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Change to 16x6.5 wheels, cheap?


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24 replies to this topic

#21 OFFLINE   fbov

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Posted 14 December 2015 - 04:03 PM

Interesting link there obob....

 

There's something interesting going on with that tire. I found the mfr. specs. Hopefully this is instructive (if somewhat confusing due to header mismatch).

 

(table completely scrogged, no point in post without it)


Edited by fbov, 14 December 2015 - 04:05 PM.








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#22 OFFLINE   okashira

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Posted 14 December 2015 - 06:06 PM

Things may be more complicated than this math.  I got this from a post from this article:

http://community.car...-do-they-matter

 

 

Michelin says this about load rating:

"A tire with a higher load index than that of the Original Equipment tire indicates an increase in load capacity. A tire with a load index equal to that of the Original Equipment tire indicates an equivalent load capacity. A tire with a lower load index than the Original Equipment tire indicates the tire does not equal the load capacity of the original and should not be considered for installation on the vehicle.

Didn't really learn anything there. Guy installs garbage cheap tires on his car three load ratings below the original spec and he has tire problems.

 

Michelin says don't use tires rated lower then OEM. Do you expect them to say "it's ok to lower the load rating if it's only a little bit." ?  ;-)

 

 

You are going to do what you want to do, regardless what we say.

 

Our job is to make sure your eye are open. The best we can do is point out the cliff, and hope you see it in time. Your Energi is 18% more massive that the Soul EV, before you even open the door, yet you continue to think they can use the same tires. That's poor judgment.

 

You got the wrong load ratings in your post (5732 is 4x OEM rating, your goal), which leads one to suspect other technical errors in your estimates. That's a sign of poor understanding.

 

Poor understanding combined with poor judgment is unlikely to result in a happy outcome. I hope it's one you have the opportunity to learn from.

 

That's the best good intentions can do.

 

You're not technically minded. Ok. But this is not a pissing match nor is it high school debate session. But to play along, let's address at some of your points:

 

  • The Kia Soul's load rating and factory weight is 100% irrelevant. All that matters is the tire I want to use has a load rating of 92. Let me note that you've mentioned the Kia Soul multiple times now like it makes any difference here.
  • You discussed the Nexen N Blue tires (and their 91 load rating) yet nowhere did I suggest I would be using such tire.
  • You pointed out that I used 92 instead of 93 when I mentioned the factory tire load rings, and suggested that might have something to do with my understanding of the situation. Okay. Yet, what really matters is the difference in load rating, which will match what I posted. Mind taking the time to point out the difference since you might have the time?
  • You came to your conclusion that I have poor understanding and poor judgement without knowing anything about me except random irrelevant tidbits. 

Now, I am technically minded on the other hand. In fact, I've worked as a mechanical engineer for my career and I design safety equipment for billion dollar projects. I've also done just about everything you can imagine to a car, including engine, suspension, and tires. I also design rubber products for a living.

I know a few things about safety factors.

Please try to be specific and technical when you make any arguments or draw any conclusions.

 

More random things for other poster:

  • It's not really relevant that the hybrid has a 2.5 gear ratio an the energi has a 2.9 ratio. They were originally designed like that. Ford does analyze these things you know.
  • Putting larger tires on the car will increase ride height and thus drag, this is pretty much a fact when it comes to automobiles.
  • Anecdotes of people saying their mileage increased when they installed larger tires should generally be ignored since these sorts of things are famously affected by the placebo effect
  • Putting larger tires will increase torque load on ALL components including CV joints, splines, transmission gears, engine and motors. I'm not saying this would not actually be okay, it would probably be fine, but the stock tires are already large to begin with. I don't want to use larger tires.

 

 

Going to a lower load tire doesn't seem to be that big a deal to me.

 

Here are some numbers

 

Energi weight   3895 lbs

Load capacity      825  lbs   (3895+825 = 4720)

 

Weight distribution  (front-back)  55/45

 

And weight at capacity will most likely mostly be added to the rear.

 

On both tires, original and the replacements, the capacity exceed the capacity of the car.

 

(I got the numbers from Consumer Reports)

 

Note: Load Capacity is the same for energi and the hybrid.  Weight of hybrid is 3615

 

 

Here is a basic example of how you make a technical argument. Note that actual numbers are used and the poster is specific and to the point.

The energi has a load rating of 4720. N Blue EV tires have a load rating of 5556. Factory tires have a load rating of 5732. Both are comfortably above the factory load rating.

And he's correct that generally, excess extreme load would be in the center of the car (rear passengers) and the rear of the car (hatchback)

 

 

 

/had a bad day rant.


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#23 OFFLINE   fbov

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Posted 15 December 2015 - 12:53 PM

...You're not technically minded. Ok. But this is not a pissing match nor is it high school debate session. ...

...Here is a basic example of how you make a technical argument. Note that actual numbers are used and the poster is specific and to the point.

The energi has a load rating of 4720. N Blue EV tires have a load rating of 5556. Factory tires have a load rating of 5732. Both are comfortably above the factory load rating....

It would be helpful if you were as technically competent as you believe yourself to be. Very good examples, of the adage: "A little knowledge is a dangerous thing", and the danger of internet "learning."

