Results 1 to 18 of 18
  1. #1
    mtbr member
    Reputation: GnarBrahWyo's Avatar
    Join Date
    Jun 2012
    Posts
    1,899

    Deflating tubeless tires

    Let's say you put maybe more pressure than you would like in your tubeless tire. If you let air out of the presta valve is goo gonna come out? Also, dude at bike shop to run my tubeless at 35-40 psi, all the threads I am reading say in the 20's. What gives?

  2. #2
    AZ
    AZ is offline
    banned
    Reputation: AZ's Avatar
    Join Date
    Apr 2009
    Posts
    19,998
    Rotate wheel until valve is at 12 o'clock to minimize sealant loss. If your not running ghetto tubeless I see no reason to run pressures that high if you don't want to. My two centavo's.

  3. #3
    Gumnut Peddler
    Reputation: Grinderz's Avatar
    Join Date
    Aug 2012
    Posts
    564
    40psi is way too much for on the trails in my opinion.
    Fine for riding on the road, but thats about it.

    Try dropping to 30psi, and go for a ride. Drop in 2-3 psi increments to the point where the bike starts to feel a bit squeamish. Add 1 pump of air, and test it again.

    If the bike feels awesome on the corners and you are not banging rim on rock/logs, then jobs done.

    I am not too sure about goo coming out, as I am running tubes at the moment. I guess deflating with the valve in between the 11 - 1 o'clock position would help with this.
    Burning fat, not oil.

  4. #4
    I just let one RIP
    Reputation: Jwiffle's Avatar
    Join Date
    Jan 2004
    Posts
    2,136
    You don't get much spray of goo when deflating, since the goo mainly sits at the bottom of the tire. Even if you deflate with the valve at the 6 o'clock position, the goo is still down at the bottom, so it doesn't really come out of the valve.

    Tire pressure can vary widely depending on the tire, the trail, and the rider's size and preference. I tend to ride my tubeless 2.3" wide 29er tires in the 25 psi range, and I weigh about 155 lbs. My 250 lb friend rides tubed 26er at 45 psi, because he's pulled the tire off the rim on corners with less pressure than that.

    Just play with tire pressure to find a spot you like...where the tire hooks up well, still rolls quickly, and the rim doesn't bang or pinch flat the tire (I've done that twice!)
    A ride a day keeps the therapist away.

  5. #5
    RTM
    RTM is offline
    #1 Latex Salesman
    Reputation: RTM's Avatar
    Join Date
    Sep 2005
    Posts
    1,576
    let out about 5 psi more than your end-goal, then pump the tire back up to your desired pressure. it should help clear the valve.
    "The bitterness of poor quality remains long after the sweetness of a low price is forgotten." - Benjamin Franklin

  6. #6
    mtbr member
    Reputation: Snfoilhat's Avatar
    Join Date
    May 2010
    Posts
    441
    I have been trying out 60 psi tubeless on my fourcross bike (on super smooth hardpack BMX tracks). Sealant loss is very low (+1 turning the valve to 12 o'clock).

    A single issue: one morning I inflated my rear tire to 60 psi, rode practice, rode my motos, and was sitting at the start gate for after-practice, and by then it was early afternoon and the sun had come out. The rear tire blew right off the rim as I sat at the gate, and man was I startled. So there is an upper limit, but it is way higher than the pressure anybody will use trail riding.

    Never mind the shop guy. Try the No Tube's formula as a starting point. Tire Pressure

  7. #7
    mtbr member
    Reputation: GnarBrahWyo's Avatar
    Join Date
    Jun 2012
    Posts
    1,899
    Thanks, guys! This forum rules!

  8. #8
    mtbr member
    Reputation: Tystevens's Avatar
    Join Date
    Nov 2011
    Posts
    1,557
    Quote Originally Posted by GnarBrahWyo View Post
    Let's say you put maybe more pressure than you would like in your tubeless tire. If you let air out of the presta valve is goo gonna come out? Also, dude at bike shop to run my tubeless at 35-40 psi, all the threads I am reading say in the 20's. What gives?
    A little bit comes out, but not too much to make a mess.

    Re: pressure, it is probably based on a couple factors. I run my tubeless around 30 front and 35 rear. I'm heavy, I don't want to risk dinging my rims and I don't want to burp a tire due to too low pressure. Most of my riding is in very rocky areas, and I don't want the rim to contact the rocks ever.

    Second issue is preference/feel. Maybe too many years of riding at 40 psi, but I didn't like the feel of the tires squirming too much the day I tried pressures in the mid 20's on a relative smooth trail to try it out. After a couple corners on firm dirt, I was looking down because it felt like I had a flat rear tire.
    '11 Specialized Enduro Expert for the trails
    '13 Felt Z4 for the road

  9. #9
    mtbr member
    Reputation: GnarBrahWyo's Avatar
    Join Date
    Jun 2012
    Posts
    1,899
    Quote Originally Posted by Tystevens View Post
    A little bit comes out, but not too much to make a mess.

    Re: pressure, it is probably based on a couple factors. I run my tubeless around 30 front and 35 rear. I'm heavy, I don't want to risk dinging my rims and I don't want to burp a tire due to too low pressure. Most of my riding is in very rocky areas, and I don't want the rim to contact the rocks ever.

    Second issue is preference/feel. Maybe too many years of riding at 40 psi, but I didn't like the feel of the tires squirming too much the day I tried pressures in the mid 20's on a relative smooth trail to try it out. After a couple corners on firm dirt, I was looking down because it felt like I had a flat rear tire.
    I am going on a trail ride tomorrow. Gonna try 35 psi and see how that works.

