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Discussion Starter · #1 ·
I first saw prototypes of the 26" tire at Eurobike last year. Now the 29" end product sits on my desk in front of me. 2 tiny rolls of tire. 464 or 465g and 467 or 468g, depending on which difital scale I trust best.

I can't wait to test them on my favorite trails and in the races, but from what I know about tires, it's hard for me to imagine these performing any less than tires being used to win national races, such as Maxxis Flyweights and Continental Twister Supersonics. After all, the 29" size helps a bit too.
This low a weight for a non-skinny tire that is also tubeless-specific, that's HUGE. The closest thing to it in the 29" world are the Kenda Karma's, and those are a very fresh offering. My set weighs 1070g and already a huge leap in terms of racing performance compared to which previously were the best raceable tires.

Already before riding the Crows, I'm sure these tires will change the whole view on 29" bikes by racers and other 26" holdouts, if they just test a bike with these mounted. The weight gap between 26" and 29" race bikes just got another big chunk taken out, a good 100g over the Karma, which already was some 150g lighter per pair than tires such as the Specialized Fast Trak and Maxxis Ignitor.
And tubeless, which cuts some 8W over tubes right there!
With such specs, a tire can almost only disappoint, quite something to live up to. Holding them in my hand, they seem really well thought out, and well made.

Stan and Mike at NoTubes deserve the highest credit for taking on this challenge, and setting such high standards for themselves with a first attempt on a tire. Ride reports I got were very promising. Where last year I was in advance sure a Crow would only find it's way to my rear wheel, I already feel comfortable putting it on the front as well, even a fully non-directional tire.

I hope these tires will soon prove to be the best on the market in 26", as then 29" will finally have an edge, where since it's birth in '99 there has been a significant technological lag. It started out with 700+g wire bead WTB Nanoraptors (still popular BTW), and we have these 464g tubeless tires. Amazing.

If only half my dreams come true, I'll win a minute per one-hour race just from the lower rolling resistance over tires I ran previously. Yes, weight is a factor, and my bike could now dip under 8kg if I really tried, but the performance will come from the tubeless and low tread.

The casing spread flat out is some 132mm wide. apparently the 26" version is wider. But then, 26" wheels need more meat to find the same comfort, grip and traction anyway. But, resistance is futile.. :)

More reports later. I hope to conduct semi-scientific rolling speeds tests. I have this cycling tunnel under a river just 1000m from my door, an excellent venue to test rolling speed, with constant wind conditions (it's not zero) and fast rolling enough to carry out tests at low speed, elimination most of the air drag. Testing on dirt will be just as important though, as that will tell more about the tread pattern, the tunnel mostly addresses the casing.
 

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Discussion Starter · #2 ·
Think so? I guess that would depend on rider weight, pressure and riding surface.
I think a Nano is little wider than a Crow. Spread out flat, there's less than 10mm between a stretched kevlar Nano (the kind that wrecked even with tubes) and my fresh Crows.

For me, the Kenda Karma's are much faster offroad than wire Nano's. Front tire also grips better for me. I'm 180lb and ride them just above 30psi. I'd run Nano's just under 30psi, probably because of the less compliant casing. Casings are both 50mm.

I'd be interested to hear why thick casings would roll faser. Doesn't deforming an n amount of tire material create an x amount of rolling resistance?

With your theory, shaved down DH tires should be the fastest men could make? I bet you can find DH tires with worn tread for very low costs and lower mileage just about anywhere.
 

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At 180lbs make sure you don't make the same mistake I did w/the Crows. I started out with like 25lbs and promptly burped out all my air from the front on a small drop and went down hard. Put in five more lbs and was doing great until I went through a rock garden too fast and promptly destroyed both of my ZTR rims. I run em at 38lbs now. There is very little meat to these tires so I find I have to run em at a much higher pressure then my Ignitors. At your 180lbs I'd start out with more then you need and bleed off until you find your sweet spot. These tires are FAST.
 

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Discussion Starter · #4 ·
I'm an extremely smooth rider (I think). I'm the heaviest racer around, but run among the lowest tires pressures. since I have older ZTR rims, I'll be using the 57g rubber strips provided with them, which should reduce burping to zero. I run my Karma's just around 30psi I think, depending on the course. Our courses are quite tame though, few impacts, and I even race rigid mostly. Even my Karma's never burped, though I definately used too little and too diluted a latex mix, which saw them going soft faster than I liked, I replaced the goo with tubes one race by one.