 

"The energi has a load rating of 4720. N Blue EV tires have a load rating of 5556. Factory tires have a load rating of 5732."

 

An engineer would say the Energi has a rated load capacity of 2866 lb. on the front axel and 1854 lb. on the rear axel. In fact, they did, on the door placard. I'm assuming rated axel load capacity does not exceed the OEM tire load index rating (about 60/40). What's the placard actually say? 

 

The N'blue tires in this size have a maximum load rating of 1389 lb. at 44 psi. What does that mean? It depends if this is an ETRTO tire or a P-metric tire. That's the difference between the two Michelin ES/AS 225/50-17's; the OEM tire is rated 1433 lb. at 51 psi, the other is 1477 lb. at 44 psi. Logical? No, but real.

 

You're using an ETRTO size, so the ETRTO load tables apply. Here's a link to the Toyo application guide, which has the tables.

- ETRTO specifies load at 36 psi, so a 92 load index has 1389 lb. load capacity at 36 psi. 

- P-metric specifies load at 35 psi, so a 93 load index has a 1433 lb. load capacity at 35 psi, consistent with door placard.

 

Here's what a technically minded person would understand about your choice of tire and size.

 

Your car is using its full OEM tire rated load capacity to achieve placard loads. There is no excess capacity available. 93 load index is a mandatory minimum.

 

Assuming a 3900 lb. curb weight and 60/40 split, you'll need at least 30 psi in the tire (per the tables) before you should let the car down off the jack... but you can't get in.

 

Assuming a 34 psi TPMS limit, you'll have a 600 lb. functional load capacity. Taking a family on a long, summer vacation would be foolhardy. You might be safe in a solo commute in an unladen vehicle.

 

Note that this assumes 100% of the safety margin is in the tire load rating, and that non-catastrophic transient loads are not a significant factor in the service life of the tire. There's a reason no one recommends this course of action.

 

Please reconsider,

Frank



#24 OFFLINE   Plus 3 Golfer

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Posted 16 December 2015 - 04:10 PM

XX 


Edited by Plus 3 Golfer, 16 December 2015 - 09:15 PM.


#25 OFFLINE   okashira

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Posted 20 December 2015 - 07:10 PM

It would be helpful if you were as technically competent as you believe yourself to be. Very good examples, of the adage: "A little knowledge is a dangerous thing", and the danger of internet "learning."

 

"The energi has a load rating of 4720. N Blue EV tires have a load rating of 5556. Factory tires have a load rating of 5732."

 

An engineer would say the Energi has a rated load capacity of 2866 lb. on the front axel and 1854 lb. on the rear axel. In fact, they did, on the door placard. I'm assuming rated axel load capacity does not exceed the OEM tire load index rating (about 60/40). What's the placard actually say? 

 

The N'blue tires in this size have a maximum load rating of 1389 lb. at 44 psi. What does that mean? It depends if this is an ETRTO tire or a P-metric tire. That's the difference between the two Michelin ES/AS 225/50-17's; the OEM tire is rated 1433 lb. at 51 psi, the other is 1477 lb. at 44 psi. Logical? No, but real.

 

You're using an ETRTO size, so the ETRTO load tables apply. Here's a link to the Toyo application guide, which has the tables.

- ETRTO specifies load at 36 psi, so a 92 load index has 1389 lb. load capacity at 36 psi. 

- P-metric specifies load at 35 psi, so a 93 load index has a 1433 lb. load capacity at 35 psi, consistent with door placard.

 

Here's what a technically minded person would understand about your choice of tire and size.

 

Your car is using its full OEM tire rated load capacity to achieve placard loads. There is no excess capacity available. 93 load index is a mandatory minimum.

 

Assuming a 3900 lb. curb weight and 60/40 split, you'll need at least 30 psi in the tire (per the tables) before you should let the car down off the jack... but you can't get in.

 

Assuming a 34 psi TPMS limit, you'll have a 600 lb. functional load capacity. Taking a family on a long, summer vacation would be foolhardy. You might be safe in a solo commute in an unladen vehicle.

 

Note that this assumes 100% of the safety margin is in the tire load rating, and that non-catastrophic transient loads are not a significant factor in the service life of the tire. There's a reason no one recommends this course of action.

 

Please reconsider,

Frank

Ok. Thanks for you concern, but it will be OK. I promise. I will be using the maximum pressure on the sidewall, of course - 44psi cold.

If something happens I will update... :-)

Don't forget I'll be running with about 120lbs of weight reduction.

Thanks for linking to the extra technical information on load ratings. I also understand this is a consumer product, and safety factors are well higher what I use for oil & gas applications which are pretty conservative. When it comes to rubber products, nothing is black and white when it comes to hard numbers because the there is a large element of uncertainty due to the nature of the rubber mechanical properties and the mixing & molding process.

If I need to take the family on a trip with 700 lbs of extra load I will think twice about the situation.

You indirectly do make a good point - a thinner tire will require a higher pressure, and it did concern me that the N Blue EV tire had a max sidewall pressure label of only 44psi. I wonder why it is so low..


Edited by okashira, 20 December 2015 - 07:19 PM.







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