Mini Spare For Model 3, Hyundai Genesis 18" works

[chinnam3]

I want to add some caution/details to the spare tire replacement. There is a 10mm brake rotor bolt holding it to the Hub. The OE wheels have a hollow space accommodating that 10mm bolt. But aftermarket spares like genesis spare does not/may not have this provision. Hence to mount this spare you may have to remove that 10mm bolt before you can mount the spare donut or wheel. This may apply to some aftermarket wheels also.

Also, I had bad luck with seller sending the 17 inch spare even though I ordered 18 inch Genesis spare donut tire. Seller said he did not have it in stock, and gave credit for that 17 inch wheel. Since I have this 17 inch steel spare, I thought I would try and see.

17 inch steel wheel could not clear brake caliper in the back, but it worked fine for the front. So, I can still use it for the front. If my rear tire fails, I may have to put spare on the front, and mount front tire on the rear. This is in fact better than mounting the spare in the rear as this is a rear wheel drive car, and puts more stress on rear wheels(donut is weak ). This would be still faster than waiting for roadside assistance which only flatbed the vehicle anyways, and then trying to find a tire patching service, or even worst looking for tire replacement.

See the image attached for 10mm bolt. It is there for front as well as rear. Bolt shown in the rear, bolt removed shown on front rotor. Also see the clearance of brake caliper for the front. There is an indent on Spare wheel to align with bolt location, but indent is very shallow and not enough to clear that 10mm bolt.

Also, I tested the torque for wheel nuts. They are no where near 129lb-ft spec. These are torqued to 105lb-ft which closer to typical cars in this size range. Typical torque for most cars would be 85+/- 5 lb-ft. When I saw the specs 129 lb-ft, I felt it is too much.
So, I would suggest go easy on wheel nuts and keep the torque around 105+/- lb-ft.

 

[Thomas Edison]

I want to add some caution/details to the spare tire replacement. There is a 10mm brake rotor bolt holding it to the Hub. The OE wheels have a hollow space accommodating that 10mm bolt. But aftermarket spares like genesis spare does not/may not have this provision. Hence to mount this spare you may have to remove that 10mm bolt before you can mount the spare donut or wheel. This may apply to some aftermarket wheels also.

Also, I had bad luck with seller sending the 17 inch spare even though I ordered 18 inch Genesis spare donut tire. Seller said he did not have it in stock, and gave credit for that 17 inch wheel. Since I have this 17 inch steel spare, I thought I would try and see.

17 inch steel wheel could not clear brake caliper in the back, but it worked fine for the front. So, I can still use it for the front. If my rear tire fails, I may have to put spare on the front, and mount front tire on the rear. This is in fact better than mounting the spare in the rear as this is a rear wheel drive car, and puts more stress on rear wheels(donut is weak ). This would be still faster than waiting for roadside assistance which only flatbed the vehicle anyways, and then trying to find a tire patching service, or even worst looking for tire replacement.

See the image attached for 10mm bolt. It is there for front as well as rear. Bolt shown in the rear, bolt removed shown on front rotor. Also see the clearance of brake caliper for the front. There is an indent on Spare wheel to align with bolt location, but indent is very shallow and not enough to clear that 10mm bolt.

Also, I tested the torque for wheel nuts. They are no where near 129lb-ft spec. These are torqued to 105lb-ft which closer to typical cars in this size range. Typical torque for most cars would be 85+/- 5 lb-ft. When I saw the specs 129 lb-ft, I felt it is too much.
So, I would suggest go easy on wheel nuts and keep the torque around 105+/- lb-ft.

One downside to that 17" wheel is the extra weight being that it's not aluminum. Any chance you can throw that thing on a scale?

 

[chinnam3]

One downside to that 17" wheel is the extra weight being that it's not aluminum. Any chance you can throw that thing on a scale?

Sure, I wanted to do that anyways to get an idea how much weight in general it adds to car. I will check to night. But I highly doubt there would be much difference in weight of this vs 18 inch Aluminum one.