For me the 29" Nano's never matched the rolling speed of 26x2.35" Schwalbe Fast Freds in qualifier compound. Even the grip of the Fat Fred was better than the 29" Nano's, which gave me nothing but understeer.
There are rumors for both wider versions of the Karma and Crow, either I would welcome a lot. A bit of weight for a lot of volume and grip. IMO wider is only faster, but to mate that to thick casings just seems wrong. tell CX racers that ticker casings are faster, when no-one's won a big race on anything but custom Dugast tubulars in years :)

A friend of mine (despite going back to the dark 26" side) now runs 650c x 43mm Dugasts with Michelin XCR Dry treads. 500g each. Smaller, narrower, heavier. He rolled one off the $$$ 24mm wide carbon rim at a recent race.
BTW, Dugast now offer 700c x 45mm casings. Someone could just bring them a set of Crows and really have something special. it would require wider tubualr rims than we have now though, I'm afraid. I've working on sketches for a tubular rim strip that creates a wider surface for the tubular tire to sit on.
It will be interesting to compare, a 700c fatty tubular with Crow tread and latex innertube vs. the real thing, NoTube.

My friend does say the Dugast XCR Dry feels like gruel to the trail, and he runs it at really low pressure. Can't say I find him fast on it so far, but it sure is a kinky setup.

But why mess with $200 tubulars when you can get $40 Crows?
 

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Are you aware of any real RR data yet for the Crows? I put in 4 hours on them yesterday on the same terrain that destroyed my rims. This time I was more prepared w/higher tire pressure and a bit of restraint through the rocks and drops and log rollovers. The more I ride them the more impressed I am with these tires. One thing is really clear to me, though- I really need to have lots of air in the rear to avoid that squirmy feeling in hard cornering and accelerating out of corners. A larger volume version would be interesting.
 

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Discussion Starter · #6 ·
Only Germans do testing on tires, it seems?
On the Weight forum someone set up ways to quantify RR by finding the tires' natural top speed (forgot the term) down a hill. You need to know the exact slope though, and multiple slopes to compare top speeds between.

I'm planning to just mark a line in a tunnel (no real flat bit in the middle, right back up, ever so gently) to start rolling from. and then for various tires and pressures line on the other end to where they managed to roll. Or maybe time a downhill drag sprint (let go of brakes on "go"). Really gentle hill, my tunnel again. Low speeds, long times, might be a good chance to measure differences and half weight and air drag be quite small factors, as well as consistent ones.
 

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Good to hear you're still gonna do this test.

(I only worry that you're SO excited about this tire, that your enthusiasm is going to find a way into the measurements.) I think the advantage of doing a test based on timing will be that your ability to ride straight at the end will not be a source of error, as with the roll-out method. However, it's possible the times will be seperated by small margins, and that you will need a second person with a stopwatch. Either way, I think you'll need to do a standing start, and have an object or person from which to stabilize yourself at the start. Is that what you're thinking?

Thanks.
 

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Jesseg said:
(I only worry that you're SO excited about this tire, that your enthusiasm is going to find a way into the measurements.) I think the advantage of doing a test based on timing will be that your ability to ride straight at the end will not be a source of error, as with the roll-out method. However, it's possible the times will be seperated by small margins, and that you will need a second person with a stopwatch. Either way, I think you'll need to do a standing start, and have an object or person from which to stabilize yourself at the start. Is that what you're thinking?

Thanks.
Wondering....how does tire pressure affect RR? That is, if you run different pressures in the same tire I assume it will have a "sweet spot" at which it rolls the fastest. Will this "sweet spot" remain constant across tires or will this vary?
 

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Axis II said:
Wondering....how does tire pressure affect RR? That is, if you run different pressures in the same tire I assume it will have a "sweet spot" at which it rolls the fastest. Will this "sweet spot" remain constant across tires or will this vary?
I have done a lot of "bicycle science" (and this is an accepted term) reading. From what I have gathered (there is not a lot out there in this field), I think...

For the purposes of the test on pavement, you just have to pick a pressure that you think you could get away with on dirt (that is, keep it low, but not unrealistic) and keep it the same across all the tires in the test. To do slightly more justice to your question, I think that for a given rider weight, hardness of dirt, and frequency/average-size of obstacle, every tire will have an ideal sweet spot for that ride. The reason for this is based on differing tire volumes and on casing elasticities across tires.
 

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Axis II said:
Wondering....how does tire pressure affect RR? That is, if you run different pressures in the same tire I assume it will have a "sweet spot" at which it rolls the fastest. Will this "sweet spot" remain constant across tires or will this vary?
The "sweet spot" you mentions really only exists on dirt and that sweet spot will vary greatly, mostly depending on the softness and the roughness of the dirt, but also on the tire.

