245/40-20 on Mag R/T AWD?

**FrenchMag** · 12-28-2005, 03:08 AM

Hi,
I'm new to the forum (1st post), while I've been reading many threds and found it quite useful to start some mods on my Mag here in Paris, France.

Question: I'm getting some OCG RACING DESIGN WHEELs MODEL M703B in Size: 20x8.5" with 35 offset (black with chrome lips) from AutosportsUSA on eBay.
Will these fit with 245/40-20 on my Mag R/T AWD?

Any other tires recommandation with these rims?

Many thanks

**desmo_dude** · 12-28-2005, 02:34 PM

It should fit fine.... you could possibly even go with 255's without rubbing the front tire well while turning up into driveways, etc., but with 245's you'll be okay... 245/40 just might leave too much void in the well (in my opinion), enough that it's worth at least trying to fit a 255. My 20x8.5 ET40 w/ 255/45-20 don't rub at all, so I'm thinking your ET35 w/ 255/40-20 would be roughly the same clearance to the well that I had.

Wow, a Magnum in Paris!

:grin: How'd that happen? Do the French turn their noses up to your big silly American car while they putt around in their little Renaults? Be careful.... Are the riots still going on? Aren't they burning cars by the hundreds every night around Paris? One of my co-workers is from a Paris suburb, and said that the car-burning is nothing new. They were burning them by the dozen every night loooong before these riots ever started and will continue long after the riots are over. :mad:

**FrenchMag** · 12-30-2005, 06:11 AM

Desmo_dude, Thanks for the advise.

I got the Magnum imported via Canada. Quite unique in Paris.. lots of question on what's that car...

No more big riots in Paris, and yes, in some poor suburds there has always been burned cars. No big deal. Quite often, they burn their own old crap cars, so they get money back from insurance...

**Res18cuE** · 12-30-2005, 08:43 AM

Originally Posted by FrenchMag

Quite often, they burn their own old crap cars, so they get money back from insurance...

I can't believe someone would really do this! Although, one time..at band camp...I saw this car struck by lightning...

So FrenchMag, were things as bad as they were made to sound, or was it another case of something being blown out of proportion on the evening news?

**FrenchMag** · 12-30-2005, 08:34 PM

It was really blown out of proportion by the news. Yes, there has been 2 to 3 thousands cars burned in 3 or 4 weeks, but these where in very limited and specific suburb areas. No big deal. Travellingin to Miami at that time, I was amazed to see how the US tv channels were making it like a full riot all over France. It all over now. .. just a couple hundreds every nights..

**MattRobertson** · 12-30-2005, 09:28 PM

FrenchMag,

Consider putting on 245/45/20's on the front and 255/45/20's on the rear. This is actually the stock setup for a Magnum SRT8 (which means a dealer with a StarScan can correct your tires for rotational speed vs. speedometer. They use the 255 size for that I believe, despite the staggered sizing).

I, like a lot of other guys with 20" rims, have 255/45/20's on (Toyo Proxes in my case). My Magnum is also lowered 1.75" and has sway bars on it. The wheel wells are filled, to say the least.

I get some rubbing on the front 255's on extreme cornering (and I mean *very* extreme). Thats why I mention the 245's. As a counterpoint, Obiwan has a supercharged R/T with 255's, sway bars and KW V2 coilovers and he reports no rubbing at all.

Strictly speaking narrower tires (245's) should give a bit more responsive handling, too. Use the 255's in back for max traction.

**Res18cuE** · 12-30-2005, 10:55 PM

Originally Posted by MattRobertson

Consider putting on 245/45/20's on the front and 255/45/20's on the rear.

I'm just thinking outloud here (in print?), since FrenchMags got an AWD, will the different widths be any issue? The aspect ratio's the same, the width shouldn't matter, should it?

**MattRobertson** · 12-31-2005, 01:00 AM

oooh I hadn't realized that. May not be such a bright idea, then.

