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Discussion Starter · #1 ·
I purchased a brand-new Hi-Fi Pro (with Bontrager XDX, 29x2.1 (53/51), tubeless ready tires) about 10-12 days ago.

After riding on trails for only about 4 hours of use, I encounter what was initially thought to be a pinch flat on the rear tire. However, when the repair guy at my local Gary Fisher dealer examined the tire more closely, he said he couldn't really find definitive signs of such a pinch flat. He said he wasn't really sure what caused the flat; he couldn't point to anything specific.

So I get back out on the trail. Within just about 10 minutes, the front tire starts to go flat (slowly, like under pinch flat conditions). The next day I'm back in the shop with the same diagnosis: no truly definitive signs of a pinch flat or anything else that might have caused the problem.

So out of caution, the guy replaces the rim tape on both of these brand-new rims. He doesn't know what else to do at this point.

The next day I'm back on the trail for just another 10 minutes and the rear tire starts to go flat again (loosing all its pressure in about 5 minutes).

What gives????

The repair guy doesn't understand what's going on either. The rim looks perfect and there are no discernible holes or tears in the tires either.

Any ideas…….?
 

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Harmonius Wrench
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Where are the holes in the tubes, or are you running tubeless?

If you have tubes then the tubes will tell you where the problem is. You just have to match up the hole in the tube with the corresponding interface with the tire/rim/foreign object.

If you are running tubeless it may be a number of things, but should be diagnosed with some soapy water and a brush which you can slosh over the tire and look for air leakage.
 

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And He was Not
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Pump up the tire and put the tire and rim under water,. It will tell you where the system is leaking.
 

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WNC Native
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If you are running tubes, it will show you the problem like GT said above.

Pump up the tube, then either stick the entire tube underwater or get some soapy water to soak the tube with. Where ever the tube starts bubbling, dry the tube off and circle the hole with a pen. The place the tube beside the wheel and rotate the stem to the correct location on the wheel. Then your circled hole will show you exactly where the problem is.
 

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Discussion Starter · #5 ·
Thanks for the info!

Many thanks for all of the information you guys have provided!

Sorry that it has been a few days since I have contributed to this discussion. I have been out of town on business.

In the meantime, I did contact Bontrager regarding this ongoing situation. Thought I would share the information:

Thanks for writing. I have seen this once before actually and it has to do with tight tires on the rims basically. Have they tried the cloth Velox rim tape? Honestly, if that doesn't do it then I would strongly suggest just going tubeless. That will alleviate all your problems plus it will ride a lot better as well. I went tubeless last year and I will never go back. Have your shop give me a call and I'd be happy to discuss this situation with them.

Ride on,

Chris Long|Trek Bicycle Corporation 801 W. Madison Street, Waterloo, WI 53594|Technical Services​

It definitely sounds like tubeless is the way to go. Anyone have any follow-up comments on going tubeless...?

Thanks again!
 

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Harmonius Wrench
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highland99 said:

It definitely sounds like tubeless is the way to go. Anyone have any follow-up comments on going tubeless...?

Thanks again!
#1: Stay away from the Bontrager Super Juice.

#2: Use CaffeLatex sealant. Better than Stan's, but Stan's isn't bad.

#3: If the shop sets up the wheels and tires for you, you should be golden. Try experimenting with lower psi. I run anywhere from 20-30 psi mostly, but you should play around with that.

#4: Sealant inside will require you to check pressure once a week at least, and eventually it will need replacing. Stan's lasts a minimum of about 3 months, CaffeLatex goes longer than Stan's. I would check the sealnt once a year minimum. (You can see if you can hear the sealant "sloshing" inside the tire by shaking a wheel. )

#5: Sealant will help seal puntures, and maybe small tears, but it is no panacea against flats. Carry a tube, tire levers, and know how to remove the tubeles valve stem in case you have an issue in the field. Also, small punctures or tears may require you to stop and get the sealant to pool over the hole to seal it. Then you may need to top off the air pressure. Make sure you are prepared with whatever you use to inflate tires with. Long, epic rides may require the tire boot, and tubeless patch kit to be stowed in your gear.

#6: Enjoy! :)
 

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Discussion Starter · #7 ·
Guitar Ted said:
#1: Stay away from the Bontrager Super Juice.

