Converting old 26" to Tubeless
 

Hey guys -

So still working on my vintage Bridgestone MB-3 upgrade project. I bought some used 26" rims which will accept my 11 speed cassette, but only later did I realize that one rim is presta and the other was drilled out for shrader. I don't really want to carry two different style of tubes while riding, so I guess I have two options:

1. Drill out the other presta rim so they are both shrader
2. Convert the rims to tubeless so I can run lower pressure / not worry about tubes

Option 1 is obviously easier, but I would prefer option 2. Is this something that is plausible / doable?

My concerns are:

1. The drilled out hole is large for a shrader valve - aren't all tubeless valves set up for presta? Won't the hole be too big?
2. What are some cheap-ish tubeless-ready 26" tire? I can't seem to find much info on Maxxis tires as to whether they are tubeless ready.
3. If I want to try this on the cheap, can I use gorilla tape instead of expensive tubeless tape?

I have not actually done it, but I have thought about using silicone sealer to seal each spoke, instead of tape.

The only success I had with tubeless on the old bikes was "ghetto" style. Get a 24" tube and stretch it around the rim. Split it open and mount the tire and see if it will air up. If it does, add sealant, air it up and do the stan's dance. After it sets overnight trim the excess tube along the rim with a razor knife. It usually permanenlty bonds to tube and tire together by the time the tire is worn out enough to replace.

Just to say it. You can run a presta tube in the wheel that has been drilled out for schrader, it really doesn't matter.

The right way to do it is was with a Stan's conversion kit, but they seem to be gone like the dodo. They have a thick rim strip that fills in the deeper clincher channel and provides the ramps and grooves for seating the bead. Getting the tire to seat is a pain without it, but it can be done. I used 2 layers of Gorilla on my first go and it worked, but not great. I've not tried the "ghetto tubeless" approach with the slit 24" tube. For this bike it would be easiest just to stick with tubes.

Just gotta ask: Are these tubeless compatible rims?

Tubeless valves are available in both Schrader and Presta.

Gorilla tape works just fine. One downside to it is that if you need to re-tape, it is a pain to get all the glue of the rim. Personally, I'd drop the $15-20 and get the tubeless tape.

Any Maxxis Tire that is Tubeless Ready will say so. Indicated with "TR". Many 26" tires have not been updated since the ubiquity of tubeless and are not TR. However, I am currently running a non-TR DHF on a Stans rim with no issues.

There are at least three different products made for keeping the presta valver snug in a rim drilled for schrader.
1. A rubber grommet that snaps into the shrader hole and has a hole in it that fits a presta valve.
2. A metal collar that does the same thing.
3. A presta valve nut that has a shoulder on it that fits into a schrader hole. I believe the Schwalbe inner tubes come with this style nut as do a few other brands.
Brent

Happy Thanksgiving Brent!


This is Paul in the South Bay. I'm reading on bike forums now because I'm healing up at the moment.


I've converted quite a few 26" rims to tubeless. I've had good results using heavy UST tires and sealant, and goriilla tape on non-UST rims. Three or more good reasons for UST DH tires is that they have been cheap (haven't looked lately to see if there are any left), they are tough and excellent mtb all around mtb tires, they hold air, and because I seek the widest size that will fit they sit wide on the rim, they are possible to set up tubeless.


I haven't had to do this (except on my fat bike), but one tactic is to start with filling the tire up at first with an innertube, then on one side with the tire soft, squeeze latex on the bead/rim interface on one side and let the wheel sit for a day so that the bead adheres to the rim on that one side. Then on D-Day remove the innertube out of the loose side and proceed with the tubeless conversion. That way at least one half of the wheel is sealed to begin with.


I have not successfully converted non-UST tires/26" rims to tubeless. These attempts have always failed even after working for a couple of rides.


I have not used the ghetto slit 24" tube method yet, but I might soon.


