Builds mcgaskins' 2016 build thread - Ruby (3 Viewers)

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Looking for a tire expert to help with something I find a bit confusing. I have 285/70/18 Ridge Grapplers now and the only thing I’d change about them is a little more sidewall height. Fortunately they are available one size up at 285/75/18, but the specs show they’re actually narrower in the larger size. @gaijin any thoughts as to why this might be?

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Couple things.

Note that this is the "overall width" dimension. It doesn't speak to tread width, which is very likely within spitting distance between the "285" tires. Overall width is the widest point at the bulge of the sidewall. It may be that the profile of the tire is somewhat more square.

More likely however. Note the "rim width". The number in parenthesis, is the rim width that was used to measure the dimensions.

On the 285/70R18, it was measured on a 8.5" wheel.

On the 285/75R18, it was measured on a narrower 8.0" wheel.

That likely is what's accounting for the majority of the .24" width difference. Very possible with the same wheel, the 285/75R18 is actually a tad wider.
 
Ouch 10lbs a corner extra. You're gonna feel that.

Ya 10 pounds per corner is definitely not ideal. I don't drive the 200 often though, and when I do it's usually for a long trip. I think the additional unsprung weight would bother me a lot more if I daily drove the truck, but I'm driving the Tesla 95% of the time - assuming my wife doesn't take it and stick me with her CRV 🤣


The Cooper ST Maxx have a smiliar size difference. About .5".
Doesn't really make sense to me either.
Interested in hearing the reasoning.

I like the ST Maxx a lot, but the only size I see that would get me the diameter I want is a touch too wide. I like the stock 18" wheels, and it looks like I'd have to go to a 12.5" width to get a 35" diameter which I think would cause rubbing. Tried a 35x12.50x17 on my 2014 with spacers, KDSS relocation, etc. and just ended up going to a narrower tire which solved all the problems. I like the fact it appears a 35" Nitto will only be around 11-11.5" wide, but reality may be different.

Couple things.

Note that this is the "overall width" dimension. It doesn't speak to tread width, which is very likely within spitting distance between the "285" tires. Overall width is the widest point at the bulge of the sidewall. It may be that the profile of the tire is somewhat more square.

More likely however. Note the "rim width". The number in parenthesis, is the rim width that was used to measure the dimensions.

On the 285/70R18, it was measured on a 8.5" wheel.

On the 285/75R18, it was measured on a narrower 8.0" wheel.

That likely is what's accounting for the majority of the .24" width difference. Very possible with the same wheel, the 285/75R18 is actually a tad wider.

Good eye. I didn't even notice they posted the measurements on differing rim widths, so I think you are right the 75 spec tire should be the same width if not a little wider on the same rim.
 
Still going through the Cruise Moab pics and videos and wanted to share some in this thread. Here is a video of the truck showing how well the multi terrain select system works on the 16+ trucks. I had the earlier system in my 14 LC, and I can confirm it did not work nearly as aggressively as it does in this truck. You can see slight wheel slip and the brakes working to stop it and send the power to the wheel that needs it. I was the first person in our group to go up this section, and the truck made it up easily on the first try without a spotter (just walked it first to see what it looked like).

When I came down to snap pics of the other guys in my group, a group of ~6 Wrangler Rubicons on 35-37" tires had lined up behind me to up the same obstacle. I figured it wouldn't take long at all for them to work through our group, but that was a very wrong assumption. The first Jeep took ~15 minutes and 5 attempts to climb it, and the attempts were not kind to the Jeep. The next couple were much worse and took longer, and I was afraid they were going to flop or break an axle or driveshaft at a minimum. I don't know what their skill level was, but I could tell they were VERY frustrated a 4runner/Sequoia/Highlander thing walked up the same section with zero drama.

 
And this video shows why I like these Ridge Grapplers so much. My buddies were running Cooper AT3 XLTs and Mickey Thompson MTZs, and they both spun quite a bit, lifted tires and took a couple of attempts to get up the same line. The Ridge Grapplers and MTS just gripped like crazy and made it look easy. I know people say any tire works well in Moab, but it was clear to me the RGs were working better than most.