#2: Use CaffeLatex sealant. Better than Stan's, but Stan's isn't bad.

#3: If the shop sets up the wheels and tires for you, you should be golden. Try experimenting with lower psi. I run anywhere from 20-30 psi mostly, but you should play around with that.

#4: Sealant inside will require you to check pressure once a week at least, and eventually it will need replacing. Stan's lasts a minimum of about 3 months, CaffeLatex goes longer than Stan's. I would check the sealnt once a year minimum. (You can see if you can hear the sealant "sloshing" inside the tire by shaking a wheel. )

#5: Sealant will help seal puntures, and maybe small tears, but it is no panacea against flats. Carry a tube, tire levers, and know how to remove the tubeles valve stem in case you have an issue in the field. Also, small punctures or tears may require you to stop and get the sealant to pool over the hole to seal it. Then you may need to top off the air pressure. Make sure you are prepared with whatever you use to inflate tires with. Long, epic rides may require the tire boot, and tubeless patch kit to be stowed in your gear.

#6: Enjoy! :)
Thanks for the info!
 

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No really, I am that slow
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highland99 said:
Have they tried the cloth Velox rim tape? Honestly, if that doesn't do it then I would strongly suggest just going tubeless.
This is not an acceptable answer. Even with tubeless, you get flats & you'll need to put in a tube. If your tire/wheel punctures your tube, you might have a long walk out. Frankly, diagnosing the problem shouldn't be that tough. Mark the tube, tire & rim when you remove the tube, overinflate the tube & stick it under water. The leak should be readily apparent. Then use the marks to locate the spot on the rim or tube corresponding to the leak.
 

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Discussion Starter · #10 ·
First of all, let me say that it's my local Gary Fisher dealer/bike shop that is performing all of these repairs.

After working with the local shop during the past several days, they are coming to the determination that these flats are ALWAYS the result of not "seating" (their terminology, not mine) the tire properly in association with the rim.

Therefore, these flats are sometimes pinch flats and sometimes situations where, I have been informed, the beating simply wasn't properly sealed/attached to the rim. (It has nothing to do with finding where a piece of glass or other anomaly along the road/trail has actually punctured the tube.)

Again, I'm a little bit new to mountain biking, so I'm learning as I go here. It's been very frustrating, both for me as well is the repair guys. They have never dealt with these types of problems before. They are having to perform a number of hours of labor free of charge because of these recurring problems, so they want this issue solved as soon as I do.

But there is some good news: the last time the shop performed this function, they had a different guy do the repair. He is the senior guy in the repair shop, and he said that what he did was a little bit different, even though he didn't go into a lot of explanation. (He just kept going on by saying he got a really good connection with the beading of the tire, and I know that it is the beading of the tire that needs to be sealed to the rim properly in order to prevent these ongoing problems.)

It has now held for the past 3 days of very heavy, very hard riding.

After all of this -- even with the last few days of success -- I still have a desire to go tubeless, however. I have done a lot of reading on a lot of different forum posts and it seems to me that the benefits outweigh the risks.

It's also probably important to point out here that I am between 6'6" and 6'7" tall, amateur bodybuilder (very wide frame), and I weigh 295 pounds. From what I have read -- and correct me if I'm wrong -- tubeless tires are even more advantageous for heavier riders.
 

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from my experience with bontrager wheels, you need to intially get the psi up very high (around 60 or more) to get the beads to seat. you even need to do this with the initial tubeless set up. once the beads are set, back the psi off back down to a normal level.
 

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Discussion Starter · #12 ·
Captain_America1976 said:
from my experience with bontrager wheels, you need to intially get the psi up very high (around 60 or more) to get the beads to seat. you even need to do this with the initial tubeless set up. once the beads are set, back the psi off back down to a normal level.
Many thanks for this info! :)
 

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not a problme at all. you will hear a loud snap once the pop into place.

whats your experience been with super juice?
from my experience it sucks. it does not seal very well, and its expensive. for the cost of 2 small bottles of super juice, i mixed up a gallon of sealant in the "best tubeless brew" thread. the only good thing about the super juice is the bottle it comes in. :D its handy for measuring and inserting sealant into the tires. :D
 
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