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I got specialized s-works captains with my stumpjumper and am toying with the idea of going tubeless with Stans. a couple of questions:

1. generally, what type of weight can i expect to shed from moving to tubeless (i run standard bontrager tubes and would replace the stock rim tape with Stans tape)?
2. I've read that running a lower PSI is a benefit of tubeless. According to the tire specs, it is rated for 35-65 PSI. I am only 5'8" 155 lbs so i typically run between 32-35 as is is. Would i want to try going even lower than this? i don't want to risk a sidewall failure if i can avoid it.

Thanks for any info!
 

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gnuH
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I'm 150 lbs and run my 2.2 s-works captains (on Mavic ST rims) at 27 psi front and 29 psi rear. So far so good with no roll-over or burping. I ran my 2.3 Eskars at the same pressures also with no probs.
 

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abernard said:
I got specialized s-works captains with my stumpjumper and am toying with the idea of going tubeless with Stans. a couple of questions:

1. generally, what type of weight can i expect to shed from moving to tubeless (i run standard bontrager tubes and would replace the stock rim tape with Stans tape)?
2. I've read that running a lower PSI is a benefit of tubeless. According to the tire specs, it is rated for 35-65 PSI. I am only 5'8" 155 lbs so i typically run between 32-35 as is is. Would i want to try going even lower than this? i don't want to risk a sidewall failure if i can avoid it.

Thanks for any info!
1) I run the Captain S-Works, and being somewhat of a weight weenie, I weigh all of my parts before they go on my bike. The Captain S-Works 26'' 2.0's were 520g and 520g (1.146lbs). Specialized has been getting a lot better with consistency of their tire weights within the batch.

2) PSI is kind of hard to determine over the internet, you would need to experement with tire pressure yourself. I am 5'10'' and 155lbs. On my Cannondale Rush I run a Stans Olympic wheelset. I run 27 psi in the front and 29 in the back. PSI is a very rider specific thing. You would have to run the PSI and see if it feels good to you. Judging by your set up, it would probably be a bit higher than my PSI, I would guess about 30-33. I would take a mini pump with a PSI guage on your first ride with the tires and ride the same portion of the trail to eliminate variables between the tests and change the PSI. If you wash out in corners, its likley that the PSI is too high, the tire needs some room to flex so the side knobs get a nice solid contact with the dirt. Make sure you never excede 35 PSI, I have a buddy that blew a Specialized Sauserwind 1.85 off is ZTR Olympic Race set...we couldnt hear for like 5 min, then again he was filling it up with our shops air compressor and probably put like 50 PSI in. Luckily his tire just blew off the rim and didnt explode. Never overinflate the tires, it can be pretty bad for the tire and the rim. As I said before, with the set up that you are going to run, I wouldnt excede 35 PSI (unless someone suggests it who has more personal experence with the Stan's rubber kit).

3) Heres where it gets tricky:

I think the bonty tubes are about (I think) 250g (.551lbs), I can weigh one later to confirm. Thats almost 500g (1.146lbs) in tubes, which is about 1 Captain S-Works. The Stans rubber rim strip is probably like 50-75g (.110-.165lbs) (I've never weighed one, so if anyone else has please correct me). This tubeless conversion could save you a lot of weight, but I could not fully determine because I dont know what tire you run on your bike.

EDIT:

I weighed the tubes and the weights were inconsistent. I weighed 2 of the same tube with a .02 gram band holding them in place.



 

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The S-Works Captains are between 550g and 565g each. Very light, and fast rolling- for a tubeless-ready tire. You only need about 50g of Stans per tire, to go tubeless and they will give you no problems even running them at 28psi.
 

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Zachariah said:
The S-Works Captains are between 550g and 565g each. Very light, and fast rolling- for a tubeless-ready tire. You only need about 50g of Stans per tire, to go tubeless and they will give you no problems even running them at 28psi.
The newest batch is about 520. We just got some more in at the shop I work at.
 

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The Specialized TheCaptain S-Works 2Bliss are tubeless-ready tires, meaning that they're not true UST. They have tubeless sidewalls and a standard tread/carcass. Using sealant is an added security for better sealing of the rim/sidewall junctions as well as, of course, preventing flats. Even a true UST tire can benefit from pouring some sealant inside, though.
 

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kneecap
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It's my impression specialized tubless ready tires have only a Kevlar tubeless bead, rest of tire is a standard rubber compound. I love my captains & eskars, they seal up magacailly. Probably would work without sealent, but I use it just for the cover your a$$ protection.
Specialized has really hit a home run with this technology.
 

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So in other words a true UST tire combined with a UST rim should not need any form of sealant added, but people do so just for added security and the ability of the tire to seal itself in the event of a puncture.
 

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mightymouse said:
Is the 2.2 captain a true 2.2? I normally run a 2.3 Conti Vertical on the front/rear and don't want anything narrower than that.
The Specialized tires tend to be bigger than the «average» size, meaning they're true to advertised size (of course, it depends on the rim you're using too).
 

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I'm running the 2.0 as they run on the large side. I love them, great grip in just about everything! Side walls do seem to be on the thin side so durability is in question but thus far no issues. Plus there pretty light.
 
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