Sidewall height is dependent on the tire width (in this case "45" is 45% of 255 or 245 millimeters) So the fronts will be a little smaller than the rears. SRT's are RWD only and I would not know if this setup is good/bad/indifferent tto AWD... but I would guess that you want it to match up. So 255/45/20's front and rear, then. A common tire combo.

It is extraordinarily difficult to get matching-offset rims *at all* for AWD's. So much so that only guys who have sprung the REALLY big bucks for custom wheels have done it. Other AWD owners: Is his reported offset correct or is he going to have tires outside his fender wells?

**desmo_dude** · 12-31-2005, 07:55 PM

Yup, trust me, I've looked into staggering AWD's... it ain't easy. I decided it wasn't worth it. We have to be very careful... it's not just a matter of clearance, it's about keeping the tire circumference from front to back identical, or risk damage to the tranny. When I was considering staggering 20's on my AWD, the tire combo I found that most closely matched front/rear circumference, I later found out was the same as what's on the new Cherokee SRT8, which is 255/45R20 in front, and 285/40R20 at the rear. The fact that Goodyear designed a new tire specifically for them to be able to stagger a 4WD is a good indication of how important it is to match the tire circumferences. It would've looked mean as hell, but not worth it because those sizes are only available in Goodyear RS-A run-flats at this time, which are a lot heavier than regular tires. I'm curious to hear from some of these AWD'ers who have spent the big $$ to get their rims staggered, and what sort of tires (brand/specs) they're using.... I doubt that many of them did it with tight circumference tolerances in mind.

The 35mm offset that FrenchMag is using should have the rim sitting just about flush with the protruding fender well, maybe even a mm or 2 beyond. Mine sits 28mm further out than stock, and I still have probably another 5mm til it's flush.... I'm thinking his 35mm offset will sit even better than mine.

**desmo_dude** · 12-31-2005, 08:58 PM

By the way I just saw that wheel on eBay. Very nice looking. I take it you already spoke with the seller to confirm it has a 35mm offset? None of his auctions show offsets. I would make sure it's at LEAST 35mm.

**FrenchMag** · 12-31-2005, 09:54 PM

Yes, That the 20" ones I'm getting from eBay, shipped from LA. The seller confirmed he is sending me these with 35mm offset. Now the question is which tires will fit my Magnum RT AWD on european roads.... 245/40, 245/45 , 255/40 or 255/40?

All those sizes are not very commun out here, I wont have any chance to reconsider
once ordered to my local seller.

Thanks to all for your support.

I'll send you pictures with the Eiffel tower and the Mad Mag.

**desmo_dude** · 01-01-2006, 12:15 AM

You know, looking at the picture of that wheel again, I hope your front brake calipers don't rub against those spokes.... I had that problem with a 20x8.5 Foose Nitrous with 42mm offset.... Your wheel looks like it has a very similar layout to the Nitrous, but you have an extra 7mm of offset, so hopefully that will give you plenty of room. Let us know what happens.

**Clutch-n-Throttle** · 01-01-2006, 01:58 AM

Originally Posted by desmo_dude

I later found out was the same as what's on the new Cherokee SRT8, which is 255/45R20 in front, and 285/40R20 at the rear. The fact that Goodyear designed a new tire specifically for them to be able to stagger a 4WD is a good indication of how important it is to match the tire circumferences. It would've looked mean as hell.

Do you know what the wheel sizes are for the Cheri SRT8 are?

I have the MSRT wheels on my RT. 20X9's. I was thinking about putting the 245/45-20 for the fronts and using the 285/40-20 for the rear. I checked the Goodyear web site. They recommend the minimum rims width of 9.5 inches. Anybody see a problem using the 285/40-20 on a 9 inch wheel?

**desmo_dude** · 01-01-2006, 05:53 AM

No, I was curious about those rim sizes myself... I don't think 1/2" smaller rim width would make any difference at all. If 9.5" is the recommended width, there's usually at least a +/- of an inch of rim width where the tire will still perform to spec. Then again, I don't know anything about run-flats other than they're heavier than sh!t, so I could be wrong. Are you looking at GY run-flats or did you find the 285/40's in another tire?