Synchrotech Carbon Synchro Kit for FK8 Civic Type R

Synchrotech Carbon Synchro Set - 2017-2021 Civic Type R (FK8)

The FK8 gearbox is good, and it's also attached to an engine that encourages you to use it. Enough hard shifts and enough track days and the synchros start letting you know. These are Synchrotech's carbon synchros, sold as first and second, third and fourth, or the full 1-4 set, so you can replace what's actually worn rather than everything.

Carbon Only, And That's Right For This Car

Unlike the older Honda platforms where brass makes sense for a daily driver, this is a carbon-only offering, which suits what an FK8 actually is.

Synchrotech's carbon synchros use a full carbon composite lining built on carbon-carbon technology originally developed for aerospace. The material acts as a braking element during engagement, stopping the gear faster than brass can. That means less grind on the high-rpm shifts an FK8 owner is regularly making, and less wear on the sleeves and engagement teeth over time.

On a car that gets tracked, autocrossed, and driven hard on the road, carbon is the material worth having.

Buy Only What's Worn

Sold in three configurations, and wear on these transmissions is rarely even.

First and second (SYN-FK8-1) take the most abuse by a wide margin. Highest torque multiplication, hardest shifts, and the gears you're using on every launch and every corner exit. If your grinding is isolated to the low gears, this is your set.

Third and fourth (SYN-FK8-3) for wear further up the box, which typically shows on cars seeing a lot of track time where you're spending real time in those gears.

Full 1-4 set (SYN-FK8-1-4) for a complete refresh, or when you've inspected and found wear throughout. Given what it costs to get into the transmission, this is often the sensible call even if only two gears are obviously bad.

Triple Cone And Dual Cone

Worth knowing what's in there, since it explains why these are split the way they are.

The FK8 uses triple cone synchros on first and second and dual cone on third and fourth. More cones means more friction surface, which is how Honda got the shift quality this car has, and it's also why the two groups are different parts.

That's the reason you can't buy one set covering everything from one to four as a single design. The 1-4 set is both types packaged together.

First Through Fourth Only

Worth saying plainly so you're not left wondering. Synchrotech covers gears one through four on this transmission. There are no fifth or sixth gear synchros available for the FK8, and no matching hubs, sleeves, or springs at this time.

That's a limitation of what exists rather than a gap in what we stock. If your wear is in fifth or sixth, or if you find worn hubs or sleeves during inspection, you'll be looking at OEM parts or a different approach for those.

How To Tell Your Synchros Are Done

A few reliable signs, and one test worth running.

It grinds into one specific gear. Isolated grinding almost always means an isolated problem, and it tells you exactly which set to order.

Downshifts are worse than upshifts. The useful one. On an upshift, revs are falling naturally and the synchro gets help. On a downshift it has to drag the clutch disc and input shaft up to speed by itself. If the car upshifts cleanly but grinds or blocks on a normal downshift, your synchros are worn.

It's getting worse. Wear starts as slight notchiness and progresses to something you feel clearly in your hand.

One honest note: grinding can also come from a clutch that isn't fully disengaging or from the wrong transmission fluid. Rule those out first, they're far cheaper than pulling a transmission.

Inspect Your Hubs And Sleeves

The advice worth the most on this page. Synchros work against your hubs and sleeves, and if those surfaces are worn, new synchros won't fix your shifting.

Carbon on a chewed-up hub is no better than brass on a chewed-up hub. So look at your engagement teeth, your sleeves, and your hub splines before you close the case. Sharp and clean means these will transform the shift. Rounded off means you need more than synchros, and finding that out now is far better than after everything's back together.

Worth Doing Once

Getting into the transmission is the expensive part of this job, whether you're paying a shop or spending your own weekend. The parts are the cheap half.

So while it's open, inspect everything and replace what's genuinely past spec. If you're finding wear across the box, the full 1-4 set is better value than going back in six months for the gears you skipped.

Fitment

2017-2021 Honda Civic Type R (FK8)

Triple cone first and second, dual cone third and fourth.

Who Should Run These

This is for the FK8 owner whose transmission has started grinding, and for the builder going through a gearbox on a car that's earned it. Track days, autocross, or a car that's simply been driven the way a Type R invites you to drive it. Carbon is the right material for how these cars get used. Inspect properly, order what's actually worn, and get your shifts back.

Fits: 2017-2021 Honda Civic Type R (FK8). Material: Synchrotech carbon composite. Configurations: 1st/2nd (SYN-FK8-1), 3rd/4th (SYN-FK8-3), or full 1st-4th set (SYN-FK8-1-4). Design: triple cone first and second, dual cone third and fourth. Note: 5th and 6th gear synchros are not available for this transmission.