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Ripping tires off-Problem

demo 9

demo 9

Turbo Monkey
Jan 31, 2007
5,910
46
north jersey
Bit of a long read, but i think it may help to solve the issue. I cannot stop ripping tires off the rims while riding-no idea why :confused:

*been tubeless since 2006, only burped 3x since then-period, and none of them enough to get the bead off
*tubeless on all of my bikes except the dirt jumper.
*generally run 35-40 PSI-none of these occurred with less than 35 psi
*rear tires only-so far


All of my DH life-i have ran mavic 823s, this year i swapped to stans Flow EX rims. Seated up really easy-good so far. First race out (duryea DH) raced the hell out of them, sent the jumps, did very well-tires held up perfect. Race #2 was mtn creek GRT. Friday practice and saturday practice were all good. Sunday AM practice i blew the tire off in a tight rocky chicane. I was really pushing the bike-we can say i deserved that one. Re-seated it up and it was fine for the race. Next race was platty GRT, no burps, but it was a slow mudfest, and there wasnt really anything crazy. Next race comes mtn creek GES #1. Saturday practice i come hauling into a rock garden, boom, tires blows off and i ride the rim for 100 feet trying to stop. *rim holds up pretty good*

After sunday's race, I go for a freeride run, doing a berm-berm gap on their slalom track. (indycross) i Blow the rim off again. (sideloaded) *I HAVE NOW BLOWN THE TIRE OFF 3X* (2nd time for this particular tire)

Next weekend, riding Creek again, blow off the tire a 3rd time-again in a berm. (4 total) Throw the tire out since its mostly worn anyway, and probably damaged bead as well.

Next race was this past weekend, Blew the tire off in the finish line berm during practice. *decide this tubeless isnt going to work on these rims, toss a tube into it!

Next run, blow the tire off in a different berm-with the tube in it.

Frustrated :mad:
Toss a new wheel on the bike, mavic 721 with a DHF.(tubed) 3 runs later, i blow that off-due to rainy conditions i swap to swampthings-still using the 721s. Blow the tire off in the finish line berm-WTF!!!! Put a new tube in it, and go for a ride, 2nd run and it blows off in the starting gate (literally) Nothing visibly wrong with the bead or the rim. Put a bunch of mud on the bead and remount-works for the rest of the weekend.

Come home with a bunch of problems-so i toss all the problem tires aside, and go to "start over" Put a fresh DHF onto the 721 and at 20 psi it blows off as im pumping it up.

The flow looks like crap, so i am replacing that rim tomorrow, and going to just try tubes.


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Does anybody have any idea wtf is going on?
 
demo 9

demo 9

Turbo Monkey
Jan 31, 2007
5,910
46
north jersey
kidwoo said:
So what you're saying is.............you had no problems with a real tubeless rim.
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yes, but i have also been pulling tires off mavic 721s, which are a pretty popular rim that nobody else has a problem on. Id like to stay off the 823s because they weigh a ton. the stans were 3/4 pound lighter. that said, they arent workin...
 
William42

William42

fork ways
Jul 31, 2007
3,936
680
why I no longer run tubeless. Especially since I tend to hit my rims pretty hard from time to time.
 
kidwoo

kidwoo

Artisanal Tweet Curator
Aug 25, 2003
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demo 9 said:
yes, but i have also been pulling tires off mavic 721s, which are a pretty popular rim that nobody else has a problem on. Id like to stay off the 823s because they weigh a ton. the stans were 3/4 pound lighter. that said, they arent workin...
Click to expand...
721s are the same width as what's on my 5" trail bike. Yes people have problems with them. Me for instance. Those things are too skinny for 'real' dh riding and dh tires. I know it's only 2mm difference with the 823s but they've got that superglue bead wall that grabs and holds onto almost anything. Fvck popular. Stans shlt is 'popular' but their rims also happen to be some the biggest pieces of shlt ever made that were surpassed in quality and weight about 10 years ago. And 721s get weird with any tire bigger than a real 2.3.

You're bigger than I am so I completely understand you having problems with tubeless setups (I'm actually surprised you never had any problems with 823s tubeless). But go with what works. And once you blow a tire off, it does stretch in the process. You're not likely to get it to stick to a rim it's already abandoned at some point.

Next time you go shopping buy some 729s. Or stick those 823s back on there. But give up on the stans shlt regardless.
 
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Beef Supreme

Beef Supreme

Turbo Monkey
Oct 29, 2010
1,434
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Hiding from the stupid
kidwoo said:
Next time you go shopping buy some 729s. Or stick those 823s back on there. But give up on the stans shlt regardless.
Click to expand...
This is pure speculation on my part but I am guessing it has more to do with the bead interface than the width. DeeMax/823 wouldn't still be the most widely used world cup DH set up if it didn't keep tires on the rims.
 
Jm_

Jm_

sled dog's bollocks
Jan 14, 2002
19,041
9,701
AK
kidwoo said:
Fvck popular. Stans shlt is 'popular' but their rims also happen to be some the biggest pieces of shlt ever made that were surpassed in quality and weight about 10 years ago.
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This. Stan got popular because he made rims lighter with less material...which made them fail more and more fragile. He made his business in the first place by selling bottles of latex dissolved in ammonia and water, which you can buy from any hobby shop, so I'm not sure which team of engineers he has designing wheels, but they would never be my first choice.
 
M

marshalolson

Turbo Monkey
May 25, 2006
1,770
520
dude, you gotta bail on running those stan's rims. they are barely up to the task of trail bike use.

