{"product_id":"ciloyu-35-series-mini-bike-rear-sprocket-40t-37mm-bore-6-hole-alloy-replacement-for-ct100u-db30-mbx10","title":"CILOYU 35-Series Mini Bike Rear Sprocket 40T 37mm Bore — 6-Hole Alloy Replacement for CT100U\/DB30\/MBX10","description":"\u003cp\u003e\u003cstrong\u003eCILOYU's 40-tooth rear sprocket for 35 roller chain is a precision machined replacement designed to improve power delivery and durability on small-displacement mini bikes and go-karts.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThis replacement rear sprocket is built for riders who need a reliable, compact 40-tooth gear with a 37 mm center bore and a 49 mm (1.92\") bolt circle to match many popular mini bike frames. Machined from a stout metal alloy, the design includes six evenly spaced mounting holes for easier alignment and compatibility with a wide range of Coleman, Baja, Motovox, Monster Moto and other mini bike models. Because this sprocket uses 35-series roller chain, it can be trimmed to fit shorter drives, and its smaller tooth count compared with larger factory gears will change final drive characteristics.\u003c\/p\u003e\n\n\u003ch3\u003eHow will swapping to a 40T sprocket affect my mini bike's ride?\u003c\/h3\u003e\n\u003cp\u003eChanging to a 40-tooth rear sprocket alters gearing so the engine runs at lower RPM at a given road speed, which can reduce engine strain and improve straight-road speed potential. Expect a quicker engine response at lower speeds and a different top-speed\/acceleration balance than a larger sprocket.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eLower engine RPM at cruising speeds for potentially better efficiency.\u003c\/li\u003e\n  \u003cli\u003eFaster top-speed potential on flat stretches compared with much larger sprockets.\u003c\/li\u003e\n  \u003cli\u003eAcceleration feel may become slightly sharper off the line depending on front sprocket size.\u003c\/li\u003e\n  \u003cli\u003eChain length may need trimming to match the new sprocket's smaller diameter.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWill this sprocket fit my model CT100U, DB30, or MBX10?\u003c\/h3\u003e\n\u003cp\u003eThe sprocket is made to cover many popular mini bike and go-kart models, including Coleman Powersports CT100U, CC100X, RB100, DB30 family machines, Motovox MBX10\/MBX11, and several Monster Moto\/ Mega Moto models. Compatibility depends on matching the 37 mm center bore and the 49 mm bolt-circle mounting pattern; measure your hub before ordering.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCenter bore: 37 mm (1.45\")—matches corresponding hubs or can be adapted with sleeves.\u003c\/li\u003e\n  \u003cli\u003eMounting holes: 6 holes with 49 mm bolt-circle spacing.\u003c\/li\u003e\n  \u003cli\u003eChain size: compatible with 35-series roller chain; chain shortening may be necessary.\u003c\/li\u003e\n  \u003cli\u003eCommon fit for Coleman, Baja, Motovox, Monster Moto, and similar mini bikes.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat are the construction and design highlights that make this sprocket durable?\u003c\/h3\u003e\n\u003cp\u003eThe sprocket is crafted from a heavy-duty metal alloy and precision-machined for consistent tooth profile and mounting alignment. The thicker material and 6-hole mounting pattern lower flex under load, improving longevity compared with thinner aftermarket pieces.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eThick, alloy construction resists deformation under torque.\u003c\/li\u003e\n  \u003cli\u003ePrecision-machined teeth for smoother chain engagement and less wear.\u003c\/li\u003e\n  \u003cli\u003eSix-hole mounting distributes load evenly across the hub flange.\u003c\/li\u003e\n  \u003cli\u003eImproved hole spacing designed for straightforward installation.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow should I install and size the chain when switching to this sprocket?\u003c\/h3\u003e\n\u003cp\u003eInstallation is straightforward if your hub matches the 37 mm bore and 49 mm bolt circle; align the six mounting holes, secure with appropriate fasteners, and trim the 35-series chain to the correct length. Check chain tension and alignment after a short test ride and re-torque hardware to factory specs.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eConfirm hub bore and bolt-circle measurements before mounting.\u003c\/li\u003e\n  \u003cli\u003eShorten the 35 chain as needed; ensure proper rivet or master link installation.\u003c\/li\u003e\n  \u003cli\u003eSet correct chain slack per manufacturer recommendations after fitting.\u003c\/li\u003e\n  \u003cli\u003eRe-check mounting bolts and torque after initial run-in ride.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: This CILOYU 40T 35-chain rear sprocket is aimed at mini bike owners, small go-kart riders, mechanics, and DIY enthusiasts who need a compact, sturdy replacement sprocket for Coleman CT100U\/DB30 series machines, Motovox MBX models, and comparable small-displacement bikes. Choose this part if you require a shorter, durable rear gear with a 37 mm bore and improved six-hole mounting for easier fitment and a different gearing profile than larger factory sprockets.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Does this sprocket fit a CT100U without modification?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: It often fits CT100U models that share a 37 mm bore and 49 mm bolt circle; verify measurements before ordering.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Can I use my existing chain with this 40T sprocket?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: You can if your chain is 35-series; you may need to shorten it to match the smaller sprocket diameter.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"CILOYU","offers":[{"title":"Default Title","offer_id":48085636841630,"sku":"B0D95P8PNH","price":43.98,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0781\/2041\/9486\/files\/ciloyu-sprocket-front-view.jpg?v=1785875842","url":"https:\/\/northtrailauto.ca\/products\/ciloyu-35-series-mini-bike-rear-sprocket-40t-37mm-bore-6-hole-alloy-replacement-for-ct100u-db30-mbx10","provider":"North Trail Auto","version":"1.0","type":"link"}