I’ve got a retro ish hardtail that I’ve got built up with Mavic d521 rims on it. Currently running tubes with cheapie tyres but just ordered some On One tyres that are tubeless compatible I think (chunky monkey / smorgasbord).

Technically I don’t think the D521 is tubeless ready, but I’ve read online some people have run them tubeless.

It sounds like you run normal rim tape, then add either a stans rim strip (seems an expensive option for 2 of these) or go ghetto wih a 20″ bmx tube stretched inside the rim?

The rim is currently drilled for shrader valves which may add complication. Is it cheapest to go down the bmx tube route -In which case how is this done – do you have to cut the tube up, and how far up the inner wall of the rim do you have to go?

I’ve still got to check the front tyre will actually fit through my fork – I’ve run 2.35″ IRC tyres through a Bomber z1 before but this new tyre is a 2.4″. Fingers crossed.

I think I would just use the duck tape method, which works better than either of the above IMO. There are probably a billion YT videos on how to do it.

I guess you can just sacrifice a Shrader inner tube, put the valve in, and it might/should just work.

If your Shrader valve core can’t be removed, you can just put the wheel milk in by prising the bead away from the rim. But it’s much easier if the valve core is removable (do such things exist for Schrader? I don’t know).

For the BMX tube method….

1) get some decent normal rim tape on the rim
2) without cutting it yet fit the BMX tube to the rim with no tyre in place. It will be tight but you’ll get it on.
3) Once you get to this point with the tube evenly spread out around the rim then you can cut the tube open along the centerline of the rim. Kitchen scissors are best for this IME.
4) The tube should now be opened out with the excess hanging (stretched) down on either side of the rim.
5) Now fit one side of your tyre. It will be tighter and you need to be careful not to nick the cut tube.
6) Mostly fit the other side then slop in plenty of sealant and finish putting the second bead on again being careful not to damage the cut tube.
7) Soap the tyre beads and pump it up quick.
8) Check tyre is sitting straight.
9) Do the whole shake and rotate and leave it on a bucket thing (see Stans website for a video).
10) Once it seems to be holding air slice or cut off the excess inner tube with kitchen scissors or Stanley knife. My preference is to cut about 2-3mm away from the tyre wall as it makes later tyre changes a bit less faffy.

Hope this helps.

You can buy tubless Schrader valves.

Then just gorilla tape them

FWIW I have got good seals on the rim from the tape only method too but on the rims I’ve used I’ve found the tape method is more sensitive to correct number of wraps Vs slicing a cheap tube open.

Either is good.

By coincidence I run 1999? D521’s with Chunky Monkies/Smorgs split tube method with Z1 Bombers.
Been fine, when I just used tape I found I could burp the tyre just by leaning hard on it. Ghetto rim strips seem much better.

I got a Joe’s no flats kit with rim strips and sealant for £17. Works well on my old not tube less wheels.

I’ve found the split tube method to be more secure on non tubeless specific rims than gorilla or Stans tape. There’s a bit more faffing but you only need to do it once.

I use the inner tube method, it’s pretty simple. Just follow the instructions above, with a few extra tips:

1. Inflate the tube before you fit it to the rim. This makes it easier to get it straight.

2. After you cut the tube, clean it thoroughly with a wet rag and dish soap to remove all the talcum powder inside. Then, after you have inflated the tyre, dribble a little bit of sealant between the flap of the tube and the tyre bead, then try to work it down under the bead. This will cause the tube to stick to the bead and help to prevent burping.

3. Before you cut the excess tube off, take the bike for a ride and then leave it overnight. Don’t trim the tube back until you are certain it will retain pressure overnight.

4. I use a box cutter with a new blade to trim the tube back. I trim it right back to the rim by running the blade of the knife against the rim as a guide. I used to leave a quarter inch flap hanging out, but I had a rim strip tear where the cutting was a bit jagged. If they tear, you have to throw it away and start again. Cutting smoothly around the rim seems to fix this problem.

5. Don’t bother trying to reuse the rim strips. It just isn’t worth the hassle.

Wow, thanks for all the replies!

Looks like I’m going to give the bmx inner tube method a go first then and see how that goes. I’ve already got stans sealant and a tubeless inflator as I run (proper) tubeless on my Aeris. Therefore all I need is the inner tubes to give it a whirl.

Do I need 20″ bmx inner tubes with a threaded valve / one of those screw up rings to hold the valve in tight, or does air pressure do a good enough job?

