{"product_id":"synchrotech-b-series-mainshaft-b16a-b18c-b18b","title":"Synchrotech B16A\/B18B\/B18C Pro Series Mainshaft","description":"\u003cul\u003e\n\u003cli\u003eComplete Mainshaft Assembly Exceeds OEM Specs \u003c\/li\u003e\n\u003cli\u003eFitments for the B16A, B18B, and B18C Transmissions \u003c\/li\u003e\n\u003cli\u003e3.23 First Gear, Factory Ratios Retained \u003c\/li\u003e\n\u003cli\u003eCompatible with EM1 Civic Si, Del Sol VTEC, Integra GS-R\/Type R\/LS \u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- split --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli\u003e\u003ca class=\"active\" href=\"#Description\"\u003eDescription\u003c\/a\u003e\u003c\/li\u003e\n \u003cli\u003e\u003ca href=\"#VehicleFitment\"\u003eVehicle Fitment\u003c\/a\u003e\u003c\/li\u003e \u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\n\n\u003cli class=\"active\" id=\"Description\"\u003e\n\u003ch3\u003eSynchrotech Pro Series Mainshaft - B16 \u0026amp; B18 (1994-2001)\u003c\/h3\u003e\n\n\u003cp\u003eThe mainshaft carries first and second gear, and those are the two taking the worst of what a B-series does. Launches, hard 1-2 shifts, and the highest torque multiplication in the transmission all land here. If yours has been damaged, or you're building a gearbox properly from the case up, this is the Synchrotech Pro Series replacement at factory ratios.\u003c\/p\u003e\n\n\u003ch4\u003eTwo Versions, Split By Second Gear\u003c\/h4\u003e\n\n\u003cp\u003eBoth variants share the same \u003cstrong\u003e13-tooth 3.23 first gear\u003c\/strong\u003e. What separates them is second, and that's what determines which one you need.\u003c\/p\u003e\n\n\u003ctable\u003e\n    \u003cthead\u003e\n        \u003ctr\u003e\n            \u003cth scope=\"col\"\u003ePart Number\u003c\/th\u003e\n            \u003cth scope=\"col\"\u003eSecond Gear\u003c\/th\u003e\n            \u003cth scope=\"col\"\u003eFits\u003c\/th\u003e\n        \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eSG-B190-MS\u003c\/td\u003e\n            \u003ctd\u003e1.90 ratio, 20 tooth\u003c\/td\u003e\n            \u003ctd\u003e1994-2001 Acura Integra GS-R and LS (B18C1, B18B)\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eSG-B210-MS\u003c\/td\u003e\n            \u003ctd\u003e2.10 ratio, 19 tooth\u003c\/td\u003e\n            \u003ctd\u003e1994-2001 Acura Integra Type R (B18C5), 1999-2000 Honda Civic Si and 1994-1997 Del Sol VTEC (B16A)\u003c\/td\u003e\n        \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cp\u003eThe Type R and B16 cars run a shorter second gear than the GS-R and LS, which is part of why those transmissions feel more aggressive through the low gears. Match your engine and transmission rather than going by the car alone, since plenty of these have been swapped over the decades.\u003c\/p\u003e\n\n\u003ch4\u003eFactory Ratios, So Nothing Changes\u003c\/h4\u003e\n\n\u003cp\u003eBoth versions run the same ratios your transmission had from the factory. That means the car drives exactly as it did before, same gearing, same shift points, same speeds in each gear.\u003c\/p\u003e\n\n\u003cp\u003eYou're replacing a damaged or worn component with a stronger version of the same part rather than changing how the transmission behaves. If you wanted a ratio change, that's a different product. This is the one you buy when the gearing was never the problem.\u003c\/p\u003e\n\n\u003ch4\u003eWhy First And Second Fail First\u003c\/h4\u003e\n\n\u003cp\u003eWorth understanding, because it explains why this is the part people end up needing.\u003c\/p\u003e\n\n\u003cp\u003eThe lower the gear, the higher the torque multiplication through it. First and second see far more load than fourth and fifth, and they see it in the most abusive way, on launches and hard shifts where the driveline gets shock loaded rather than gradually loaded.\u003c\/p\u003e\n\n\u003cp\u003eAdd power to a B-series and that gets worse quickly. A transmission that was fine at stock output starts damaging teeth or shafts once you're making real torque and using it. On cars that are now thirty years old and have often been built, swapped, and driven hard, the mainshaft is a common casualty.