I have searched alot of the old posts on wheel backspacing and tire size for 1968 camaro and have not been able to find a consistent answer on the topic!SO if someone out there could help give me a definite answer? Here is my question.i have a 1968 coupe with hotchkis 2" lowering springs on the front with drum brakes. On the rear i have hotchkis 3 packs.1 1/2" lower than stock.I will be running a 15x7 on the front and a 15x8 on the rear,l5x8 1/2" on rear if it will work? What size tire for the front and what size tire for the rear? and more importantly what back-spacing should i use front/back with no trimming etc etc.Naturally i would like to as much tire as possible If anyone could pleeeaase help me get the scoop!!! Thankyou in advance.I will be going to the tire shop tommorow to order wheels and tires or as soon as i can get some help with size.......

anyone?

Here is what I run on my '69Z with Hotchkis springs. I have front discs though.

Front:
15x8 4.5bs wheel with 235-60-15 tire
Requires buttonhead screws for the X33 wheel moldings.
I also run lots of negative camber for better handling and to get the top of the tire away from the fender.

Rear:
15x8 4.5bs wheel with 255-60-15 tire
The 255 tire is very tight - some guys experience rubbing on the fender lip depending on the rear housing alignment.

Neil, thankyou for your reply. I'am under the belief that the 69 and 68 have different wheel-well openings.Again i do appreciate your reply.But if someone on this site that sees this message has a 1968 camaro or 67 and knows for sure what will work please let me know?

:confused:

Whoops, I didn't see that your car was a '68. I hope someone can help you out.

neil, graemlins/beers.gif

MadCow, me thinks it's just not a good thing to post a definitive answer that one of our brother s will use to spend cash...

Too many variables, from car to car and setup to setup. The post at the top of wheels and tires has a lot of info regarding what people have made to fit, and it really depends on what you want and how big they gotta be

Thanks Jim. I just want wheels and tires that fit.As best as i can tell from past threads a 15x7 with a 4-1/4" backspace for the fronts with a 215/65-15 bf goodrich and a 15x8 with 4 1/2" backspace for the rear and a 255/60-15.if you or another member has experience with this size tire/wheel combo on a 67/68 that has the Hotchkis sprngs on there car.please reply.I too am looking at spending some dough on rims.Thanks again in advance...... graemlins/waving.gif

fyi... my rallye's were 15x7, not sure of offset, w/ 215/65/15's all around and fit fine.

My new wheels are 16x7, 3 7/8 bs w/ 225-50-16 in front, 17x8, 4.5 bs, w 255-45-17 in back

Both sets fit great, naver rub, BUT... I don't have hotchkiss springs, and I have drum brakes in front. They all a lil different, ya know?

I think maybe a 7" rim w/4.25 bs might be too much, and rub on the frame when you turn sharp

I just finished rebuilding the suspension on my wife's 68 convertible with hotchkis lowering springs. I am going through the same process as you are now. I also added SSBS's disk brake package, to the front only.
The original 14 x 7's that came off the car had a 3-3/4" backspace. I've borrowed a 15 x 7 wheel with a 4-1/4" backspace to mount and take some measurements. I'm assuming I need the wheel centered in the wheel well as much as possible. If I'm not sure when I order wheels, I'll probably go with more backspace than I think I need and shim, if I need to.

There's a ton of info on here about tires sizes... but I guess if we didn't rehash it we'd have nuttin to do...

David, on your stock setup, the wheel would be offset 1/4" toward the inside of the car (from zero offset).

On a 67 or 68, the outside fronts can rub at the top of the wheelwell on compression, or the inside at the frame rail at full turn. This is all complicated by the stock alignment specs, and the suspension geometry, which lets the top of the front tire camber out on compression. (The guhldstrand mod, which I've done too, reverses that) On top of all that, stock disc brake cars shift the wheel a 1/4" out compared to drums, and with aftermarket brakes, who knows?

With the lowering springs, you for sure want an alignment before you start measuring for rubber.

Thanks for you're response's. Jim What is the guildstrand modification exactly? As for the backspace issue i still do not have an answer!Does anyone Know!.....Dave if you could let me know how the 15x7 with 4 1/4 backspace works for you that would be great! I already ran a 15x7 with a 3 3/4 inch backspace and the 225-60 tire's rubbed both sides on the top of the wheelwell like you descibe Jim-but that would not jive with your 15x7's with no rub i'am guessing that your car was not lowered in which case it would not matter.maybe if you knew the backspacing that would help? Then there is still the matter of the backspacing on the rear wheels is the size that i'am thinking of running 15x8 with a 4 1/2 backspace a correct fit or can i go 8 1/2 with more backspace? anyone?...... :confused:

No guarantee, but you want about a 25 +" tall tire, 235 or narrower up front on a 7" wheel with 4.5 bs up front (4" or less will probably rub and if you go with too short a tire (at 25" or less), looks come into play because of the round wheel well opening (even though you're dropped).