Found schwalbe do a tube with these but at £7 a pop it seems a little steep for inner tubes (I’m trying to keep this bike budget given how much money has gone into the FS bike).

Jamesoz- good to hear this setup works wih the tyres I’ve ordered / the same rims / basically the same forks!

I’d use Presta valves even if the rims are drilled for Schraeder. I always use Schwalbe BMX tubes, as they have removable cores which makes initial inflation easier and also you can add/top up the sealant without popping the tyre off.
There’s no air seal going on between the outside of the ghetto rimstrip and the rim as there’s a complete rubber-rubber seal between tyre and rimstrip so I don’t suppose it makes any difference whether or not you have a threaded valve stem and locknut. As I said though, I always use Presta (which of course have locknuts) anyway.

What’s the reasoning behind presta over schrader if the rims are already drilled for schrader? I’ve got both pump options already so it doesn’t make too much difference in that respect.

I see your point with the rubber / rubber seal so thanks for that. Less worried about a locking ring now.

Schrader valves have removable cores. Very easy to top up sealant, also fit the standard compressor fittings down at the petrol station in case you have any problems with inflation.

Stans do a ‘problem solver’ presta valve for rims with larger valve holes drilled, They have a bigger rubber grommit than standard

joebristol – Member
What’s the reasoning behind presta over schrader if the rims are already drilled for schrader? I’ve got both pump options already so it doesn’t make too much difference in that respect.

The only advantage of Presta is that if you have to initially inflate with the core out then it’s easier to replace a Presta core than Schrader one without losing all the air……IME anyway.
But otherwise, use whichever you fancy.

Ah I see. Something to think about before buying tubes. If I can remove the core on schrader to put in sealant then I’m inclined to do that. I should be able to pop the ire onto the rim with either valve type with the airwave thing I’ve got I think – just need to check the head can do schrader as well as presta.

For the BMX tube method….

1) get some decent normal rim tape on the rim
2) without cutting it yet fit the BMX tube to the rim with no tyre in place. It will be tight but you’ll get it on.
3) Once you get to this point with the tube evenly spread out around the rim then you can cut the tube open along the centerline of the rim. Kitchen scissors are best for this IME.
4) The tube should now be opened out with the excess hanging (stretched) down on either side of the rim.
5) Now fit one side of your tyre. It will be tighter and you need to be careful not to nick the cut tube.
6) Mostly fit the other side then slop in plenty of sealant and finish putting the second bead on again being careful not to damage the cut tube.
7) Soap the tyre beads and pump it up quick.
Check tyre is sitting straight.
9) Do the whole shake and rotate and leave it on a bucket thing (see Stans website for a video).
10) Once it seems to be holding air slice or cut off the excess inner tube with kitchen scissors or Stanley knife. My preference is to cut about 2-3mm away from the tyre wall as it makes later tyre changes a bit less faffy.

Sorry to be thick, I’ve never tried using split tubes. So you trim off the excess tube AFTER the tyre is fitted, leaving 2-3mm flapping about/protruding from between the rim and the tyre ? Doesn’t this look like a dog’s dinner ?
Or have I got the wrong end of the stick ……

I’ve been running my 521s Ghetto tubeless with BMX tubes for years, they’ve never had a problem. Schrader valves work really well for tubeless as you just remove the valve core and the spout of the small. Stan’s bottle fits in the valve so no mess.

Once the tyres are seated and sealed you can trim the BMX tube flush with the tyre so it looks better
Cheap and effective.

Tom KP

So you trim off the excess tube AFTER the tyre is fitted

You need to have the tyre inflated to trim off the excess tube. Best to make sure the tyres will stay inflated before trimming, so I generally go for a ride without trimming then trim once I am confident it will stay up. Once it’s trimmed back, you would have to look very closely to spot that it’s not just a regular tyre with a tube.

With a 2.4 tyre on 21mm internal width, non tubeless ready rim, you’re going to have problems with bead interlock and tyre burping.

Thanks for the comment – although someone above confirmed they use the same tyres / rims / ghetto tubeless setup – unless the tyres I ordered are sometimes available in a narrower width (but weren’t when I ordered).

If it doesn’t work I’ll just run tubes in them I guess- it would just be nice to be able to run 25 psi without pinch punctures as the trails in Bristol are primarily compacted stone trail centre jobs that get very slippery with any moisture on. Even dropping from 30psi to 25psi makes a huge difference on my main bike (running minion dhf 2.5/dhr2 2.3 both in 3c compound).

Note – only the front is a 2.4, the rear is a 2.25.

