Diet Taco... trying to keep things light

Awesome photographic work. Brings me back to my recent trip in my mind, and I'm sure encourages others to get out there and see DV. It really is a natural treasure and special place. My trip was only 6 days and reports like yours above remind me I only scratched the surface of what's out there. Can't wait to get back.

 

Fixed it for you.

 

Queen of Sheba mine is very cool. I've been twice. The last time I climbed the same hill you did, and explored some of the adits and mine openings. You have to keep your wits about you near the adits, lots of places to fall in and never been seen or heard from again.

Any wildflowers popping when you were there?

 

There's nothing I'd like more.

Not going to happen.

https://youtu.be/U3RXf0E_Vuw

 

Older definitely makes things steadily get better. Hope the rest of your year starts to suck less at some point!

I don't think there were any frogs in the photo, at least I looked around a lot and never managed to spot one of them despite there being noisy ones about. I do see a frog shaped shadow there though!

I've been going back for about 22 years! Never gets old!

Didn't really see any flowers at all, but was a bit early and a rather dry year. There were a fair number of desert holly with berries on them.

Right back at you! Waiting for your Sonoran Desert report...

Wait don't you already have your own "build thread" full of surrealist weirdness? I'd like to keep the Amazon recommendations at the bottom of this thread related to truck and camping gear unlike the "I Can't Believe They Invented It" stuff at the bottom of yours.

 

My bad. Don't want to muck up your thread. But in my defense, @DoorDing was taunting me.

Will this redeem me?
1.2 Ultraprecision machining In recent years, different methods have been investigated for fabrication of optical freeform surfaces in order to obtain high quality components. These techniques include diamond micromilling (Brinksmeier & Autschbach, 2004; Stoebenau & Sinzinger, 2009), ultraprecision diamond turning (Yi & Li, 2005; Yi, et al., 2006), diamond flycutting (Stoebenau & Sinzinger, 2009) and ultraprecision grinding (Van Ligten & Venkatesh, 1985). Diamond micromilling is an alternative to machining aspheric or complex lenses with small positive and negative curvatures. Diamond flycutting can be employed to generate optical elements with small radius of curvature and high aspect ratio. Ultraprecision grinding is capable of providing very fine surfaces but it is difficult to set 4 up and has relatively long machining cycles. On the other hand, diamond turning process is one of the widely used machining processes in optical industry, for example, well established fast tool servo (FTS) is applied in the area of contact lens and freeform lens manufacturing (Michaelis, et al., 2008). In a fast tool servo process, the diamond tool is mounted on a piezoelectric actuator which is capable of oscillating at extremely high frequency, and the oscillation position is determined according to both the radial and the angular position of the workpiece. However fast tool servo method also has limitations, such as the typical travel range is less than 1 mm (Tohme & Lowe, 2003). The approach used in this dissertation is slow tool servo (STS) diamond machining which is a similar but uniquely different process to fast tool servo. In slow tool servo machining, z axis slide provides the control in the direction of cutting depth. This arrangement allows large deviation on machined surfaces but has limits on the dynamic movement of the cutting tool due to inertia of the heavy mechanical slide used. The slow tool servo diamond machining can be easily applied to fabricate regular metal mold materials with optical quality, such as aluminum and copper nickel alloy. However, the machining on brittle materials, for example crystalline silicon, leads to micro fractures during material removal. Hence, ultraprecision machining of (crystalline) silicon has been studied frequently in the last two decades. The focus of the investigations has been largely on the basic understanding of the brittle to ductile transition (Blake & Scattergood, 1990). One of the key findings of these studies shows that a large negative rake angle is a critical process condition in reducing fractures and enhancing tool life (Blackley & Scattergood, 1991). In practice, diamond tool tip is simply titled against the silicon substrate, therefore the clearance angle is usually much 5 larger than the nominal value. Fang et al. introduced a concept of extrusion as opposed to shearing to explain the nanometer scale diamond turning mechanism (Fang, et al., 2005). A large negative rake angle increases the pressure on the substrate and resulting in threedimensional volumetric deformation (Patten & Gao, 2001). In a more classic view using shearing (plane) concept, energy is more concentrated on the shearing plane, generally a 2D scenario (Yan, et al., 2009). Therefore it is of great interest to understand and predict the damage distribution threedimensionally and further optimize the machining process when freeform optics is in consideration. In this dissertation, the subsurface damage model was modified to study 3D damage distribution in slow tool servo diamond machined silicon. The prediction of the 3D damage distributions on freeform surfaces were compared with experimental results and their close match demonstrated the feasibility of using this modeling technique to effectively assist freeform diamond machining on silicon or other similar brittle materials. In addition, the development of the damage distribution and two different machining strategies were analyzed in order to understand brittle material machining process and improve surface quality.