 

[Thomas Edison]

Sure, I wanted to do that anyways to get an idea how much weight in general it adds to car. I will check to night. But I highly doubt there would be much difference in weight of this vs 18 inch Aluminum one.

You might be right, the 18" one weighs 31.5lbs.

 

[CameronB]

Some nice sturdy tie downs to hold a keg or carboy, or propane tank would really go a long way. Nothing like having a propane tank loose in your trunk right? I guess you just have to seat belt them into the back seat?

Agree having tie-downs would be appreciated and could come in handy from time to time.

But as far as propane tanks, while I don't make a habit of keeping them in my car beyond the few miles from my house to where I fill them up (and certainly hope not to have an accident whilst transporting one), I have have found milk crates to be ideal.

Either the real ones from a grocery store or the manufactured-for-other purpose commercial ones you can find at department stores. A propane tank fits perfectly inside one and will provide a nice flat bottom that will keep the tank from tipping over or rolling around in your trunk.

 

[chinnam3]

You might be right, the 18" one weighs 31.5lbs.

17 inch steel donut wheel weighing around 31.8 lb to 32 lb between several measures with about 65 psi air pressure. So, not much difference in weight as expected.

 

[stayfocus18]

I keep finding the 17" version

 

[SageBrush]

I'm still vacillating

How about an inflatable 18" tyre ?

 

[Thomas Edison]

I'm still vacillating

How about an inflatable 18" tyre ?

I tried finding an 18" compatible spare with that style tire, no luck. Anyone else look into it with any success?

 

[SageBrush]

I tried finding an 18" compatible spare with that style tire, no luck.

In what way(s) were they incompatible ?

 

[SomeJoe7777]

Also, I tested the torque for wheel nuts. They are no where near 129lb-ft spec. These are torqued to 105lb-ft which closer to typical cars in this size range. Typical torque for most cars would be 85+/- 5 lb-ft. When I saw the specs 129 lb-ft, I felt it is too much.
So, I would suggest go easy on wheel nuts and keep the torque around 105+/- lb-ft.

Ummm, no.

The spec is 129 ft-lbs, thus you tighten them to 129 ft-lbs. You don't pull a number out of thin air because you "feel it's too much". You have not a shred of evidence that a lower torque value is safe or properly places the wheel studs into the proper stress range for functional operation.

 

[chinnam3]

Ummm, no.

The spec is 129 ft-lbs, thus you tighten them to 129 ft-lbs. You don't pull a number out of thin air because you "feel it's too much". You have not a shred of evidence that a lower torque value is safe or properly places the wheel studs into the proper stress range for functional operation.

Seems reading the text is not your strong suite, is it? I tested torque on 2 wheels, that is total 10 nuts. Guess how much they are torqued from factory? 105ft-lb. I bet you have never wrenched any cars or mechanically inclined either.

Think about it, use some common sense, what was original tire pressure on Jamb? 45 Psi, what is now 42 Psi, and what Musk said, 38 Psi provide more comfort. So keeping at 38 Psi suddenly tire is unable carry the weight?

Same here, cars with similar weight/even heavier with more load per wheel with similar stud pattern do not need torque more than 100ft-lb. If you do not have experience, go and read values from some comparable cars with similar weight and power, and educate yourself instead of commenting "Not have a shred of evidence".

It is a suggestion based on actual experience, if you do not want, ignore and walk away. Suddenly it seems some folks feels as if they are some gods after owning few Tesla's. I am an engineer I know what I am talking about.

 

[BioSehnsucht]

Seems reading the text is not your strong suite, is it? I tested torque on 2 wheels, that is total 10 nuts. Guess how much they are torqued from factory? 105ft-lb. I bet you have never wrenched any cars or mechanically inclined either.

How did you test this, measuring the peak torque required to start loosening them? That's not going to tell you what it should be tightened to.

