Special Goodyear tires and rims are supplied as original equipment on standard 1970 Sportster (high ground clearance) models. The tires are identified on the tire sidewall as follows:
Front - 3.75 x 19 Sport Rib
Rear - 4.25 x 18 All Traction
These tires must be used exclusively for replacement on these rims. This type rim has a special tapered bead seat with a safety hump as shown in sketch below. Standard tires such as Goodyear 3.50 x 18, 4.00 x 18 or 3.25/3.50 x 19 sizes will not fit correctly and will result in unsafe operation if installed for any reason.
Correct inner tubes for use with tires are identified as follows:
Front - 3.25 x 18, 3.50 x 19
Rear - 4.00 x 18, 4.50 x 19
New "C-Section" rims can be positively identified after tire is removed from rim by the following part numbers stamped in rim.
| Type of Rims | Position | Part Number | Size |
|---|---|---|---|
| Steel Rims | Front | 43003-70 | 19 x 2.50C |
| Rear | 43004-70 | 18 x 2.50C | |
| Aluminum Rims | Front | 43010-70 | 2.50C - 19 |
| Rear | 43008-70 | 2.50C - 18 |
See the Harley Davidson Service Bulletin No. 597 from September 16, 1969.
| Description | Original Front | Repl Front | Original Rear | Repl Rear |
|---|---|---|---|---|
| Manufacture | Goodyear | Cheng Shin | Goodyear | Cheng Shin |
| Size | MM90-19 | 3.25/85H19 | 4.25-18 | 4.25/4.60H18 |
| Tread Design | Sport Rib | C-199 | All Traction | C-199 |
| Type | Tube | Tube | Tube | Tube |
| Ply | 4 | 4 | 4 | 6 |
| Cords | Polyester | Nylon | Rayon | Nylon |
| Overall Width in inches | 3 13/16 | 3 1/4 | 4.50 | 4 5/8 |
| Load Range | B | B | ? | C |
| Profile | Low | Low | ? | High |
| Max Load | 475 | 470 | ? | 740 |
| Load ? | . | 54H | . | 65H |
| Max pressure | 32 | 40 | ? | 40 |
| Made in | ? | Twian | U.S.A. | Twian |
| Serial numbers | MH61 MTA201 | . | MH6E MPA103 | . |
| Circumference (with 11,000 miles) |
? | 80 1/8 | 83.25" | 81.5 |
| Diameter (with 11,000 miles) |
? | . | 26.50" | . |
| Recommended Tire Pressure | 18 | ? | 30 | ? |
| Increase for each 50 lbs. over 150 lbs. |
+1 | ? | +2 | ? |
| Total Weight of rider and passenger | Front | Rear |
|---|---|---|
| 150 lbs. | 18 | 30 |
| 200 lbs. | 19 | 32 |
| 250 lbs. | 20 | 34 |
| 300 lbs. | 21 | 36 |
| 350 lbs. | 22 | 38 |
| 400 lbs. | 23 | 40 |