Yokohama AVID ENVigor Tires

Back in January 2014, after my OEM Dunlop Enasaves wore out, I replaced them with Yokohama AVID ENVigors.

http://myimiev.com/forum/viewtopic.php?p=14928#p14928

Further on in that thread (now closed) I provided further discussion of the Yokohamas, with the conclusion that, although their roadholding was good, they were not as efficient as the Enasaves. They also had a higher road-noise level than the Dunlops.

Now, after 16,000 miles on them, the front tires are starting to wear out (especially the left front, probably due to my zooming on and off Interstate cloverleaf ramps), and I suspect I may be replacing the entire set by the time winter rolls around.

The good news is that with this wearing out the i-MiEV's range appears to have returned to 'normal'.

I have also heeded the sage advice of Don on this forum and, since I often let others borrow this i-MiEV, in the interest of 'safety' I have reduced the tire pressures to 44psi. The i-MiEV's manufacturer-recommended tire pressures are 36psi.

For the following, this is my comparison for Dunlop, Continental, and Yokohama tires on the front only. The rear tires in all circumstances below are Dunlop.

Koorz has Yokos on the front, while Bear has Continental on front, but both have Dunlop on the back. Last weekend, I swapped the front wheels between the two to weed out an alarming "scrunching" noise coming from the front of Bear. Turns out that the Continental tires are making the noise :| . The Dunlop tires make a similar noise, but it much quieter. The Yokohamas are silent in a straight line, but make a lot of noise in corners. Anyway, after driving with Yokohamas on Bear for a week, I did notice a drop in RR, but I can't be certain yet as I did change routes at the same time. But, judging on where I lost my first bar in comparison with other tires (Dunlop and Continental), I was losing it roughly where I lose it in the winter when running on Dunlop tires. I have all my tires set at 40 PSI.

So, in essence, I agree with Joe that there is a noticeable decrease in range when running Yokohama tires (for me, it was 1 mile less on the top bar). But, if that isn't a concern, there are considerable handling improvements and overall reduction in noise compared to Continental front tires. It also seems that bumps don't hit as hard with the Yokos.

Also, I can confirm that we do have radio-frequency tire pressure transponders. Roughly 15 miles after the first swap, my low-pressure light came on. After switching back, it went out within 1/2 mile.

WARNING: DO NOT OVERPRESSURIZE YOKOHAMA AVID ENVIGOR TIRES

I had hoped to give a detailed writeup on my troubles with the Yokohams, but this convoluted summary will have to do, as I'm leaving town next week for a month.

As some of you remember, I'd been running my tires variously at 60psi, 51psi, 44psi, and the OEM-recommended 36psi. My reasoning for overinflation -

1. Reduce rolling resistance
2. Improve handling
3. Reduce sidewall flexing leading to tire heating

No problem running at 60psi with the OEM Dunlop ENASaves for two years - wore out the first set (evenly) at 23K miles.

Replaced the tires on Mitsi (my original i-MiEV) with Yokohama AVID ENVigor and continued experimenting with tire pressures, eventually settling on 44psi after I became convinced that the higher tire pressure did not noticeably improve efficiency.

My second i-MiEV Mitti already had the rear tires replaced with Yokohamas (previous owner had damaged tire and replaced both rears with Yokos). With this car, I also experimented with tire pressures before settling down on 44psi.

Long story short: in hot weather a short while ago, the right rear Yokohama on Mitti catastrophically had tread separation at around 55mph, whapping and damaging the bumper. The tire (inflated to 44psi) DID NOT DEFLATE. This happened 50 miles from home and luckily I had my two Gen1 Insight spacesavers + jack onboard and was able to replace both tires. Went home using back roads with dashboard lit up like a Christmas tree (due to tires of unequal size front to back) but everything working fine once the car's ASC or ABS or whatever got over trying to react to the weird tire diameter. Replacing the tires with OEM Dunlops took away all the warnings. The failed tires had about 15K miles on them.

Shortly thereafter, Mitsi (my original i-MiEV) developed a rumbling noise in the front after about 18K miles on the Yokos (lots of treadwear). The left front tire tread had started a bubble. No sooner had I replaced the two front tires with OEM Dunlops that a rumble in the right rear started - same thing, a bubble. Replaced tires. Now have all my cars running on OEM Dunlop ENASaves, the only difference being a quieter ride than the Yokos and the car's range now appears to be identical amongst all three cars, despite wildly different battery ages. Can't tell any difference in handling. I'm running all tires at 44psi, despite Mitsubishi's recommended 36psi.

So, three out of six Yokohama AVID ENVigors had tread separation, two of which I caught before the tread fell apart.

Was my previous driving at 60psi the cause? Probably a contributor. I didn't keep records so I don't know how many miles I put on the tires at what pressures. These are the first tires I've experienced failure with after ten years of running higher-than-allowable pressures in both the Gen1 Honda Insights (special ultra-low-rolling-resistance Bridgestone Potenza RE92) and i-MiEVs.

Let this serve as a warning. Once again, maximum pressure allowable by tire manufacturer is 51 psi, with i-MiEV recommended pressure being 36psi. Don, you can now say you told me so...

Sorry to hear that. Hopefully Mitti isn't damaged too badly.