Why it Takes Less Torque to Loosen a Bolt Than to Tighten It

 

[chinnam3]

How did you test this, measuring the peak torque required to start loosening them? That's not going to tell you what it should be tightened to.

Wow! Wait a moment. You do not lose the bolt to test how much it was torqued to. You keep increasing the torque wrench settings while tightening until the nut starts to rotate(Torque wrench clicks). That will give you approx torque it was tightened. Not otherway around. When I tightened first one, clicking stopped around 105. Got the doubt, so I tested other bolts too only to realize all are torqued around 105.

But, when local Service Center replaced one of the alloy wheel other side, they did tighten to 129.

 

[SomeJoe7777]

Seems reading the text is not your strong suite, is it? I tested torque on 2 wheels, that is total 10 nuts. Guess how much they are torqued from factory? 105ft-lb.

That just means that the nuts loosened on the first few miles of travel, which is expected. That's why lug nuts are required to be re-torqued after being driven a few miles.

I bet you have never wrenched any cars or mechanically inclined either.

And you'd lose that bet. I have done a lot of my own auto maintenance for over 30 years. I have owned a Model S and now a Model 3 for close to 4 years total, and I've done every tire rotation on them myself, with my own jacks, impact wrenches, and other tools.

Think about it, use some common sense, what was original tire pressure on Jamb? 45 Psi, what is now 42 Psi, and what Musk said, 38 Psi provide more comfort. So keeping at 38 Psi suddenly tire is unable carry the weight?

Of course not, because safe tire pressures fall within a range bounded by the load index, the gross vehicle and gross axle weight ratings (GVWR and GAWR), as well as the top speed that the car will be driven. GVWR and GAWR then depend on cargo weight in the vehicle, including passengers, and to a lesser degree the weight distribution.

Stress/strain values on the lug studs directly depend on the torque value of the lug nuts. Safe operation of the wheel depends on the wheel being able to resist side forces during turns and to a lesser degree torque forces during acceleration and braking. To hold these forces, the lug stud must be under a stress value that places it high in the elastic deformation region. Insufficient torque will place it low in the elastic deformation region which will not exert enough counter force to stop unwanted movement.

Same here, cars with similar weight/even heavier with more load per wheel with similar stud pattern do not need torque more than 100ft-lb.

One reason is because few of them have the handling capabilities of the Model 3, which can exert far more side loads on the wheels during turns than normal vehicles.

Another reason is that torque values will vary considerably when the cone seating surface area of the lug nut is different. Small lug nuts with a low surface area in the nut/wheel contact area require less torque to stress the stud to the same value as a lug nut with a high surface contact area. This happens due to friction between the surfaces, which increases with larger surface area.

A third reason that torque values can vary considerably is due to thread pitch. Higher pitch threads on the lug studs/nuts results in lower torque value for the same stress because of leverage effects.

What this adds up to is that torque values between two different cars are not comparable. Unless the thread pitch is identical, the lug size is identical, the lug studs are made of the exact same alloy/material, and the surface contact area of the lug nuts and the wheel are identical, then the torque values bear very different relations to the lug stress.

If you do not have experience, go and read values from some comparable cars with similar weight and power, and educate yourself instead of commenting "Not have a shred of evidence".

I believe the experience question in both automotive applications as well as physics has been answered here. As far as who needs to be educated, well I think that speaks for itself.

I am an engineer

A poor one since you're not using any engineering principles in your analysis.

 

[chinnam3]

That just means that the nuts loosened on the first few miles of travel, which is expected. That's why lug nuts are required to be re-torqued after being driven a few miles.

Ok, lets assume for a moment that all 10 bolts somehow are loosened to 105lb-ft. Why is that Tesla does not call back every car after a week/month and re-torque all the wheels? Even after a wheel change, why didn't they bother to re-torque other wheels, esp if the torque is not going to be within safe range?

Again use common sense, Do you remember any manufacturer calling back all cars and re-torque after a week or a month? Nope, Nada. Do you know why? I will let you guess about range.

