Winter Tires and Bang-for-Your-Buck

December 17th, 2016 by Potato

When it comes to safety and your vehicle, seatbelts are likely the obvious winner in bang-for-your-buck. They’re cheap and save a whole bunch of lives. Yet when I was a kid, I knew adults who wouldn’t wear their seatbelts and just “wouldn’t drive like idiots.”

When I was a cheap grad student driving an older car, I also said something similar as a rationale for not getting winter tires. I didn’t want to buy dedicated rims for a car that might only live another three or four years. I didn’t drive to work so I could always plan my driving to avoid the worst winter storms, and I mostly drove on the highway which was excellently plowed. Well, of course none of that was really true: there were always the storms that came in by surprise (or because I didn’t always check the forecast), or the times when it was important to brave the weather, or the times when most of the route I wanted to drive had been plowed and salted, but part of it was slushy or icy. And even driving carefully there would be a time or two when instead of stopping at the line as I meant to, I’d stop in the crosswalk. Or I’d slip and spin the wheels trying to get started. Never with anyone there, thankfully, but visceral reminders that you can’t cheat winter.

Finally, my tires needed to be replaced. And at the time a new kind of tire was on the market, an “all weather” tire (vs “all season”) called the Nokian WR. They’re good enough in winter conditions to earn the mountain+snowflake mark of winter tires, but the rubber stays hard enough in the heat that you can drive them all year long, so no need for a second set of rims and twice yearly change-overs. They were such a huge improvement over all seasons in winter driving.

So huge that I didn’t need fancy equipment like tape measures and controlled conditions to see the difference. It was like night and day in the ability to drive, and I was never going back to trying to muddle through winter with all-seasons (or “three seasons” as called by car buffs).

Now, they are a bit more expensive, but for the amount of safety edge they give you, it’s really cheap. And important – I definitely recommend them to everyone. After all, “Tires are the sole point of contact to the road. Do not underestimate their importance.” And I used the words “night and day” above – go and find people who have put winter tires on their car and see how many express the increase in traction that way. Yes, it’s anecdotal data, but try to find the number who say “meh, I’m not sure winter tires were worth it.” I could find a few such opinions online, but in person everyone I knew who had got winter tires was satisfied with the value for them and would not go back. The only people who weren’t sure winter tires were worth it were people who hadn’t tried them.

I idly speculated on Twitter that winter tires were possibly the second-best bang-for-your-buck when it came to safety, after seatbelts. Determining how much added safety you get is a bit of a tough metric to come up with, but we can bracket in the cost side fairly easily.

For my Nokian WRs, they cost about $200 more, all-in, than the set of three-season tires I would have purchased instead. There was no hassle about changing them over, storage, etc. So if we assume that a car would need about three sets of tires in its lifetime, that’s about $600 total.

For dedicated winter tires on my Prius, I paid about $850 for the first set, which included steel rims. Then, I had to either pay $20-30 each season for a change-over, or $100 for a jack and jack stands to do it myself (plus the hassle of actually doing it myself). However, the cost of the tires is offset a bit because while the winter tires are on the car, the three-seasons are not getting worn down. So the added cost of winter tires for a 15-year car lifespan would be about $850 for the first set, $650 for the next two sets, $600 for 30 change-overs, less $800 for saving a bit over one round of three-season replacements. $1950 all told over the lifetime of the car.

Safety margin added? Huge. Tremendous. Just enormous. See this video (H/T Preet) for a demonstration of just how much extra traction winter tires provide (and don’t forget that even on clear, dry roads, the cold temperatures alone increase the stopping distance of three-season tires).

What would some other bits of gear people often pine over for their cars for safety reasons?

How about all-wheel-drive, which many people say they need for winter driving? Well, on a Rav4 adding AWD will run you $2,265 on the sticker price, and it will decrease your fuel economy by about 0.5 L/100 km. The total lifetime cost could be over $3,500. Safety margin added? Really not much. As much as people swear by AWD, it really does not add much on safety. If you can’t “get up and go” on two wheels, it’s maybe a sign you shouldn’t be driving, rather than that you need help from the rear wheels. Plus every car has all-wheel-stop (i.e., brakes on all four corners), so AWD sometimes provides a false sense of confidence when you get going, which is shattered when you try to stop. I’d take a FWD car with winter tires over an AWD SUV with three-season tires.

