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Discussion Starter #1 (Edited)
Today's research data after reading many, many threads on replacement tires. Topics include diameter deltas wrt T-case issues. I'm in the market after my GY wear issue... I thought I'd share what I collected today.

Avoid side wear issues...BE SURE TO SET ALIGNMENT CAMBER DOWN TO -0.125 to -0.25 range (per jim383)
STOCK RIM SIZE = Front 9.0, Rear 10.0 (some tires below are outside of this spec)

Question: anybody have issues with rubbing on wider sizes on OE suspension, if so, what model?
Question: any reason to be concerned with buying tires outside of manufacture's rim width specs?

I learned that not all brands are available in OE and/or larger sizes.

Enjoy...

[Transferred from XLS, some formatting and table alignment not showing up pretty]

http://www.nittotire.com/Tire/nt420s#size
NITTO 420S (all season, non-directional)
OE SIZES Diameter Width Tread CIR
255/45R20 29.13 9.88 11 91.514594
285/40R20 28.94 11.38 10.7 90.91769139
DIA DIFF: 0.19
CIR DIFF: 0.006565308
CIR DIFF (%): 0.66%

UTQG (420)

BIG SIZES Diameter Width Tread CIR
275/40R20 **NOT AVAIL IN SIZE** #VALUE!
315/35R20 **NOT AVAIL IN SIZE** #VALUE!
DIA DIFF: #VALUE!
CIR DIFF: #VALUE!
CIR DIFF (%):#VALUE!



http://toyotires.com/tires/pattern/proxes-st-ii-sport-truck-all-season-tires
Toyo Proxes STII (all season, directional)
OE SIZES Diameter Width Tread CIR
255/45R20 29 9.9 10 91.10618695
285/40R20*** **NOT AVAIL IN SIZE**
CIR DIFF: #VALUE!
CIR DIFF (%):#VALUE!

UTQG (420)

BIG SIZES Diameter Width Tread CIR
275/40R20 28.7 10.7 11 90.16370916
315/35R20 28.6 12.2 11 89.84954989
note: approved rim width 10.5-12.5!
DIA DIFF: 0.10
CIR DIFF: 0.003496503
CIR DIFF (%): 0.35%



http://www.nittotire.com/Tire/motivo#size
NITTO MOTIVO (all season)
OE SIZES Diameter Width Tread CIR
255/45R20 29.29 10.08 10 92.01724882
285/40R20 **NOT AVAIL IN SIZE** #VALUE!
DIA DIFF: #VALUE!
CIR DIFF: #VALUE!
CIR DIFF (%): #VALUE!

UTQG (560)

BIG SIZES Diameter Width Tread CIR
275/40R20 28.78 10.83 10 90.41503657
315/35R20 28.54 12.52 10 89.66105433
note: approved rim width 10.5-12.5
DIA DIFF: 0.24
CIR DIFF: 0.00840925
CIR DIFF (%): 0.84%



http://www.nittotire.com/Tire/motivo#size
NITTO NT05 (summer/track tire)
OE SIZES Diameter Width Tread CIR
255/45R20 29.06 10.08 7.2 91.29468251
285/40R20 **NOT AVAIL IN SIZE** #VALUE!
DIA DIFF: #VALUE!
CIR DIFF: #VALUE!
CIR DIFF (%): #VALUE!

UTQG (200)

BIG SIZES Diameter Width Tread CIR
275/40R20 28.62 10.79 7.2 89.91238175
315/35R20 28.62 12.4 7.2 89.91238175
DIA DIFF: 0.00
CIR DIFF: 0
CIR DIFF (%): 0.00%



http://atturo.com/pdf/Atturo-AZ800-Sizes-Specs.pdf
ATTURO
OE SIZES Diameter Width Tread CIR
255/45R20 29.1 10 11.2 91.42034622
285/40R20 **NOT AVAIL IN SIZE** #VALUE!
DIA DIFF: #VALUE!
CIR DIFF: #VALUE!
CIR DIFF (%):#VALUE!