And you'd lose that bet. I have done a lot of my own auto maintenance for over 30 years. I have owned a Model S and now a Model 3 for close to 4 years total, and I've done every tire rotation on them myself, with my own jacks, impact wrenches, and other tools.

I see you had some tire swaps under your belts! Congrats on that.
Lol, you are telling that to some one who's jobs was overseeing major overhauls of engines and transmissions decades ago for a company with fleet of thousands of different vehicles as an auto engineer. Have been doing all my repairs in my garage for decades now, does not matter if it is just a tire swap or big end seal replacement, including necessary programming. Tip: Get a Service manual for reference though, those do make life easy. Wish it is as easy to get a service manual for Tesla.

Of course not, because safe tire pressures fall within a range

Yes, you got that. It has a range! good catch( refer to first point again)!

Stress/strain values on the lug studs directly depend on the torque value of the lug nuts....

Yada, yada.. Sorry man it was too long of a lecture. What does it tell, you are not a veteran in this area and take everything as gospel.
FYI, you missed point about lube, temp and impact of wheel diameter on the lug nut torque.

I don't know why many people gets this kind of attitude after owning a Tesla. Tesla did not invent Physics! Ok. There is nothing special about Tesla lug nuts, it is just one of the variant of existing design.

There are many cars with more torque and better dynamics than Tesla Model 3, just that those are more expensive. Unless it is a Semi-wheel lug nut, 100lb-ft very well within safe limit to 99% cars including Tesla.

Take it easy, mine was a suggestion. If you do not want, do not follow.

 

[SomeJoe7777]

Yada, yada.. Sorry man it was too long of a lecture. What does it tell you

It tells me that you're incapable of following or understanding engineering analysis.

Unless it is a Semi-wheel lug nut, 100lb-ft very well within safe limit to 99% cars including Tesla.

Again, you have no proof of that. Tesla (and other manufacturers) publish their specs for a reason. It's because they've done extensive engineering and testing of their parts and have determined, with proof, the manner in which to safely operate the vehicle. You have not.

There is nothing special about Tesla lug nuts, it is just one of the variant of existing design.

So you admit that the design is not identical to other vehicles, that it is indeed a variant. But somehow this variant can simply use torque specs from other vehicles? Your logic doesn't follow.

Take it easy, mine was a suggestion. If you do not want, do not follow.

The time for taking it easy has now passed, as you are the one who began with the insults instead of having a facts-based scientific discussion. Your "suggestion" is possibly dangerous and violates an ethical responsibility to ensure that what you post for the world to see is good advice.

Not only will I not follow your "suggestion", but I'll discourage anyone else who reads this thread from following your "suggestion".

Take your potentially unsafe practices elsewhere. There is no room for them on an automotive forum, no matter who the manufacturer.

 

[chinnam3]

You could not answer my questions above but came back with same uptight responses as if you are some expert at engineering analysis regurgitating something you read on internet somewhere.

What you copied over there are basics. There are lot more things go into design process. See my point above about Wheel diameter, temp and lube for example you missed.

Have the design background, and hands on experience. Sorry, I already spent too many cycles to make you understand.

Its the problem with half-knowledge, you think you know something. Good luck.

Feels very silly like kids to talk about who started it, but it is your ridiculing comment that started this conversation anyways, and no point harping on wasting resources.

 

[BioSehnsucht]

Perhaps 105 ft/lb is perfectly fine and safe to be at after they drop naturally from 129, but torquing to 105 might mean they drop to something like 85-90 later which may be unsafe.

The correct value to torque to can be 129 and 105 can be a perfectly safe value for it to be at, these could both be true. And so could 105 not being a safe value to torque to.

 

[RFernatt]

Anyone have any experience with this item from an eBay seller? Looks like the make a similar kit for MS and MX.

2017-2018 Tesla Model 3 Complete Spare Tire Kit - Modernspare | eBay