20" Tire Sizes

CALYP50 · #1 (**permalink**) 10-15-09, 06:39 PM

I'll be in the market for new rear tires for my '07 GT soon and I'm curious about the tire sizes everyone is running for a 20" staggered setup.

Currently, I'm running a 20x8.5 rim up front with 255/35s and 20x10.5 in the rear with 285/30s. It's only by about a 1/10th of an inch shorter in the rear, but to me, the rears are noticeably shorter than the fronts and frankly look like rubber bands and have no overlapping sidewall. When I bought the rims, the rear tire size decision was based on the fact that they were the same height as the stock tire (as per the salesman) and they were cheap.

This time around, I'd like to match (or slightly exceed) the front tire height as I don't think it looks right with smaller tires on the rear than on the front. I looked at 305/35s, but it's between $400 and $500 PER TIRE to go this route whereas the 285/30s are between $200 and $300 a piece. Other 295-305/30-35 sizes were either just as pricey, few brands, or non-existent. What are your recommendations?

Wind-Farmer · #2 (**permalink**) 10-15-09, 11:20 PM

that 35 in the front and the 30 in the rear is your problem. Mostly every tire place you go to will tell you to go with this setup. BUT from my experience, you are right, the sidewall height is VERY noticable...and looks UGLY IMO.

No matter what, you always go with the sidewall height(middle number) the same or greater. I would say a 285/35/20 would look fantastic in the rear, or if your wanting to go bigger, go with a 295.

Those are my thoughts.

NastyStang113 · #3 (**permalink**) 10-15-09, 11:41 PM

305/35/20s look good ... Soon to be 315/35/20s.

Wind-Farmer · #4 (**permalink**) 10-16-09, 07:50 AM

yup..you just convinced me to do a massive burn-out. It'll have to wait till spring though, to much snow already.

CALYP50 · #5 (**permalink**) 10-17-09, 09:09 PM

Thanks to all for the help. I realized that I typed my rear wheel size wrong. I have 20x10, not 20x10.5. Does this change anything as far as fit when stepping up to a wider 305 series tire?

Wind-Farmer · #6 (**permalink**) 10-19-09, 07:46 AM

no...you will be just fine

NastyStang113 · #7 (**permalink**) 10-19-09, 01:45 PM

Quote:

Originally Posted by CALYP50

Thanks to all for the help. I realized that I typed my rear wheel size wrong. I have 20x10, not 20x10.5. Does this change anything as far as fit when stepping up to a wider 305 series tire?

Nope 20x10 is perfect for 305s.

ViperNuge · #8 (**permalink**) 10-20-09, 11:07 PM

Nasty, your setup look amazing!

Right now I have just the stocker 235/55, 17 inch bulitt wheels. I plan to drag race every month with this car and would like to keep doing it without drag radials. Whats the optimal rim size and widest tire combo I can use and not hurt my times? I was at the stealership last week and was loving how the gt500's have a 285 in the back. I love that fat rear tire look. Can I do a 18 inch rim with 285's in back and ? up front?

patrick

**walter** · #9 (**permalink**) 10-20-09, 11:54 PM

Quote:

Originally Posted by ViperNuge

Nasty, your setup look amazing!

Right now I have just the stocker 235/55, 17 inch bulitt wheels. I plan to drag race every month with this car and would like to keep doing it without drag radials. Whats the optimal rim size and widest tire combo I can use and not hurt my times? I was at the stealership last week and was loving how the gt500's have a 285 in the back. I love that fat rear tire look. Can I do a 18 inch rim with 285's in back and ? up front?

patrick

I just asked the same question on another thread. Kooldawg seems to be of the opinion that you can run 285 all the way around but I think that may hurt your handling and ride quality up front. The car will follow every little unevenness on the road which may get annoying steering could also get very slow trying to rotate over such a wide tire. You'll also definitely pick up some oversteer going hot into corners if you're quick with the wheel.

Roush seems to want to do 275's all the way around for their kit. 285 may be a dab too much sidewall up front.

NastyStang113 · #10 (**permalink**) 10-21-09, 12:54 AM

Thanks. The tires aren't going to really hurt your times. If they do that just means you need more power! I'd do 255s in front with 285s in the rear.

ViperNuge · #11 (**permalink**) 10-22-09, 02:30 AM

Quote:

Originally Posted by NastyStang113

Thanks. The tires aren't going to really hurt your times. If they do that just means you need more power! I'd do 255s in front with 285s in the rear.

What I tried stating but did a bad job of........ ....... is what tire size is optimal for drag racing? ie 17 or 18 inch? I have read that the 20's will slow your time down. And is 285 the widest we can go for the back tires of the s197? I believe the gt500 has the same tire sizes front and back as you Nastystang............and it looks cool!!

Walter you are correct about the wide tires up front tracking the road....my tires on my truck are (stock) 305 40 22 and they do that. Its no biggie for me since I am on Maui with no freeway driving.

patrick

NastyStang113 · #12 (**permalink**) 10-22-09, 10:49 AM

Quote:

Originally Posted by ViperNuge

What I tried stating but did a bad job of........ ....... is what tire size is optimal for drag racing? ie 17 or 18 inch? I have read that the 20's will slow your time down. And is 285 the widest we can go for the back tires of the s197? I believe the gt500 has the same tire sizes front and back as you Nastystang............and it looks cool!!

Since we're talking about street tires, I see no difference between the 17" or 18" wheel. Run what you'd like. No 285s are not the widest tire than will fit. I'm running 305s right now and I'm going to be putting 315s on my car and I know they will fit.

kooldawg6 · #13 (**permalink**) 10-22-09, 10:17 PM

When I stepped up from the 235 to 255 up front, I noticed the car wanting to "track" (I had a Ranger with 16" wide tires on 14" wide wheels, so I knew how that worked

). However, when I went from the 255 to 275...I noticed no difference in the way it handled

If you plan on racing it often on street tires I wouldn't go any wider than 255 up front. Depending on the wheel you get, you might want to stay at 235. Just that when you get to the track, air them up to about 40 psi to lessen the rolling resistance some. It won't be a lot of help, but when you're looking for any little advantage... The reasons 20"s are so bad at the track is the added rotational mass of the wheel and not enough sidewall flex to aid in traction. HeavyGT used to run the OEM 17" Bullitt up front with a very closely matching aftermarket 18x10 Bullitt out back with a massive tire

NastyStang113 · #14 (**permalink**) 10-22-09, 11:37 PM

There are people running 10s with a ~600 rwhp on 20" wheels and Nitto NT555Rs. It can be done.

ViperNuge · #15 (**permalink**) 10-23-09, 12:24 AM

Quote:

Originally Posted by NastyStang113

Since we're talking about street tires, I see no difference between the 17" or 18" wheel. Run what you'd like. No 285s are not the widest tire than will fit. I'm running 305s right now and I'm going to be putting 315s on my car and I know they will fit.

Nice..... 315s, I imagine would look awesome. Now and then I will see a sn95 stang with those wide ass wheels on it.............and its the bomb IMO.

What size rim do I need to handle a 305 or 315 wheel? I am trying to plan out my wheel budget in advance and appreciate your input.

Kool.........thanks for the tip. I was thinking the same, 255 up front and wide as possible in back.

patrick

Steel Horse · #16 (**permalink**) 10-23-09, 10:59 AM

You could always go with a 295 out back. There seems to be more options with 295s than 305s and 315s.

NastyStang113 · #17 (**permalink**) 10-23-09, 12:21 PM

295s or 305s are going to need a 10" wide wheel. A 315 is going to require at least an 11" wide wheel.