What does Honda Recommend for Upper Limit Road Force for Pilot?

[fxmyhed]

W-MART recently turned my super smooth riding Honda Pilot into a vibrating disappointment. They could not eliminate the vibration with two different sets of tires and repeatedly insisted the tires were balanced and defect-free. I ended up at 3 different W-MARTS in 2 different states, balancing my new tires 4 different times. All this never eliminated the vibration. I took the car to a privately owned service center that takes pride in their reputation. This center also uses a precision "Hunter" dynamic road force tire balancer that measures "road force" among other state-of-the-art precision capabilities. The machine dictates if the tire should be rotated on the rim, and provides laser accuracy for the weights. This link provides some short videos explaining the equipment capabilities: Hunter GSP9700 Wheel Vibration Control System).

I was told "road force" of 26-28 lbs. is consider "very upper limit" of acceptance. Theoretically, lower numbers are better. A similar thread about Discount Tire: Road Force balancing technical question - AcuraZine Community indicates that GM uses 24 lbs as their upper limit, and that Discount Tire is incompetent. And yet another thread indicates that 18 lbs. is the upper limit and that BMW uses 16.

So here were my road force measurements before and after the Hunter:

RF was 16 & adjusted to 4
RR was 16 & would not adjust any lower.
LF was 30 & would not adjust down. It was deemed non-service-able. Installed my extra 5th tire that I had bought & adjusted down to 7
LR was 28 & adjusted to 23

In addition, improper weight was observed on RR (off by 0.50 oz) and LF (off by 0.25 oz.) each exceeding the industry observed*** imbalance limit. TOTAL service charges: $102.

So how do I interpret all this?

1) After road force balance, I can detect a night-and-day difference and only very subtle vibrations at higher speeds with these tires. I assume it is the LR at 23.

2) Goodyear Viva 2 tire quality is questionably low based on random chance that 1 out of the original 4 had exceedingly high road force and deemed not service-able.

3) W-MART is not equipped nor capable of balancing tires. (And I am sorry to be the one to learn the hard way.)

4) I will not install another set of tires with any shop on any car without requesting documented road force balance measurements for each tire. It seems that the better shops will include this as part of the install. I may also go so far as to contract for less than 16 lbs before I buy.

5) I have discovered that some tires now come with a 30 day money back guarantee which could simplify recourse.

6) FYI, After speaking with multiple tire shops around my home and reading numerous reviews, the General Grabber HTS seems to be one of the highest rated tires for Honda Pilot.


***Reference: Excerpt from Bass Tire Company :: Road Force

In the past, most tire/wheel assembly vibration was considered balance related. Because of this, tire service professionals tend to relate tire/wheel vibration in terms of balance weight. Road Force will be best understood when related to the amount of balance weight required to cause a similar vibration in a wheel that rolls round under a load. In other words, "How much Road Force creates a similar vibration caused by tire imbalance?

Most tire service professionals and factory service manuals agree that residual static imbalance should not exceed .30 oz. on average size wheels and .60 oz. on larger light duty truck wheels.

Radial Force is determined by measuring loaded radial runout. On an average passenger car tire/wheel assembly, one thousandth of an inch (0.001") of loaded radial runout is equivalent to approximately one pound of Road Force.

Tests on a Chevrolet Lumina were performed using a chassis dynamometer in a Detroit test lab. The purpose of the test was to determine how much balance weight would be required to produce the same magnitude of force as a measured amount of loaded radial runout.

The tests were performed with the vehicle running at different speeds. The first test was at 50 miles per hour and the second test at 70 miles per hour.

At 50 MPH: A measured .030" (about 30 pounds) of loaded radial runout caused the same amount of vibration as 1.5 ounces (42 grams) of wheel imbalance at 50 mph. This is 5 times greater than the .30 (1/4) ounce imbalance limit.

At 70 MPH: A measured .030" (about 30 pounds) of loaded radial runout caused the same amount of vibration as .75 ounces (21 grams) of wheel imbalance at 70 mph. This is 1 1/2 times greater than the .30 (1/4) ounce imbalance limit.

[ltp646]

WOW!!! I have no idea of what I just read. Didn't know that installing a set of tires could be that complicate.