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Discussion Starter · #1 ·
Need some help. Purchased a set of 20" x 11" Factory Reproduction (FR77) Wheels, +22 offset. Mounted 305/35ZR20 Michelin Pilot Sport 4S tires. I haven't heard of anyone having issues with rubbing on the charger with 305's and have seen a lot of people saying they are running 315's without issue. I know some challenger guys have to use spacers but I thought the chargers had more room. I am getting a good bit of rubbing on the front inside the wheel well. Tried massaging the liner with a heat gun but there is framing directly behind the liner in this area. Do the PS4S run wider? Has anyone else had to run spacers with this setup. I got 305's to avoid needing spacers, is there another solution, or is it okay for them to be this tight with a little contact in the wheel well? If you had to use a spacer what did you use. Please help point me in the right direction.
 

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Discussion Starter · #2 ·
Looking on Tire rack it lists the 305 PS4S as having a "Section Width" of 12.3" and a "Tread Width" of 11.2". Comparing that to the 315 P-Zeros it is listed as a "Section Width" of 12.6" and a "Tread Width" of 11.1". Not knowing the accuracy of these numbers not entirely sure what to make of them, but they make it seem like these PS4S tires are in the ballpark, in width, of some 315's. Still looking at spacers, is 3mm enough?
 

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They seem to run wide . More offset for the 11" rim may have helped too. My 11" MR392 rims are +24 with 305 firehawks which are 12.3" section width and tread width of 10.6" I just had to cut maybe 1/4" of the lower trailing edge of the plastic liner where it was curling inward on both my challengers.
 

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Discussion Starter · #4 ·
They seem to run wide . More offset for the 11" rim may have helped too. My 11" MR392 rims are +24 with 305 firehawks which are 12.3" section width and tread width of 10.6" I just had to cut maybe 1/4" of the lower trailing edge of the plastic liner where it was curling inward on both my challengers.
Was your rubbing on the outside of the wheel well or the inside. I'm getting rubbing on the front inside corner. Seems like adding a wheel spacer is the only way to go. I'm not sure how much space the wheels actually need between the liner and the wheel. The drivers side is making solid contact, the passenger side is maybe a paper gap at best.
 

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It was the inside bottom rear corner of the plastic liner on both sides and that was just because it was slightly curled at the ends. Never rubbed on the outside or up top etc.

Obviously chargers have more room back there but those 305 tires you have (per tire rack) are wider than their 315s in same tire which are 10.9 and 11.1 depending on if its for ferrrari or porsche spec.
 

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You can also take a heat gun and carefully remold the plastic liner closer to the body and gain some room that way too.
 

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Do you mean here? Gap 2.jpg I'm getting the 10 1/2" from them, with 25MM offset. I'm also getting the 315/35, and hopefully on the narrow rim, it will pull it in a tad more. They said that I may need a 3MM spacer, to clear the inside sidewall.
 

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Discussion Starter · #8 ·
Do you mean here? View attachment 570237 I'm getting the 10 1/2" from them, with 25MM offset. I'm also getting the 315/35, and hopefully on the narrow rim, it will pull it in a tad more. They said that I may need a 3MM spacer, to clear the inside sidewall.
Yes, im getting rubbing on the inside corner of that area. Just doing the math with published specs, 11" wheel with 22mm offset and 305 PS4S that moves the tire sidewall about 1.4" closer to the inside of the wheel well. I'm going to attempt to measure the stock clearance this afternoon. A 25mm offset will put your setup 3mm closer, not sure how much the 10.5 wheel will pull in on that tire but the 305 on an 11" is probably similar to 315 on a 10.5''. I'm just guessing at this point...lol
 

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Discussion Starter · #9 ·
Do you mean here? View attachment 570237 I'm getting the 10 1/2" from them, with 25MM offset. I'm also getting the 315/35, and hopefully on the narrow rim, it will pull it in a tad more. They said that I may need a 3MM spacer, to clear the inside sidewall.
Looking at your post in the other thread you said you have about a 1.8" clearance, so even on paper I still should have had enough room for my setup as well as yours. I'm calculating a width of 178 mm from wheel hub to side wall on my setup, stock is ~161mm. That's where I got the 1.4" change.
 