UTQG (420)

BIG SIZES Diameter Width Tread CIR
275/40R20 28.7 10.9 11.3 90.16370916
315/35R20 28.7 12.5 11.3 90.16370916
note: approved rim width 10.5-11.5
DIA DIFF: 0.00
CIR DIFF: 0
CIR DIFF (%): 0.00%



Can't find official DILENTE website??? …only tire vendors??? Anybody have an official URL to confirm DL4000 specs below?
DILENTE DL4000
OE SIZES Diameter Width Tread CIR
255/45R20 **NOT AVAIL IN SIZE** #VALUE!
285/40R20 **NOT AVAIL IN SIZE** #VALUE!
DIA DIFF: #VALUE!
CIR DIFF: #VALUE!
CIR DIFF (%):#VALUE!

UTQG (580)

http://www.cherokeesrt8.com/forums/showthread.php?t=65165
http://www.cherokeesrt8.com/forums/showthread.php?t=67192

BIG SIZES Diameter Width Tread CIR
275/40R20 29 11.4 ? 91.10618695
315/35R20 29 13 ? 91.10618695
DIA DIFF: 0.00
CIR DIFF: 0
CIR DIFF (%): 0.00%



http://www.conti-online.com/generator/www/us/en/continental/automobile/themes/car_tires/performance/extreme_dws_en/hidden/printable_datasheet_en.pdf
Continental Extreme Contact DWS (all season)
OE SIZES Diameter Width Tread CIR
255/45R20 29 10 10 91.10618695
285/40R20 **NOT AVAIL IN SIZE** #VALUE!
DIA DIFF: #VALUE!
CIR DIFF: #VALUE!
CIR DIFF (%):#VALUE!

UTQG (540)

BIG SIZES Diameter Width Tread CIR
275/40R20 28.7 10.9 10 90.16370916
315/35R20 28.7 12.6 10 90.16370916
note: approved rim width 10.5-12.5
DIA DIFF: 0.00
CIR DIFF: 0
CIR DIFF (%): 0.00%



http://www.vredestein.com/car-tyres/search/size
VREDs (Ultrac SUV Sessenta model??)
OE SIZES Diameter Width Tread CIR
255/45R20 **NOT AVAIL IN SIZE** #VALUE!
285/40R20 **NOT AVAIL IN SIZE** #VALUE!
DIA DIFF: #VALUE!
CIR DIFF: #VALUE!
CIR DIFF (%): #VALUE!

UTQG (280)

BIG SIZES Diameter Width Tread CIR
275/40R20 ? ? ? #VALUE!
315/35R20 ? ? ? #VALUE!
DIA DIFF: #VALUE!
CIR DIFF: #VALUE!
CIR DIFF (%): #VALUE!



http://www.goodyear.com/en-US/tires/eagle-rsa-emt
GY Eagle RSA EMT (all season)
OE SIZES Diameter Width Tread CIR
255/45R20 29.1 10 11 91.42034622
285/40R20 29 11.4 12 91.10618695
DIA DIFF: 0.10
CIR DIFF: 0.003448276
CIR DIFF (%): 0.34%
UTQG (260)



http://www.nittotire.com/tire/invo#size
NITTO INVO's (street tire)
OE SIZES Diameter Width Tread CIR
255/45R20 29.02 10.12 10.0 91.16901881
285/40R20 **NOT AVAIL IN SIZE** #VALUE!
DIA DIFF: #VALUE!
CIR DIFF: #VALUE!
CIR DIFF (%):#VALUE!

UTQG (260)

BIGGER SIZES Diameter Width Tread CIR
275/40R20 28.62 10.94 10.0 89.91238175
315/35R20 28.62 12.40 10.0 89.91238175
DIA DIFF: 0.00
CIR DIFF: 0
CIR DIFF (%): 0.00%


http://www.bridgestonetire.com/tire/dueler-hp-sport (show all sizes link)
Bridgestones Dueler H/P Sport (Summer Tire)
OE SIZES Diameter Width Tread CIR
255/45R20 29.1 ? 11 91.42034622
285/40R20 **NOT AVAIL IN SIZE** #VALUE!
DIA DIFF: #VALUE!
CIR DIFF: #VALUE!
CIR DIFF (%): #VALUE!

