You also have to consider the damping of a tire. A Double Down tire is stiffer than EXO but that doesn't mean it will have less grip because the heavier casing add damping too. We also tend to compensate by running less pressure. Certainly some tires feel stiffer than others but depending on the forces the tire experiences this can be a good or bad thing. A really light casing may mean you have to run high pressure and this usually gives worse grip.

Typically though I'd assume grippier rubber with a stiffer casing (and lower psi) will give more grip. The T9 vs T7 compound is going to make a much bigger difference than Grid vs Grid Trail.

 

Compound. And if you find I'm wrong, that soft rubber compound tire you buy won't last very long anyway.

 

Softer compound, thicker casing, lower PSI = more grip

Personally I pick a casing for how durable I need it to be... not grip. In certain brands/models, one has less leeway if you want softer compound. Some prefer thicker casings, in part, because they offer a ride quality in addition to being more durable.

 

I primarily ride along the Front Range of Colorado and am also a fan of Specialized tires. The Butcher is my go-to on the front and I've run it in Control, Grid, and Grid Trail casings (with and without CushCore inserts).

I can easily feel the difference in grip and rolling speed between a Butcher and an Eliminator, DHF, or DHR2 on the front of my bike. However - other than using slightly different air pressures - I haven't felt much difference between the various casings on the Butcher.

 

Interesting points about the tougher casing tires offering some dampening, hadn’t considered that. But the points about running lower pressures with a tougher casing are definitely good too. I’ve currently got a grid casing on the front and control rear and yeah I run pretty significantly different pressures to keep the rear from feeling too squirmy.
Honestly this whole thought stemmed from topping off my sealant the other night and seeing how beat up and sort of pointless looking my tubolight insert looked, so I also don’t mind the idea of going for a tougher casing and skipping the insert entirely.
Appreciate the responses!

 

Seems a bit backwards, running control on the rear, as that’s where the tougher casing or the grid makes sense.
On my trail bike I run Eliminators grid t9,f/ Grid Trail t7 rear, and Ground Controls Grid t7 f/r or just as a rear with the eliminator front.
On my family’s XC bikes I run a mix of Ground Control, Fast Trak, or Renegades.
you listed your bike as a trail/xc so I’ll stick with Control Vs Grid in T5vsT7, as they don’t make xc treads in Grid Trail, although I contest that the Ground Control needs to come in a Grid Trail for e-bikes and big boys!

Softer casing in the front will increase compliance over small trail chatter if pressures are low enough, think of the tire conforming around a small stick instead of bouncing off/over it. This will lead to spongy, folding cornering if the rim isn’t wide enough for the given tire size. 27-30id rim on specialized 2.35 is pretty good. Otherwise, higher pressure is needed, negating the weight savings.
a grid casing allows for lower pressure but may be less compliant over small chatter at the same pressure (compared to control) but may be a step up in durability/cornering. If grid allows lower pressure, it may be more compliant than the control (or even the 120tpi s-works) if higher pressure is needed to prevent folding. But if you’re a light rider with sufficient rim width, you can get away with a lighter casing in front for comfort and weight.
In the rear, I go with the toughest casing my desired tire comes in. But I’m a big boy and ride rocks/features often, your needs may vary, depending on the goals of comfort/speed/durability.

the fast Trak is an interesting case study for specialized, it comes in the most casings and compounds for their xc line. You can get a grid t5 compound for the rear, this would be the fast rolling compound with the tougher casing. Ideal for a rear tire.
but can also get a t7ort5 in grid and control, this gives you the option of same durability with grippier compound, or even lighter/more compliant casing with grippier compound options.
Then there’s the s-works t5/t7 combo in 120tpi. I don’t get to consider these lightweight tires at my weight, but am looking into them for my high school racer. Could be an awesome x front tire (only rear if duty and rider weight is low enough)

More of a brain dump than a cohesive suggestion, but hopefully some helpful nuggets of thought to help lead you to the right question or path for you

 

Seems a bit backwards, running control on the rear, as that’s where the tougher casing or the grid makes sense.

I saw your second post where you re-read my initial, but yeah I agree, I’d rather not run control on the rear. I think maybe they’ve added a couple combos recently because I’m 90% sure when I bought my current tires the renegade I have in the rear was only available in Control/T5 or Grid/T7. And I just remember thinking that was so odd because it seems like you’d want (as you say) the tougher casing but also faster rolling compound in the rear, but that Grid/T5 combo I swear didn’t used to exist in the renegade at least. (Ordered one yesterday, ha).
interestingly, it looks like for the Ground Control a control casing/T7 combo still doesn’t exist, which is probably what I’d consider for a front tire if it did.

You mentioned the S-works T5/T7 tires and I’ve considered those too but a lot of them seem to only be available in 2.2 and I’ve heard from the gravel side of things at least that the S-works casing is so flimsy it isn’t worth the weight savings compared to the regular one (which is a lot of weight in the case of the Pathfinders), could be different on the mtb side though I suppose?

Either way, I appreciate the thorough responses!

 

Re reading the initial post.
hard rubber/hard compound for rear:
renegade grid t5
Need more grip: fast Trak grid t5

soft(er) compound, lighter casing front, in order of fastest to most grip:
Sworks renegade, fast Trak, ground control
Too flimsy? Or need more grip?
Renegade and fast Trak are both available in control casing in t7, GC in control is only t5, need to step up to grid for t7, currently for the GC
If you need t9, now we’re no kk get trail/xc, we’re into trail/tech which points to eliminator
For reference: my kid races fast Trak control t7 front, control renegade t5 rear. May move to s works now that he’s getting more competitive and because we have a race-only wheelset, so can train with a heavier setup and race on the light.
Wife (slower and prioritizes grip) rides t7 GC front and renegade t5 rear. We have control casing on there now, but a puncture has me going grid when it’s time to replace.
we ride Midwest hard pack/flow, I tend to seek out the tech, and weight more, so I run a more aggressive setup, previously mentioned

 

Casing ? Compound ?

Nahhh... finding the right tire pressure = grip.

 

Good point, although I think the casing you choose would somewhat dictate what pressure you end up running. And between two identical tires with a soft or hard compound you’d probably go for the soft compound for grip even if you ran them both as the same pressure wouldn’t you?

Either way, I probably shouldn’t have mentioned grip in the title since that’s not totally what my question was, I guess I was more curious on when folks would choose a certain casing or a certain compound, or when they’d weight one more heavily than another if, as in the case of some spesh tires, you can’t have both of what you might want.

 

casing: only strong enough for the ride style and terrain. I'm in the camp that don't want stiffer casing. Stiffer casing reduce tire flex so it ride stiffer and NEED lower tire pressure to achieve the same comfort/grip. Flexier casing is easier to flex so it doesn't need as low of the tire pressure.
So... just get the most supple casing that can endure the terrain and ride aggressiveness.

compound: compound does not matter for loose stuff. It only make big difference when trying to grip rigid surface like rock, roots, wooden bridge, road etc. If the terrain include tricky hard slippery surface, get softer compound. If you ride loose dirt trail. Save rolling resistance and get hard compound.