 
@mcgaskins, what was your tire pressure in those videos?
 
@mcgaskins, what was your tire pressure in those videos?

I believe I was at 20 psi. I rarely go below 19 and rarely above 22 psi off road, and that seems to work great just about everywhere.
 
Matt, in the first video what "settings" were you using?
 
Matt, in the first video what "settings" were you using?

I was in rock mode with the CDL locked. I generally leave the CDL unlocked when wheeling until I need max traction while climbing, but otherwise it's off especially when going downhill or turning sharp. I also typically have the MTS set to loose rock or mogul until I get to an obstacle and dial it to a more aggressive setting like rock only for the obstacle then dial it back down again. Most slickrock trails don't need the rock setting because there's already great traction, but it's helpful on steep climbs with some loose sand on the rock.
 
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Looking for a tire expert to help with something I find a bit confusing. I have 285/70/18 Ridge Grapplers now and the only thing I’d change about them is a little more sidewall height. Fortunately they are available one size up at 285/75/18, but the specs show they’re actually narrower in the larger size. @gaijin any thoughts as to why this might be?

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Not a tire expert, but these were the other finalist after I ruled more aggressive muds out. Looking forward to your fit up and report.

I did do a gear ratio change to support the weight and diameter difference going 31 to 35.
 
Ouch 10lbs a corner extra. You're gonna feel that.

I agree with you, that less unsprung weight is always better. Interesting, it's not a big a deal as most think for our large rigs. In terms of ride quality or performance.

For example, I run 71lb 305/55r20 tires on my LX570.

Ride quality is still superb. Absolutely still Lexus like and passengers continue to be suitably impressed by luxury sedan levels of NVH (not even realizing the AT tires). In some ways, ride quality is better on account of more sidewall to absorb hard transitions or hits. Any loss of ride quality is more related to specific tires or suspension.

Performance in terms of acceleration and deceleration is damped to be sure. But that is more due to gearing losses and braking leverage losses from the larger diameter tire. Less due to any increase of rotational inertia as our rigs don't exactly accelerate like sports cars to spin up or spin down tires as frenetically.

Where the high unsprung weight is really felt is in high speed driving with high frequency bumps. More onroad than off, because when off-roading, the tires are aired down such that they can react and absorb many little bumps without major deflections. On-road however, the speeds can be higher and air pressures higher, where the large unsprung weight doesn't like to deflect in as quick of a frequency and can result in less traction.

On a sports car with quick inertia changes, where high speed and high force tarmac work is the name of the game, I'm all for optimizing every pound of unsprung weight. 👍
 
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With all the good tire sales for Memorial Day, I had to pull the trigger on some 35s. The 285/75/18 Ridge Grapplers should be here on Tuesday!

If you had 17’s, you could have bought my nearly new Ridge Grappler 35’s... Up for sale but unannounced...
 
Yeah baby! What offset will you use?

Just the stock 18” wheels with the .75” spacers which puts them just about perfect.


If you had 17’s, you could have bought my nearly new Ridge Grappler 35’s... Up for sale but unannounced...

These are barely 11” though so they should clear easier than the more common 12.5” width. I hope so at least!
 
Just the stock 18” wheels with the .75” spacers which puts them just about perfect.




These are barely 11” though so they should clear easier than the more common 12.5” width. I hope so at least!

Ahhh... Yes.
It was the width I had to get away from.
 
Yep. Skinny is in.

Yep.
I have decided that slimmed down or not...Bubba is still a Beast...even down a bit to 34’s with 285/75/17s... :) If I had 18” rims, I might have done what @mcgaskins did... (tall & skinny).

I’ve been pleasantly impressed with how these perform better all around.....and still look good...
D8185709-57AB-497C-8EA3-23D961034B8C.jpeg
 
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