\u003c\/p\u003e\n\n\u003ch4\u003eBuy The Assembly, Not Just Gears\u003c\/h4\u003e\n\n\u003cp\u003eThis is a complete mainshaft with first and second, which matters more than it sounds.\u003c\/p\u003e\n\n\u003cp\u003eThe shaft itself is a wear item. Splines and bearing surfaces take load every time you shift, and a shaft that's been through a gear failure often carries damage you won't spot until it costs you again. Starting with a fresh assembly removes that variable rather than gambling on a used shaft you can't fully inspect.\u003c\/p\u003e\n\n\u003ch4\u003ePro Series Construction\u003c\/h4\u003e\n\n\u003cp\u003eSynchrotech has spent decades working specifically on Honda transmissions, developing materials and heat treat processes with metallurgists rather than adapting generic parts. Their Pro Series components are built to handle considerably more than the factory pieces they replace, which is why their name comes up whenever someone's gearbox lets go on a car making real power.\u003c\/p\u003e\n\n\u003ch4\u003eWhile You're In There\u003c\/h4\u003e\n\n\u003cp\u003eReplacing a mainshaft means the transmission is fully apart, which is nearly all the labor on this job. Use the access.\u003c\/p\u003e\n\n\u003cp\u003eInspect your synchros, sleeves, hubs, and bearings while everything is exposed and replace what's past spec. Anything that ran alongside a damaged gear has likely taken debris or abuse, and closing the case up with a fresh mainshaft next to worn synchros means doing this again sooner than you'd like.\u003c\/p\u003e\n\n\u003cp\u003eIf you're finding wear throughout, a full rebuild kit is better value than replacing pieces individually.\u003c\/p\u003e\n\n\u003ch4\u003eFitment\u003c\/h4\u003e\n\n\u003cp\u003e1994-2001 Acura Integra GS-R and LS (SG-B190-MS)\u003cbr\u003e1994-2001 Acura Integra Type R, 1999-2000 Honda Civic Si, 1994-1997 Honda Del Sol VTEC (SG-B210-MS)\u003c\/p\u003e\n\n\u003cp\u003eSelect your application at checkout.\u003c\/p\u003e\n\n\u003ch4\u003eWho Should Grab One\u003c\/h4\u003e\n\n\u003cp\u003eThis is for the builder who's opened a B-series and found damage on the mainshaft, and for anyone assembling a transmission for a car making enough power to justify doing it right. Factory ratios mean nothing about how the car drives changes, you're just replacing a weak point with something stronger. Confirm your second gear ratio, inspect everything else while you can see it, and close it up once.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eFits:\u003c\/strong\u003e 1994-2001 Acura Integra GS-R and LS, 1994-2001 Integra Type R, 1999-2000 Honda Civic Si, 1994-1997 Honda Del Sol VTEC. \u003cstrong\u003ePart numbers:\u003c\/strong\u003e SG-B190-MS (3.23 first \/ 1.90 second) and SG-B210-MS (3.23 first \/ 2.10 second). \u003cstrong\u003eRatios:\u003c\/strong\u003e matching factory. \u003cstrong\u003eType:\u003c\/strong\u003e complete Pro Series mainshaft assembly.\u003c\/p\u003e\n\u003c\/li\u003e\n\n \n\u003cli id=\"VehicleFitment\"\u003e\n \u003cp\u003e1994-2001 Acura Integra GS\/LS\/RS\u003cbr\u003e1994-2001 Acura Integra GS-R\u003cbr\u003e1997-2001 Acura Integra Type R\u003cbr\u003e1999-2000 Honda Civic Si\u003cbr\u003e1994-1997 Honda Del Sol VTEC\u003c\/p\u003e \n\u003c\/li\u003e\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\u003c\/ul\u003e\n","brand":"Synchrotech Transmissions","offers":[{"title":"B18C1\/B18B","offer_id":46745508675618,"sku":"SYN-SG-B190-MS","price":439.95,"currency_code":"USD","in_stock":false},{"title":"B18C5\/B16A","offer_id":46745508708386,"sku":"SYN-SG-B210-MS","price":439.95,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/2218\/5701\/files\/synchrotech-b16a-b18b-b18c-pro_eh46.jpg?v=1788287890","url":"https:\/\/www.hybrid-racing.com\/products\/synchrotech-b-series-mainshaft-b16a-b18c-b18b","provider":"Hybrid Racing","version":"1.0","type":"link"}