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Only $10 for all 2026 SX, MX, and SMX series.
If you buy 1 tire shipping is $39, definitely not worth it.
But I put in 2 fronts and 2 rears and shipping still says $39. In that case its definitely worth it. $74 fronts and $85 rears shipping included ($316.60 vs $411.52 on rocky mtn). I didn't go farther than that though, wonder if shipping changes when you put in address and payment info.
you guys have some heavy tubes. I actually have been sourcing some at the 600 grams weight. Compared to a tube that came from a stock GasGas that was at 800 grams. My first thought was no way 600 grams is going to cut it so i pushed back on the factory to go up to 700 and waiting for my sample. I will say the lighter tube is slightly easier to install.
Must be a 434 thing...
I switched to Maxxis Fat Bike (MTB ) tubes years ago and haven't looked back. Not one flat.
I had weighed them and compared to standard mx tube they were significantly lighter.
So far have yet to find a downside.
Been running them with Michelin StarCrosses and riding at Perris, Pala, Cahuilla, Glen Helen, Barona Main Tracks. *Shrug* Lot cheaper and easier to get than those Stargy Vargies.
Are you guys running the 26” fat bike tubes front and rear? What do you do with the excess length of tube? Do you just fold it in there or what? I like to put my tube inside the tire before mounting. Not sure if that would work with the fatbike tubes.
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Yeah they work front and rear. I've been running them in the fronts of my bikes for years.
Although they are 26'', the diameter of the tube is virtually the same as the diameter of a 21'' and 19'' MX wheel, so there is no excess tube.
I use the same fitting technique as any other tube, so half the tyre on the rim, feed to tube in (lightly inflated to get some shape), then spoon the other half of the tyre on
Which tubes (part number) are you using? Schrader or Presta valve?
Exactly. I had an RK MXU chain loaded up in the cart because their price was really low on that item. The $25 shipping killed it though. No big deal; I know they’re not trying to be a parts house. Just thought I could sneak an order in and save some money.
Better yet, can we just get a dedicated thread to fat bike tubes? This idea is intriguing. I was at my in laws house yesterday and my wife’s dad has a new fat bike with the skeleton rims so you can see the tubes. The tubes seem better constructed and stronger than typical Mx tubes. I’m about to mount new tires and want to try them.
I've used Schwalbe with a Presta valve (pain in the ass), Maxxis with a Schrader, and now just generic ebay tubes with a Schrader (cheaper, still works fine).
There's really nothing to it... remove a normal tube, replace with a 26'' fatbike tube, fit as normal and inflate to your usual pressure and crack on.
I typically only run them in the front just out of security during racing. But they do work in the rear as well. If you are heavy, aggressive and ride harsh, choppy, stoney tracks etc it may not be worth it. But I've not suffered anymore flats since switching.
left is an ultra hd tube, which came with the bike (crf bought used). right is a Michelin standard mx rear tube, never had any flats with these. you can imagine how this freed up the rear wheel. 584 grams is about 1.3lbs...
fat bike tubes are about 150g lighter. here i had some flats and the presta valves are easy to be ripped of. i would try the maxxis out on the front again...
Cool to see such ultralight polyurethane innertubes finally making their way to the moto-community!
I want to share some more details on these tubes as it was actually my best friend inventing them like 14 years ago over here in Switzerland, holding patents and manufacturing such tubes for Mountainbikes & other bicycles. I was heavily involved in the process and Testrider No.1 from day 1. Years of testing and prototypes went by before the swiss made ECLIPSE BICYCLE TUBE was actually born. There are also patents etc...the Eclipse-Tube was way lighter than anything else available on the market. A typical 29" butyl-innertube weighs about 180g. The ultralight Eclipse just 58g. As soon as i put the first pictures out there on specific cycling sites there were critical voices: "...such a lightweight innerube won't hold up....too fragile....too expensive...."
Well - the biggest MTB magazine in Europe (german BIKE magazine) did a comparison test between ca. 20 different innertubes.