I’ve been using Chunky Monkeys on Mavic 521, with the ghetto split tube method, in Greece for the last four years and I’ve never had any burping problems. That’s using about 20psi front and 22 rear.
Are you speaking from experience, Scienceofficer?

Ah, wonderful Andy, fingers crossed it should work. I don’t even run my proper tubeless DT Swiss e1900s that low – normally around 25psi – sometimes a little higher if going to a bike park hitting stuff hard.

Perhaps I’m being a bit too cautious as only been tubeless since May ’17?

Never had a bmx tubless tyre burp. i`ve had leaves stuck between rimstrip and rim before when i crashed with low pressures though. 😀

The tyre seals to the tube and makes it virtually impossible to burp.

i always like to point out that jared graves won the ews using the bmx tube method while at yeti. if its good enough for him its defo good enough for me.

you can re-use the strips if you are careful.

an Halen – Member

i always like to point out that jared graves won the ews using the bmx tube method while at yeti. if its good enough for him its defo good enough for me.

you can re-use the strips if you are careful.
8
You can indeed, the ones on my bike out in Greece have gone through about four tyre changes. If you take a little care when you start to remove the tyre you can just leave the rimstrip in place – it sort of moulds to the rim anyway.
I’m building up another bike to ship out to that Greece this spring – I’ll be using the split tube method on that too, based on the fact that it’s always worked well for me.

I’ve ghetto’d 521/721s and 729s both with tape and proper valves (cone based seal, presta jobs) as a well as with split BMX tubes…

Either method works perfectly well, TBH I do prefer tape and a proper valve for reducing faff when changing tyres slightly…

Sorry to be thick, I’ve never tried using split tubes. So you trim off the excess tube AFTER the tyre is fitted, leaving 2-3mm flapping about/protruding from between the rim and the tyre ? Doesn’t this look like a dog’s dinner ?
Or have I got the wrong end of the stick ……

Not being thick at all, you’re quite right.

The more aesthetically precise will get rid of the last couple of mm (as per post up there somewhere suggesting a box cutter for a neater job and some excellent tips not in my post). For my tyre / rim combo I don’t really notice the little bit sticking out as it merges with the tyre unless you look really closely and that particular bike is usually filthy anyway!

I use Decathlon BMX tubes with unthreaded Schrader valves as rims are Schrader drilled and never found myself needing to remove the cores. They’re cheap too.

Maybe a stupid question, but do all schrader valves allow the cores to be removed?

With a 2.4 tyre on 21mm internal width, non tubeless ready rim, you’re going to have problems with bead interlock and tyre burping.

nah, not IME. 2.4 chunky monkey on 719 on the rear of my old chameleon at about 20-22psi ( i was surprised to find out ), and 2.3 hans dampf, bonty xr4, and spesh butcher on the front at ~ 16-18psi. i typically run my tyres as low as they can go and expect to smack the rim on the rear if i’m clumsy, but do up the pressure if i find i’m doing it a lot. i used to find the tyres would roll a bit under cornering but later tyres have had stronger side walls so this hasn’t been noticeable to me either over the past few years, or i’ve just increased pressure bit from where i was.

do all schrader valves allow the cores to be removed?

Yes.

Perfect! Been out in my lunchtime and purchased a couple of 20″ bmx inner tubes and I already have sealant. The bike shop have me a free plastic valve core remover too which was a result.

Once my new tyres arrive I’ll give it a whirl……

Want to try the split-tube method on my fatbike, wheels are 26″ with 3.8″ tyres currently. What size tubes should I use do you think ? 20″ or 24″ ? Widest I can find are 1.95″s.

How wide are your rims / won’t they be tubeless compatible already?

Er, I’m going to sound really thick here, but why, if you are going tubeless, would you use another tube that you then cut open? Surely that defeats the whole weight saving point?

It’s not always about weight saving, if it was I doubt the OP would use Mavic 521’s.

Yeah, it’s not for the weight saving, it’s so I can run lower tyre pressure (without pinch puncturing) for more grip as the local trails are pretty slippery.

I’m running D521’s / Marzocchi Bomber Z1’s / a heavy RSP dropper so weight saving isn’t a priority, that said, this bike is likely a good chunk lighter than my Bird Aeris.

That’s it I’m off to see if my Aeris, D521s, Chunky Monkies and Bombers are where I left them.

Haha, your bike with bombers on it isn’t a Kona is it?

Kona Steely

Not quite exactly the same rides then – mines a 2004 aluminium Kona Caldera…..