ice racing theory!

[7thgear]

I'm looking for literature or insight into motion physics relating to a very specific case.

A rubber-to-ice class of ice racing, meaning NO studs.

A friend and me are hoping to put together a car for next season and I'm doing some preliminary research. Unfortunately, it seems that this activity is not well documented. Everything I find talks about defensive driving techniques or a reliance on studded tires to combat adverse winter weather conditions.

Our combined educations and logic dictate that for a car to accelerate quickly on ice you would want

- as large a diameter wheel as possible
- width matched properly to vehicle size/weight
- as long a gear as possible
- minimal torque and low engine rotational speed
- and in the case of a FWD car, as much weight on the front axle as possible


Also this car needs not only to accelerate quickly in a straight line on ice but also turn well.

So for anyone interested I'd like to hear your input on what would maximize traction in a scenario where the entire track is solid ice (about a foot thick), both left and right turns, and you don't get to put on studded tires!

[xwd]

I ice raced for a few years both with rubber and studded tires. Autocross time trial type, not wheel to wheel.

Really with no studs on bare ice, it comes down to how you drive and control the car more than anything else. You need to control the torque either through your foot or less power, brake in a straight line. It's probably one of the single most frustrating things I've ever participated in. With no studs on just ice car prep doesn't make a whole lot of difference in my experience apart from a good set of ice/snow tires.

If there is a chance of snow or you have a chance to runoff into snow then using narrower tires might be better. It puts more weight on a small contact area so you can cut through the snow potentially but it really depends on the conditions. Use snow banks to your advantage.

[7thgear]

See, this is how most of the local ice-racers feel, that it's all about the driving and most dismiss any attempt at tuning the car beyond just getting the best tires and running them through a tractionaizer. (for rubber-to-ice classes)

I was up north at a race this past weekend and rode shotgun with another friend of mine. He wont both his races in a field of 19 cars, his first race he had to start from the middle of the pack and the 2nd race (since hewon the first) started at the top. His second race we just sailed through 12 laps at the front and he put a good 20-25 car lengths ahead of the closest competitor.

His car is a bone stock Toyota corolla (88 I think?) and he was driving very smooth, so this certainly backs up the notion that it's all about the driving, but he did say that it helps that his car seems to have a very linear power curve so that using the gas to modulate is "easy", and we all know that easy in motorsports = better consistency.

So this got me to thinking of ways to improve if not grip, then the way power is delivered, and I think if you increase things like tire diameters and use longer gears with just the right amount of torque this will make it easier to modulate and be right at the limit.


With regards to narrow tires, my dilemma is figuring out the relationship of pressure on the ice without studs and how much pressure is too much since more friction would melt the ice and if the tire can't get rid of the water fast enough it will be worse off.

So where do you draw the line? How could you find it?

Curious minds wish to know!

[xwd]

You definitely want linear power delivery. I used to ice race in a 350WHP WRX with a lot of torque, after doing the power mods that's when I made the switch to studded tires. With the torque and especially the non-linear aspect of it, it made controlling things almost impossible.

The easiest cars to drive were lightweight FWD cars for the most part, such as CRXs, old GTIs/Rabbits, etc. as well as stock AWD cars like older 2.5RSs and even the 2L WRXs.

The fastest guys even on rubber were still in AWD turbo cars but they were very good drivers. We also almost always had snowbanks to use which helped those cars out. I remember times when it was just glare ice and trying to brake and literally sliding for 75 yards off course after getting up too much speed.