Tube troubles! Need help.

[svt2224]

I have a 04' ec250 with the DID wheels that has now been renamed the tube mauler. I have been out four time over the last month or so three of which I came home with a flat. I am running a dunlop 803 @ 8psi, Motion pro locks (2), and Moose HD tubes. I marked the wheel and tire and I know that the tire is not moving. Do you guys know how I can keep from ripping the valve stems out.

Thanks
Jason

 

[JoshP]

You are ripping the stems? It doesn't sounds right for the tire not to move and still rip your stem off. You are certain your spokes are nice and snug and not piercing the tube? I usually don't tighten down my stem nuts so that the tube can move a little without damaging it. I notice the tube will move more but never breaks the stem. I will just tighten the nut up against the stem cap just to keep the cap snug. Hope it helps.

 

[svt2224]

Yes, it the stem that is being ripped off. I have left the retainer nut loose on all of the tubes and they all end up tilted and pulled tightly against the rim. Before I went out last Sat. I straitened the stem out and within 20mi it was pulled tightly againts the rim, it is not flat yet but I would not be comfortable taking it to far from the truck.

Thanks
Jason

 

[eff]

Try running more than 8 psi. My guess is that the tube is rotating inside the tire.

 

[bergerhag]

the tyre is probably flexing a bit with that low pressure, and the tube might be hooking up inside and gradually increasing the stress on the valve stem.
Put some baby powder in your tyre before putting in the tube.

 

[WoodsRider]

When I first started running a trials tire, on my '01 XC300, I found that the tire/tube would creep at anything less than 12 psi. And that was using 2 Motion Pro rim locks with a Bridgestone UHD tube. On my '03 EC300 I'm back to using one MP rim lock and 12 psi. Yes, with lower pressures, a trials tire gets a lot better grip, but you have to sacrifice some of that "exceptional grip" since trials tires aren't really designed for enduro bike applications.

 

[blitz11]

Go with Talon Rim locks. They actually dig into the sidewall rather than relying on a friction between the two rubber entities (the tire and the rubber rim locks). Some rim locks use a serrated side, but nothing compares to the Talon rim lock. The talons use an aggressive pattern to grab the tire.

 

[svt2224]

I'm not having a problem with the tire itself moving, it has stayed right on the mark. I had a feeling that the tire psi was my problem but the traction was so good at 8psi I wanted to find some other fix. I have been using armor all but I will give the baby powder a shot. Do you think that a std. weight tube would be less likely to move?

 

[HydroDog]

Jason,
I've been running the same combo as you and had the same problem with the valve stem. I finely just tightened down the stem nuts and never had a problem since for the last 1000 mi.
The 803 has a stiffer side wall than the IRC and Michilin which leads to the lower air pressure and more tube creep. When my 803 dies I will switch back to the IRC

 

[Nick]

The armorall is probably letting the tube slide inside the tire as there is no friction to hold it in place. I've seen tubes that stretched by a couple inches in lengh inside of a tire. Ditch the lube.

 

[Eric K]

The armorall is probably letting the tube slide inside the tire as there is no friction to hold it in place. I've seen tubes that stretched by a couple inches in lengh inside of a tire. Ditch the lube.

I second that. Armorall is great if you want you tube to slip all over the place.

I have run Moose HD tubes as low as 5 psi with no slip inside the Mitas trials tires. I do not use any armorall, baby powder, etc.

I use Talon rim locks as I have had pinch falts caused by the sharp edges of the motion pro rimlocks.

 

[svt2224]

Thanks guys, I'll pull the tube and clean it and the tire. As far as the locks I ground them down on the edges, hopefully that will ward off pinch flats.
J

 

[Loosenut]

Hold on a minute. I have used Armour All on every tube I have installed for about 7 or 8 years now. I coat the entire tube and the inside of the tire carcuss. My tubes last longer and they are near impossible to pinch. I have had one pinch since then and it was a doozy that I was lucky to walk away from. The talc people use is for lubrication. I run Dunlop 756's, as the trials tire and I don't get along so well on the 300s.

My valve stems are sitting at about 80 - 85 degrees after riding.

FYI, I am still using the stock tubes and rim locks on my '05 EC300.

 

[iancp5]

Try running more than 8 psi. My guess is that the tube is rotating inside the tire.

That would be my bet - had it happen to me. Heavy tubes will spin under braking when you lock the rear wheel suddenly. Don't run HD MX tubes in low pressure trials tyres. At low pressure the weight will spin the tube and rip the valve. Make sure the tyre & tube are clean unusually you want as much friction between tube and tyre as possible. You could try looking for a bigger tube. The dilemma is that running more pressure negates the point in running a trials tyre. I found with a standard, lightweight 140/80 x 18 tube they are fine at 8 psi but go lower or use a heavy tube and they turn under sudden lock up braking. If you want to run lower, which I have you either need a bigger tube or maybe avoid the rear brake at speed on slippery ground.

 

[svt2224]

Thanks for all the info guys. As a last ditch effort I am going to try a larger std. thickness tube with no lube. Maybe that will work out, if not I'll go up a few #'s.
J

 

[JoshP]

I used to get the Michelin heavy duties, but I don't think they make those anymore. I have since switched to this one it's only $19.00 on RockyMountainATV.COM "Bridgestone Ultra Heavy Duty Motorcycle Tube". Probably have about 2 years on my current rear tube with typically 2 days a week / 12 month riding schedule (Just got my new trelle front I'm stoked for snow! ). So it's alot of tube with no pinches or stem breaks and my stem will be at a total 65 degree angle after riding. Sometimes I don't even fix it and ride like that for a month before I change out my tires. No lube, no powder and no complaints. Oh yeah and we run 8 to 10 PSI, I typically run 10 but have run 8 with no issues but slams too much as the tire degrades.

 

[gasser]

I used to have the same problem on my 250 and 300 but much less so on my 200 due to less power. What's happening is the trials tires can flex by more than an inch (I've actually got pictures of this somewhere) so those heavier tubes that don't stretch as much as the thinner ones will jerk the stem out when they move with the tire. I had absolutely no luck using extra baby powder, rim locks (tried two), or wd40. My problem completely stopped when I went back to a standard weight tube. - Ken

 

[svt2224]

Ken,
The std. weight tube fixed the problem. No problems with flats, so far it has made it trough 100mi of Arkansas rocks and 30mi of sand and hardpack.
Thanks guys
J

 

[fury1]

I just went back to my trials tire that had been on the shelf for two or three years,forgot how much fun and what a cheater this tire is,got it about 12PSI and havent had any issues running a H/D tube,we have had a serious mud race where most didnt finish the race,eight guys finished the course,I finished 9th O/A but houred out at the last check,then I took it to NY where it was mostly hills and off camber stuff and the bike shined everywhere,no disadvantages anywhere,been practicing hard with it lately as we have four more runs till the end of the season and I like sitting in first in class! trying to get crem55 to make the switch,but without some practice time he might not be able to adjust to the different riding style in time before the next few races

 

[skid jackson]

I just switched from an Irc back to a 756. The irc had plenty of life left on it but I wanted to see what a knobby in the back would be like ... I ran the irc at 12psi w/one mp rim lock and b stone uhd tubes. I had no issues with tube movement and I ride nasty rooty rocky stuff. after I burn through the 756 I'm going to put a d lop 803 on the back. Cheater tire is right!! Trials tires kick butt!!