Shifting to lower gear and synchro wear

[Lil bastard]

There are lots of times where downshifting is necessary - flowing in traffic, elevation changes, turning, etc. And in these times matching revs is a good way to minimize synchro wear.

Then there are times when downshifting is totally unecessary and just causes excess wear to the drivetrain, like approaching a stop.

If you're a good driver, you can anticipate 99% of your stops - there's a sign alerting you to a stop ahead, you see the stoplight or stop sign, etc. This is the wrong time to downshift. Stay in gear to allow the car to bleed off energy while applying the brake, then go into neutral and stay on the brakes to stop the car.

It doesn't sound as cool, or get the attention of the blonde at the bus stop, but you will end up burning $150 brakes instead of $600 clutch and/or $2000 synchro replacement.

Of course, in an emergency, do whatever you need to stop in the shortest distance possible - downshift, throw out a boat anchor, anything!

Otherwise, respect the machinery - use the brakes to stop and the tranny to go.

Your car, and your wallet, will thank you.

Cheers!

[Frank M]

A syncro will wear quicker when speed shifting. This is similar to hard braking wearing tires faster.
When there is enough wear the syncro has difficulty slowing down the gears to properly mesh, similar to a tire with little tread not grabbing well on a curve or hard braking at high g force.

When this starts to happen then the syncro grinds and makes its teeth as well as the teeth on the gear round off.
The answer to syncro long life is to shift normal including down shifting approaching a red light. One will find they will tire of the vehicle before the syncro will require replacement.

Shifting fast will cause quicker wear similar to hard driving wears tires.

I find premature syncro wear on vehicles that do not replace the lube with the factory required lube. OEM is best no matter what.
The syncros in modern transmissions are made of different materials and the lube is engineered to the specific application.

[Quickurt]

I downshift only to be in the correct gear to accelerate into, through and out of a turn.
In the supposed "good old days" we would downshift to save the brakes from excessive heat and/or wear, but those days are long gone.
LB hit that nail on the head.
With Boxster brakes, you're actually wasting precious braking concentration on screwing with downshifts and probably screwing up your stopping/slowing distance.
If braking properly, you don't have time to row through more than one gear anyway. Stand on that center pedal, double clutch/heel toe down into 5th gear (4th in a base model) and you're already down to third gear speed. Before you can get it into another gear, you're nearly stopped.
You're better off spending that precious brain matter calculation time estimating the gear you will need to be in for the corner you're approaching and then making that one shift - smoooooooooooooooooooooooooooooooothly - and being in that gear BEFORE you' re done braking.
I have a set braking point for the turn in to my subdivision entrance road. From 70 mph I brake at the beginning of the previous driveway - 75 ft from the beginning of our entrance road curve in. I stand on the brakes, downshift from 5th to 2nd while gently turning in (loving the Porsche anti-lock system) and end up in the driveway, on the proper side of the road, at our 20 mph subdivision speed limit. The entire process takes maybe 3 seconds.

[Vaughan]

Originally Posted by Quickurt

I have a set braking point for the turn in to my subdivision entrance road. From 70 mph I brake at the beginning of the previous driveway - 75 ft from the beginning of our entrance road curve in. I stand on the brakes, downshift from 5th to 2nd while gently turning in (loving the Porsche anti-lock system) and end up in the driveway, on the proper side of the road, at our 20 mph subdivision speed limit. The entire process takes maybe 3 seconds.

That's what I'm talkin about.