yannisg

Since I had 2 punctures that sealed themselves I didn't want to push my luck any further.
My tubeless Hutchinson fusion 3 tire had 4000k on my DuraAce tubeless C24 front wheel so I replaced it with a new same type tire.
After cleaning the rim with a hard nylon brush to remove all the residue from the Stan's sealant I decided to inflated the tyre first w/o sealant.
Note that the sealant does create pitting corrosion on the interior of the rim, but does an excellent job of sealing punctures. After considerable effort with a
compressor I couldn't inflate the tire. So I decided to insert the sealant. Then I discovered that the reason I couldn't inflate the tire
was 1.5 mm hole in the rim below the braking surface. I couldn't locate the hole with the soap solution because it was concealed by
a tire to rim leak that got sealed once the sealant was used. Apparently a small hole on the interior part of the rim from the
pitting must had developed allowing air to enter the rim. The hole on the side of the rim could had pre-existed, but didn't create a
problem as long as air was not entering the rim.
Any views on this matter are appreciated.
YannisG

Clem von Jones

Is it a hole at the rim joint opposite the valve stem? Maybe the rim just needs new tape.

yannisg

Thanks for the response.
The tubeless rim doesn't have any tape. The rim is completely sealed.
YannisG

RubeRad

or at least it used to be...

dsaul

Even though the rims don't need tape, its usually a good idea to use some tubeless rim tape to protect the aluminum from the sealant. The tape should go slightly up both sidewalls, so it is trapped by the tire bead and completely seals the rim surface from contact with the sealant.

well biked

The earliest Shimano tubeless ready rims are not to be used with liquid sealant, Shimano stated emphatically that doing so would void the warranty on the rims because the sealant (particularly Stan's) would corrode the rims. I thought this was ridiculous at first, but I've seen some nasty corrosion on those Shimano rims after sealant was used. I also thought it was ridiculous that Shimano would make a "tubeless ready" rim and have it not suitable for use with liquid sealant (including Stan's). But that's just the way it is with those early generation Shimano tubeless rims...their current generation tubeless ready rims are sealant approved I believe. FWIW, I've used just about any brand of rim you can name tubeless, except Shimano, including many rims that were never intended to be run tubeless, and I've never had a corrosion problem in using Stan's sealant. I'm talking 15+ years of tubeless, mostly on mountain bikes, but in recent years quite a lot with road tubeless also.

Darth Lefty 

Fascinating. I wonder what alloy or finish they used that everyone else avoided

yannisg

Thanks for yr replies.
I have read some comments about using rim tape on tubeless rims that the tape might interfere with the lip of the tubeless tire causing an unsafe condition.
My Shimano DuraAce rims bought in 2011 definitely has extensive corrosion from the sealant. I have a newer Ultegra tubeless wheel bought in 2015, but have not yet checked its condition.
Of course, I don't know if the Ultegra has the improved alloy or not. How can you tell?
YannisG

well biked

I believe your 2015 Ultegra wheels are sealant approved, but I would double check with Shimano (email, call customer service, etc) or try and find Shimano publication on the wheels. I believe it's the anodization process that was the problem with the older Shimano rims with sealant, not sure. In Shimano's defense, they tried to make it clear that you cold not use liquid sealant with those rims. When I talked to them about it once, they said Stan's would cause the most damage.

gsa103

Inside of the rim was un-anodized. Since the rim is CF bonded to Aluminum, there was no need to anodize or coat since the brake track would be left bare anyway. Before putting sealant in my rims, I used a bunch of Boeshield to coat the rim inside.

Yannisg, what sealant were you using? Stan's is well-documented to cause issues, many others are supposed to be better.

FBinNY 

I don't know if Stan's corrodes aluminum or not, so I'll take your word on that without comment.

However corrosion in aluminum is cancer, and the complications are worse than a comparable amount of rust in steel. That's because most aluminum alloys are prone to notch failure at stress risers. Rims undergo constant flex cycles and even undamaged rims will eventually develop stress cracks, usually at spokes, at the base of the tire flange, or in the "web" spanning both sides under the tire.

