( and no, there is no entry in the reviews section yet or I would have put this there )

[ and mini- means mini-time not mini-writeup, just for clarity as I got poo'd in my home forum for this idiosyncracy ]

First off, I am accustomed to the Continental Tires having a good tire coumpound, that tends to wear well and have better than average grip - particularly in wet / rooty conditions, but have never been in love with their over-sized specs ... a 2.1 is usually more like a 1.95 or 2.0 in tire volume for example.

Not quite so with the Diesel ... it stacks up nicely against the WTB MotoRaptor 2.4 that my friend Schippers rides and appears to actually have slightly more casing volume and to have slightly wider tread. Note that this just eyeball tests at the trail with the tires head-2-head though, nothing scientific.

For those who don't know, I'm a substantial fellow - weighing in comfortably over 200# w/o gear, and ride a 31# bike that is built such that choices of durability vs lightweight went into the durability camp. I ride aggressive "technical" xc trails mostly, lots of rocks 'n stuff, mostly in Central Texas at this point. Both me and my bike like to cruise downhill at speed. As such, reasonably strong tires that have good sidewalls, non-squirmy tread, and rim-saving tire volume are things I look for. Having "fast" tires in nice but a decidedly secondary concern as I don't mind taking longer to get "there" and enjoy the whole trip w/o equipment breakage.

By the web-site, the Diesel 2.5 tires come in at a relatively portly 800g, but since I'm accustomed to about the same weight on a 2.4 Motoraptor I did not consider this bad. The fact that the Diesel has shorter knobs, more volume, and a higher tpi casing (170 vs the wtb's 60 IIRC) means that the tire SHOULD be more supple at even higher pressures ... giving me more lattitude with rim-saving PSI w/o losing traction.

The last four days of riding have born this out, and while this is just an early review and by no means definitive, I'm going to give these things an early thumbs-up.

Now, before you rush out and buy some keep in mind that ... 1) they are big, like >60mm wide and bigger around than a 700x38 tire in outer circumference; 2) they are about 800g w/o tube; and 3) big tires look good on an MTB. :P

Ride impressions ...

ride 1 : off-camber loose, steep climbs and descents

Rode with the tires at about 30 psi since it was a slow-paced less-rocky ride. I figured I could always pump a bit more pressure in if necessary, but in the end didn't feel the need. Trail was best characterized as a sequence of mixed off-camber tight singletrack with some good fall-line switchbacks, rocks, roots, g-outs, and some other stuff put in just to keep you on your toes. I never felt any issue with getting the wheels moving (e.g. they did not feel heavy), I never noticed any tire slip, either straight-line or off-camber, whether climbing or descending (e.g. braking), pretty impressive. Pretty much held the line I pointed them at, with the tire volume they handled the rock stuff with grace and did not let go under high-torque mini-slab climbing or even climbing in some of the looser leaf- and scree-infested stuff. Very happy ride.

ride 2 : Flat Rock Ranch, big loop (Red), fast hardpack, some loose, some mud

Seeing as I knew this trail (mostly) and knew that there were sections where I would be letting the Quasi roll itself out (speeds over 25 mph WERE in fact clocked) I aired up the tires to 40 psi to ward off the evil snake of the bite.

Tires rolled pretty dang fast, I gotta say. Even at 40 psi I felt confident in the cirnering and was able to hold onto lines and simply carve turns (felt a bit like skiing, truly) at speed in many places. Climbing traction on the hardpack and the rocks was truly strong, never had tire slippage once, which was fabulous. I ended up having a flat about 2 miles into the ride, but it was a thorn puncture that near as I can tell I picked up the night before ... which yielded another nice piece of info that the tire even when very low on pressure (rear tire, down to probably 15-20 psi) still held on strong and did not wander and still had good rim support.

Of course, airing up a tire like this after fixing the flat was much easier with a co2 cartridge. Still took about 40 pumps off my Blackburn Mammoth mini-pump to bring it back to full pressure, but it was worth it as the rest of the day was blemish free.

There was the predictable lessening of tracking on loose stuff, but at 40psi I was expecting much more tire bounce and skibble over the little stuff than I got, so kidos to Conti for that. I figure if I had run 35 psi here it would truly have been "the bomb."

ride 3 : BCGB Social featuring Travis Country, Cheesegrater, Jedi, and some main trail

Today, I'm riding with slime (okay, Specialized Airlock) filled tubes 'cause apparently the Thorns Have Arrived And I Hat Flats, so there's a bit more rotating mass on the wheels.

This was a long meandering slacker-paced ride in many ways, punctuated by faster and more energetic sections both up- and down- hill. The tires were aired at 35 psi for the rear tire and 30 psi for the front ... I normally run a few more # in the back tire to make up for, er, rider presence, yeah, that's it, rider presence. This ride features a nice smorgasboard of conditions for the BCGB related trails ... good bumpy rocky climbing (pumping station, cheesegrater), fast paced loose 'n rocky-ish downhills (jedi sections), and a general mixture of other stuff. The Deisel's just railed the whole time ... just ask Bizarro as he was following me down some of the faster sections and was commenting on how well the tires were holding the line. I never felt that at the pressures set that I was having any tire squirm, nor did I feel like they were ever bouncing off of anything inappropriately. There was only one climb that I blew totally - that steep one just before *that* switchback on upper Jedi - but then I so rarely make it any distance up that, just too many pizza slices on board. Other than that the tires never ever let go. Acceleration was good, rolling was consistent, bumpy climbs were handled easily, they didn't slip off sloped rock, pretty good.

Only one more really different trail type to test ...

ride 4 : City Park, fast loop, hardpack, scree, babyheads, rock ledges and some off camber stuff

The Diesel's Rocked.

What can I say.

Still running the 30/35psi from Sunday. Climbed all my usual stuff, plus a couple bonus obstacles. No probelm with the short bombing run down from The Bench, made it 1/2 way up the Cheesecake Challenge, which is better than average, and more importantly the turn 'n climb at the bottom was a total traction fest ... for tires hooking up like this I like the phrase "holding on like rabid badgers."

No problem with short accelerations, e.g. turn 'n climb ledgework, no feeling of lag- or energy loss. Just traction moving forward.

Fast flat sections were brought up to speed quickly and were easy to hold at speed ... 800g tires have inertial that does work for you after all.

Traction was consistent at all lean angles, I never ran out of tread to hook on, either accelerating or braking.

Tire wear so far ... so we've put about 50+ miles on them in about four days, not all of the "nubblies" are gone yet ... not even from the main centerline tread of the rear tire. The small steps on the knobs are still all present, so signs are good so far. We'll see how they look in another month.

web site:

http://www.conti-online.com/generat.../diesel_en.html

tires to compare against, in my limited experiences ...

WTB MotoRaptor 2.5
Kenda Blue Groove 2.35
Kenda Nevegal 2.35
Kenda Cortez 2.4
Geax Sturdy 2.25
Specialized Adrenalin Pro 2.2