Since I don't drive Koorz that much, I can't say how the Yokohama tires are holding up, except that I run all tires at 40 psi. On the Continentals I'm running on Bear, I did notice some excessive wear on half of the outside tread (halfway around the tire is good, but the other half is worn down, on both fronts), plus there is a small tear in the tread block on the front right. Beyond that, the center and inside tread is fine and the rear Dunlop tires are wearing evenly and considerably slower than the original tires.

I doubt it's the tires - I've had Yoko's on 3 cars for the last 10 or 12 years and never had a problem with any of them. I like Yokohomas because I prefer tires made in Japan and they're getting harder to find in most brands. IMO, Japanese rubber products have no equal - You can drive more than 100,000 miles on OEM fan belts, hoses and wiper blades and then when you replace them with something made here (Gates, Goodyear, Trico etc) you will replace them 3 or 4 more times over the same period of time that your OEM products lasted

Tires need to be able to flex to protect themselves - If you hit a chuckhole with a rock-hard tire, you'll be damaging the tire because it couldn't flex to absorb the impact. We had a graph here some time ago which showed how much rolling resistance lowered as the tire was overinflated - Just about all of the gains to be had were realized by the time you got to 40 psi. Increasing to 45 or 50 gained almost nothing

But . . . . if the tire manufacturer has a max inflation pressure printed on the sidewall of the tire, whatever you do, don't go above that number - Nothing to be gained and likely you'll be shortening the overall life of the tire

Don

This is all good to know. Thanks. As this is the only maintenance I can look forward to aside from washing my car (two days ago) it's good to be on top of this. It's a little early as I only have 5k miles on the car but I have been running 44 psi in the tires and the car handles the increased pressure just fine (compared to other cars I've had). The suspension seems to soak up the bumps well.

I do have to replace the tiny rear windshield wiper though. I may stop on the way home tonight and pick one up. :mrgreen:

Don said:

Tires need to be able to flex to protect themselves - If you hit a chuckhole with a rock-hard tire, you'll be damaging the tire because it couldn't flex to absorb the impact.

Click to expand...

Agreed. I recently mistakenly overinflated a tire on an electric scooter and the tire sidewall failed while riding it because the tire could not flex.

PV1 said:

For the following, this is my comparison for Dunlop, Continental, and Yokohama tires on the front only. The rear tires in all circumstances below are Dunlop.
So, in essence, I agree with Joe that there is a noticeable decrease in range when running Yokohama tires (for me, it was 1 mile less on the top bar). But, if that isn't a concern, there are considerable handling improvements and overall reduction in noise compared to Continental front tires. It also seems that bumps don't hit as hard with the Yokos.

Click to expand...

My experience with all four Yokohama AVID ENVigor Tires compared to all four Dunlop Enasaves:

There are many differences in the two tires, including tread depth, tread width and tread design. Also the Dunop tires are rated Low Rolling Resistance and the Yokohama tires are not.



I measured the remaining battery state-of-charge driving the exact same route at the same speed. With the new Yokohama tires I had an average of 10% less charge than I did with the new Dunlop tires.



Also, I ran the test at 36 psi and 50 psi and there was no difference in remaining battery state-of-charge.

Comparing new tires with old tires or new tires with deeper tread to new tires with less tread it's really hard to get and true statistical data because as you highlighted, the revolutions per mile for the various tires are different and the car bases it's calculations on the odometer, which gives different readings for tires with different circumferences - Differing revs per mile which means differing odometer readings

I recall Joe's great alarm when he first installed the Yoko's - He went from literally bald OEM tires to the Yoko's which have a deeper tread than the stock tires did even when new and it apparent miles per Kw went down drastically the day he installed the new tires . . . . but by the time they were about bald, things were back to where he was used to them being. Nothing compares to a bald tire when you're measuring EV efficiency!

Don

I just got Yoko tires installed on the rear @ 36,000mi. The Yoko tires in the front were installed at 22,000mi.
The rear tires are for sure louder than the old OEM, almost bold ones. I have driven the rear tires for about 750mi and still have to be very careful turning and accelerating in D-mode when the roads are wet. They tend to loose grip even under moderate acceleration.
How long will that last for?

Don said:

Comparing new tires with old tires or new tires with deeper tread to new tires with less tread it's really hard to get and true statistical data because as you highlighted, the revolutions per mile for the various tires are different and the car bases it's calculations on the odometer, which gives different readings for tires with different circumferences - Differing revs per mile which means differing odometer readings.

Click to expand...

The odometer readings were not much different:
42.5 miles with worn out Dunlops (all three runs)
42.3 miles with new Yokohamas (all four runs)
42.4 miles with new Dunlops (all three runs)
42.4 miles with 5,000 mile Dunlops (one run)

But I was not concerned with the tire diameter or the odometer reading, only how much battery charge I had left (starting out at 100%) after driving the exact same course at the same speed and conditions. I just want the tire that uses the least amount of battery charge. Which tire gives me the most range?



I consistently had less battery charge left with the new Yokohamas, compared to new, almost new, and worn out Dunlops.

What were the manufacturing dates of the tires? I've had some tires from batches that were just dogs. The replacements a year or so later were fine.

So to me it looks like the testing and data verified that the LRR rating is a true factor--thanks for running the test and sharing your findings.