1.250" 4130 Chromoly Tubing
At 1.250" OD, 4130 tubing moves from bracing into structure. The size is common for chassis diagonals, door bars, engine and transmission mounts, motorcycle frame rails and the larger tubes of a bicycle frame.
Where 1.250" OD 4130 Tube Is Used
Fabricators choose 1.250" when a one-inch tube is not stiff enough but a 1.500" tube is more than the load needs. A 1.250" × 0.065" tube carries noticeably more bending load than 1.000" × 0.065" for a modest weight increase, because stiffness rises quickly with diameter.
In roll structures this diameter is normally limited to secondary members such as diagonals, gussets and door bars. Main hoops usually require a larger tube, and the governing rulebook decides what is allowed. See the roll cage tubing size guide for how those rules are normally written.
Ordering 1.250" OD Tubing
Quote the full description: OD, wall, condition and standard. If the tube will be bent, say so, because a slightly heavier wall often gives a cleaner bend on tight radii. The weight chart explains how to work out the weight of any size you are comparing.
1.250" OD 4130 Tubing: Wall, Bore and Weight Table
The table lists the bore, metal cross-section and theoretical weight for 1.250" (31.75 mm) outside diameter across the walls normally requested in cold drawn seamless 4130.
| Wall (in) | Wall (mm) | ID (in) | ID (mm) | Section area (in²) | Weight (lb/ft) | Weight (kg/m) |
|---|---|---|---|---|---|---|
| 0.035" | 0.89 | 1.180" | 29.97 | 0.134 | 0.45 | 0.68 |
| 0.049" | 1.24 | 1.152" | 29.26 | 0.185 | 0.63 | 0.94 |
| 0.058" | 1.47 | 1.134" | 28.80 | 0.217 | 0.74 | 1.10 |
| 0.065" | 1.65 | 1.120" | 28.45 | 0.242 | 0.82 | 1.23 |
| 0.083" | 2.11 | 1.084" | 27.53 | 0.304 | 1.04 | 1.54 |
| 0.095" | 2.41 | 1.060" | 26.92 | 0.345 | 1.17 | 1.75 |
| 0.120" | 3.05 | 1.010" | 25.65 | 0.426 | 1.45 | 2.16 |
| 0.156" | 3.96 | 0.938" | 23.83 | 0.536 | 1.82 | 2.71 |
| 0.188" | 4.78 | 0.874" | 22.20 | 0.627 | 2.13 | 3.18 |
| 0.250" | 6.35 | 0.750" | 19.05 | 0.785 | 2.67 | 3.98 |
Values are calculated from nominal dimensions (weight = (OD − wall) × wall × 10.69). A row in this table is a dimensional reference, not a statement that the size is held in stock; confirm availability when you enquire.
Frequently Asked Questions
What is the ID of 1.250" × 0.065" 4130 tubing?
The nominal bore is 1.120". Subtract twice the wall from the OD to get the bore of any size.
How heavy is 1.250" OD 4130 tubing?
From about 0.45 lb/ft at 0.035" wall to 1.45 lb/ft at 0.120" wall. The table above gives the figure for each wall.
Is 1.250" OD tube used for roll cage main hoops?
Usually not. Most rulebooks set a larger minimum diameter for main hoops and allow 1.250" only for bracing. Check the current rules for your class before ordering.
What is 1.250" in millimetres?
31.75 mm. It is not the same as a 32 mm metric tube, though the two are close.
Enquire for 1.250" OD 4130 Tubing
Provide your required wall thickness, condition, standard, and footage for a 1.250" OD 4130 quotation.
- OD: 1.250"
- Wall Thickness
- Standard (ASTM A519)
- Condition
- Footage / Quantity
- MTC 3.1 required
- Delivery