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Forged vs Cast Wheels? Weight/Strength/Longevity

fastwheels

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" and my experience is that All-Season tires are good in all seasons, but great in none "
This is what I've been saying for years about A/S tires: jack of all trades - master of none.

All our vehicles that are driven year round have 2 sets of wheels/tires. Makes the garage a bit more crowded storing the off season set, but the driving improvement in all seasons is worth it.

I'm still in a quandary about my choice for wheels on the R1T. I would prefer the 20" wheels (especially since they are forged) but will not accept the A/T tires. I would be much happier with a summer or even A/S tire (95% of my travels will be street) and then I will just get a winter wheel/tire set for the snowy season.

As it sits now, I have speced the 22" wheels but hope Rivian will offer more of a street tire for the 20" wheels before launch.
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Whmorken

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I also just changed out the well-worn Pirelli's on a used Volvo XC60 to Michelins, but went with the new Pilot Sport 4 S summer tire for light trucks and SUVs. I went for a set of Nokian LT3 Hakka's for the winter. Both sets seem quiter than the Pirelli’s, but I'm pretty sure the Pirelli’s were the second set. As such, they likely didn't have any acoustic foam inside. Having configured my R1T with the 20-inch wheels and A/T tires, reading this thread cements that choice for me, especially hearing about these wheels being forged.

Like others, I'm hoping to find safe, reliable, and less expensive options for a set of 22-inch performance wheels and tires, although the Rivian/Pirelli 22's would be preferred. It may be spendy to have a second full set, but I really like to get the most of any vehicle, and my experience is that All-Season tires are good in all seasons, but great in none. Just like a decathalete has different shoes for different events, buying a great vehicle with the wide-ranging capabilities of the R1T & R1S but not connecting them to a surface in the best way seems wrong.
Agree. In my circumstances, prefer two sets of wheels and tires, one for deep winter.
 

twinprice

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I am still hemming and hawing over the choice of wheel, and while I know we don't have to decide now, I am curious to see if anyone has any predictions:
  1. If we go with the 21" wheels, anyone want to take a real guess at the cost of each tire? $350? $400? $500?
  2. Does anyone want to guess at the difference in efficiency between the 27565R20 the 27555R21 and the 27550R22?
I am tempted to just stay with the 21" wheels and suck up the additional cost once I need new Tires but I do worry about supply if I blow a tire. Also hate the idea of going with the 22" wheel and being stuck with a shorter sidewall and grippy tire that wears out faster, and is less efficient.
Thoughts?
 

IHScout

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I am still hemming and hawing over the choice of wheel, and while I know we don't have to decide now, I am curious to see if anyone has any predictions:
  1. If we go with the 21" wheels, anyone want to take a real guess at the cost of each tire? $350? $400? $500?
  2. Does anyone want to guess at the difference in efficiency between the 27565R20 the 27555R21 and the 27550R22?
I am tempted to just stay with the 21" wheels and suck up the additional cost once I need new Tires but I do worry about supply if I blow a tire. Also hate the idea of going with the 22" wheel and being stuck with a shorter sidewall and grippy tire that wears out faster, and is less efficient.
Thoughts?
I am having the same thoughts/questions. Thank you for articulating this better than I could have done.
 
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BigE

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I am having the same thoughts/questions. Thank you for articulating this better than I could have done.
Just from past personal experience, I will never buy another vehicle with a low volume tire, ie the 21". My wife had a Honda Odyssey with run-flat Michelin tires. No tire dealer would even talk to me about changing wheels or to a different tire because the OEM tires were seen as a "safety device" and changing would be a violation of the law. Crazy. That being said, in searching TireRack they have Zero 21" tires in the Rivian size. For the 20", lots of selection, and the stock tire is ~$291/tire. For the 22", again there are several good choices. Michelin has their Premier LTX, very good tire for $258 each. Hopefully, we will all get to look at Rivian's in person prior to decision time and maybe even get a test drive before final purchase time.
 

