{"product_id":"spark-exhaust-bent-tube-90-degrees-32mm","title":"Spark Exhaust Bent Tube 90° Ø 32 × 1.0 mm Stainless Steel Universal G9128","description":"\u003cp\u003eThirty-two millimetres through ninety degrees. The hard corner in the first of Spark's thin-wall sizes.\u003c\/p\u003e\u003ch2\u003eKey Features\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eMandrel-formed 90° bend, AISI 304 stainless steel.\u003c\/li\u003e\n\u003cli\u003eØ 32 mm outside, 1.0 mm wall thickness.\u003c\/li\u003e\n\u003cli\u003eStraight tangents at both ends.\u003c\/li\u003e\n\u003cli\u003eMatches Spark's 32 mm straight tube, article G9006.\u003c\/li\u003e\n\u003cli\u003eSpark part number G9128, made in Mantova, Italy.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eAround the Downtube\u003c\/h2\u003e\u003cp\u003eOn a small single the header leaves the head forward, and the frame downtube is directly in its way. Getting round it is a right angle followed by another one lower down, and thirty-two millimetres is the size that fits between the tube and the crankcase.\u003c\/p\u003e\u003cp\u003eIt is the classic small-bike routing problem, and it is why the smallest diameters get the sharpest corners.\u003c\/p\u003e\u003ch2\u003eWhat a Right Angle Costs\u003c\/h2\u003e\u003cp\u003ePressure loss through a bend rises steeply with angle and falls with radius. A ninety at a production radius costs several times what a thirty does, and about twice what a single forty-five does.\u003c\/p\u003e\u003cp\u003eOn a small engine that matters less than it sounds — the gas volume is modest and the losses are proportional. On a large one it is worth designing around.\u003c\/p\u003e\u003ch2\u003eRadius Ratio\u003c\/h2\u003e\u003cp\u003eWhat actually governs the loss is the ratio of centreline radius to tube diameter. A bend with a radius of one and a half times the diameter is tight; three times is generous. Production tooling sits near the tight end, because that is what fits on a motorcycle.\u003c\/p\u003e\u003ch2\u003eChecking a Formed Right Angle\u003c\/h2\u003e\u003cp\u003eStand the bend on a flat surface with one tangent down and put a square against the other. A formed ninety is generally within a degree; a hand-bent one is generally not, and the error only becomes obvious once it is welded into a run.\u003c\/p\u003e\u003ch2\u003eTwo Bends Facing Each Other\u003c\/h2\u003e\u003cp\u003eTwo 90° bends with a straight between make a U. At this diameter Spark does not offer a 180° article, so that pair is how a small-bore run doubles back — one extra joint, and full control over how wide the U is.\u003c\/p\u003e\u003ch2\u003eLeave a Straight Afterwards\u003c\/h2\u003e\u003cp\u003eGas leaving a sharp corner is separated from the inside wall and takes several tube diameters to reattach. Anything sitting in that region — another bend, a joint, a sensor boss — works in disturbed flow. Two or three diameters of straight after a ninety costs nothing and recovers most of it.\u003c\/p\u003e\u003ch2\u003eOrdering\u003c\/h2\u003e\u003cp\u003eOne bend per article. Spark builds 30°, 45° and 90° at thirty-two millimetres.\u003c\/p\u003e","brand":"Spark Exhaust","offers":[{"title":"Default Title","offer_id":53618247041290,"sku":"G9128","price":38.0,"currency_code":"BSD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0949\/7831\/0410\/files\/6087d041898f9_77d676f1-444f-495e-9d98-456c2264fe8e.png?v=1788348502","url":"https:\/\/inter-pace.com\/en-bs\/products\/spark-exhaust-bent-tube-90-degrees-32mm","provider":"Inter-Pace","version":"1.0","type":"link"}