Bigger tires, changing gearing.

[Waldi]

[E1]

Thanks, I guess it depends on whether one goes remote, then.

Mine are great on the highway, too. The only Contis I ever used were on a racing kart -- and they sucked, too.

But I imagine they do make good tires for other things.
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‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman

[Syncronoid]

So, I did the rolling test just now. My 215/70R16's (27.8" Diameter & 746 Revs/MI per BFG) measured at 254" for 3 full revolutions, or 84.66667"/Rev, which is 748 Revs/MI. So, the BFG website numbers (746) seem fairly accurate.

Based on that, making the jump to their 235/70R16 (28.9" Diameter, 718 Revs/MI) results in a theoretical 3.75% reduction in RPM's. Seems somewhat benign, but I guess there's only one way to find out.
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'90 Syncro Westy w/GW2.5L

[Pcforno]

Syncronoid - may I highly suggest researching the Cooper AT3 in this size. I changed from KO2s and would never go back. The tread lasts longer (silicone based), is quieter, and performs better off-road. They’re also lighter. If you do a bit of research you’ll find that expedition portal and other reviewers found them tops as well.
Cheers!

[E1]

Cooper makes tires for racing series a couple drivers I know race in, so I'm all ears in supporting Cooper.

The Big One: D-Rated???
_________________
‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman

[Syncronoid]

235/70R16 KO2's are on. Small but noticeable difference around town. I can notice being able to run it out a bit longer before shifting. Will drive to work tomorrow on freeway to get a sense of the lower RPM's at speed, then off to Bend for 12 days Friday. The real test comes on I-5 going over the Siskyous, Shasta and doing some off roading above my house.
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'90 Syncro Westy w/GW2.5L

[j_dirge]

[Pcforno]

[Pcforno]

[Waldi]

[Waldi]

[Syncronoid]

Who here was looking to perhaps acquire my barely-used 215/70R16 BFG KO2's??? Please message me. Thx.
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'90 Syncro Westy w/GW2.5L

[Pcforno]

Or put them on Craig’s list. Mine sold the same day

[TheMonk]

[levi]

The rpm where torque and h.p. meet, that should be it.
_________________
One of these days I'm gonna settle down,
but till I do I won't be hangin round.
Going down that long lonesome highway,
gonna see life my way

https://youtu.be/cSrL0BXsO40

[?Waldo?]

There is nothing special about the rpm where hp and torque "meet". Power = Torque X Distance (rpms). Where the two cross on the graph is just a function of the units used. With horsepower and foot-pounds used, the graphs always meet at 5252 rpms.


Link


The most efficient rpm to drive at (highest BSFC) is typically max torque. The rpm where you have the most power is, yup you guessed it, max horsepower.


Link

[E1]

Air density per water grains vs. power, air density via humidity, altitude, and drag, also play into finding the sweet spot of mpg.

What I do know as fact over theory is what my per-every-tank mpg math tells me, that when traveling the same overall speeds, adjusting for speedo error, we got better mileage with taller tires. I suspect the biggest factors in our case were changed gearing (via taller tires) bringing less revs.

We also changed the R&P to accelerate better and changed 4th to about 50 less revs, both likely inconsequential in us being on the open road more often than in city traffic. I believe aero to not be a significant factor, as in I drive at matched speeds to the 14s, and with such an under-powered car it is extremely likely VW weighed mpg vs. selling a rig with the feel of an even-more underpowered engine.
_________________
‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman

[vik]

Any results so far?
Just wondering if the 225(235)/70 R16 tires on 7x16 ET30 rim will fit stock Syncro without rubbing.
_________________
T3 Syncro camper in progress

[Syncronoid]

I have the 235/70R16's on 16" Mefro steelies with 2" lift and FoxShox. Very slight rubbing on higher speed entry maneuvers, but nothing that would cause any noticeable impact or damage to the wheel wells/arches.

[PDXWesty]