From our ultralight one to more regular ones up to heavy-duty downhill tubes. Materials ranged from Latex, Butyl and also ours out of Polyurethane. Weights range from 55g - 460g….
As you can see below the testresults speak a clear language: They tested specifically against pinchflats and also against penetrating objects...and they also tested rollingresistance which on a bicycle is a very important factor as well.
Just for clarification:
in the test above the clear winner in the pinchflat-test was a Tubular tire which they ran just for comparison reason. Therefore it got coloured red since it wasn't tested with the same configuration. Actually the best here would be the Onza Downhill Tube at 460g. But just slightly better. Ranked 3rd is a regular tube BUT this time it was tested with a sturdy "Enduro" Tire...as opposed to all others which got tested always using the same tire&rim combo. You can see the 3rd ranked innertube "Schwalbe 13" tested as second to last when using the tire all others got tested with....they wanted to show the importance of the tires carcass . BUT - the ultralight Polyurethane tube is up there with the Downhill tube and also at the same level as the tube which got tested with that sturdy tire....it is like 50% more resistant than your regular tube at about 30% of the weight!
Already back then I asked my friend he should do such innertubes for MX or Enduro Bikes as well….in a racing environment losing like 1 Kilo per wheel would be huge! But the manufacturing was really complicated and he did all on his own…no time nor would he have the capacity for such big Motorcycle tubes…
Anyway – years passed and I now see the Stark Varg arriving with such tubes. By the colour of them my guess is they are a product of Tubolito. But anyway – the technology is the same and they will be the new benchmark!
As you could see in the testresults of the MTB innertube…the material is drastically more resistant than your regular Butyl tube ! So you can reduce the materials thickness and by doing so loose weight without sacrificing durability or resistance against flats !!!
BUT I will tell you more about the use of them as I run such tubes for 14 years already. There is no one having more insight on them.
ADVANTAGES:
There is no better place to save weight than on the wheels! Rotating mass counts twice! Not only the weight itself but the rotational forces get diminished quite a bit which makes for a MORE AGILE HANDLING. Let’s talk about a flickable feel….changing lines with ease… throw the bike around in general…
One of the most overlooked factors though is the fact that lighter wheels also make for FASTER ACCELERATION !!! Again - that same German BIKE magazine in another issue also tested different wheelsets and it is obvious that in order to bring a heavy wheel up to speed it needs more energy than accelerating a lightweight one. In reverse lighter wheels need less energy to get up to speed…Those of you who cycle know that wheels & tires have a tremendous effect on how your bicycle handles and accelerates. Our leg power is minimal so you immediately feel the difference there. We are talking about +/- 100g here!! Lighter wheels accelerate faster! It is actually the best tuning you can do. Most wouldn’t believe the difference such a lightweight wheel setup can have but if you have lighter wheels, light tires, sprocket and bolts etc… and lightweight innertubes we are looking easily at like 1-2 kilos savings PER WHEEL ! I have done so on my own 125cc bikes. It is now 8 years I’m using lightweight innertubes for FATBIKES at about 400-450g. The tech-geek I am I was maybe one of the first doing so and with great results. I ride and race older 125cc Hondas and believe it or not-I got many holeshots with my 30 year old machinery even against 450s ! Ok I also have one of my bikes down to the lower weight limit but that’s still part of the main goal to have your racebike as light as possible. I succeeded to bring my AF build to the lower weight limit of just 87,5 kilos / 193 lbs by saving over 8 kilos in the process! Also my ’89 vintage racebikes got on a diet and are sub 90 kilos (stock they are around 93 kilos). So a 125 is about 30 kilos lighter than your typical 450....that's huge.
Again – everyone asks “…but do they hold up?....don’t you get more flats…?”….YES they hold up and no there is not more flats! As you can see in the testresults of the german magazine against pinchflats the thickness of the innertube makes little to no difference. It is mostly when you would have a thorn or glass penetrating the tire where thicker tubes will help. But on a MX tire we don’t have penetrating objects! It is all about pinchflats when running low pressure for best grip or in MX where we get heavy impacts from landing off of jumps or G-outs.