Electronic stability control is another feature that adds a margin of safety in winter driving, helping you to keep steering in the direction you want to go and preventing an uncontrolled skid. This one also has a fairly high addition of safety. However, I can’t even find a set of models to compare to tell you how much extra it costs now because many manufacturers have made it standard equipment — and when I was thinking of ranking features by bang-for-the-buck, this one was one I thought might possibly beat out winter tires.

Conclusion

Winter tires will cost a bit more money than three-season tires. However, they add a huge margin of safety to your winter driving. In terms of the bang-for-your-buck, they’re well worth the money in my opinion, the only thing you can optionally buy for your car that provides that kind of value. Plus you can think of them like insurance: you pay a bit more to get them and hope that you never need those extra few meters of stopping distance – you can still not drive like an idiot, but it’s there if you need it.

Go ahead and ask around, this is one area where there is virtually zero disagreement from experts and those who have tried it. Winter tires are awesome and well worth the price.

With winter-rated all weather tires now available, there really is no excuse to not at least have something winter-rated and better than a typical all-season. Not having storage or the ability to do a change-over is no longer an excuse, and the extra cost is so small that if you can afford to drive in the winter at all, you should be able to afford to drive on something decently safe.

What if you really can’t afford it? Like, driving at all is barely within your grad student budget? This may be bad advice in the end, but if you need to sacrifice something on your car to afford the trade-off for all-weather cars, sacrifice an oil change. Many people change their oil twice per year – dropping one of those should free up the money you need to buy a slightly better set of tires.

Changing My Tires and Pants

November 12th, 2014 by Potato

I just changed my tires over to the winter rubber. It was a gorgeous day for it, but it made me reconsider what I’ve been doing.

It may surprise you to learn this, but not so very long ago I had something called “free time” — as a grad student (and then post-doc) I had a lot of flexibility in when I could show up to work. I didn’t have a daughter so I could do pretty much whatever I wanted to on the weekends. And I didn’t lose nearly 12 hours out of my week, each and every week, to the ever-fucking TTC. Because I didn’t make much at all, giving up some of my free time to save money was a good, good deal.

Back then I paid $20 each spring and summer to get my tires changed over. Well, the last time I went and had someone else do it they seriously scratched a hubcap trying to use a crowbar to take off a tool-less wheel cover, they said they were upping the price to $30 for a change over, and I had to spend nearly three hours to get it done between the drive there and waiting on-site. I said never again: I’d start doing my own tire change-overs. It’s not mechanically complicated, and a good wrench, jack, and jack stands were only a few hundred bucks — I’d make it back in just a few years. Plus it gave me the flexibility to do it on my schedule (like Sunday afternoons), something that suddenly mattered as I had just landed a “regular job.” An added bonus was that I wouldn’t have to remove the car-seat to fit the tires in, which would add an extra half hour or so to the process of going to a shop. Everything pointed to DIY tire change-overs. That Potatomas the in-laws got me a jack and stand kit and I was in business.

So I’ve done my own changeovers for a few years now. Each year I come out aching because I am too old for this ish. But it counts as exercise, so yay I guess. It takes me way longer than I ever expect — the first two times were nearly four hours, and even now that I’m better and faster it still takes at least two. But I can do it more-or-less on my schedule. And having a proper jack and practice came in handy when I got a flat and had to change it in sub-zero weather. The math has kind of balanced out and I have all the tools now, so I just keep going with it.

This fall’s iteration has changed the equation though: I ruined a pair of perfectly nice pants*. Now that’s partly my fault for not thinking ahead: I have not-nice pants and shirts specifically for tasks like that, so not getting changed into the proper attire was sheer idiocy. I keep thinking that my time is much more valuable these days and I should just pay someone, but it still takes about the same amount of time to go somewhere — and this year I was limited more by the never-ending fall drizzle than by weekend availability. And paying someone would entail a lot less effort and sweating — and I could possibly read or write something useful while in a waiting room somewhere.

Getting the equipment for changing my tires was going to lead me on a whole automobile maintenance self-sufficiency quest: next I would start doing my own oil changes, and well… actually, that was about as far as I ever intended to go. The pros can handle the rest. Anyway, ruining pants that were only a few months old has really thrown a wrench into the frugality aspect of DIY car maintenance — that’s like the cost of two changeovers right there. I like knowing that I can do it myself, and that it’s a minor challenge I have met, but it is not a fun pastime that I would do anyway. If I have to add in the cost of ruining clothing to the DIY column, taking the car to a shop looks a lot more appealing for this spring.