On the rear, I'd recommend 8" w/ 4.75" bs, 8.5 would be pushing it at 5" bs. (I'd bet you'd get rubbing) Tire should be 26" or taller, width 255 (max).

Again, looks come into play on the '67 & 68, see my post & pic under the top sticky.

I beleive if you stray from these, you better have a very tight suspension or you'll have to do well mods.

Let me know if something's unclear...

JD


JD

I am a sick man, you got me running around with a straight edge and ruler in my jammies at 8am (lmao)

Before I forget, my original rallye's are verified at 15x7, 4"bs, w/ 25" tall 215-65-15 tires.

Look in Suspension, AND in DAVIDPOZZI's website for info on the Guldstrand mod. Basically, this is a real simple thing that road racers developed in the '60's to completely change the suspension geometry of a 1st gen. You relocate the inside pivot of the upper a-arm, about 3/4" back and 1" down. It changes the camber curve to keep the tires planted in turns, and builds some caster in.

I run 1/4 degree neg camber, it shifts to 2 degrees neg when the suspension compresses. Before, it shifted to 2 degrees pos! As compared to stock, this is moving the top of the tire over 1/2" further inside the fender when the suspension compresses!

I get 3.5 degrees pos caster, with almost no shims at all.

Tools required include a drill and a sawzall. It took me an hour, but the suspension was all ready apart. Cost is ZERO. Benefit is UNBELIEVABLE.

As for my ride ht... the rallye's were on the car when I got it, suspension was 35 years old and stock - no rub.

I rebuilt the suspension / did the guldstrand mod, and cut a coil off the original springs. Car was WAY LOW- no rub.

It was TOO low, so new springs, then new wheels and tires. Right now, the front fender lip is 25 1/4" off the ground, the tires are 23 3/4" tall - no rub, ever.

My rear wheelwell lip is 28 1/4" off the ground, tires are 25 1/4" tall. I have lots of room on the inside, over an inch. This is the first time I ever really measured clearance in the back. I've always thought my oem replacement 5 leafs were too high, seems it's a good thing. If my car was at the ht. I'd like it to be, the tires would be in the fenderlip by 1/4" Another 1/2" of bs would have been a better choice.

Ride and handling have been my priority with this car for 5 years. I'm on a pretty strict budget, so it's taken time. My car is a driver, and not the prettiest in the world. Before the ragtop, I had 3 new vette's in the '90's, so I'd like to think I'm experienced in what a good handling car feels like. My ragtop has become a good handling car.

john why would a shorter tire rub? I also tried to locate the top sticky for the pic's but was unable to locate it.Jim and John and all the fellow Camaro Tech folks who responded to my post I thankyou graemlins/thumbsup.gif Jim you must be a car nut like my self and i greatly appreciate your patience and efforts in helping me!I will continue to post this topic when i finally put a tire/wheel set-up on my car and it does not rub, in the hope of helping other's. Madcow Mike.... graemlins/beers.gif

Good luck wit it, Mike. At least you came to the right place for the info.

As far as my 5 year suspension project, EVERYTHING I did came from here! Thanks to guys like davidpozzi, brian lewis, pdq, just to name a few... It's real hard to screw up when you can learn from all those who've been there and done that.

** If you haven't seen david's site, go there and spend a few hours... You'll learn more than you could imagine.

With a shorter tire "Looks" come into play. Meaning that a really short tire might not rub, but will not look as good as one that fills up the well, IMO(this is all very subjective, everyone has their own tastes).

This is the sticky at the top of the wheels and tires page, my pic and description is on page two...

http://www.camaros.net/forum/ultimatebb.php/topic/8/1674/2.html

John

John, reading your post in that link, you got some outside rubbing in front... maybe a lil too much bs? I'd stick with 4"

Originally posted by JimM:
John, reading your post in that link, you got some outside rubbing in front... maybe a lil too much bs? I'd stick with 4" Actually, not enough. I shoulda went with 4 5/8" or 4 3/4"

JD

u r right, I was backwards above, oops

To quote you, John, tires on these old cars are a sticky subject indeed...

You're running a 235 on a 4.5bs 7 " rim... and a touch too far out...I'm running a 225 on a 3/7bs 7" rim, (5/8" further out!) and not only fit, but I got room to put disks on it...