Having lightweight wheels also HELPS YOUR SUSPENSION !! Obviously lighter mass is able to follow the ground better. Just hold a full bottle of water and move your arm up & down …mimicking your bikes rear swingarm moving when going over bumbs……now do it with a empty bottle…so your suspension will be able to follow the ground better as well!
Packing size is minimal. This obviously is not critical in MX where we carry our spare tubes in the van or trailer but for Enduro-riders it is a big argument: these tubes have like 1/4th the size of a regular innertube & minimal weight so they can easily be carried along in your tools bag.
How do they perform day in & day out…what to look for…what’s different??
These tubes are out of Polyurethane which is much less flexible than your typical Butyl-Innertube. So they don’t shrink when they have no air in them. And you can’t stretch them too much either. They need to fit your tires size. This means when installing them without being inflated you have a lot of thin material flapping around which easily can get hooked up between tire levers and rim…so for installation you need to have them slightly inflated to prevent them from being pinched while mounting a tire!! You really have to be a little more careful installing them.
What I always do with innertubes is to use talcum powder inside the tire. This helps the tubes to glide inside, to move freely. We all know that when removing old tires you sometimes have the innertube kind of glued to the tire….you want to prevent that also when your tire should move/slip on the rim ever so slightly, a “glued-on” tube is more likely to rip the valve off than if the tube can just move freely inside. Talcum powder lets it glide inside which also helps during the installation.
These tubes hold air better. There is less air lost over time compared to Butyl innertubes.
They can be repaired easily with sticker-patches! For bicycles there are special repair-patches available and all it takes is a clean surface. On a Butyl-innertube you need to vulcanize the patch...a whole procedure…not so on these tubes where you simply put such a adhesive-patch over the hole. We had our own Eclipse-patches made but they are also available from Park-Tool or those doing these tubes now...
If you want to see some innertube weights click on the link below which leads you to my Flickr-Album where i show lots or items on the scale:
https://www.flickr.com/photos/ottospeed/albums/72157673197341717
Needless to say i ordered 3 pairs of these Stark innertubes....let's see when they actually arrive. If they are able to deliver the bikes with them inside it says they have managed to get rid of the high percentage of reject goods we had when we started this project...
Informative.
Thank you luckynino.
What is the main issue with making them?
Perhaps getting the valve stem bonded and sealed?
Great stuff! Like I‘ve posted before, I tried fat bike tubes too and found the difference very noticeable. The only thing I worried about and could never really test was how those thin tubes wear in the tyre. I‘ve had thin standard tubes wearing through in hot weather. What’s your experience with fat bike tubes and how do you think will the new plastic tubes perform in this regard?
As mentioned i think it is mandatory to use TALCUM POWDER inside the tires to prevent inner tubes from sticking to the tire. Talcum lets them slide around inside which also prevents torn valves and also rubbing of the tube itself. I use these ultralight Fatbike tubes for years in my MXers and have no "wear issues".
The biggest issue is the seams. Wheter it is around the valve stem but also the seam which connects both ends to form a closed innertube. Polyurethan needs a very specific temperature to "melt" and since the tube has like 0,5mm of sidewall thickness or even less it is very critical to get that right. Shown below such a seam under water during prototype-testing...lots of minor air bubbles....no good.
Here's a picture of a even lighter prototype of a 29" MTB innerube we did: wall thickness was just 0,2mm !!
But there was lots of try and error before they actually hit the market....
Testing the ultralight tubes in the swiss Alps...usually guys would use heavy-duty innertubes or Tubeless and sturdy "Enduro" tires for this kind of terrain...i was using the 58g innertubes with conventional, lightweight & foldable XC tires.
Thanks. All interesting and possibly point to why the Stark tubes are unusual.
I've just fitted a 1.90 x 29 in place of a 2.25 x 29 on my mountain bike.
Can the polyurethane tubes you were doing expand to cover that sort of small variation safely?
