% improvement. I attribute that to less overall surface contact area from the snows. But with a sudden "warming" trend these past weeks, I really hate driving on the snow tires.
"Nulla tenaci invia est via"
SAAB CLUB of WESTERN CANADA (SCWC)
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12 December 2010 #3
Frank Administrator
- Join Date
- 30 Jul 2010
- Location
- USA - Netherlands
- Posts
- 7,901
- Saab(s)
- previous: 2006 9-3, 2001-06 9-5, 2011 9-4X
I started recording my fuel purchases and it will be interesting to see if it changes through the year between winter and summer tires. Does fuel mileage also depend on the outside temperature? I know much driving style is a bit more spirited when the roads are dry and clean so that's a factor for me as well.
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12 December 2010 #4
Dave T. Super Moderator
- Join Date
- 03 Aug 2010
- Location
- near Seattle, Washington
- Posts
- 1,515
- Saab(s)
- 1999 9-3SE (2013-2015), 2005 9-3 (2005-2013), 1990 900 (1990-2003)
I have all my receipts and a gas log book with complete information from 2005. I think the most comparable data is just before and after switching tires because the weather is similar and the driving patterns (city or highway) are probably similar. My driving style before the change to snow tires is about the same because it would be getting colder and I am mindful that traction in summer tires is worse in cold weather.
Even the SID display shows better gas mileage. I reset it each time I buy gas. For me, a 10% improvement would be about 2.5 mpg, 2 mpg would be 8%. It's definitely over 5% (1.25 mpg). My highest mpg have been on the stock Pirelli P6 Four Seasons 215/55R16, a tire that many people don't like.
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12 December 2010 #5
the specified tires for my car are:
- 235/45/R17 94W (Diameter total :643 mm. (+0 %)) in my car now tires.
- 225/45/R17 94W (Diameter total :634 mm. (-1.42 %))
- 225/45/R18 95W (Diameter total :660 mm. (+2.49 %)
according to the green card for ITV (vehicles technical inspection (+-3.00 %))
the width is the factor to be in count for MPG. more width less MPG. in my case diameter is not the same for the tires specified.
I can't replace with tires 215/50 R17 94W (Diameter total: 647 mm. (+0.54 %) due to is not specified in the green card.
Right now is my turn to replace the tires after 27,355 Miles with sportcontact2 continental and I am thinking to fix with Michelin Primacy Hp but not sure yet about the width 225 or the genuine ones 235.
- my Opel Omega is a bigger car and has 205/65R15 94V and get a very good MPG and comfort ride.
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13 December 2010 #6
- Join Date
- 30 Jul 2010
- Location
- Vancouver, British Columbia, CANADA
- Posts
- 711
- Saab(s)
- 2006 9-3 2.0T SportCombi "Mattie"; On SAABatical: 1993 9000 CSE 2.3T "Matilda"
Funny you should say that, Dave. Couple years ago I was ridding my old Yokohama Avid V4s and actually purchased a set of P6s. I drove out of the tire shop, went down the road for less than 3 miles, and immediately turned back to the shop. I thought the P6s were terrible ...... loud, wallowy and gave me little steering feedback or road "feel". The shop guy was nice 'nuff to let me pick any tire to switch to. I picked the RE950s. Drove away and was immediately happy with them, they felt just like my old Yokos when they were new.
"Nulla tenaci invia est via"
SAAB CLUB of WESTERN CANADA (SCWC)
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