Don't make a whole lotta sense does it?

Well I don't know how much this'll help anybody, but in the on-going quest to get the right size wheels and tires for my wife's '68, I did some more fitting last night.
The original wheel/tire combo was: 14" x 6" rally with 3.75" backspace and drum brakes (I've upgraded to disk with SSBC's kit) tires were P225/70R14's.
I put my 15" x 8" minilites with 4.5" backspace and P235/60R15's (off my '69) on the front to see where there migh be any problems.
Remember I also have the Hotchkis 2" lowering springs in front.
It looked like when the springs settled and you hit a large dip, you might rub on the outside of the tire. With the steering at full turn, the tire rubbed slightly against the backside of the outer edge of the fender-well on the drivers side and came very close to the same spot on the passengers side. Looking underneath at the frame and brackets for the brake hoses etc. there was no problem.
I looked at CRG's site the other day (somebody may have linked it here, I don't remember) but it showed that the only 15" wheel put on any Camaro in '68 was a 15 x 6. That makes me a little paranoid about going with 15 x 7's, but I'm going to see if anybody has one with a tire mounted that I can borrow.

I also noticed that the 14" tires that were on the car had an outside diameter of 25.5" and the 15" tires I was trying on the car were 25".

My alignment with 1* negative camber helped fitment immensely.

Rick the 1* negative camber seems to be the trick when running with the correct backspacing.John i saw the picture of your car, nice looking ride! but in looking further i noticed that you are running 17 " wheels can you run more b/s with a 17 than a 15 due to shock mount clearance etc etc...I need to buy the rims and tires for my car pretty soon.Right now it is sitting on jackstands until i can get through this b/s thing.I do not have a bunch of money and do not won't to get stuck with a set of custom order rims.The more this post continues the more baffled i become :confused: Again thankyou to you all it is becoming a little clearer though.... graemlins/thumbsup.gif

Mike, fitment doesn't really relate to rim diameter, important things are overall tire hieght and width, and location in the wheelwell (backspace)Larger rims let you run a lower profile tire, which vastly changes the "look" of the car, as well as the handling. A 60 series tire on a 15" rim looks much different than a 40 series tire on a 17" rim. What look do you want?

There are for sure a lot of choices, and it just depends on how YOU want the car to look.

I'll preach one more time about the guldstrand mod. It took a lot of thinking, and a certain amount of beer, and some urging from a buddy, to take a sawzall to my subframe, but it sure as heck works, handling wise, and I'm now realizing that it's helping the tires fit too.

Jim.thanks again for the reply.but it would seem to me that given a larger rim size you could run more b/s on the front rims due to the suspension components being cleared i'am aware of the look factor and definetly is a major deciding factor or i would just run 14x6.what i,am really interested in is the clearance issue.I looked at the older posts and it appeared that the guys running 17inchers ran with more b/s.Again the mod that you did sounds like something that i will seriously look at doing either that or some different a arms.Again thankyou.

[ 10-29-2004, 09:00 PM: Message edited by: madcow ]

The rims don't come anywhere near a stock suspension, the tires hit the frame first, Mike.

Most of the guys with 17's in front are running serious huge rubber...235's to even 275's, with 8 or 9.5" rims, that's why more bs is used. Goin that big in front makes it all the harder to make it fit.

thanks jim..

For you guys with the 2" Hotchkis drop, is the measurement from the center of the front hub to the fender lip consistent between your cars?

TIA

Brent

Brent,sorry i'am getting back to you this late ,just checked the site today.The space between the top of the tire and the fender is the same on both sides on my 68 with the Hotchkis springs.What that measurement is i could not tell you.I have measured it before because of the fitment issue.I still have not purchased my rims yet,shame on me i'am procrastinating a little.I will let people know what the final outcome is.So as to maybe help a fellow camaro nut....Madcow.P.S It is also the same from my front hub to fender top.As for other cars with these spings i do not know.I have heard of some spings taking awhile to
"settle".Thus giving the car lopsided stance.It is also possible to have the spring not seated all the way in the spring perch pocket.

16 X 8, 4.5 BS all four corners, 225 50 16 fronts, 255 50 16 rear, with .6* neg camber, GW A-arms which do move the balljoint aft and factory discs. I have lowered coils and Hotchkis leafs. no rubbing issues. This combo works well if you are willing to go with 16's as far as fittment and handling. I don't know if this helps or not? SS

Thanks. I have the Moog Z-28 springs on my wish list at Summit but I'm still unsure which way to go for the rear. A bit moot for the time being as I sprung for a pair of Recaros to save my spine in case of a rear ender. If the front suspension lets go first, I get to eat the steering wheel instead.

