Synchrotech B Series Synchro Spring Set for B16/B17/B18

Synchrotech B-Series Synchro Spring Set - B16, B17 & B18

Springs are the part nobody thinks about and everybody should. They're what pushes the blocker ring against the cone to start the synchronizing action every time you shift, and when they weaken, the synchro can't engage firmly enough to do its job. You get a grind that feels exactly like a worn synchro even when the synchro itself still has material left. This is the complete 1-5 spring set for B-series transmissions.

Why Tired Springs Feel Like Worn Synchros

Worth understanding, because it's the reason these get overlooked in a rebuild.

Your synchro can only do its job if it's pressed firmly against the cone. That pressure comes from the spring. As the spring loses tension over decades of heating and cycling, the synchro engages more weakly, takes longer to bring the gear to speed, and eventually can't finish the job before the sleeve arrives.

The result is a grind. Same symptom as a worn synchro, different cause, and no amount of new friction material fixes it if the springs behind it are done.

Always Replace Springs With Synchros

The practical advice worth the most on this page. If you've got the transmission open for synchro work, put fresh springs in at the same time.

They've been cycling and heating alongside everything else for the same number of years and the same number of shifts. On a B-series that's now twenty-five to thirty-five years old, that's a great many shifts, and springs don't look worn even when they've lost meaningful tension.

They're the cheapest part in the assembly and among the most annoying to have to go back in for. Reusing them behind a fresh set of carbon or brass synchros is how a rebuild ends up feeling only slightly better than it did before.

Springs Alone, Or The Master Kit?

Worth deciding before you order.

Buy this set on its own if you've inspected the transmission and your synchros, sleeves, and bearings are genuinely still good. That happens, particularly on a lower mileage car where the springs have simply lost tension with age rather than the whole assembly being worn.

If you're finding wear in more than one place, the B-series master rebuild kit includes these springs along with synchros, sleeves, bearings, and seals, and works out cheaper than buying the pieces separately. Given the labor to get in there, most people going this deep want the full kit.

Match Your Transmission Code

Four versions, and the split is by transmission rather than by car. Check the code on your case rather than going by what the chassis is, especially on a swapped or rebuilt gearbox.

Two things worth noting. The 1989-1991 cable transmissions split two ways, so SP103 and SP105 cover the same years and different gearboxes. And the B18A and B18B take a different set than the B18C, so don't assume any B18 spring set works.

Fitment

Honda and Acura B16, B17, and B18 transmissions. See the table above for the correct set.

Complete 1-5 spring set.

Who Should Grab This Set

This is for anyone with the transmission apart doing synchro work, and for the builder who understands a rebuild is only as good as its weakest reused part. Springs are inexpensive, they're a known wear item, and they directly affect whether your new synchros engage the way they should. Check your transmission code, and if you're in there, put them in.

Fits: Honda and Acura B16, B17, and B18 transmissions, see the table above. Part numbers: SP101, SP103, SP105, SP107. Coverage: complete 1-5 set. Important: select by transmission code, not by vehicle.