* – if you must know, by being fat and attempting to squat. Riiiiiip…

Car Seats

March 5th, 2013 by Potato

We bought the Graco Snugride 35 carseat initially because all the safety research suggests that keeping kids rear-facing longer is safer. Rated up to 35 lbs, we figured that this car seat — though large and heavy — would keep Blueberry rear-facing until she was pretty much two years old. Though it’s large for an infant carrier, I was able to fit it in the Prius and still manage to get my seat to a decent position for driving (it’s about an inch further forward than I had it when I positioned my seat without any such constraints — not the most comfortable position but a workable compromise). Blueberry is very tall for her age (obviously a mix-up at the hospital), and though she still has over 10 lbs to go before hitting the weight limit she’s getting close to the maximum height for her infant seat. Time to move up.

So now we’re off shopping for convertible car seats, the next step up that can be either rear- or forward-facing. With these larger seats, it’s almost impossible to find ones that can fit behind a front seat well enough for me to drive or for Wayfare to comfortably sit. I’ve been checking various forums for tips and reviews and pictures of how they fit, and it seems like the two on our shortlist are the Britax Marathon/Boulevard or the Diono Radian. I’ll spare you my pro/con lists, coin-flipping, and hand-wringing on this decision (though feedback on those seats is welcome in the comments).

What really got me in our search was the oft-stated fact that carseats are improperly installed some huge portion of the time. I heard numbers ranging from 80% to 95% depending on the source, and it got me thinking: where does this bit of conventional wisdom come from? I’ll grant that installing the old-fashioned way with a seatbelt is difficult both in terms of skill and strength required, but I really had no issues with the LATCH install. After all, that’s what LATCH is supposed to help with. Plus, the epidemiology data all says that kids in car seats are safer, so either the install error-rate is over-stated, far more people are managing to get/pay for a professional installation, or seats are safe even if installed incorrectly. I started to wonder just how true this conventional wisdom was, or if perhaps this factiod had been invented by the stores offering a $25 installation service and picked up by the media, so I went off in search of a source.

There are some NHTSA reports that seem to be the origin of these figures. This one, for instance, gives a high error rate for installation, topping 95% for first-time installers, who in this study (or a similar one I just read) were recruited from a university’s volunteer pool (i.e.: first-year psych students giving their very minimum effort for $10 and a course credit).

The most common error is loose installation: a carseat, when properly installed, is supposed to be able to move less than an inch. Now, a carseat that can be wiggled an inch and a half is not meaningfully more dangerous than one that can only be wiggled an inch; likewise, the carrying handle for a removable carseat has a specified position for use in the car for each brand (and it is often different for each model) — though many first-time installers got it wrong, it’s also not usually critical. If they apply a severity score, then “only” about 30% of seats were incorrectly installed in a really bad way. The good news: the error rate drops in half once parents/caregivers who have carseat experience are tested, rather than novices. The bad news: that’s still a nearly 50% error rate. To pick out one more interesting factoid, there was a higher error rate for those who drove cars with leather seats.

I’m surprised that even digging into the data, the “legitimate” error rate still appears to be shockingly double-digits high. That really says that something needs to be done to make carseats easier to install safely. Some kind of standardization is most likely the answer: either continue with LATCH but standardize the connectors, or create a universal base that the manufacturer’s individual seats can clip into. Angle adjusters with a wide range of motion are also likely going to be needed — far too many official installation instructions include the use of towels or pool noodles (sold separately) to prop up one part of the base, which is frankly ridiculous. Many require a great deal of strength to tighten properly, or that the adult put their full weight on the seat to jam it down into position — a ratcheting belt-tightener would be a great feature on many of these seats.

As an aside (and not necessarily a product recommendation) this car seat is a neat one from a human factors point of view, with sensors and a display to help ensure correct installation. The video there is only about a minute long if you want to go have a watch.

Prius Year 2

February 28th, 2012 by Potato

The Prius just turned 2. Still love it, though we got pretty much the biggest infant carseat on the market (a Graco Snugride 35) because it will keep baby rear-facing longer… but it barely fits in the back, which is a bit worrisome. We have to move one of the front seats forward a bit to get it in. We did a test install a few weeks ago, and when the weather gets warmer I’ll try again to see if I can comfortably get it in behind me in the driver’s side (I know I’m never going to need to recline once I get my seat set), otherwise the passenger seat will just have to be a touch further forward than normal.