My wife's primary SS which she rides a few times a week is set up with UST tires and it works as good as anything. I have one set up that way too, which gets at least one serious ride a month and the tires stay firm for months without needing more sealant.


The DH UST tires from that era were pretty heavy and generally have serious sidewalls and deep tread. They last a long long time. Maybe not the best thing for the weight weenies here, but I don't see much of a downside. Now I wonder if there are any on eBay anymore.


Alex makes a great tubeless 26" rim. They've been sold out recently though (I have a pair on back-order). I have a wheelset built with these and some true Maxxis 26" tubeless tires, and it's the better way to go. Still, those UST DH tires are the bee knees going downhill!

nice tips, i have been considering doing the same

Hey everyone -

Quick update:

I found a pair of Hutchinson 26x2.00 Python Air Light tires which the seller on eBay marketed as "tubeless." Turns out, they are not the tubeless version and of course the guy on eBay is being an ass about it, but they do seem to work (for now).

I was able to do the conversion yesterday. I still haven't ridden the bike as I'm still working on the drivetrain, but they do seem to hold air. It was a bit of a PITA to get the tires to seal. The rear wheel sealed up on first attempted without any soapy water and without removing the valve core, but the valve stem kept leaking (I was doing the ghetto cut an old tube and use that valve stem approach). I bought a set of Stan's valve stems today and solved that issue.

The front wheel was an enormous pain as it just did NOT want to seat itself. I was using my Blackburn Chamber pump and even with the blast of air I couldn't get the bead in there. Eventually, after lots of pumping up that chamber, I was finally able to get it to seal. I left both wheel horizontal overnight and found the pressure to be the same this morning.

I'm a little nervous to see if they will hold when I actually ride them as neither the tires nor the rims are tubeless ready, but they do seem to be holding for now.

Thanks for all the help!

Bit late now, but I use Joe's Rim Strips on non tubeless rims. Kind of like a manufactured version of a cut down tube, buy the widest ones you can get, the less they are stretched the thicker they are to fill the gap between the bead and the rim. Available in presta and schrader versions, so If I was dealing with the OPs problem I'd drill the presta rim to schrader and use them. Generally now what I do with non tubeless tyres is give them a small dose of a latex sealant like Stans, enough to seal them and fix any micro porosity, ride them for a few weeks then put in the correct amount of a non latex sealant like Finish Line.

Speedy spaghetti, it might work!

It'll work out.

I'm no authority. So I've ridden many miles on non tubeless rims with non tubeless 26" tires and it's been alright, except that I'd have to keep them pumped up harder than I'd like to, and always kept a pump handy, as we should always do anyway.

Just the other day the tubeless Alex 26" rim I had on backorder arrived. It was around $35. I can't remember exactly, but it's a good rim and that's affordable.

​​​​​​I rebuilt the rear wheel of a certain bike that has been a favorite ride with that rim.

I was using a tubeless tire on the old rim. Regularly I squirted in loads of sealant to keep it holding air. The rim sort of bonded to the tire. But it wouldn't always stay sealed. Towards the end of long rides, 6 hours, it would most of the time start losing air and require pumping up a few times to make it back home.

It got so I stopped riding that bike.

Well to build the new wheel I had to take the tire off, a TLR Maxxis Crossmark, and it was no surprise at the amount of old sealant in there. It took a long time to scrape it out.

I have a wheelset on another bike that was built by a professional using the same Alex rims, I think they're called the Adventurer 2, and they have been everything I was hoping for. The Maxxis 26" tubeless tires have been tight at the pressure I want to run.

I suppose any tubeless specific tire would do the trick as well.

Recently I bought a tire I thought was tubeless on eBay, but it wasn't. It was for my wife's bike 27.5. I tried to get it to seat on a tubeless rim, but it wasn't going to work. It cost as much as the 26" rim I just got.

Well now we've got an emegency tire/tube to take on the road.

It's a pity, but it's hard to avoid making some bad purchases. Of course we try not to.


​​​​