Spark Exhaust Bent Tube 30° Ø 50 × 1.0 mm Stainless Steel Universal G9116

Fifty millimetres through thirty degrees. The round number that most exhaust hardware is designed around, in the gentlest angle Spark forms.

Key Features

• Mandrel-formed 30° bend, AISI 304 stainless steel.
• Ø 50 mm outside, 1.0 mm wall thickness.
• Straight tangents at both ends for cutting and welding.
• One of two diameters Spark also bends through 180°, under article G9165.
• Matches Spark's 50 mm straight tube, article G9005.
• Spark part number G9116, made in Mantova, Italy.

The Interface Size

Clamps, sleeves, silencer inlets and adapters from a dozen manufacturers cluster around fifty millimetres. If a project has to bring parts from more than one supplier together, this is the diameter most likely to line up without an adapter in between.

That convenience is the main reason to design a custom run at fifty even when a slightly different figure would suit the engine marginally better.

What a Shallow Bend Is For

Thirty degrees does not turn a corner. It leans a run — over a frame rail, past a shock reservoir, around the edge of a swingarm — while the exhaust carries on broadly in the same direction.

Two of them opposed, with a straight between, produce a parallel offset. Lengthening or shortening that straight sets how far the run steps sideways, which makes a pair of these bends an adjustment rather than a fixed shape.

Clamping Without Marking

A fifty millimetre thin-wall tube goes oval in bare vice jaws, and oval is the one thing that stops a slip joint working. Clamp on the straight tangent, use soft jaws or a wooden vee block, and never clamp on the curve itself.

An out-of-round end can be recovered with a mandrel and patience. It is faster not to cause it.

Weight Per Bend

A 30° bend at this diameter weighs under two hundred grams. It is a figure worth knowing when a system is being planned in detail: a run with six bends in it is a kilogram of metal before the straights and the silencer are counted.

Marking a Curved Cut

Wrap a strip of paper round the tube, line up the overlapping edges and mark along it. That gives a square line on a curved surface, which is not something a rule and a marker will do.

Freehand marking on a bend is the usual reason a butt joint ends up with a gap on one side and a double-thickness weld on the other.

Ordering

One bend per article. Spark makes 30°, 45°, 90° and 180° in this diameter, plus a 500 mm straight length.