Prius Prime and spare tire

On a prius?

Posted via the PriusChat mobile app.

 

For the Prime spare tire, see post #42 in this thread which includes Mr. Mendel's very informative spec sheet. I purchased both the wheel and tire from America's Tire which is a nationwide company.

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No.

 

Most common mechanical failure I believe is a flat tire. Battery 2nd. I used to have concern about other mechanicals hoses etc on past cars.
I've had dead batteries, I once had a throttle cable come off, an oil cap while driving pop off! It was a rubber cap that didn't screw in. Nissan. Oil all over windshield while driving. Fun times. Then I bought a prius.

Posted via the PriusChat mobile app.

 

AAA says it's batteries, tires and lockouts, followed by running out of fuel, but all of those are preventable with proper maintenance and methods (checking tire pressure, replacing at 4/32", battery checks, not locking your keys in the car, not running out of gas). After that, it's transmissions (one could argue that a Prius doesn't really have one), and engine electronics (Prius most definitely has that, but they seem very reliable).

I don't know. In over 30 years of driving I've never once had a flat on a properly-maintained tire. I've had leaks (valve stem, screw in the tire, nail in the tire, etc.) but those were always slow leaks, on the order of 1 psi per day. That doesn't strand you anywhere, you just have to find the time to have it fixed or fix it yourself.

I'm not saying random flats don't happen, it's just very uncommon to have a sudden (rapid) flat on properly-maintained tires unless you run over something like a curb or piece of bent sheet metal or something - so uncommon that a spare tire is almost always an unnecessary use of space. That said, I carry both the Prime goo kit and a separate plug kit and compressor.

 

The Prius has a CVT...continuously variable transmission. It certainly has one.

I've had a tire failure from a sharp small rock that penetrated the tire and leaks from nails or screws. It can happen. For our Prime I added Ride-On brand sealant. It will seal a small leak like a nail or screw. We'll see how that works out.

 

The Prius does not have a CVT. A CVT uses a belt or chain. Toyota calls the Prius transaxle an eCVT because in functions similar to a CVT and regulators do not have a category for the Prius transaxle.
Actually the main drive motor MG2 is part of the transaxle.

 

Since there has been so much discussion here on the fact that a Prius Prime does not have a spare tire, I thought I would share my perspective as a new Prime owner. I too was worried about the fact there was no spare tire, but after giving it a lot of thought and a lot of research, I’ve settled on a good solution.

For starters, the only time I’ve ever had a flat in 31 years of driving is in 2003 when I went out into the parking lot after work and noticed a tire was sagging and only half full from a screw in the tread. I know...flat tires can happen at any time, but if you think about it, it is pretty darn rare. One time in 31 years for me...

As long as you maintain your tires properly, in the rare chance that you do get a flat it will likely be from a screw, nail, or some other kind of intrusion in the tread. Sidewall blow-outs on properly maintained tires are super rare.

For objects that have punctured the tread, we obviously have Toyota’s flat repair kit. The problem is Toyota’s kit is a one-time use and it makes quite a mess inside your tire. This increases the repair cost and you have to replace the TPMS (tire pressure monitor system) in the effected tire as well. That can make for a pretty expensive repair. Furthermore, after using Toyota’s one-time repair kit, you have to buy another one and you guessed it: they are expensive.

The better solution, which I came across right here in the early stages of this thread, is to add the Safety Seal KAP30 Pro Tire Repair Kit to your arsenal. This excellent kit is what a tire repair shop uses when you take your tire in for repair and it is very easy to use. I’ve read numerous reviews from people that have used it and once you know what you’re doing, you can repair a flat tire in less than 10 minutes, which is arguably less time than it would take to use Toyota’s patch kit. And unlike Toyota’s patch kit, when you use the Safety Seal kit, you’re actually done. Most of the time, no further repair is needed. And last but not least, you can make up to 30 repairs with this kit, so it is not a one-time use.

I bought my Safety Seal kit from Amazon for $36, but that price seems to fluctuate up and down. You can also buy it directly from the manufacturer for a fair price. I’ve heard from plenty of people that 3rd party kits that look comparable to Safety Seal are actually junk. The original Safety Seal is the way to go.

Next up is where to store the Safety Seal kit. It actually fits nicely in the slender storage compartment in the back. The Safety Seal Kit is the red plastic case in the picture below.

The last piece of the puzzle is an air compressor to put air back into the tire after making a repair with the Safety Kit. (Toyota’s air compressor can only be used with their gu/slime and not as a stand-alone compressor.) For this, I bought a cheap car-kit air compressor from Amazon that was slender enough to fit under my front seat.

Problem solved. Flats are pretty rare, but I’m now prepared to handle 95% of the flats that do occur.

Hopefully this helps!