I still have to figure out what I want to do for protecting the seats from the inevitable baby mess. Any suggestions from the blogosphere? Some people swear by the wet okole neoprene fitted covers, but they’re pretty expensive. Canadian Tire has some much cheaper generic covers, and just scotch guard may be enough to prevent any permanent damage.

As you read in the summer, there’s only been one problem with the car: the plastic cover on the underside came loose while driving and had to be replaced (and somewhat more troublingly, removed while in the middle of nowhere). That was replaced under warranty.

For the past two years real-world fuel consumption has averaged 5.1 L/100 km, vs an expected ~9 L/100 km real-world for a comparable alternative (if I had gone with a Matrix/Accord/other). Gas has averaged $1.15/L, so I’ve saved about $1500-1600 so far, putting me on track for a ~5 year “pay back”. Of course, I’ll save that much again for the 5 years after that, and the 5 years after that, and reduce my exposure to these volatile/rapidly rising gas costs the whole while. So yeah, I’m still pleased with my decision.

What Makes Hybrids Awesome: The Engine

February 8th, 2012 by Potato

Hybrids (like my Prius) contain many awesome innovations that give it that great efficiency, leading to lower fuel use (and lower expenses!). With plug-in hybrids starting to hit the market, the ways that technology provides efficiencies increase. Yet even though hybrids have been around for well over a decade, they are still very poorly understood (particularly by auto journalists).

Quick, which one innovation contributes the largest portion of the fuel savings in a hybrid like the Prius, is it:

a) regenerative braking
b) exhaust gas recirculation
c) atkinson-like cycle engine
d) electric motors and a battery to power acceleration
e) aerodynamics, including a tear-drop shape and a plastic cover for the underside to smooth airflow
f) lightweight aluminum construction
g) low rolling resistance tires
h) continuously variable transmission
i) an engine that turns off when not in use (coasting, at stops)

All of those innovations (and I’m sure a few I’ve forgotten) add to the efficiencies. Odds are good that you answered a, or d, or i, since those are the items that are the most distinctive about a hybrid, and which get the most press. And of course, none of those three are of much good when smoothly cruising on the highway, which is why auto writers keep saying stupid, easily disprovable things like “all that hybrid gear is useless on the highway.”

Yet a quick check of fuel consumption ratings shows that indeed, hybrids get fantastic highway mileage. The gap between them and a regular car isn’t as wide in the highway cycle as in city driving, but it’s still a really good improvement. So why is that?

It’s because the actual answer is (c): the atkinson-like cycle engine. Estimates vary, but something like half of the total improvement in overall mileage (and nearly all of the highway-rating boost) is because the engine is simply more efficient at turning hydrocarbons into motion (the “thermal efficiency”). All that business with the electric motors helps, and there certainly is some benefit from pairing the properties of an electric motor (which generates maximum torque at low RPM, and is great for helping to meet peak demand) with a gas engine (which needs to rev up to produce acceleration, and which has a high-density fuel source for steady-state power demands), but it’s there largely because with an Atkinson engine, you’re not going to get anything approaching an acceptable 0-60 time. That efficient engine needs help getting going.

If you wanted (e.g.: if you’re an automotive engineering student looking for a summer project), you could strip out all the electronic stuff from a hybrid and just drive around with the Atkinson engine, and you’d get a big part of the benefit. Of course, you couldn’t actually use that in traffic since it would take you forever to accelerate, but on a closed course to prove a point…

Anyway, once you’ve got the electric motor in there for the acceleration boost, you can do all the extra tricks with it to squeeze out even more efficiency, like shutting off the engine when coasting, regenerative braking, etc.

So now that you know about the importance of the Atkinson-cycle engine, you see why hybrids still rock on the highway. In fact, improved thermal efficiency is also the reason why diesels get decent fuel consumption numbers on the highway: the higher compression of a turbo diesel is also more efficient at turning hydrocarbons into motion. In terms of litres burned per hundred kilometers, diesel (like a Jetta or Golf TDI) is on par with a hybrid like the Prius; though once you factor in the higher energy density of diesel, well, you can see who the winner is (and I won’t get into the issue of city driving, too).

And of course, knowing that this is the single biggest source of efficiency is why I was so upset that GM didn’t include an Atkinson-like engine in the Volt, instead just slapping in an off-the-shelf engine, which is why its efficiency isn’t so great once the charge from the plug-in is used up.