With the test Cloxxki was thinking about, on pavement, higher pressure will always have less RR ....to a point, but this point is probably above the recomended max pressure of the tire. I've seen tests of RR of road tires where they all decresed in RR with an increase in psi up to about 120-150 psi, when they started to increase in RR. I think at those pressures the irregularities of the pavement may have become an issue. On a smooth wooden track, I doubt you'd have that problem.

On pavement, generally wider tires require a lower pressure to have equal RR to a narrower tire (everything else equal) If the pressure is kept contant, the wider tire will almost always have less RR (again assuming everything else equal)
 

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grawbass said:
The "sweet spot" you mentions really only exists on dirt and that sweet spot will vary greatly, mostly depending on the softness and the roughness of the dirt, but also on the tire.

With the test Cloxxki was thinking about, on pavement, higher pressure will always have less RR ....to a point, but this point is probably above the recomended max pressure of the tire. I've seen tests of RR of road tires where they all decresed in RR with an increase in psi up to about 120-150 psi, when they started to increase in RR. I think at those pressures the irregularities of the pavement may have become an issue. On a smooth wooden track, I doubt you'd have that problem.

On pavement, generally wider tires require a lower pressure to have equal RR to a narrower tire (everything else equal) If the pressure is kept contant, the wider tire will almost always have less RR (again assuming everything else equal)
Thanks. That answers my question. Maybe the best approach then is to run the test at the highest possible pressure? I dunno....:confused:
 

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couldnt agree more

Axis II said:
Are you aware of any real RR data yet for the Crows? I put in 4 hours on them yesterday on the same terrain that destroyed my rims. This time I was more prepared w/higher tire pressure and a bit of restraint through the rocks and drops and log rollovers. The more I ride them the more impressed I am with these tires. One thing is really clear to me, though- I really need to have lots of air in the rear to avoid that squirmy feeling in hard cornering and accelerating out of corners. A larger volume version would be interesting.
they are squirmy at low pressure, need bigger volume. mike at no tubes is saying mid 20's
for pressure. no way, they feel flat and squirmy. i couldnt get 1 to seal so i am back to latex tubes which i think allow lower pressure because they provide structure for the tire.
 

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Axis II said:
Maybe the best approach then is to run the test at the highest possible pressure? I dunno....:confused:
Run the pavement test at a pressure that you would usually like to run on real dirt. This is to guage the casing's resistance to rolling at the pressure you will actually be using it at. If you pump them up extra, you will learn less about how the casing (and tread-squirm) behave at the pressure you care about. More importantly, higher pressures will minimize differences between tires, and therefore increase error variance. Most of the difference in rolling resistance between tires comes from the casing construction, and can be measured on pavement. And because pavement decreases the error that will find its way into this ad-hoc test, this is the best we can do.

BTW, I agree with everything Grawbass said in his last post. Consensus, Yay!
 

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dmrun148 said:
Anyone have much riding time on the Crow? I am interested in getting a set. I ride mainly hard pack and sand here in AZ.
I dunno about the sand but they rock on hardpack. I've got maybe 20hours on them between the 26er and 29er versions. I'm riding both now as my main tires. I don't know if I could go back at this point unless I find really wet conditions. Try em.
 

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Follow up on the Crows: Ok, these tires rock. I raced my first race on em last night and won. I ran 35lbs of pressure for my 165lbs. I was passing people on the climbs much easier then before. I had multiple attempts where people tried to sprint past and I was able to out-accelerate them. The difference was palpable. I look at this tire as a race tire. It races well. It's not your all-conditions tire like the Ignitor/Exi. Use it if you want to go fast and not if you want something to do everything or handle epic rides. It's staying on my rig for races.
 

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i am a 160lb expert

racer, and these tires are a handful off road unless you are on smooth hardpack. even then
they are very sketchy under hard cornering. they slide all over roots and rocks unless you
are going in a perfectly straight line, small volume allows the tire to sink in sand instead of
float. they may work better if you can run like 25lbs, but they feel extremely squirly at
that pressure, like the tire has no structure. i am back on the nano for racing. the nanos
tread pattern rolls faster but you can feel the xtra weight compared to the crow. my perfect race tire would be a nano "lite", same volume as the current one with a little less
material in the carcass, 127 tpi, stronger bead, tread half as tall as the current one with a
weight of 575.
 

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Cloxxki or others,

How's the Rolling Resistance test coming along? I would love to see some results, even if the pavement test doesn't make the Crow look like the fastest tire out there.

Please, please, please, please, please...
 
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