I lost some power somewhere... anyone have a guess where?

[ConnClark]

ummmm.... How does new tires translate into more rolling resistance. New tires have stiffer side walls and the belts are stiffer. This leads to to lesser deformation which has the same effect as hyperinflation and means less rolling resistance. Every time I get new tires my mileage goes up. Further proof of this is when new tires are tested for rolling resistance they use brand new tires not used ones.

In discussions with my father who used to work in designing tires for Firestone he confirmed that stiffer side walls and belts would lead to lower rolling resistance. In fact its the stiffness of the belts is what gives radial tires better performance and lower rolling resistance than ordinary tires.


as for a drop in power and fuel economy any wind that is not a tail wind is going to require more power to travel the same speed. cars are designed to travel through the air forwards not sideways.

[RH77]

Originally Posted by BlackDeuceCoupe

My Honda B16 motor is widely ridiculed as a "torqueless wonder". At 8000+ rpm it will propel my ride like a white hot comet, but "cresting a gentle hill" at even 3000 rpm will cause my engine to labor, and the speed to drop precipitously!

Try a B18B1 with an automatic! Max torques at 5200 at a smokin' 127 (142 hp at 6300). It still scoots when prompted, but requires finesse below 3k.

I had a fierce headwind the other day, coupled with cooler temps. Didn't need the window down, but it was a real struggle to get/keep highway speeds. The dense air usually makes a bit more power without an FE sacrifice, but the cooler temps did it. IATs have dropped as well.

I cruise at 60-70, which is 2500-3000 RPM. I keep it in 4th/TC locked, 19TPS -- build up some momentum (depending on the hill, maybe go up to 21TPS) and hold the throttle to bleed the speed. MPGs drop, but hills do that. I make it up on the next downhill (hopefully). Unless I get impatient, the TC won't budge.

RH77

[lyd]

Originally Posted by ConnClark

ummmm.... How does new tires translate into more rolling resistance. New tires have stiffer side walls and the belts are stiffer. This leads to to lesser deformation which has the same effect as hyperinflation and means less rolling resistance. Every time I get new tires my mileage goes up. Further proof of this is when new tires are tested for rolling resistance they use brand new tires not used ones.

In discussions with my father who used to work in designing tires for Firestone he confirmed that stiffer side walls and belts would lead to lower rolling resistance. In fact its the stiffness of the belts is what gives radial tires better performance and lower rolling resistance than ordinary tires.

Well, that may be true if you are getting the same new tires, but even then more tread == more rolling resistance, and in my case I went from a "summer tire" with a low tread depth to begin with to an all season with a much more aggressive tread pattern, lots of siping, and easily twice the depth of the previous tires.

The upside of this is that I definitely noticed improved traction when driving in heavy rain, and I am probably going to be much happier this winter.