Did you notice a change in your mpg with the new tires?Just replaced my Drive Guards with plenty of tread with new Michelin Pilot a/s 3+. My wife was complaining about ride quality and road noise.
Before doing that, I used my iPhone to measure the db on this one stretch of road, going 35 mph (85 degrees F). It came in at 70 db. After the replacing the tires, I went to down the same stretch of road and it measured at 65 db. By comparison, that’s the sound level at a stop light with AC blowing full blast. So there is a minor reduction in road noise.
Subjectively, it’s a little smoother but not by much. I wouldn’t say it’s night and day as some people rated the change from RFT to Non-RFT. If I could do it again, I’d probably wait until the Drive Guards were done or damaged before switching.
If you really have to keep RFTs, I’d recommend the Drive Guards for the fact that their noise and ride quality is very similar to non-RFTs.
I guess the ride quality and road noise is just something I’d have to live with. Time will tell if these Michelins will improve with age.
Same front and rear? My PSI door panel recommends 38 front, 36 rear but I am always in two minds about this, at the moment I run 36 all round because I worry about the dreaded front tire inner edge groove re-appearing on my Michelin PS 4S's after my disastrous foray with the Pirelli P-Zero's.Hot months 35.5 / 31.5 static at ~72F
Cold months 36.0 / 32.0 static at ~65F
From my long term tire tread wear data 36/32 avoids the center wearing faster than the edges but need rotation every 5k for even wear among all 4Same front and rear? My PSI door panel recommends 38 front, 36 rear but I am always in two minds about this, at the moment I run 36 all round because I worry about the dreaded front tire inner edge groove re-appearing on my Michelin PS 4S's after my disastrous foray with the Pirelli P-Zero's.
Thanks @jmc I don't carry Monster-In-Laws about in the rear seat, so will 'depressurize' the rears to 32 and keep the fronts running at 36. I run nitro in them and rotate every 6 months (about 8,500 kms for me).From my long term tire tread wear data 36/32 avoids the center wearing faster than the edges but need rotation every 5k for even wear among all 4
Too much curb weight upfront for 36 rear unless always carrying monsterinlaws i mean rear passengers even then maybe 33 else high center wear again
Keep in mind every 0.5psi is about 1.5% and for my tires over 22k miles the 0.5 static differential between hot and cold months (so total increase due to motion and ambient is similar) kept that center tread block from accelerated wear
Will see if i can dig up some plots ...
Keep an eye on the center and edge tread depths ... its the relative wear rates between them that helps get the correct cold pressures
OK .. bear with me here!
OK .. bear with me here!
So these are examples of plots I was referring to, tied to the oem Bridgestone RE050A RFTs over the course of their use on a 250 FWD from 3/31/14~5/12/19, covering 22044mi with no alignment change, no tread surface scuffing noticed (alignment ok), and standard air fills.
View attachment 64848
This is the overall tread depth data, center groove, to 0.1mm, and the inflection points are due to rotations. The overall front and rear tread wear rates are somewhat consistent, though after the initial year of use the rubber density variations start to show their effect and the trends diverge a little, but not too bad considering all the possible variables over >5 years. The wear rates (plot slopes) all slow down over time perhaps due to the rubber densities increasing from densification. Who knows what else.
View attachment 64849
These are the actual depth measurements at the beginning and at the end. The 4 data points per tire refer to the 4 grooves in the tread. The tires were never removed from the rims and the measurement point was always the same (at the valve position). The center grooves of course wear a little quicker than the edge ones, though with 35.5~36.0psi F and 31.5~32.0psi R (cold) the differential between the center and edge grooves seems minimized.
View attachment 64850
View attachment 64851
These two are the front (LF) and rear (RR) tire pressure examples, logged periodically over their lifetime. Figure about 11 pressure checks per month, including static pre drive checks, and warm post drive logs. The top dot plots in each graph are the readings taken at each point in time (with some variation in logged corresponding temperature of course) and the lower dot plots refer to the difference from the cold psi references. So over the course of time, the fronts averaged out to 37.5psi with a 1.74psi averaged variance from reference, and the rears 32.9psi at 1.10psi. Since the logged temperatures ranged from 33F (0.6C) to 86F (30C) and the measured pressure's temperature dependence was ~0.057psi/F, this overall data is about right.
Bottom line -- for the RE050A RFTs (225/40-18 UTOG 140 AA) driven in moderate climates on decent roads, with consistent cold pressure checks, good (unchanged) alignment, and rotations every ~7000mi, the cold reference of 35.5~36.0psiF and 31.5~32.0psiR yields very even tread wear, considering the tread material change and typical road conditions over 62 months.
Could have been worse, ay?
how does it go? once an academic always an academic?