Wet Weather Driving

This month, resident Miata pilot Carson Orud is going to give some insight on how to cope with wet and slippery conditions. Carson is 2015 Rookie of the year, 2017 S2 Champion and a regular top PAX finisher at OR-SCCA events. 

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Living in the Pacific Northwest and loving autocross you may be thinking ‘I didn’t choose wet weather racing; wet weather racing chose me!’ Have no fear – today we’re here to develop some thoughts and strategies to mitigate all that moisture on course. Let’s get to it!

One concept to think about when racing in the wet is that your power-to-grip ratio is much greater than in the dry, so you have much more power to put down per the grip that you’re used to when driving in the wet. This means you’ll need to be ever so slightly more cautious when rolling on to throttle, just to give the tires that extra fraction-of-a-second they need to continue gripping as more power is applied. If you’re in one of the under-powered Street classes this means you won’t be able to use your throttle as an on/off switch as you normally do.

Feeding in smooth and punctual throttle will also prevent your car from bobbling on corner exit which even if slight, eats up precious time as you gather up the car and speed down to the next feature. Whether your car understeers or oversteers, one way to envision wet weather corning (vs dry) is to picture your car weighs an extra 500 lbs. Imagining your center console filled with dark matter, you wouldn’t be able to pitch your car into corners like you normally would, so how do we compensate?

This is where altering your line comes into play. In general, a wet course presents minimal opportunities for carrying significant speed. Most of the time, it is usually best to simply cut distance and be as tight to the cones as you can. However, any opportunities you do have to carry speed become all that much more important! Let’s say you have a moderate corner leading onto the longest straight section of the course. You might take a wider entry to this corner and allow the car to track out wider than you normally would, just to make the most of the fast section of course. Remember when you have reduced grip, whether caused by a wet course or by the super-heavy space particles in your console, the less you crank your steering wheel the better. Less steering input equals more grip you have in the bank for cornering speed. A wider entry and exit onto the longest straight allows you to account for the low grip conditions while maintaining speed at this critical feature.

Playing out this wet weather course a little further, let’s say the long straight leads up to a relatively tight turnaround. In dry conditions you may do some trail braking as you bleed into the corner, getting every last bit of speed off the previous straight. In the wet it will likely be more efficient to get your braking done in a straight line so the car is already settled as you set your pace for the corner. Threshold braking in the wet is hard enough, and working in trail braking, at least coming off the fastest straight, affords you very little margin for error.
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Now that we’ve covered some helpful wet weather racing concepts and cornering tactics, you might be thinking “OK, now what about car setup?”. I thought about diving into this but candidly, I do nothing different. The rain racing setup in my E-Street Miata consists of making sure the defrost ducting is secure so my windows don’t fog up, so I’ll leave this advice to other folks in our club. Unless you have a separate set of tires just for the rain, I would say your time is better spent on the driving concepts, and to that end I hope I’ve helped!