RotaryShrink

I recently changed over to new 17" rims with Dunlop Wintersport M3's in preparation for the winter weather. In spite of the 50-50 weight distribution in this car, has anyone found it helpful to throw some extra weight into the trunk to assist with traction? I have a couple 75 lb. dumbells in mind for this purpose.

alnielsen

iTrader: (4)

When I was living on my parents farm in Michigan, my dad put a 200 lb. tractor wheel weight in the trunk of my 72 Duster. The roads were covered with snow. The first corner I got to, I turned the steering wheel and the car went straight. I got the car turned around and got that weight out. What is the moral of this story you ask. Weight will give you traction, but too much will ruin the cars steering, braking, handling, etc.

wakeech

if you needed to drive through either deep fresh snow, or hard icy and packed old snow (especially when there are hills involved), adding more weight over the drive wheels is almost necessary.

being that the incredible dynamics of this car, benefitted by its uncanny balance, shouldn't be tested in these sorts of conditions outside of the rather teenage 15kph doughnuts in a huge empty parking lot, adding weight will enhance the tyre's ability to cut through/into the snow, and give it as much pressure as it can on ice (really the only thing you can do, aside from studs as those're illegal except for off road).

the trunk is the easiest place to put more weight, but just more weight in general would be good (accompanied by even slower and more gingerly driving) in conditions where you know you'd constantly be afraid of sliding off the road. in the post above, the concern was not being able to make a turn, which is definitely a symptom of a significantly more massive car and significantly less grip. more weight must be accompanied by slower braking, lower speeds in corners, and in general just as much care in driving as when you hadn't added the weight, but the difference is that you've got a whole lot more push straight ahead when you need it.

because you already have snow tyres on the car, you're in pretty good shape and should be alright in even a mild Canadian winter. if you were so inclined, or had the poor misfortune, of driving during a storm or in a town which had seen +4ft of snowfall adding more weight would definitely be prudent.

oh, and remember to turn off the ABS, or your brakes may not work when you need them.

zojas

how do you turn off the ABS? or did you actually mean to turn off the dsc?

MP3Guy

Ha! Reminds me of the days when my dad tossed a huge bag of Sakrete in the trunk of his Lincoln Mark III. Now there was a car with "balance!"

http://www.me.mtu.edu/~prater/carpic...ns/70mark3.jpg

Nothing like a 5500 lb. "coupe." How did we ever live with these monsters?

mdmaclean

I certainly did not follow this advice last winter. I have winter tires (Toyo Garritt HT's), and left ABS and TCS and DSC on. I found that worked quite well in the conditions here, including heavy snowfalls which had other cars in the ditch.

What I have done with my previous car (BMW 540), was turn off TCS if I was stuck in a parking lot just to get going, and then turned it back on. The stability systems work very well in almost all real-world conditions.

The RX-8's limit slip differential makes it's winter use even easier than the BMW.

I know that strictly speaking a car will stop quicker in unpacked snow with ABS off. Personally I find that the occasions when that is a problem are considerably outnumbered by the times when ABS is my friend. Of course that is based upon my local weather, and YMMV.

I would only unbalance my car intentionally if I was stuck, and never for regular dring.

Sputnik

I also disagree with adding weight in the trunk. Any weight you add to the car obviously increases the mass of the car. And that will negatively affect braking and controlling the car in a turn. The more weight you put in to increase your traction, the worse your braking and handling will be. So you end up trading one for the other, and frankly, in poor conditions, I'd rather not trade braking and car control for forward traction. I am alot more comfortable feathering the throttle.

Another thing to consider is having that much weight loose in the car. While barbell weights in the trunk aren't going to fly into the passenger compartment and knock you upside your head, any sudden movement might cause whatever to slide or shift, and damage something in the trunk. And shifting weight when braking or handling is also a bad thing.

And as Mdmaclean said, the only time taking ABS off would help is in unpacked snow, and the times that most of us find ourselves in that situation is actually pretty rare. Most of us will more often find ourselves on packed snow, slush, ice, wet, and even dry surfaces much much more often than in unpacked snow. Keep in mind what conditions are, and what surfaces you are actually driving on before making that decision (each of us find ourselves in different situations and conditions, so one answer won't work for everyone). Remember, this is a sports car that 99.9% of us will not be driving around through unplowed streets that haven't been driven through before.