 

The bottom left corner of the picture. Half submerged rock in the center of the water looks like a frog to me.

It definitely gets easier. My 5yo won't let me go anywhere without him and he starts complaining if it's been more than a week or two without sitting at a campfire.

I'm hoping for one more trip to DV before it gets hot.

 

Ah! No, that is definitely just a rock. I checked that pool pretty carefully in person but I can see what you mean in the distorted corner of the photo there.

March 10 for my daughter and I. Fingers crossed for no spring windstorms while we are there.

 

Tire Wear

My presumption when I bought the truck was that my tires would age out before they wore out. That is the tires would need to be replaced because they were too old (don't use tires longer than six years past date of manufacture) before their tread depth became too small. I assumed this because the truck is pretty low mileage.

The first problem already written about was a bad alignment which ripped up two tires pretty good. Excluding those two tires though wear still has not been particularly great. New tread depth is 15/32 for these tires and of course 2/32 is the end of life of the tread. So there is 13/32 of wear to be had in the life of the tire. Because of the five tire rotation each tire has been on the truck for a different number of miles so far. In the table below are the miles run on each of the three tires not subject to bad alignment, the current measured center tread depth, what fraction of the total usable tread that represents and a predicted life of the tread based on the wear rate so far.

Mileage|Depth| Worn | Life
17,000 | 6/32 | 70% | 24,000
11,000 | 8/32 | 53% | 21,000
10,000 | 9/32 | 46% | 22,000

The poor tires that were on the front during the bad alignment are at 5/32 but they will bounce between a rear wheel and a spare so they should end their tread life at about the same time as the three listed above.

This is pretty sucktacular tread performance in my book. Maybe my standards are off though.

From a few references [1],[2] rough roads can reduce tread life by up to 80% and underinflation is a bear too. Naturally though most of my miles are on the highway at proper pressure getting to the rough roads where I then air down. That said Diet Taco probably has seen about 1,000 miles of aired down dirt travel so far. Assuming 80% derating of tread life for those 1,000 miles that means the tire that's been on the truck the whole time saw the equivalent of 21,000 miles of travel rather than 17,000 giving a equivalent highway service life of 30,000 miles. Better, still underwhelming though.

On the other hand this 15,000 mile report over on ExPo for a dedicated trail runner shows 12/32 remaining. Accounting for my smaller tire size would mean I'd see 11.5/32 after 15,000. I'm definitely well shy of that!

Worse still of course I have no desire to run a tire at 2/32 off road! So these tires are actually getting pretty darn close to the end of their life for me because I'd consider 5/32 or 4/32 to be time to replace.

So what went wrong? There are signs of running over-inflated. The three tires above do show a bit more wear in the center than on the edges. Chalk test would probably be in order. But even taking the slightly higher shoulder numbers the performance is still pretty poor.