By running a 1.9 tube inside a larger 2.25 tire you obviously strech the tube quite a bit.That's no big deal on a Butyl tube...but obviously the Butyl gets streched and thinner and therefore is more prone to flats. The Polyurethane is not that flexible. It might cover this change in size however the already uber-thin material gets streched even more....and it won't go back! Once you have the Poyurethan streched it keeps its size.I wouldn't suggest it. So i guess Stark did those tubes for 120 wide 19" rear tires...you can easily fit them in slimmer tires but going larger is going to strech them which makes them weaker.
(By the way - on a MTB go Tubeless! No tubes but adding liquid sealant! I actually invented the whole Tubeless-thing in 2000....that was ME over here in Zurich Switzerland as i was a crazy weight-weenie back then and was looking for a way to save weight on innertubes....). That's actually where it all started...my friend then did the ECLIPSE TUBELESSKIT which were the first sold tubelesskits on the market ! Before Stans Notubes and all others started selling similar products. Also the lightweight innertube thing was because of my crazyness (obsession) about losing weight on bicycles. I actually carried this over to my MXers years later when i picked up riding again in 2013.
Ok. Good information.
With that butt joined tube could you telescope the tubing, bond it, rather than vulcanise, and use that stronger area for the valve?
Pit Row
Nino’s post are always some of the most informative. Glad to see your still around, your project bikes are the best builds I’ve ever seen.
Thanks
it's like 7 years now i'm competing in the italian vintage championships. So my projects are now more focussing on vintage bikes but since the italians have very restrictive technical regulations there is just very little margin...still enough for me though - i like that!
I actually became italian 125cc champion last year and we raced on tracks like Arco di Trento (Pietramurata) and also famous Maggiora...some of the most iconic tracks in MX.
My vintage machinery...in front my original racebike of 1989 (VRP Mugen Honda CR 125)....in the background the actual '89 racebikes. Now guess what kind of tubes i mount
^Grouse bikes.
I did like 4 days at Moab on a fat tire mountain bike tube just cuz that's what I had on the bike from racing the AMA district racing. No flats unbelievable I just made sure to keep plenty of air in it and I was real careful installing it.
Well - i actually race the same pressures as always. If you need to go up in pressure it might not be ideal for you. And it might have been the fear of the thought of getting a flat which made you inflate more for security reasons....For me lightweight parts don't have to compromise performance...they should only alter it !
So based on the posts by Nino, these tubes don't stretch very well, or at least should not be stretched out because they won't return to their original size. Being that Stark Varg sells tires on their website and they specifically only sell 80/100 (80mm x 80mm) fronts and 110/90 (110 x 99) rears and give no other options, does that mean you can only run those size tires on these tubes? A 90/100 front (90mm x 90mm) and 120/80 rear (120mm x 96mm) are out of the question then? What happens when you switch tire brands and get a manufacturer who massages their tire measurement numbers like Michelin or Hoosier? Is there enough play in these tubes that they can still work properly?
Experience will be the best answer of your question. I asked the same re bicycle sizes.
Seems that the tubes are like the Stark; prototypes and with extremely limited availability, so that experience is not going to be had soon.
I think that if featherweight urethane tubes where easy, reliable and economical, and gave the traditional tube makers no liability issues, they'd be on the market.
well - they are extremely difficult to manufacture. The technology ours was made was medicinal technology to extrude such thin material...as mentioned the seam is another difficulty and obviously the raw material itself is costly to start with...
Unless you can get your friend to do it.
Just got a notification from DHL that my Stark tire tubes are on their way, should be here (Canada) in a couple days. I placed my order on June 8th.
Now, do I order the bike to go with the tubes..? Estimated delivery date would be January 29th, 2025 if ordered today.
Me too i got a mail that my tubes are on the way...
They're here...
21" front: 131g
19" rear: 154g
Just for comparison reasons i also show a regular , lightweight (!) 21" MX front innertube ...check the weight and size difference!
21"
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