No not an attempt at a pun. Racing on a frozen lake.
They allow studded tires but they are spun in designed pockets in the tread. That means they can ( and are) pulled out when the torque applied to them exceeds the the holding power of the pocket.
Racing studs really aren't studs. They are more like washers with a tip on them so the "washer" rolls over on its side presenting the edge to dig into the snow ( ice)
I'm thinking the peak torque at zero RPM will pull out studs right away? Thus handicap an EV from the start?
It shouldn't be any different in terms of abuse to the studs than any ICE car with a decent bit of power. If you've got enough enough power to spin the tire from a standing start (which many cars will on ice, even with studs), you're going to beat up the studs a bit and will occasionally lose a couple. They don't usually stick into the ice well enough to just tear out from raw power though.
My experience is those things are through bolts. Pack the tire with rags and run a tube, hope the bolt doesn't back out. You'll see guys grinding (sharpening) the tips sometimes.
It depends? I went ice racing in Stevens Point with Teslas last winter. Just had snow tires. The cars with studs (none of the EVs) all ripped into the ice and created ruts.
So, an electric motor is capable of producing its max torque at zero RPM, but it does not always produce that amount of torque. If you feed the motor less electrical power, the motor puts out less mechanical torque.
For comparison: a random internal combustion engine may be capable of producing its max torque at 2500RPM and WOT, but at partial throttle the engine can run at 2500RPM without producing max torque. Throttling losses, BSFC, whatever, etc.
These are efficiency graphs for the first two versions of the motor used in the Nissan Leaf, comparing electrical power put into the motor vs. mechanical power coming out of the motor. The rest becomes heat. The Leaf motor can operate anywhere within the shaded area, at varying degrees of efficiency. It puts out max torque only when max electrical power is applied. The 'post-upgrade' EM-57 motor has reduced max possible torque output, but it runs more efficiently at mid-range RPM (the physics are different but conceptually similar to changing intake runner or exhaust manifold geometry).
(edit to reword some stuff)
In reply to Oapfu :
The concept of an accelerator pedal that's not welded to the firewall is foreign to some :)
Keith Tanner said:
In reply to Oapfu :
The concept of an accelerator pedal that's not welded to the firewall is foreign to some :)
Right. If your driving style is "floor it and see what happens", the EV is probably going to be more destructive (....probably to everything, not just the tires). But if you're doing a good job of throttle modulation attempting to keep reasonable wheel speed, there's probably not much difference other than whatever effects arise from the EV likely being heavier than a comparable ICE vehicle. In this situation, applied torque is limited by surface traction, not available engine/motor torque. I suppose an ICE might be a bit easier to do said throttle modulation since the EV can spin up to basically top speed, where the ICE is going to be gearing limited, and provide a bit more audible feedback that you're wildly overpowering the available grip.
Note that on that certain Audi/sports drink promotional video with the electric SQ, they noted that the biggest problem they had was destroying tires, and this was with an endeavor where they were more concerned with spinning the tires on pavement than going fast on ice!
I have no answers, but I find discovering the questions to be interesting.
One of the reasons I like playing with rotaries on dirt is the low inertia makes it easy for the tires to regain grip if you want them to, with little engine braking to swing the slippage the other way. I have only driven powerful EVs (all Model 3s) in normal city operation, so I have no idea what their characteristics are when the tires slip. The other EVs I have driven were GEMs which couldn't break the skin on a pudding.
Racing ( especially on ice) is about getting ahead of the pack. Imagine trying to race in the blizzard kicked up by all those studs.
Clearly leading provides the best visibility.
In a race when the green flag drops. The race starts. Foot flat to the floor.
In reply to frenchyd :
You would not be starting the race in the lead in any car that has more power than grip. Wheelspin is wasteful.
In reply to frenchyd :
As an ice racer in a series that uses standing starts I can say that you don't rip out the studs off the the line.
One tire revolution without moving and the studs simply spin in the trench created.
A gentle launch with progressively more throttle once rolling is key.
The stress from asking the stud to receive max loads in more then one direction at the same time is far more likely to rip them out.
Pete. (l33t FS) said:
Note that on that certain Audi/sports drink promotional video with the electric SQ, they noted that the biggest problem they had was destroying tires, and this was with an endeavor where they were more concerned with spinning the tires on pavement than going fast on ice!
I have no answers, but I find discovering the questions to be interesting.
One of the reasons I like playing with rotaries on dirt is the low inertia makes it easy for the tires to regain grip if you want them to, with little engine braking to swing the slippage the other way. I have only driven powerful EVs (all Model 3s) in normal city operation, so I have no idea what their characteristics are when the tires slip. The other EVs I have driven were GEMs which couldn't break the skin on a pudding.
Driving a dirt sprint car can be the same thing. Dry dusty track with visibility near zero. If you wait for traction to catch up to your tires. You'll be eating a lot of dust. So you floor it.
This is racing. No 1/2 measures.
No 1/2 measures doesn't mean you disconnect your brain. Digging a hole is not the fastest way off the line.
