Tire criteria

So I'm looking at new front tires in the next year or so. Right now, my criteria are:

• Max Inflation - 50%
  
• Min Revs Per Mile - 30%
  
• Min Tread width - 10%
• Max Tread depth - 10%

In today's market, the leaders are:

1. Yokohama Avid - 51 psi, 837 rev/mi, 6" tread width, 10/32 tread depth
2. Fuzion Touring - 44 psi, 840 rev/mi, 5.5" tread width, 11/32 tread depth

The Yokohama Avid is clearly ahead by max psi and lowest rev/mile. Tread width adds 1" in profile area and tread depth is slightly lower. But this is a city commuter, not a highway, cross-country car.

Any experience with the Yokohama Avid tires?

Bob Wilson

 

It has an effect but I have yet to quantify it.

The "CVT" or Power Split Device (PSD) is the gear that connects to the engine crankshaft. There are gear stages that reduce the rpm, multiply the torque, until it reaches the differential that splits torque to feed the two drive wheels. By increasing reducing the 'revs per mile', we turn these multiple gears slower at any given true speed compared to the OEM tires. This reduces stirring losses from the transmission gears having to 'move the oil' about between the teeth and part of the rolling drag.

There is also a reduction in tire rolling drag because the rubber hysteresis at the contact patch is reduced in frequency (i.e., the rate the tire rotates) and displacement (i.e., a larger tire has a lower angle change than a smaller tire.) This is solid theory but hard to quantify, yet.

Bob Wilson

 

Details?

Bob Wilson

 

Thanks,

It looks like they have a 185/70/14, 14" rims, that might work but finding them south of the Mason Dixon Line has been a challenge. I haven't given up but I'm reminded that one of the best ways to hide information is the Internet. <GRINS>

Still, I have three leads: two in Tennessee and one in Michigan. We'll see what pops.

Bob Wilson

 

I optimize my ride for maximum MPG and don't really do much for 'ride quality.' So I just had the rear pair of Yokohamas installed on the 2003 Prius. The front pair were too large for the rear wheels. So after checking for rear wheel clearance, I'll 'fully' inflate them and restart my stunt drive.

I went with Yokohama's because they are the only ones that support 51 psi on 14" rims. I started with P195/70R14 but they only work in the front where they are mount today. The rears have P185/70R14 that from the specs should work just fine. Their tread width is the same as the Sumitomo T4 P195/70R14 that I had been running. Both sets are larger diameter (i.e., lower revolutions per mile) so I'll be using a Garmin as the GPS speedometer.

My first test with just the front mounted Yokohamas showed a 107.2% overdrive effect for the 50 miles initial calibration check. This was before fully inflating them. So I am reasonably happy with my set but they might cause you grief.

A relatively low-cost way to approach tire testing is to buy just one pair and put them on the front. This will let you see the handling and ride without having to buy the full set. If they are OK, buy a rear pair. If not, buy your next choice for the front and move the others to the rear wheels.

GOOD LUCK!
Bob Wilson