Cheers,
Bryan

 

"Electronically controlled Continuously Variable Transmission (ECVT)"
2017 Toyota Prius Prime Engine & Mechanical Features

Something has to serve as a transmission when the car is powered by the gasoline engine.

 

Here is a video explaining things.

 

What the Prius has is a power splitting device that directs power from the Gas engine and electric motor in various directions in varying amounts. The gas engine's connection to the wheels is actually in a fixed gear ratio that is equivalent to a top gear. What seems like low gear is actually the electric motor by itself or in combination with the fixed torque of the gas engine. Yes, Toyota calls it an eCVT but it is correct to say that it is not a transmission in that it does not shift gears. It resembles a transmission in that it varies torque/power to the wheels, so you can say it "serves as a transmission" if you like. Hope that makes sense.

The eCVT or power splitting device uses a very reliable gear set much like the differential that the drive shaft goes to in a rear wheel or all wheel drive car.

I don't see this as an argument, mostly a discussion of terminology and of how the Prius eCVT differs from a traditional transmission.

 

Technically, any and every thing between an engine or motor and the wheels is a transmission. The gears, chains, or whatever is transmitting the engine/motor rotational output to the wheels. To be truly called transmissionless, the output shaft of the engine would also have to be the wheel axle.

The HSD transaxle has a planetary gear set known as the power split device. A fixed percent of the engine's produced torque is diverted from the drive line to the wheels to M/G1 by the PSD. By controlling the engine's and M/G1's speed, the computer can change the effective gear ratio that the engine torque going to the wheels is modified by. This is why the system is referred to as an eCVT.

 

Good choice. I have and have used the Safety Seal kit on all my vehicles many times since 2003. Great kit, highly recommended. I wanted to keep it for offroading trips in my 4Runner and wanted a dedicated kit for the Prime that would always be in it, so I went with the Boulder Tools flat kit for the same price and quality plus a few extra tools in it, and a Viair 87P compressor. The Viair clips directly to the battery so no blown fuses in the interior 12V adapter and it has a capacity to do several tires (without overheating) or the same one several times and/or to do this while at altitude in thin air. Pumping at sea level is one thing, but at 8,500 ft in Ouray, CO is another.

 

Thanks Mark. I will have to take a look at that compressor. I also have a Tacoma and want to add a Safety Seal kit and a good compressor to my off-road kit. Thanks!

 

Since my 4Runner has large tires and we run at altitudes above 10,000 ft, I use a 100% duty cycle Extreme Outback portable compressor for offroading. It's 100% duty cycle pumps on every piston cycle and I can take four 33's from 12 PSI to 45 PSI at 10,000 ft + in 30 minutes.

I use Staun tire deflators with it.

PS, the Viair 87P compressor only goes up to 31" tires .

 

John Kelly in that Weber State U video is amazing. The design of the transaxle is both brilliant in its simplicity and brilliant in its execution.

The most interesting part to me is the MG1 planetary gearset. I've always seen planetary gearsets where one of the components was held firmly, and the other two components provide the gear reduction in a very light, compact package. This one is so interesting with the ring gear driving the final drive, the planetary section connected to the engine, and the sun gear connected to Motor/Generator #1.

The gear reduction available to the engine is fully variable. The MG1 is controlled to drive the sun gear at various speeds in either direction so the engine can be running in (effective) neutral, or driving the final drive through the planetary gears to the ring gear at an engine rpm that best suits the conditions. And, the engine can drive both MG1 and the final drive to charge the battery and drive the car. I think I heard that the engine is started from this MG1 gearset, (I need to re-view the video) so there must be some way to lock out the sprag clutch that normally prevents overrunning. If that's the case, there may also be a way to lock the sprag clutch out so the engine can be driven by the final drive to supply engine braking.

About the sprag clutch. It is a one-way device so if the engine is turning faster than the planetary carrier, the sprag clutch engages and the engine drives the planetary carrier. If the planetary carrier is turning faster than the engine, the sprag clutch disengages so the engine is not turned. If there is a way to drive the engine for starting or engine braking, then somehow they lock out the one-way effect.

 

You got it, so now you'll likely enjoy this:

Toyota Prius - Power Split Device

No, it locks the other direction - so that MG1 can drive the wheels without turning the engine backwards. So, when MG1 is providing motoring torque it's trying to turn the engine the wrong way, which means it's normally acting as a generator when the engine is running (but not always).

 

That's what I should have bought. I went cheap and got Viair 70P. It was powerful enough for my need, but it came only with interior 12V adapter, and was keep blowing fuses.

 

Ask Viair if the plug can be changed to clips. It's still a good pump. If you can swap the connection style, you're good to go.

 

It's ridiculously easy to do it yourself - just cut off the plug and attach some suitable alligator clips, either solder type or screw type.