In reply to Keith Tanner :
Apparently you are not familiar with ICE racing. Like regular road racing they are all rolling starts. If you're on the pole you get to start at whatever pace you choose.
If acceleration is your strength you start at a slower pace than if cornering is your strength.
914Driver said:
My experience is those things are through bolts. Pack the tire with rags and run a tube, hope the bolt doesn't back out. You'll see guys grinding (sharpening) the tips sometimes.
That is how motorcycles do it. But they are missing out on the traction of modern Ice racing studs. Which is a misnomer because they really are a sort of washer designed to tip over on edge and use the washer like a cleat on a caterpillar track.
Studs that look kinda like needles will roll over and lay flat under the weight and thrust. While the washers with a spike in the center also roll over but have the whole edge of the washer to grab the snow and ice.
Oapfu said:
So, an electric motor is capable of producing its max torque at zero RPM, but it does not always produce that amount of torque. If you feed the motor less electrical power, the motor puts out less mechanical torque.
For comparison: a random internal combustion engine may be capable of producing its max torque at 2500RPM and WOT, but at partial throttle the engine can run at 2500RPM without producing max torque. Throttling losses, BSFC, whatever, etc.
These are efficiency graphs for the first two versions of the motor used in the Nissan Leaf, comparing electrical power put into the motor vs. mechanical power coming out of the motor. The rest becomes heat. The Leaf motor can operate anywhere within the shaded area, at varying degrees of efficiency. It puts out max torque only when max electrical power is applied. The 'post-upgrade' EM-57 motor has reduced max possible torque output, but it runs more efficiently at mid-range RPM (the physics are different but conceptually similar to changing intake runner or exhaust manifold geometry).
(edit to reword some stuff)
I like how "low efficiency" on the graph is 90% 
Last time I was at an ICE race the fastest cars were either 4WD or a Porsche 911. The problem was when the higher powered cars came in to switch drivers or refuel. They all needed to replace the tires because of so few or no studs left in place. Volunteer pit crews weren't very fast at changing 4 tires, refueling, and switching drivers. It typically cost a few laps. Allowing cars without studs to almost catch up.
There is a limit on the number of studs. I can't remember exactly what it was but something like 88 or 121? Roughly one stud in every 3 sockets. The tires were special snow tires as well. 85/90? aspect ratio Tall and narrow.
That way you you could get 3 or more race weekends out of a cheap recapped tire.
In reply to dps214 :
Torque control can happen a lot faster with EVs than for an ICE. Just a matter of controlling electron flow rates (which is really fast) vs controlling spark-fuel-air (from the fastest to slowest ICE control).
To the OP, all modern EVs have traction control, so the instant slip is detected, it can be mitigated. And for a good, sporty, EV it may even have a drive mode that makes studded launches almost perfect. It's hardly a binary system.
In reply to frenchyd :
If you say so. But how in the world can you enforce that? There's probably no real way to fully turn TC off in an EV. It's really hard to turn it off for a new gas car anymore.
But you keep thinking. That's what you do.
In reply to frenchyd :
There is EVERYTHING wrong with using another car to do your braking and turning.
And believe me,the added weight helps NOTHING in ice racing same as every other motorsport.
frenchyd said:
In reply to alfadriver :
There are no launches in ice racing.
So then what the berkeley are we discussing here? The whole premise of your original post was the effect of "max torque at zero rpm", which is only relevant to standing starts.
The torque of an EV is going to be brutal under acceleration. Because unlike an internal combustion engine ( can I use ice? To describe the engine and ICE to describe frozen water). it makes peak torque at zero rpm.
That means acceleration away from corners will be equivalent to a big block at 4800rpm. Powerful cars in ice racing don't win because they quickly tear out the allotted studs.
But there are a lot of superficially damaged EV' s in Junkyards. And they sell cheap. Exactly what should be a winning car.
frenchyd said:
The torque of an EV is going to be brutal under acceleration. Because unlike an internal combustion engine ( can I use ice? To describe the engine and ICE to describe frozen water). it makes peak torque at zero rpm.
That means acceleration away from corners will be equivalent to a big block at 4800rpm. Powerful cars in ice racing don't win because they quickly tear out the allotted studs.
But there are a lot of superficially damaged EV' s in Junkyards. And they sell cheap. Exactly what should be a winning car.
The advantage of massive torque from electrics is "fixed" on low grip surfaces by the use of traction control. Electric traction control is MUCH easier than internal combustion, since it only needs to control current to the drive motor. So, even though there is a lot of torque available, only what CAN be used is applied.
frenchyd said:
The torque of an EV is going to be brutal under acceleration. Because unlike an internal combustion engine ( can I use ice? To describe the engine and ICE to describe frozen water). it makes peak torque at zero rpm.
That means acceleration away from corners will be equivalent to a big block at 4800rpm. Powerful cars in ice racing don't win because they quickly tear out the allotted studs.
But there are a lot of superficially damaged EV' s in Junkyards. And they sell cheap. Exactly what should be a winning car.
Go for it and post the outcome.
