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#1 of 62 Will Narrower Tires With Wider Sidewalls Return, To Improve Fuel Economy?
Jun 04, 2008 (12:07 am)
Put another way, will the drive to improve fuel economy stop, or even reverse, the trend of the past several years, to larger wheel diameters, coupled with wider, lower aspect tires? I wouldn't be surprised if it did, as wheel and tire shapes and sizes have changed to meet changing needs over the decades.
Do you have any thoughts on this?
Jun 04, 2008 (6:01 am)
If times are so desperate that GM finally admits it can no longer churn out 15 mpg vehicles and stay solvent, then, yes, everything's on the table.
And the truth is, cars don't have to get much smaller. Only engines do.
Family sedans don't need 300 hp to get the kids to school and mom to Wal Mart. The ability to go 0-60 in 5.9 seconds doesn't make rush hour traffic move any faster.
Families can still enjoy enough interior volume for comfort. They just can't have all that, and high performance, too.
#3 of 62 Sounds like a return...
Jun 04, 2008 (6:25 am)
...to cars like my 1988 Buick Park Avenue. Its 3.8 V-6 only churns out 165 hp, but its adequate enough for a decent getaway from the traffic light or cruising on the highway. It also has wider sidewall tires than my 2007 Cadillac DTS w/18" wheels that look like rubber bands in comparison.
#4 of 62 This probably isn't much of a reference point...
Jun 04, 2008 (6:56 am)
but a couple years ago, I replaced the 235/75/R15 tires on my '85 Silverado with 255/70/R15's. Slightly larger diameter: 30" versus 28.9", and about 3/4" wider tread. Revs per mile reduced from 719 to 692, so that could make the speedo and odometer read about 3-4% low.
As for weight, according to some specs I found on www.tirerack.com, it looks like the bigger tire weighs around 37-38 lb, compared to around 30 for the smaller.
I really didn't see a noticeable difference in fuel economy with this change, but it could just be the type of vehicle. For instance, my truck only has a 3-speed automatic, and is pretty torquey, so it really doesn't have to do a lot of shifting. But on a more modern vehicle with a lot of gears and less torque, putting on bigger, heavier tires that cause more friction and end up making the overall ratio fairly taller just might make the car rely more on the lower gears in some situations, which could use more fuel. But on the flip side, perhaps going to a smaller, lighter tire on that same car would make it rely a bit less on the lower gears, saving a bit of fuel?
#5 of 62 Safety vs. mpg?
Jun 04, 2008 (9:36 am)
I believe much of the reason for making tires wider have been to provide better handling and braking, with our cars. The more friction the better for those attributes. So 1 of the questions is are you willing to lower the safety of the vehicle to get better mpg.
Similarly you could get mpg gains by making lighter vehicles? Would we strip structural strength and airbag systems, to make a lighter vehicle to get better mpg?
I don't think so as the gain in mpg is minimal compared to the public problem of reducing safety.
You could also if people wouldn't get sticky soft rubber snowtires, just so they could get better mpg with their All-season tires.
#6 of 62 Narrower, yes....
Jun 05, 2008 (6:39 am)
As cars get smaller and perhaps lighter the relative size of their tires will undoubtedly shrink a little. The Tire Rack recommends 185/65/15s for a Prius which is around the same size worn by my first car to wear radials back in '69. It was a TR-4A, weighing about a ton wearing 185/75/15 Dunlops SPs.
Aside from the gains in mileage and unsprung weight I'm of the firm belief that cars with skinny tires were more fun to drive, at least if they were RWD cuz you didn't need much power to get the back to rotate and oversteer through corners.
#7 of 62 Narrower, yes....(andys120)
Jun 05, 2008 (8:59 am)
Plus, narrower tires provide better traction in snow.
Hey, ties and lapels alternate between narrower and wider, so why not tires? Well, okay, ties and lapels are pure style statements, whereas tires are functional. There's an important style element in wheels and tires too, of course, judging by what people pay for upgrades and after market ones.
#8 of 62 Re: Narrower, yes....(andys120) [hpmctorque]
by Stever@Edmunds HOST
Jun 05, 2008 (10:08 am)
I liked my skinny tires I had on my old '82 Tercels. They did good in Anchorage winters, and I could buy a whole new set for like $80. 14" rims iirc.
Maybe the discussion title would be a bit clearer if it said narrow tires and "taller" sidewalls? Or maybe it's a regional speech thing, like Coke or pop, cart or buggy?
Jun 05, 2008 (2:23 pm)
91 mustang gt 'vert 225-55-16
02 explorer 245-70-16
04 escape 235-70-16
07 fusion 225-50-17
the mustang was considered to have larger than average tires when it was new.
tread design and tire composition also affects mileage.
#10 of 62 Re: tires sizes [explorerx4]
Jun 05, 2008 (4:03 pm)
tread design and tire composition also affects mileage
So do tire pressures. Recommended pressures on hybrids are typically high. Tire makers and car makers may start to build tires designed to run higher pressures to improve mileage. Suspensions would be re tuned for these higher pressure levels.