---jps

RX8_Buckeye

I don't know... there are a lot of people who swear by adding weight to the trunk. These are people who have driven with and without the weight, and feel much more comfortable driving WITH the added weight. This will be my first full winter with a RWD car, so I'm going to try it both ways and decide for myself.

I don't know if I buy the argument that the added mass will signficantly reduce braking and steering capability. I think that's an oversimplification, because both are affected not only by the mass of the vehicle, but by the traction (friction) between the tire and ground. If the traction stays about the same when mass is added, then I agree that braking and steering capability will be degraded. However, isn't traction in the ice and snow significantly affected by the contact pressure between tire and ground, which increases proportionally with vehicle mass? If so, does the extra traction offset the added momentum carried into a turn or while braking? I keep going back and forth on this one. Any tire experts care to chime in?

r0tor

iTrader: (1)

I carry around like a 70-100lb bag of sand. My personal theory is yea braking and turning may be negatively effected a bit, but at least i'll be able to go somewhere in the first place! Also if you carry around something like sand instead of dumbells, if your stuck on ice you can always dump out some sand and help with traction... i wouldn't suggest salt though because it can be messy and rust out your trunk.

The ABS and DSC system actually works very well in the snow with some snowtires on.

Shamblerock

The 8 is quite a diffeent animal that rear wheel drive cars of yesteryear. What we should listen to is guys who have had the 8 last winter and what their stories/recommendations are. Anybody else used their 8 last year besides MDMACLEAN, who's feedback was very good to have?

mdmaclean

My opinion is that the same balance that makes the RX-8 fun to drive in the summer is what makes it easy to handle in the winter. Personally, I would not place a significant enough weight in the trunk that the balance would be affected.

I also drove a V8 powered BMW 540 for 3 winters (with snow tires), and again the 50/50 balance and TCS made it easy to drive. I have never gotten stuck (I do live in the city) with either car. YMMV.

r0tor

iTrader: (1)

umm... i drove mine in the winter and gave you some feedback

jaedcem

I don't have an RX-8, but do have experience with RWD cars in winter. The reason to add weight in the trunk is to change the weight distribution. I had a 1969 Firebird that wouldn't go anywhere without at least 100 pounds extra in the trunk. I suspect this car had about 60/40 weight distribution front/rear. Adding the weight shifted the weight distribution closer to 50/50. (I used kitty litter, for the same reasons sand has been suggested - it's useful for when you get stuck.) I now have a Porsche 928 with 50/50 wt. distribution, and have never felt the desire to add any additional weight at all. I have been able to comfortably drive (with Blizzaks) through worse conditions than many of my friends with SUVs or 4WD pick-ups. Balance really is better than simple forward grip.

On another point, ABS can be helpful, or dangerous. I assume the RX-8 has an ABS system that controls each wheel individually. My wife's full size Ford van has a more primitive system. When it senses lock-up ay ANY wheel, it modulates brake pressure at ALL wheels. This means that you lose braking power whenever one wheel slips. I live in rural Wisconsin, and usually drive on roads that have hard-packed snow or ice on the edges, with a clear center. My 928 (1985) can brake very well with two wheels sliding on the icy side of the road, but the van will not slow down at all. The right wheels lock up, and the ABS system takes away all braking force. I assume this won't happen on the RX-8, but would like to hear from someone who may have tested this.

Another well known concern about ABS is that in some cases, a locked wheel will have more friction than a rolling wheel. Basically, this is loose snow or gravel. The reason is that a wedge of snow or gravel can build up in front of the tire and help slow the car. As stated by others, this is a rather rare condition for most of us.

dannobre

iTrader: (3)

You can stop in the shortest distance on ice by locking up all 4 wheels at the same time. Will slide straight and stop shortest. Problem is...most people won't brake hard enough to do this. They will lock up one wheel....causing a spin. Also with all wheels locked...you can't steer. So there is something to be said for ABS for most situations. Just don't fool yourself into thinking that you can stop in a shorter distance with ABS. This gets a lot of people in trouble.

Best rule on ice/snow.....don't do anything fast. Braking, cornering, accelerating all decrease the available traction between your tires and the road. Drive carefully and smooth, and it will go a long way towards keeping the shiney side up

RoninJai

Before I got my 8, I drove an 02 Mustang, and before that, a 96 Camaro. I've always used my cars all year round through Michigan winters. I used salt bags in the trunk to add weight.

jaedcem

That's interesting - I'm not aware of any situation in which kinetic friction is GREATER than static friction. I'll have to give my old physics professor a call and complain about his poor instruction.