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Did you chat with them yet? They seem to know exactly what is needed for each wheel.
 

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Discussion Starter · #11 ·
Did you chat with them yet? They seem to know exactly what is needed for each wheel.
No I haven't done that wasn't sure if they would be able to help with different setups. I'll give them a call for sure.
 

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Are you concerned about the Standard Load vs. Xtra Load rating? I'm going with the 315/35 for that reason also.
 

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Discussion Starter · #13 ·
Are you concerned about the Standard Load vs. Xtra Load rating? I'm going with the 315/35 for that reason also.
No I'm not concerned. The the SL vs XL just means that the tire can carry a heavier load at a high pressure. 41 psi vs 36 psi. For SL the load rating does not increase beyond 36 psi. For our cars with OE tires, 106Y load rating, at 32 psi they have a load capacity of 1682. For the 104Y 305/35/20 you just need to adjust your tire pressure accordingly. At 30 psi the 305/35/20 has a load capacity of 1704 lbs, exceeding the OE spec. With the 315's the correct pressure would be 28 psi. You just cannot use a tire that cannot meet the load required by your vehicle without exceeding the max tire pressure.

Here is a application guide. There are some online calculators as well. I wouldn't go 315 for that reason alone, Paying more for tires, when the 305 is just as wide on an 11" wheel. That was my logic anyway.

How to apply the load inflation tables (toyotires.com)

However I now have the unexpected rubbing.
 

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I thought that the sidewall was stiffer too? For flexing during high speeds? Yeah, I'm nervous about how they will fit when I try them in a couple of weeks.
 

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Baabootoo,

I did the the 10.5" repro with 315 on the rear in a 35 series (Nitto Motivo). I needed ALL season tires. I was worried about the 11" rim due to it possibly rubbing... The 10.5" seems to be PERFECT... no issues.

My rears have a offset of +22mm if that helps.
 

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Discussion Starter · #16 ·
I thought that the sidewall was stiffer too? For flexing during high speeds? Yeah, I'm nervous about how they will fit when I try them in a couple of weeks.
I think some of that comes from forum post that are misunderstanding how to interpret tire load ratings. I think another contributing factor to that thought is link to grumbles from people who have wide tires on OE wheels, and/or have not done this conversion and are running there tires at the wrong pressures, then blaming it on sidewall stiffness, ect. You could look at two tires the same size but one is a 104Y and the other is 106Y at 32 psi they are both rated for the same load at 186+ mph, however the 106Y is rated for a higher load between 36 psi and 41 psi. Our chargers are spec'd for 1682 lbs load per tire. (other note, this load rating is done at max load, 36 psi and 186 mph for an extended duration, much harsher conditions then real world driving)
 

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Discussion Starter · #17 ·
Baabootoo,

I did the the 10.5" repro with 315 on the rear in a 35 series (Nitto Motivo). I needed ALL season tires. I was worried about the 11" rim due to it possibly rubbing... The 10.5" seems to be PERFECT... no issues.

My rears have a offset of +22mm if that helps.
So it seems like the conclusion here is the main contributor to the rubbing is likely the 11" wheel vs 10.5" not necessarily the 315mm width of the tire.
 

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Discussion Starter · #18 ·
So it seems like the conclusion here is the main contributor to the rubbing is likely the 11" wheel vs 10.5" not necessarily the 315mm width of the tire.
I bought this setup from another forum member, who was running these on a challenger without rubbing, so my assumption was that is should be plug and play on my charger. I know you see more rubbing issues with the challengers. I did send an email to Factory Reproductions, to see what they know about this particular setup.
 

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Thats what i have seen. My guy that does my tires advised the 11" would most likely rub.That is the reason I went with the 10.5 to be safe
 

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Discussion Starter · #20 ·
Thats what i have seen. My guy that does my tires advised the 11" would most likely rub.That is the reason I went with the 10.5 to be safe
I was more focused on the tire width than the wheel. Hopefully a 1/8" spacer give me enough space. It might be possible to remove a little material from inside the wheel well and get the required clearance as well.
 
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