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DucRider

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For the 20", lots of selection, and the stock tire is ~$291/tire.
The tire listed on tire rack is not the stock tire - it is the generic version.
Pirelli has developed special versions of its Scorpion Verde All Season, Scorpion Zero All Season and Scorpion All Terrain tires (Pirelli’s dedicated range for SUVs and pickups) to meet Rivian’s specifications, and to enhance the vehicles’ unique characteristics following the “Pirelli Perfect Fit” strategy. Indeed, all Pirelli tires developed for Rivian have a special marking on the shoulder: RIV and Elect.
There will be a premium for any of the Rivian specific tires. Other tires of the same size will certainly fit (and perhaps some other sizes as well), but handling characteristics and range will likely be different. Some drivers never push their vehicles hard enough to where they would notice the handling difference, others will.
 
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BigE

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The tire listed on tire rack is not the stock tire - it is the generic version.
Pirelli has developed special versions of its Scorpion Verde All Season, Scorpion Zero All Season and Scorpion All Terrain tires (Pirelli’s dedicated range for SUVs and pickups) to meet Rivian’s specifications, and to enhance the vehicles’ unique characteristics following the “Pirelli Perfect Fit” strategy. Indeed, all Pirelli tires developed for Rivian have a special marking on the shoulder: RIV and Elect.
There will be a premium for any of the Rivian specific tires. Other tires of the same size will certainly fit (and perhaps some other sizes as well), but handling characteristics and range will likely be different. Some drivers never push their vehicles hard enough to where they would notice the handling difference, others will.
True...but. Pirelli has lots of these so-called "Special Version" tires. Acura is also quoting the same thing about its New MDX & Pirelli. Pirelli & Ford got together for 2 years of development for "Tailor-Made" tires for the new 2021 F-150's. Is there really anything special or tailor-made about these tires? Do we have a tire engineer on here who can tell us? I'd be willing to bet if you match up load ratings, etc. the "generic" version will be just fine or maybe impossible to tell the difference without instrumentation.
 

DucRider

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True...but. Pirelli has lots of these so-called "Special Version" tires. Acura is also quoting the same thing about its New MDX & Pirelli. Pirelli & Ford got together for 2 years of development for "Tailor-Made" tires for the new 2021 F-150's. Is there really anything special or tailor-made about these tires? Do we have a tire engineer on here who can tell us? I'd be willing to bet if you match up load ratings, etc. the "generic" version will be just fine or maybe impossible to tell the difference without instrumentation.
I guess we won't really know until we see them, but Pirelli is claiming a difference:

22" Zero:
For its vehicles, Rivian asked Pirelli to develop an even “grippier” version of its Scorpion Zero All Season tires. To achieve this request, Pirelli’s engineers introduced nano-composite compounds to ensure maximum grip and stability. Then they focused on the tread pattern, introducing a dedicated mold with a larger tread width, able to provide more contact area and, consequently, leading to a better handling performance.
All Terrain:
In this case, the challenge to create a dedicated version of these tires for Rivian has been to match their low rolling resistance targets with the off-road applications of the Scorpion All Terrain.
To achieve this result, Pirelli’s engineers designed a dedicated mold in order to reduce the weight of the tire, adding then a special compound for light trucks that made the tires more resistant to cuts and lacerations.​
 

Mjhirsch78

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Heh, still not sure.
1. 21” will likely serve 90-95% of our driving needs.
2. The 2-3 winter trips through the mountains plus the 10 or so trips each year to chase snow on our snowboard seems like the 20” AT is right.

Do I leave the default 21” and then order a spare set of the 20” wheels?
Can I buy just the wheels and not the tires to give me room to find a snowtire as that is really what I need for those trips?
Do I just assume the snow runs on highway or generally decent road will be fine on the 21” all-season?
 

fastwheels

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Heh, still not sure.
1. 21” will likely serve 90-95% of our driving needs.
2. The 2-3 winter trips through the mountains plus the 10 or so trips each year to chase snow on our snowboard seems like the 20” AT is right.

