I'm getting ready to get new rubber and I'm not sure what size to get.First it's a stock ride with a suspension rebuild in the very near future.I have 15x8 AR outlaw 1's in the back and 15x7's in the front with whatever the backspacing would be if you didn't order anything special 3.75 I think.I currently have 245/60's all the way around.I would like to put a 275/60/15 in the rear but not sure about the front.I thought about a 255/60/15 in the front but the tire guy insists that they'll rub?Or should I go with a 70 series.Any and all advice and PICS will be greatly appriciated.Thanks smile.gif

No 68 owners out there?I find that hard to believe.I need some advice here guys.Thanks

Todd,
I've got 275-60-15s on my 68.
I'm running 15" TTDs 7" wide, and 3.75" backspace.

Not sure, but 15" x 8" wheels with 3.75" back space might put you too close to the quarter panel.

I'd try to get a wheel with more backspace, (like @ least 4.25").

Hope you understand people don't like to answer questions they aren't sure about. And there are a bunch of variables, what works on my 68 might not work on yours. Some guys have replacement quarters, that have a wider lip, some have rear axles from different years.

Best thing is to test fit, a friends wheels of the size you want, or just measure real careful.

Hey Thad thanks for the responce.I just got off the phone with AR and they said the back spacing on my rims were 15x8=3.375 15x7=3.375.Now that we know this info what would be the biggest size i could get on there?Thanks

Todd,

I don't have any reference material here but this is what I would suggest. On a 15X8 Wheel with 4.5" BS you can fit (on the back)a P275 60R with plenty of clearance so there should be no fear of rubbing. This is what I have on my 70 and the fit is pretty close to the same on 68-72 as I recall. This would make your 3.375 BS a problem with a P275 tire most likely. You might get away with a P255 60R but you need to get width dimensions from a tire store and do the math. If my calculation is correct that tire is 3/4" narrower and still might not work. Call a tire store and get the sidewall/tread width and calculate. You say you have P245's all the way around and they must work. You should be able to measure your clearances you have now and get tire size dimensions and see what will work.

Robert

Sorry I don't have any input 4 ya, I'm still runnin' 69Magnum SS 14's on mine.............Motor,suspension,rear end,and electrical first........

Ok anybody out there ever been in this situation?I want to get the fattest tire on the back that I can.The rim BS is suppose to be 3.375 for a 15x8 and 15x7 does this sound right?,I think I'm going to pull a front and back and measure myself.Also once I rebuild my suspension is this going to make a difference in what I can put on it?

Ok anybody out there ever been in this situation?I want to get the fattest tire on the back that I can 31x16.5x16's here on my 68 :D

gonna take just a little trimming to get them in though :D

The 3.375 BS in the back is not enough on a 68 for the 275/60/15

My first wheel/tire combo was with that setup except my wheel was a 15x8.5. They rubbed unless I ran a bunch of air in my air shocks. As you can see in the pic below (sans motor/trans/interior)
That with the 3.375 BS the tire sat too close to the wheel well lip.

http://chevelles.com/showroom/ACE841/OldBlujan97.jpg

On the front I ran 235/60s on 15x7 with the same BS.

Edit:
Ed why such a small tire? I have 33x19.50s under mine tongue.gif

Todd,
The biggest I've seen on a 68 is Purs.

Check this link.

http://www.chevelles.com/forum/ultimatebb.php?ubb=get_topic;f=8;t=002531#000012

He's got 15"x10" wheels, with 325-50-15 under there.
Read the whole thread to see if he had to do any trimming.

Yeah I seen that,looks sweet.The only problem is I'm stuck with the wheels I have.

toddc,

Thanks. The pic at the first of the post referenced above is 325/50's on back and 235/70's on front. I now have switched the front tires to 255/60's and like the look better.

Ok guys,what should I do?I'll probably be getting my new shoes this weekend.Anybody live around Northen Ky,Cincinnati,Oh area that might have a set up on thier ride with the same size rim I have I might be able to check out or try on to get a better idea?

Todd,

Here is what you should do. You ain't going to like it but the other advice given above you don't like what you are hearing so it appears you are looking for a magic pill answer that is going to make a larger size tire work on your car. But here goes.

1. You are not willing to change wheels so
the 3.375 backspace is what you have to live
with
2. The consensus above is that P275 is an
absolute no-go... with an 8" rim and 3.375 bs
3. An option of P255 is possible but I think it
will be too close for comfort and your tire
guy already thinks they will rub so is it
worth the risk for .3937 of an inch

4. Where did I come up with the .3937? Well, you
already say you have P245's and the P255's
are .03937 X 10MM wider or .3937. Now you can
measure your existing clearances and see
whether you will have enough room to go up 1
size. If not stay with P245's ... you probably
won't even notice it.

You asked "What should I do?" I think we have been offering advice, but you don't like what you are hearing. You want somebody to tell you that P275's are going to fit with no modifications (275X.03937 = 10.82 inches) and it is not possible
P255 X .03937 = 10.04 inches & P245 X .03937 = 9.65 inches (tread width I believe) Will 10.04 fit? I don't know. How much clearance do you have now?

R. Stacho

Double post...don't know what happened? :rolleyes:

No I'm not looking for a magic pill,just good advice.I measured yesterday,and got about almost 2 inches from the side wall to the wheel well on the inside and to the lip on the outside.The 245's I have now don't look bad there just 12 years old,no miles,dryrotted from sitting :( .I was hopeing I could get a little taller and fatter with out changing rims.Thanks for the advice. graemlins/waving.gif

Oh,and the tire guy was talking about the 255/60 rubbing on the front.