Originally posted by railing68:
16 X 8, 4.5 BS all four corners, 225 50 16 fronts, 255 50 16 rear, with .6* neg camber, GW A-arms which do move the balljoint aft and factory discs. I have lowered coils and Hotchkis leafs. no rubbing issues. This combo works well if you are willing to go with 16's as far as fittment and handling. I don't know if this helps or not? SS Railing68,
Do you have any pictures of your car with the 16" wheels on it?
I'm trying to find pics of '69's that have been lowered and have 16" wheels. I'm definitely not looking to run 15" rims on mine, and I think 17's might be too big.

I find tons of combos running 16's and 17's but no pics. And everyone runs 50 series tires. I'm going to be putting some miles on this thing when it's done so 50's are out of the question. More like 60\65's.

Joe, you might double check your math. 60's on a 15, 50's on a 16, and 40's on a 17. Is the cross section stays the same, they will all be close to the same hieght. A 60 on a 16" rim would be kinda tall.

My truck: 275-55-20 = 31" tall
Wifes truck: 255-65-16 = 28" tall
My camaro front: 225-45-16 = 23.5" tall
my camaro rear: 255-55-17 = 25.5" tall

btw, can't wait to see your car done!!

Joe, I'll take and send you some pics.

Thanks Rick!

The reason I don't want to run a 50 series tire is because the lower profile transmits more of the road to the passengers. I realize they'll handle better in all aspects, but seeing as how this is going together as a daily driver, I need to keep a little bit of the comfort factor in things.

Picking wheels has to be one of the most difficult parts of designing your ride! Even more so than picking a color for the body, or an engine. You screw up the wheel\tire combo and you just watsed a HUGE amount of money that you'll never get back.
I'm just not sure I want to go with a 17" wheel and short profile tire. I'm aiming for something larger than a 15" (which I think are just too dinky) that'll fill the wheel openings well and still give me SOME comfort in the ride.

Having lowered the car front and back, I think 16's will do me just fine and leave me with enough room to play with wider and taller tires that won't look stupid. Don't get me wrong, 17's look absolutely great on a '69 and I'd love to stuff them into stock wheel openings, but the tire profile will have to be too short for a comfortable, daily ride.

16's are a great compromise. Just pick a target height and cross section (225 & 25"?) and choose the aspect ratio that will deliver it.

** other than truck tires, you won't find many 16"s taller than 50 or maybe 55 series.

Joe, I run 245/50-16's(F) and 255/50-16's (R) and the ride is great. I really don't think you'd see any degradation with that ratio. The rear is 26" tall. Joe, I get 'flood protection turned on' when I try to email you.

[ 11-08-2004, 11:50 AM: Message edited by: RickD ]

Must be on your end Rick.
My email folders are empty and I can email myself just fine. I CERTAINLY have no problem getting SPAMed a 25 times a day.

Try sending the email(s) differently... broken up or something.

Alright Jim, I'll start hunting. And if people think a 50 series tire rides nice, then I don't have a choice. I'm going for the widest rubber that'll fit!

I got my rims and tires today and the rear wheels hit the lower shock mounts with the 15x8 and a 4.75 backspace. The 255-60-15 fit fine with room to spare on the inner and outer wheelwell openings.i looked at some really old posts and found that if i run the ssm traction bars that it will move my lower shock mounting points in board allowing more backspace.Or if i go to a 17 rim it will clear the lower shock mount and ride inside of the wheel.The fronts are a 15x7 with 4.25 b/s and do not rub anywhere in or outside with the 2" hotchkis springs and drum brakes,and 215-60-15.I also have a 225-60 that i will try up front as it looks like i have the room....madcow....

Ain't that a kick in the teeth! how bad they hit, would a 1/4" spacer get em out the way?

Sorry for all the trouble you've had finding the right combo, mad cow. But for anyone else having the same problems could i suggest going to one of the bigger car shows. Drive a couple of hundred miles if you have to, the info and different combos you will see will be worth the drive. Check out ''Goodguys rod and custom'' or a ''Super chevy show''these are nationwide shows and one should be near to everyone.

thanks,J.I did look around a few of the local car shows and you are right they are a good source of info.i will do that more as i continue with my carI don't know why i got 4.75 b/s i goofed i meant to get 4.5 b/s i went into the store tired and confused with all the numbers running around in my head and the rest is history i now own rims that do not fit.My own fault,pretty stupid.