721's have a much taller internal wall at the bead, so you have to build 4-5 layers of gorilla tape up to take up the extra volume and raise the tire bead to be in contact with the top and bottom of the bead seat. otherwise, tires blow off those rims pretty easily.

otherwise, 823 and 729 work great.
 
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saruti

saruti

Turbo Monkey
Oct 29, 2006
1,169
73
Israel
use ghetto tubeless. the tire just become one with the cut tube. and that make it stick together.
never had problems with it.
sorry for my English...
 
Tomasis

Tomasis

Monkey
Feb 26, 2003
681
0
Scotland
saruti said:
use ghetto tubeless. the tire just become one with the cut tube. and that make it stick together.
never had problems with it.
sorry for my English...
Click to expand...
this.

i have both 823 and 721. 823 hold tires much better and I see a reason for ghetto setup for 721.
 
rollertoaster

rollertoaster

Monkey
Aug 7, 2007
730
179
Douglassville , PA
Justin, it's the flows, not you. Get rid of them. The same thing happened to me a duyrea, I ended up going back to spanks. The flows don't have enough sidewall to hold the tire on. Some tires may work, but the specialized dh tires I'm using are a definite no go.
 
demo 9

demo 9

Turbo Monkey
Jan 31, 2007
5,910
46
north jersey
rollertoaster said:
Justin, it's the flows, not you. Get rid of them. The same thing happened to me a duyrea, I ended up going back to spanks. The flows don't have enough sidewall to hold the tire on. Some tires may work, but the specialized dh tires I'm using are a definite no go.
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Maybe so-but what about all the tires i pulled off a 721? Everybody uses those with no issues?
 
BigBoi

BigBoi

Monkey
Oct 31, 2011
310
50
Long Island, NY
Sounds like you are just blowing everything you can get your hands on.

But seriously, everyone on here seems to hate DT rims however my FR600's have been awesome, and I'm a 240lb hack.
 
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dump

dump

Turbo Monkey
Oct 12, 2001
8,240
4,512
chillindrdude said:
Hmmm...im running tubeless in flow ex...i have had trouble maintaining pressure (slow leak) even with appropriate stans. May be time to switch to Enves.
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Beware. Enves lead to overly-emotional breakdowns when they inevitably crack :D
 
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slyfink

slyfink

Turbo Monkey
Sep 16, 2008
9,360
5,111
Ottawa, Canada
demo 9 said:
I havemt even tried the 721 tubeless-i tore them all off with tubes
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could it be that by the time you used the 721 you had stretched the bead of the tire enough through all the previous blow-offs for it not to hold on properly anymore?

I run Flow EXs on my trail bike, but wouldn't trust them tubeless for real DH. in fact, I wouldn't trust any tubeless system for 'real DH'... I'd rather change a tube if I pinch flat than change a tire if I pinch flat / gash the sidewalls...
 
demo 9

demo 9

Turbo Monkey
Jan 31, 2007
5,910
46
north jersey
slyfink said:
could it be that by the time you used the 721 you had stretched the bead of the tire enough through all the previous blow-offs for it not to hold on properly anymore?

I run Flow EXs on my trail bike, but wouldn't trust them tubeless for real DH. in fact, I wouldn't trust any tubeless system for 'real DH'... I'd rather change a tube if I pinch flat than change a tire if I pinch flat / gash the sidewalls...
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i wont rule it out, but it has been 2 different tires on the 721, both of them new. its acting like the rims are 25.5 inches or something.

I am totally clueless on this one
 
kidwoo

kidwoo

Artisanal Tweet Curator
Aug 25, 2003
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demo 9 said:
i wont rule it out, but it has been 2 different tires on the 721, both of them new. its acting like the rims are 25.5 inches or something.

I am totally clueless on this one
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Narrow rim, big lateral leverage. And every tire brand/rim brand interface is different. Grab another brand of tire if you don't want to give up on the 721s. But hurry up and break those things so you can get some real dh rims.
 
weedkilla

weedkilla

Monkey
Jul 6, 2008
362
10
Hmm, I had a string of Maxxis (3 i think) that I couldn't keep on rims. I bought some more, no dramas. I think there is enough inconsistency that its just something that happens. And once they've been blown off they are rubbish bin material.
 
William42

William42

fork ways
Jul 31, 2007
3,936
680
don't run tubeless. more pinchflats>>>ripping a tire off in a corner. Burps suck almost as much.

I don't know why the hell this "tubeless is the holy grail for a DH bike" thing caught on, but I wish it hadn't.
 
Beef Supreme

Beef Supreme

Turbo Monkey
Oct 29, 2010
1,434
73
Hiding from the stupid
William42 said:
I don't know why the hell this "tubeless is the holy grail for a ANY bike" thing caught on, but I wish it hadn't.
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Fixed. It is the internet hive mind. A bunch of retards on the internet have convinced themselves that tubes are worse than STDs and tubeless is the best thing since not having STDs.

The logic works something like this: you have to go tubeless so you can run lower pressure but then your tires fall off and you up your pressure so you can keep running tubeless because it is so fvcking awesome.

Enough ranting for now. I have to go convert my granny's wheel chair to tubeless. It will be one of the top three performance upgrades she has ever made!
 
William42

William42

fork ways
Jul 31, 2007
3,936
680
I find if anything I have to run higher pressure then I would like with tubeless to avoid burping on a variety of rims. Not getting pinch flats is nice, but not as nice as not ever burping tires/tearing them off at speeds.
 
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