  10. #10
    mtbr member
    Reputation:
    Join Date
    May 2006
    Posts
    11,271
    Quote Originally Posted by GnarBrahWyo View Post
    I am going on a trail ride tomorrow. Gonna try 35 psi and see how that works.
    I start with about 30 psi front and back....

    I ride for about a month.......then the back usually starts to feel a little squirmy in corners etc....

    So I pump them back up to about 30 again and ride on.

    The goo doesn't spray out at all for me....course I don't tend to do it very often....

    Maybe at top of a particularly rock section if the tires are feeling a little hard.

  11. #11
    Suckin wind like a boss
    Reputation: big terry's Avatar
    Join Date
    Apr 2012
    Posts
    2,062
    I weight 235ish naked, so I probably push 245 on the bike. I run mavic 819s (true UST wheels) with maxxis ignitors (bad choice for this time of year but whatever.) I tried running in the high 20s/ low 30s, but would burp a tire every time I rode. I blew my front on a night ride and ate it pretty hard and that was it for the low pressures for me. Now I am back in the high 30s front and rear for the time being.

    The size of your tire will definitely play a part. My ignitors are a 2.1 nominally but they are smaller than any other 2.1 i have run; thus they are a lower volume tire and (for me) require higher pressure to stay in the sweet spot. I could run lower pressure in a higher volume tire, but maybe only a few pounds lower since I can barely squeeze a 2.35, if I am lucky.

    As far as the stans leaking out? not even when I burp one or blow a bead, but then again I dont run that much stans anyhow. I usually seat mine at 60 pounds and let em sit overnight before i deflate them to ride, and never even worried about where the stem was when i went to bleed off some air. even if the stem was at 6 o'clock, you shouldnt have so much stans in your tire that it would squirt out.
    If you arent bleeding, you arent riding hard enough.
    http://about.me/bigterry

    Quote Originally Posted by Hutch3637 View Post
    I don't need sex. My life fvcks me daily.

  12. #12
    mtbr member
    Reputation: GnarBrahWyo's Avatar
    Join Date
    Jun 2012
    Posts
    1,899
    The range of tire pressures I have seen here has been large. I assume the skinny little XC dudes run PSI in the 20's because of the gentle XC terrain and their weight. I weigh 185 and like to get fairly technical. I don't like a mushy tire because it makes me feel sluggish and like I have a flat. I rode around my block at 40 psi last night and the high pressure made it so the tread was loud on the pavement. Going off of curbs felt like I had less suspension than I really did. Still getting used to this tubeless stuff...

  13. #13
    mtbr member
    Reputation: Saul Lumikko's Avatar
    Join Date
    Oct 2012
    Posts
    1,166
    In addition to the traditional question of tire volume, it's also relative to the riding style and weight.

    The goal of adjusting tire pressure is not to go low (MTB paradigm) or high (road paradigm), but find the sweet spot where you are taking advantage of the tire volume (smooth riding, better traction) without damaging your rims or destroying cornering performance.

    Because it's easier to notice the effect of too little pressure, we drop the pressure until it's too low and increase a bit from that. Lowering pressures is not a goal, it's a means to an end. What we hope to achieve is the right pressure, not too low or high.

  14. #14
    RTM
    RTM is offline
    #1 Latex Salesman
    Reputation: RTM's Avatar
    Join Date
    Sep 2005
    Posts
    1,576
    Quote Originally Posted by GnarBrahWyo View Post
    The range of tire pressures I have seen here has been large. I assume the skinny little XC dudes run PSI in the 20's because of the gentle XC terrain and their weight. I weigh 185 and like to get fairly technical. I don't like a mushy tire because it makes me feel sluggish and like I have a flat...
    The best advice I can give is to figure it out what you like by riding and feel. It really is a personal thing. Contrary to what you were thinking, XC guys usually go firm for less rolling resistance. DH riders go as soft as possible to allow the tire to wrap around rocks, roots. I've got the DH background so for me, low pressure feels right. High pressure freaks me out. My friends on our weekly trail rides think I'm tempting the pinch flat gods, but to me it feels good. I work a little harder on climbs I'm sure but it gives me confidence on fast descents. Especially in corners. Once you get that prefect pressure for you, you will know it. After a while you wont even look at a gauge. Just give the tire a squeeze and "thats about right" and off you go.
    "The bitterness of poor quality remains long after the sweetness of a low price is forgotten." - Benjamin Franklin

  15. #15
    Bro Mountainbiker
    Reputation: Sheepo5669's Avatar
    Join Date
    May 2010
    Posts
    3,507
    Be careful letting it out at 12 o clock. If you get it on your rotors you will not be happy.
    Raised in a Chicken-Coop by Chickens

  16. #16
    Tool
    Reputation: Pedalphile's Avatar
    Join Date
    Aug 2008
    Posts
    1,978
    Quote Originally Posted by Sheepo5669 View Post
    Be careful letting it out at 12 o clock. If you get it on your rotors you will not be happy.
    It does not matter what position the valve is in when you let air out. What is most important is to make sure the valve stem has been drained of sealant before letting air out. This is why the positions between 9-12 (clockwise) can be problematic: even though the sealant is all at the bottom of the tire, if the valve stem has some sealant in it when you purge air, sealant is going to start gunking up the valve.

    -Pete
    I can barely get my mouth around it.

  17. #17
    mtbr member
    Reputation:
    Join Date
    Aug 2010
    Posts
    381
    I usually just stick a screwdriver in the sidewall to release some pressure...it seals up in no time and I ride away...

  18. #18
    The Original Suspect
    Reputation: HitmenOnlyInc's Avatar
    Join Date
    Jul 2012
    Posts
    1,363
    My riding weight is about 165-167 with camelback and all. I run 25-30 lbs ghettos style...never had a burp.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •