What are the retrofitted outriggers hanging over the wheels of this car?

March 17, 2016 7:02 AM

My friend snapped this picture of a strangely modified sedan. Does anyone know what the devices on the wheels are?

The car was a Hyundai with Michigan manufacturers' plates. He saw it north of Los Angeles a few days ago.

Our debate so far has been whether or not the outriggers themselves look sturdy enough to withstand the torque of regenerative braking, and whether there's enough stationary hardware for that as well. I thought it might be a system for varying tire pressure on the fly? What can you suss out that we've missed?

posted by qbject to Technology (9 answers total)

It's definitely looks like a manufacturer's test mule. Just a guess but maybe those things measure torque at each wheel. I don't think they'b de used for regenerative braking, either. Maybe they're testing the stock tires that will be fitted on the car and want data on tire grip/slippage to compare to in-car data on acceleration/deceleration.
posted by cyclopticgaze at 7:31 AM on March 17, 2016

These look more like sensors than something that would drive the wheels.

There's nothing connected to the valve stem on the tires so I would rule out something that messes with tire pressure.

Perhaps they're wheel rotation sensors and they're monitoring the ABS and traction control systems on the car? It's odd that a) the cables are THICK and b) the whole thing is held on with duct tape. That kind of implies a temporary test and not some kind of life-test vehicle.
posted by JoeZydeco at 7:31 AM on March 17, 2016

It might be a related to the upcoming Ioniq (Prius clone). I would see if you can sell the photo to Jalopnik or one of the other automotive blogs for lunch money. They'd probably be the best people to tell you more too if they aren't under a Hyundai NDA at the moment.
posted by mattamatic at 7:33 AM on March 17, 2016 [4 favorites]

I suspect they're measuring wheel acceleration in 2-space and not speed, because each wheel very likely already has a high-quality wheel speed sensor built into the ABS system. I don't think they're measuring any kind of angle, given how they're mounted. They're very definitely sensors, though. My guess is that they're being used to tune the suspension, which requires measurement of how the wheel assembly moves when perturbed, combined with measurement of what forces are transmitted to the chassis.
posted by TheNewWazoo at 8:09 AM on March 17, 2016 [1 favorite]

Best answer: Yes, they are wheel torque sensors and are commonly used on car manufacturers' test mules. This company makes them.
posted by zsazsa at 8:58 AM on March 17, 2016 [1 favorite]

Response by poster: Excellent! Thanks very much!
posted by qbject at 9:14 AM on March 17, 2016

I asked this same question eleven years ago - albeit without the benefit of a photograph.

Glad we finally got that cleared up!
posted by russmail at 9:54 AM on March 17, 2016 [4 favorites]

Are those indeed torque sensors? The device at zsazsa's link is described as

• Measures 3 forces and 3 moments
• Measures X & Z accelerations

That sounds to me like it's measuring wheel force and not torque; or is there a meaning of torque here that I don't understand?
posted by TheNewWazoo at 10:09 AM on March 17, 2016

TheNewWazoo: They make torque sensors as well as force sensors, and they both look very similar. I wanted to get the best picture of one mounted on a car on their site and didn't notice it was a force transducer, not a torque transducer (I was on my phone). So I suppose the ones in the asker's picture could be either kind.
posted by zsazsa at 11:06 AM on March 17, 2016