Frequently Asked Questions
Find answers to Frequently Asked Questions for First Generation Firebirds that have been asked and answered on FGF. Special thanks needs to be given to all the FGF members who took the time to respond to other member's questions.
Wheels, Brakes, and Axle - Tires
Short answer: Whether 255s fit a 15×7 Rally II depends on how the car sits (sag/lowering). The catch is mostly tire height — check your clearance first. Tire diameters:
| Size | Diameter |
|---|---|
| 205/70R14 (approx. stock) | 25.3″ |
| 235/70R15 | 28.0″ |
| 235/60R15 | 26.1″ |
| 255/70R15 | 29.1″ |
| 255/60R15 | 27.0″ |
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
Short answer: The billing-history line “F70x14 RL FG / TMT / $57.93 / $41.80 / $2.93” decodes as: the tires originally installed were F70x14 Redlines, Fiberglass-Belted; “TMT” is that tire’s sales code; the dollar amounts are tire cost plus final destination/handling charges.
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
Bulletin 68-I-51 — Pontiac Motor Division Dealer Service Information Bulletin, Section 10, dated March 25, 1968. Attention: Service Manager.
Subject: Premature Tread Wear — Wide Oval Tires.
Short answer: Over-inflation causes Wide Oval tires to wear prematurely in the center rib. Maintain 24 PSI cold (front and rear) unless carrying a full-rated load.
Early tread wear in the center rib section on Wide Oval tires can be caused by incorrect inflation pressure. The illustration (see Fig. 1 in the scan below) shows a normal tread wear pattern; the upper shaded portion depicts the wear pattern resulting from over-inflation.
It is recommended that Wide Oval tires be maintained at 24 PSI* for both front and rear wheels to minimize the possibility of early wear. Higher inflation will tend to abnormally distort the tire contact surface and cause the center ribs to assume a disproportionate share of the work.
Inflations above 24 PSI should only be used when the vehicle is driven with “full-rated” loads, as described in the Owner’s Manual.
*Always check tire pressure when tires are cold.
Content last modified: June 13, 2026 at 10:06 am
Bulletin 68-I-75 — Pontiac Motor Division Dealer Service Information Bulletin, Section 10, dated May 31, 1968. Attention: Service Manager.
Subject: Wheel Balancing — Disc Brake Equipped Vehicles.
Short answer: Some dealers have had difficulty balancing front wheels on disc-brake-equipped vehicles using on-the-car balancers because the brake pads rub the disc and prevent the wheel from spinning fast enough. Two solutions are available: a two-motor balancer or the Kent-Moore tool J 22801 Disc Brake Pad Spacer.
There are two solutions for this condition:
- Balance equipment suppliers offer a two-motor balancer, which covers heavy-duty and disc brake applications.
- A special tool is available from Kent-Moore for balancing disc brake wheels. Tool J 22801 (Disc Brake Pad Spacer), price $4.90, is used to spread the brake pads away from the disc, greatly reducing the “dragging” tendency during the balancing operation.
Note: The wheel must be removed to install the spacers (see Fig. 1 in the scan below).
Content last modified: June 13, 2026 at 10:06 am
Short answer: 15×8 won’t fit inside the stock wheel wells. The front and rear handle up to a 235/60-15 without trouble; the rear can take a 255 if you roll the quarter/wheelhouse lip. Rim offset is critical.
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Content last modified: June 13, 2026 at 10:06 am
Short answer: On an unaltered 1967–69, the biggest practical tire is about 235/60-15 on 8″ wheels (members report 245 on an 8″ being too big). For more aggressive fitments, Car Craft (March 2000) published maximums for 1967–69 Camaro/Firebird:
15-inch: 15×8 with 4.5″ backspacing front and rear. With some tires the rear shocks must be mounted inboard; then some 9″ wheels work with 5.5″ backspacing.
16-inch: 16×8 with 4.5″ backspacing front and rear (rear shocks relocated inboard). Use aspect ratio 50 or less, section widths 245–250.
17-inch: 17×9 with 5.5″ backspacing front and rear. Possible lower-control-arm contact with some steering gears. Aspect ratio 40 or less, 245–255.
18-inch: 18×9 with 5.5″ backspacing front and rear. Aspect ratio 35 or less, 245–255 front and 275 rear.
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
Short answer: Original 1968 Firebird tires were Firestone:
| Model | Standard Tire |
|---|---|
| Base Firebird | E70x14 B/W Wide Oval |
| Sprint / 350 / 350 H.O. | F70x14 B/W |
| 400 | F70x14 Redline Wide Oval |
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
Short answer: Pontiac wheel/Rally II codes are confusing — per a 1971 parts book, 1967 used JA (disc brakes) and JC (drum brakes), while 1968 used JC for all (even though the disc parts were the same for 1967 and 1968). The full application/code table is below.
More detail on decoding the codes stamped on a rim: the Classic Pontiac Server wheel page and Wallace Racing’s rally-wheel date-code page.
| Application | Size | Style | Bolt Circle Diam | Code | GM Part Nm |
|---|---|---|---|---|---|
| 1967 Firebird | 14×6 | Plain Steel | 4.75″ | ||
| 1967 Firebird | 14×6 | Rally I | 4.75″ | JB | 9787860 |
| 1967 Firebird w/Disc Brakes | 14×6 | Rally II | 4.75″ | JA | 525708 |
| 1967 Firebird w/Drum Brakes | 14×6 | Rally II | 4.75″ | JC | 546495 |
| 1968 Firebird | 14×6 | Plain Steel | 4.75″ | HG HK | |
| 1968 Firebird | 14×6 | Rally II | 4.75″ | JC | 546495 |
| 1969 Firebird | 14×6 | Plain Steel | 4.75″ | ||
| 1969 Firebird | 14×6 | Rally II | 4.75″ | JC | 546495 |
| 1969 Firebird | 14×7 | Plain Steel | 4.75″ | 362052 | |
| 1969 Firebird | 14×7 | Rally II | 4.75″ | JK | 525709 |
On the 1968 Rally II, the wheel rim code is on the outside of the rim, right next to the valve stem (see below). On the inside of the rim (the flat part connecting the inside and outside) you’ll find the date code, plant code, inner-wheel code (JJ), and size (14 x 6).
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
Short answer: If your 1967 rides on 15″ Rally II rims with P225/60-15 (very close in diameter to the old G60-15 / F70-15), get the period Goodyear Polyglas in a 15″ size to match — or switch back to correct 14×6 rims if you want the original E70-14/F70-14. Don’t mount 14″ tires on 15″ rims.
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
Short answer: On a 14×7 Rally II, a safe all-around size is 225/60-14. A 235 fits the front (close) and is no problem in the rear; the rear can take a 255 or 265 depending on offset. All of these fit a 7″ rim. (Many members have moved away from a mismatched front/rear look on a street car.)
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
Short answer: A 50-mph resonance that disappears by 65 mph, felt in the wheel and pedals regardless of gear or accel/brake, is almost always a balance or driveline issue — check the easy/cheap stuff first.
- Lug nuts — make sure all are properly torqued (a loose wheel mimics this exactly).
- U-joints — a worn/loose joint is a very common cause; replace and have the driveshaft balanced.
- Tire balance / out-of-round — felt more in the wheel = front; whole car = rear. A flat-spotted tire from sitting can do it; a load-force-variance balancer (e.g., Hunter 9000) can find belt shifts and index the tire.
- Also check the rotors (pulsation when braking slowly), front and rear wheel bearings, a collapsed shock, and worn motor/trans mounts or rear leaf-spring cushions (which let the rear float).
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
Content last modified: June 9, 2026 at 7:10 am