Looking at reviews there seem to be a fair number of folks who came from the KO to the KO2 that have griped about much worse wear performance. The KO2 is actually suppose to wear significantly better on gravel roads than the old KO but particularly some folks with heavier trucks seem to be indicating really poor wear performance. There has been a rash of KO2s that can't be balanced as well. Maybe manufacturing issues? My KO2 were some of the very first manufactured in this size and the KO2 itself had only been out for less than a year. On the other hand clearly there are plenty of folks with KO2s that are wearing wonderfully and with a tire that gets sold as much as the KO2 we should expect reports from a handful of people that "have never had problems before" that happen to have bad alignment or drastically different driving conditions when they swapped to the KO2. Probably will never really know one way or another if my KO2 wore unusually quickly because of the manufacturing batch or it was just down to a stack up of "user errors" on my part.

The truck saw 12,000 miles of use for the one year we lived in CA. That's about three years of typical use now. So the reality is that even poor wearing tires that only last 25,000 miles would in fact age out on this truck in the future under a five tire rotation. Not this past round though!

I think I'll be replacing the tires in the fall. The early replacement is essentially an additional $300 cost over my anticipated replacement interval. The question is what tire to get. Right now it is likely either sticking with the KO2 or trying out the Cooper S/T MAXX. I'll be sticking with LT235/85R16 for sure though. Maybe in my summer doldrums I'll write up a post on all the tires I've been looking at and rejecting. My weird size preference does narrow the list down to begin with!

 

I don't think you'd go wrong with the Cooper S/T MAXX. I've had them on for about a year now with about 10K miles and show little wear. I have finally put them to use in snow and ice and performed incredibly well, but unfortunately they haven't seen much off road use.

 

I came from load C DuraTracs as well, no real noticeable difference in ride comfort.

 

I got around 50k from my set of Goodyear All-terrain Adventures with kevlar. They don't have a super aggressive tread but I've been all over DV with them and no complaints.

 

I get about 25,000 miles out of a set of KO2s (265/75r16). By that point they’re worn enough that I won’t take them off pavement. Tough and reliable otherwise, going to stay with them.

 

I have about 67,000 miles on my KO2s - 285/75-16 Load range E. This includes 15,000 miles of trips out west, 3 - 4,000 miles in dirt.

No complaints, except now that they are worn, they make some road noise.

I plan to replace them early this summer, in anticipation of this year's trip west. I will be replacing them with KO2s.

 

I have gotten 40-50k out of each set of KOs and KO2s that I have owned, and I usually change them due to age, not wear. I ran them on my old Dodge before getting the Tacoma. Always went with E rated.

 

Some years ago, when I had 2 trucks, I changed a set of tires due to age. Now, with only 1 truck, they just wear out!

I have always got a lot of miles from my KOs. I wonder how the E rating of my KO2s is affecting the mileage? Certainly doesn't hurt it...

 

Some folks claim a performance difference between C and E rated tires of the same size due to weight. Although I get the physics of it, and therefore believe that it's true, the difference is imperceptible to me. I went from factory Cs on my 2000 Dakota to the same size Es and didn't notice anything performance or mileage wise. Same thing when I went from the factory 31" D-rated KOs on my 2013 Baja to 32" E-rated KO2s. I went from right around 49 lbs per tire to just over 53 lbs. No perceptible difference.

 

I've always gotten 50k miles out of my KOs usually in D range with a relatively lightweight truck. I have the KO2s in E on my 2nd gen and expect to get the same. I've had five sets and only had one slow leak among them all. And that was from a nail when we were doing construction at my house. Every car got a flat that year haha.

 

Thanks for the S/T MAXX feedback! I think I'm likely to try them out next.

I'm sidewall obsessed (perhaps unreasonably so) and so restricting to tires with three ply sidewalls. That said these tires are lighter than the KO2 or S/T MAXX and sounds like good treadlife too. So a real sensible choice.

Going forward with my next set of whatever tire I'd like to get at least 25,000 before the tread is down to 5/32.

That's pretty impressive.

KO on my old truck always aged out before wear issues. Not sure what is up with my current set of KO2.

My previous experience was also with KO and I assumed KO2 would be the same or better. It seems for most folks that is in fact true. Not sure what was up this time.

Thanks everyone for the great feedback!

 

I’m sure you said it but why 235s?

Would moving up to 255s give better options?