Do I leave the default 21” and then order a spare set of the 20” wheels?
Can I buy just the wheels and not the tires to give me room to find a snowtire as that is really what I need for those trips?
Do I just assume the snow runs on highway or generally decent road will be fine on the 21” all-season?
If you are willing to go with two sets (which is what I will do) then go with the 20" wheel if they will sell us those for a reasonable price - otherwise get a winter wheel/tire package from TireRack, DiscountTire or one of the other big vendors.

You may want to consider the availability of replacement tires before you opt for the 21" size - it is not currently a very common size.
 

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GTodd

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I have a good friend which is an engineer at Michelin over design. Had a long conversation with him on these tires and will try and summarize below:
  • Avoid the 21" tire as this is sole sourced and unlikely anyone else will design one specifically for the Rivian.
  • EV's are heaver, not any tire will work as a replacement they must be rated for the load. Most will have the XL marking (extra load). EV tires also usually will have more pressure 2.1bar for typical, 2.4bar for XL's.
  • The XL tires is usually a higher polyester cord (Radial body ply) density or breaking strength (Dernier - weight per length). Sometimes they change the steel belts cords for XL. Normally you see body ply and steel belt changes on higher aspect Ratio (65-80) tires however the Rivion are lower aspect ratio.
  • Pirelli adding the Si to the compound is a good solution for improving traction for the high torque electric motors.
  • It will be a challenge with the reduced contact surface area for mileage vs. the requirements for torque.
  • The tire is essentially a bladder that holds air. You need roughly the same amount of volume to handle the weight. So a narrow tire will have more sidewall and a wider tire less sidewall. Both really have about the same volume or air but changes the contact with the road, thus rolling resistance and performance.
  • The 20" will have a more comfortable ride due to the sidewall height. The 20" will do better in mud but worse in sand. It will also fare better with potholes.
  • The 22" will do better in sand worse in mud. But much better on performance due to more road contact. It will also get less mileage.
To sum it up, all of the tires are at the same outside diameter. Air holds up the car, the tire is a air holding device. More air = higher load. So what they are doing. At 20” they have a certain tire width and aspect ratio. At 21”, they probably go wider and smaller aspect ratio. At 22” wider still, an and lower aspect. 20” tire has the tallest sidewall, then more flex, and better protection against pinch shock (rim hitting the road and pinching the tire). 22” has the best handling (wider, shorter SW is stiffer). It’s according to how and where you drive.

All that said, for myself I have ruled out the 21" and really torn between the other two!
 

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Thank you Gtodd and Fastwheels!
 

kanundrum

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All that said, for myself I have ruled out the 21" and really torn between the other two!
Does your friend know or have any recommendation for a 20" non specific tire that could potentially work for Eco Driving with the Rivian Setup? I think an ideal scenario is to get the 20" setup offroad and then swap tires because the 20" is forged and in theory would have less rotational mass. From there you could pick a 20" tire even if the aspect ratio is a little off that would have better LRR compared to the off road tire so you can optimize your driving distance by LRR tires and Forged lightweight wheels.
 

DucRider

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At 20” they have a certain tire width and aspect ratio. At 21”, they probably go wider and smaller aspect ratio. At 22” wider still, an and lower aspect. 20” tire has the tallest sidewall, then more flex, and better protection against pinch shock (rim hitting the road and pinching the tire). 22” has the best handling (wider, shorter SW is stiffer). It’s according to how and where you drive.
All the tires are 275, none are any wider than the others.
The 21s and 22s have essentially the same diameter and therefore nearly identical contact patches.
The 20s are ~4% greater diameter and will have a little larger contact patch.

Tire pressures and sidewall flex will introduce additional variables besides nominal size.
 

Whmorken

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All the tires are 275, none are any wider than the others.
The 21s and 22s have essentially the same diameter and therefore nearly identical contact patches.
The 20s are ~4% greater diameter and will have a little larger contact patch.

Tire pressures and sidewall flex will introduce additional variables besides nominal size.
. Great posts above: Heading for 20’s in mountain country with dirt and snow a-plenty.
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