UTQG (300)

BIGGER SIZES Diameter Width Tread CIR
275/40R20 Y speed 28.7 ? 11 90.16370916
315/35R20 Y speed 28.7 ? 12 90.16370916
DIA DIFF: 0.00
CIR DIFF: 0
CIR DIFF (%): 0.00%
 

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Nice job compiling the specs on the various tires for stock sizes as well as the 275/40, 315/35 combo many end up going with. I currently have the Nitto 420s. No issues with t-case with over 20k miles on the tires. I want the Motivos before winter as the 420s are not good at all in snow and tread getting low by then. Motivos have more of a difference in diameter, almost a quarter inch. The biggest problem as I see it, is there is no traceable source for the often quoted allowable 3% value between fronts and rears. That number allows for quite a difference in circumference. Searching the chat sessions I found an exchange(I posted it in my thread) with an SRT engineer and a couple of forum members that did not lend any support that this is a valid acceptable tolerance. So we really do not know how much difference is acceptable before having possible transfer case problems.
 

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Discussion Starter #3
rickrad,
Thanks. I did see your post and noted the absence of any official position made by Chrysler/Jeep. Today I sent a question off to the guys at http://www.wkjeeps.com/wk_srt8.htm to see if they have anything semi-official on the topic. I expect not. I didn't see anything in the WK TSBs they have on that site either. Looking at the Motivos compared to your 420s, the diameter percentages (delta of 0.0018 between the models) for front/back are very close to each other and in theory you shouldn't have issue or concern; and still under 1% front/back diameter difference. It would be good to hear something official though to be sure.

Did I see in your thread that you had side tire wear issues? (can't recall if that was you or not) If so, did you make the recommended camber adjustments? Did the adjustment work? If not you, I apologize, I must have read a thousand posts today in this forum topic alone.

The big thing that I'd like to understand is when going to the larger 275/40R20-315/35R20 size pairings, do people have issues with the additional width not "fitting" or rubbing in any way? (OE suspension)

Also, has ANYBODY heard of T-case issues in going to the larger sizes assuming they maintain the properly paired size, same tread front/back, etc. (275/40R20 & 315/35R20)

And has anybody experienced issues with the dealership when showing up with non-OE sizes?

I'm still well within my 5yr/100K powertrain warranty and I don't want to put myself into a corner I can't get out of if I do have a problem. I'm really leaning toward the 420s only because of the OE size availability, but it would be nice to feel confident with the larger sizes and model varieties as well.

My need: daily-driver for local commutes; not a track guy; want the tire to grab when I stand on it; would like reasonable tire life; no more stupid tire separation! Yes, I know this is a lot to ask for.

Thanks for any additional data others can provide!! Also, any feedback on:

Question: anybody have issues with rubbing on wider sizes on OE suspension, if so, what model?
Question: any reason to be concerned with buying tires outside of the tire manufacture's rim width specs? [rear rims being 10 inches and some tires spec'd min rim @ 10.5, data below...]
 

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From everything I have read, no issues with rubbing on the stock jeep. I think a few have had minor issues on lowered ones. I too asked the question about rim size given the width of the 315/35 tires on the rear. Many have used those on the 10 inch rims so yes it will work. I think the Contis may be the widest or the Atturos. Whether it looks weird or compromises handling/stability I cant answer but would like to know myself.
 

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Discussion Starter #5
...I want the Motivos before winter as the 420s are not good at all in snow and tread getting low by then. Motivos have more of a difference in diameter, almost a quarter inch...
Are there any happy Motivo customers out there? Any feedback or gory details from them?
 

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Are there any happy Motivo customers out there? Any feedback or gory details from them?
Pretty new tire...The reviews I have read have been very good. I may be the first here to have them on an SRT8 Jeep. There are things I dont like about the DWS, Toyos, and the Atturos I would not even consider. Not going the ultra cheap route here. Still want to be sure that its not too big a difference on the Motivos. I calculated revs per mile and its a difference of 6 between front and rear tires.
 