A corroded rim, especially one corroded to where it's clear through in one place, is more prone to failure, so the first step is to examine the inside for any hint of developing stress cracks, and if you decide to ride on ti, set up some kind of schedule for checking. This is especially important if you use relatively wide tires at high pressures because the internal stress on the rim is proportional to the product of width and pressure.

BTW- if Stan's is actually corrosive to aluminum, this is something that needs to be corrected, because it can't be good for anybody in the long haul.

Darth Lefty 

There's plenty about corrosion in the "best tubeless brew" thread on MTBR. pH and potential both play a role.

well biked

Well, I've used Stan's sealant from pretty much day one, 15 or so years since Stan's was introduced, in many different aluminum rims, never an issue. Most of the rims were never even intended to be run tubeless....again, never an issue with corrosion when using Stan's sealant. I don't think it's a problem with the exception of some Shimano rims such as the ones in question. Keep in mind, too, Shimano advised using NO liquid sealant in those rims, not just Stan's sealant.

yannisg

Thanks for yr responses.
I used Stan's sealant because every time I got a puncture it eventually sealed itself. I was aware from the beginning of the corrosive effect it had on my rim, and the difficulty in cleaning the rim and tire
from the gummy residue. Since it sealed well I was willing to put up with the negatives.
Looking closely at my recent problem, the hole in the rim opposite the valve is part of the rim. My problem, as I discovered was a crack-pit around the inner valve hole which allowed air to enter the interior part
of the rim and exit the hole on the side of the rim even though I had tightened the valve well. The crack-pit was big enough that the valve seat could not seal it. This crack-pit most likely is from the corrosion.
I installed rim tape, but since the rim tape covered the centre rim groove I had a real hard time installing the tire to the point of damaging the tire lip. I would never have been able to install an inner tube on a ride if the need arose. I was almost able to seal the tire w/o sealant, and it would have sealed if I added the sealant. I decided to abandon this path because of the huge difficulty in installing the tire.
I'm disappointed with the recent situation since I have been a supporter of tubeless road tires from when I started using them in 2011, and have reaped the benefits of no punctures on all my Brevets and races.
So now I'm reconsidering whether all the hassle is worth the benefits. Inner tube tire puncture resistance is improving, and I'm willing so have some extra tire weight if the puncture resistance is better.
YannisG

FBinNY 

I don't have a dog in the fight regarding whether Stan's or any other sealant cause corrosion.

I was simply pointing out that IF there is corrosion damage, the consequences go beyond the direct effects.

yannisg

FBinNY, Thanks for the reply.
The only other sealant I have used is caffe latte in my mtn bike tires, and it doesn't leave a gummy residue on the rim. As far as corrosion goes I haven't used it long enough to evaluate.
I have bought some Bontrager sealant, but not used it yet.
I was saying that Stan's seals well whether other sealant seal just as well and wouldn't corrode the specific rim, I don't know.

Since the rim has already developed a crack I am not using it.
YannisG

yannisg

Well biked
I agree its ridiculous to use a tubeless tire w/o a sealant.
Do you have issues re-sealing the tires on the rim on the road wheels?
I use a removable valve core to add sealant so I don't have to break the rim-tire seal.
When I remove the tire to clean tire and rim I usually have a hard time sealing the tire.
I use hutchinson fusion 3 tubeless on Shimano tubeless rims.
Thanks,
YannisG

well biked

With road tubeless, I find it especially easy to get the tires to inflate and re-inflate after replenishing sealant usually, because the tires are so specifically designed to be run tubeless (staying airtight at approx 100 psi is a whole different matter than mountain tubeless at very low pressure). At the moment, I don't have any of my own bikes set up with road tubeless. I had very good experience with road tubeless when I ran it, I think I had one flat in several thousand miles, was able to run lower pressures for better ride quality, etc., but the advantages of road tubeless vs inner tubes, in most situations, is not the slam dunk sort of advantage you get with mountain bike tubeless IMO. There are just too many tires I really like on a road bike that are not tubeless compatible. With that said, I'm sure I'll go back to road tubeless at some point on at least one of my road bikes, probably sooner rather than later.