If you have 2" of clearance with P245, the P275 is going to be 1.2" wider at the tread width, which means you should have plenty of clearance... but this don't make sense because with my 8" wheel and 4.5" bs I have about .5" of clearance. This is on a 70SS but I have read on this board that 68-72 are pretty much the same and that combo would not work on my car. Sounds like the wheel may have a larger bs than you think. Now I suggest you remove and measure... or maybe a 10 bolt axle is narrower?...or maybe it is really a 7" rim?

If you have more than 1/2" clearance all around on the front with P245's than a P255 might work...but remember the 255 (and the 275) are a little taller than the 245's so that needs to be considered in your clearance measurements for the front (and maybe the back to). I don't have the specs here at work but your tire shop can help you there. Maybe some of the extra clearance that you have in the back with the P245's is related to the height also. But all that can be calculated and measured on the car once your tire shop gives you all the measurements off the tires you are "wanting" to buy.(P275 & P255)

Can your tire shop do some testing for you? Mount the size you want and measure for clearances. If not OK get the smaller sizes. Maybe they will work with you for the sale. You might have to pay for additional mounting and dismounting but it might be money well spent.

Good Luck,

Robert

Ok here are the measurements,
275/60/15 OD-28.06 width-10.7 rim-7.5-9.5
255/60/15 OD-27.015 width-9.73 rim-7-9
245/60/15 I know will fit
265/50/15 OD-25.6 width-10.5 rim-8-10
I just got off the phone with Pep Boys again,he said my best bet would be a 265/50/15 for the 15x8 or a 245/60/15.He also said if they mount them and they rub,as long as I don't drive on them they won't stick me with them,they would change them.Thats cool.Thats what I was worried about,getting stuck with something that didn't work. graemlins/hurray.gif Does anybody have a pic with a 265/50/15 mounted an a 15x8 with 3.375 bs?Thanks again guys.

I think you will find the 265/50 does not adequately fill the rear wheel well. The tire looks too small. I have a pair of 275/50 drag radials on 15x8 wheels and the tire looks out of place on the rear of my 68. Sorry I don't have a pic setup with them. below is a pic of my 68 with 295/50's on 15x8 rallys (4.5bs) on the rear and the fronts are 265/50s.

http://chevelles.com/showroom/ACE841/Latest1.jpg

Follow this link to my '68 with 275s: '68 with 275-60R-15 (http://www.chevelles.com/forum/ultimatebb.php?ubb=get_topic;f=8;t=002659)

http://img52.photobucket.com/albums/v159/dreinecke/P1010028.jpg

I am not sure where the numbers came from that you indicated above but I apologize for some of the previous info that may be incorrect. I indicated that widths I gave you were tread widths but I think that may have been incorrect. I now think that would be the sidewall width... which is the width you need to be concerned with most of the time. The 245/255/275 represent the width of the tire in millimeters. I am pretty sure I am correct when I say this. So multiplying them by .03937 should give you the approximate tire width. That does not coincide exactly with the numbers PepBoys gave you. The information I have on BFG T/A's is as follows

P245/60R X15 = 8.0 Tread width 26.6 OD
P255/60R X 15 = 8.2 Tread width 27.1 OD
P265/50R X 15 = 8.6 Tread width 25.5 OD
P275/60R X 15 = 8.9 Tread Width 28.0 OD

Based on what Dave indicated above I think P275's should be out of the question with 3.375 BS ... but you say you have 2 inches of clearance. However, if I were you I would heed ACE841 warning and stay away from the P265's as I am not a fan of not filling wells very good myself. The problem is that a 50 series tire is a little squatier (sp.) tire with less side wall. I perfer to stay with 60 or 70 series tires for this reason. So if it were me I would have him try the P275's on and have some P255's (60's) there ready... if too close... for the back. If you have enough clearance in the front, I would suggest the same 255 tire as then it would simplify the spare tire situation...for the small difference the 245 is to the 255. If not then stay with the P245.

The OD change from 245 to 255 is fairly subtle (26.6-27.1) so you might not see too much of a difference in your gearing (3:73). If you do end up with P275's there is almost a full 2" OD difference and so your gearing will drop some and your speedo will be off even more than it might be off now.

Sounds like your tire shop is prepared to work with you so you should be good to go this weekend... but I re-iterate... heed ACE841's warning. I suspect you might not like the 50 series look.

Good Luck,

Robert

Hey Robert thanks again and no problem.Yeah the 50 series look ok but I'm like you and want to fill in the wheel well.It looks like its going to be either a 245/60 or 255/60.When I bought the car 12 yrs ago.It had 255/60 on it with what people were calling true spoke rims.And I don't remember or know what the rim size was or if they rubbedSince then i've had new inner wheels put in.I was young and didn't care,I had a chevelle,needless to say they come off first thing and ralleys went on.

Ok guys I've been doing some research.I can get a 15x10 AR outlaw 1 with 4" of BS.Does this open the availability of a wider tire than on a 15x8 with 3.375 of BS?

Todd,
You can put a 275-60-15 on an 8" Wheel with 4" of backspace, and have no trouble.

I'd bet you could get a 295-60-15 on a 10" wheel with 5.5" of backspacing, without much trouble.

But a 15x10" wheel with 4" of back spacing,
(I'm pretty sure) will put your tire too close to the quarter panel.

I didn't read all the posts, in my sig below is a picture of my old 68 with 255-50-16 on 16x8 4.5bs on all corners. No rubbing.

I have more pics if you need them.