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Can you update the list to include the Bridgestone 275/315 combo? I have been rocking them for about a year and love them. I suspect rubbing on stock suspension components, but upgraded to the Bwoody end links. I actually had to put the stock end link back on the drivers side, and the Bwoody on the passenger side. ( I have a thread about this).

The Bridgestones friggin' rock on wet roads. I was cruising back from MI to VA a few weeks back and had torrential downpours from DC to Richmond. It was by far the heaviest rains I have ever driven the Jeep in. I was cruising at 80 MPH hitting pools of water with reckless abandon, and only a slight wheel jerk in the deepest of pooling spots.

Not to mention, these are runflats with a decent ride. Obviously, not as good of a ride as a non-runflat tire, but WAY better than the crapyears.

Downside: $$$$$
 

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Discussion Starter #8
Can you update the list to include the Bridgestone 275/315 combo?
Thanks for the input! What specific Bridgestone model are referring to? Will do... I'll update my numbers and get them into the original post soon. Thanks!


OTHERS: what other size combos other than stock sizes and 275/315 combo have folks used without issue. I noted a couple threads with some using a combo with higher sidewall values with the hopes to "protect" the wheels a bit more. I'd like to confirm these sizes are indeed available across the different brands. Thanks for your input... I'll keep the original post up to date with all the data in single location.
 

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Thanks for the input! What specific Bridgestone model are referring to? Will do... I'll update my numbers and get them into the original post soon. Thanks!


OTHERS: what other size combos other than stock sizes and 275/315 combo have folks used without issue. I noted a couple threads with some using a combo with higher sidewall values with the hopes to "protect" the wheels a bit more. I'd like to confirm these sizes are indeed available across the different brands. Thanks for your input... I'll keep the original post up to date with all the data in single location.
I think the larger aspect ratios some are going with are more for looks...fill out the wheel well a bit. Doubt its going to offer anymore protection from wheel rake. I do know the Toyos are one brand that has this available...45 fronts 40 rears and maybe also 50 and 45. I don't think in general most brands offer these sizes that will work with our jeeps.
 

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REALLY GREAT writeup man.

I'm glad I'm not the only one that sees that 3% as not being a small delta, but in fact... quite a large one. I think it comes out to like 1.5" or something if I remember my math from back in the day semi-correctly.

I'll ask that you add the INVO's and the previously mentioned Bridgestones. (Dueler H/P Sport) There is also a cheaper non "RFT" version of that tire. It should probably be on the list as well.
The 315 RFT is supposedly the widest that we can get on our vehicles. It's a really fat tire. And on SOME it will rub a bolt on the inner fender in the rear end. Search... you'll find a few writeups and the solution. It's easy.

Also shouldn't forget the Yokohama ADVANSPORT tires, nor the Pirelli PZero's. Good tires. Very pricey.
And the Dunlop SP Sport Maxx & Michelin's. For those that want very very expensive tires.

Easy way to search for the wider tires: Search for BMW X5 tires. :)
 

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Discussion Starter #13
Edited first post: Added Nitto Invo and Bridgestone Dueler H/P Sport specs.

Both models have identical front/back diameters (0% CIR diff).

Note both are softer summer tire vs. all season. No apparent warranty on either.

Enjoy.
 

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I have the Bridgestone Dueler H/P Runflat tire in the 275/315 combo. I absolutely love this setup and as you have shown here there is zero difference in the front to rear circumference. I did go with the Bwoody endlinks in advance as it does give more clearance. I believe most will rub if you keep the stock endlinks.
 

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gofast... that's why I picked that combo. Not a lot of people had a chance to run the Dueler RFT's yet when I changed tires, so I went with a matched combo.

I'm glad there's been success with the Bridgestones though. They seem like a really nice option for a lot of rubber, RFT, and a decent price.
 

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I just check price on the stockers from Tire Rack. 2 GRAND for a set of those POS Goodyear RFTs!!! I'm leaning towards the Motivos.
 

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from what I can tell nobody actually has those tires in stock. nobody has ran them that I know of either
 

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I can't seem to make up my mind on what brand to go with! I'm really not sure if I would like the 275/315 setup on a non lowered rig, seems like they would look goofy.
 
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