Speedway Style G Bobbins — Bonded Nylon

Speedway Style G pre-wound bobbins are factory-wound bobbins in bonded nylon 66, sized to the Style G standard and sold individually or by the box of 144. Winding them on a machine under controlled tension puts more thread on the bobbin than you can wind yourself and keeps the tension steady from the first stitch to the last — which is why production shops stopped winding their own. Available in 2 colors. Ships from Miami, FL.

Which machines use Style G bobbins?

Bobbin style is decided by your machine, not by preference. These are the machines documented as using Style G:

Can I use a Style L or M bobbin instead?

They look alike and they are not. The difference reaches 1.2 mm in diameter and 2.7 mm in height — enough that the wrong one either rubs the hook and stops the machine, or rattles in the bobbin case and skips stitches. Measure before you order.

Dimensions published by The Thread Exchange and WBC Industries. Style G is not a Class 15: the two get confused constantly, and the difference is in the height as much as in the diameter.

Technical Specifications

What is this thread in denier, ticket and government size?

Each size below is the same thread described in every numbering system in use, so you can match it against whatever your spec sheet calls it.

Careful with “Nm”: for thread it means 1000/Tex (Tex 70 = Nm 14.3), but for needles it means the blade diameter in hundredths of a millimetre (Nm 110 = 1.10 mm). They are not the same number. Conversion formulas from Coats; government sizes from the A-A-59826 specification published by American & Efird.

Buy a full box and save

Order 144 bobbins or more of this product and the discount applies automatically at checkout — no code needed. That is a full factory box.

The other bobbin styles

• Style L — polyester
• Style M — bonded nylon

Frequently Asked Questions

Is Style G the same as Class 15?

No. They differ in both diameter and height, so they are not interchangeable. Class 15 measures 0.815" x 0.465" while Style G measures 0.861" x 0.390". Check your machine before ordering.

Does the bobbin thread have to match the top thread?

Not necessarily the same brand, but it should be the same fibre and a similar size. Mixing polyester on top with nylon underneath gives you two threads that stretch and shrink differently, and the seam puckers or the tension drifts. Same fibre, same or one size finer, is the safe rule.

How many bobbins come in a box?

A full box holds 144 bobbins (1 gross). You can buy them individually or by the box — the volume discount applies automatically at 144.

How do I know which style my machine takes?

Check the compatibility list above, or measure the bobbin currently in your machine and compare it against the dimensions table.