In diesem Beitrag
Tubeless tires are a fascination in itself, in the segment of road bike tires still somewhat exotic. You may have read my blog post from 2020 (already 3 years ago by now), in which I reported on the less nice sides of tubeless on the road bike. But what exactly went wrong and where are we today in terms of standards and best combinations of tubeless rims and tires? Let’s dive in!
Buying guide tubeless road bike tires
For all those who want a direct product recommendation, I’ll make it short. There are tubeless tires that can be recommended in any case, from personal experience and according to the reports from professional journals. I have highlighted the following criteria for recommendation:
- ETRTO and other standards:
- Rolling resistance according to Bicycle Rolling Resistance (https://www.bicyclerollingresistance.com/)
- Test results
Letzte Aktualisierung am 2023-09-27 / Affiliate Links / Bilder von der Amazon Product Advertising API
*) The tires were tested in an independent and traceable mechanical rolling resistance measurement procedure at www.bicyclerollingresistance.com. Watts measured at 5.0 bar (72PSI) (a lower watt value is better).
**) TOUR magazine test issue 08-2023
Why the first attempt (2020) failed to put on road bike tubeless tires
In 2019 and 2020, we saw a rapid increase in the popularity of tubeless systems for road bikes. Back then the very first professional teams relied on this new tech in the racing bike segment. These tires promise fewer punctures, improved rolling resistance values and offer the possibility of riding with lower tire pressure. Which, according to current knowledge, goes hand in hand with higher speed and better efficiency.
So I approached the topic early, as an early adopter. And shouted some curses into my workshop. To put it mildly, not everything went smoothly.
Some reasons for the difficulties were:
- Incompatible components: At that time, there was no ISO standard. Rims and tires of different brands did not always fit together seamlessly. This led to tubeless setup problems and leaks.
- Inadequate sealants: The sealants of the time were often unable to seal tires efficiently. Because on the road bike we ride significantly higher air pressures than in established tubeless systems, eg. on the car or mountain bike.
- Poor kits and components: In my test I worked with DT Swiss rims and the manufacturer supplied tubeless valves, which turned out to be a total flop.
- Missing standards: Cross-manufacturer standards were still missing in 2020.
However, the most important reason is and remains the issue of standards. Today there is a result of corresponding committees and specifications of ISO. That was all quite different in the past. The first standard came from the big brands Shimano and Hutchinson Tires that they tried to establish in 2006, but it was hardly echoed in any product. Specifications of other manufacturers, e.g. Mavic’s Road UST, followed, but also did not find much recognition on the market.
This resulted in some tires having excessive manufacturing tolerances. Rim manufacturers tried to compensate for this. In combination, this could mean: too big tire on too small rim. Or too small tire on too large rim. Although it should always be “622mm tire diameter”, there is always a tolerance built in. And this led to the fact that tires were impossible to mount on the rim, or in the opposite case catastrophically “burst” from the rim.
Compatibility – Warning!
Some tires specify a maximum air pressure (max. bar / PSI), which can be incorrect and dangerous for tubeless. For example, my Schwalbe Pro One TLS tires have a max. 7.5bar air pressure on the flank. This is dangerous and misleading!
What is meant here is merely the max. air pressure according to tire manufacturer – however, the maximum air pressure for your wheel is to be defined in combination with the rim. With the introduction of tubeless, the max. air pressure of tire and rim. For many tubeless rims and all TSS rims (see below) a maximum air pressure of 5.0bar (72 PSI) applies – no matter what is printed on the tire flank.
The current standards: What does the ETRTO say?
The European Tyre and Rim Technical Organisation (ETRTO) has recognized that clear standards are needed to support the introduction of tubeless systems in road cycling. They have given specific guidelines for the dimensions of tubeless tires and rims, ensuring that both parts fit together seamlessly.
The standards define parameters such as the inner rim diameter, outer tire diameter, rim inner width and other technical data that ensure that the tire and rim interact correctly.
Committees and manufacturers: What standards have they agreed on?
A working group of the ETRTO, consisting of leading manufacturers of bicycle tires and rims, have now also adopted standards for road bike tubeless tires. Brands such as Zipp, Mavic, Schwalbe and Continental support the dimensions specified by ETRTO. This means that if you buy a tubeless tire and a tubeless rim today that both meet the following ETRTO standards, you have a much higher chance that they will fit together without any problems.
This also finally means that there are now “reliable” labels on products. Which work universally between different tires and rims. In addition, the structural design is the same, because it was not yet clear how the rim bed should actually be best constructed for tubeless. Classic with hooks or without (straight inner side wall)?
A key outcome of the working group was agreement on such tolerances on the tire. Often manufacturers of tires had chosen them very narrow, which led to the fact that tubeless road bike tires were extremely difficult to mount. This makes it difficult for a tire to blow off the rim. But what benefits safety is more than tricky to install.
The official name for tubeless systems that follow these standards are called“Tubeless Crochect” (TC) for rims with hooks and“Tubeless Straight Side” (TSS) for hookless rims.
Tubeless “TSS” rims now have no more hooks holding the tire extra secure! What sounds contradictory at first is said to be helpful in the production of modern ultra-light carbon rims. Tire blow offs are said to be prevented by the fact that these rim and tire combinations may not exceed 5 bar (72 PSI) of air pressure.
The best combinations for road bike rims and tires
While many combinations that meet ETRTO standards should work well, there are some combinations that have proven to be particularly reliable and powerful in practice.
It is important that manufacturers are as transparent as possible about the products with which they are compatible. So rim and tire manufacturers often give out which combinations you should expect good results with. Namely some rim producers will have a list of specific tires they were tested with and support the correct ISO standard. Or, at least, with which tires which rim is compatible and safe.
According to the North Rhine-Westphalian manufacturer Schwalbe, all TLR-/TLE- models (starting from manufacturing year 2020) are compatible with TSS and TC.
With Continental only certain tires are compatible with TSS and TC. The magic word here is “TR” – Tubeless Ready. All tires, such as the “Continental Grand Prix 5000 S TR” always carry this reference in the product name and on the tire sidewall. Tires without “TR” in the name are not intended for TSS/TC. The corresponding products came onto the market relatively late (2023). Previously, the tires were also theoretically compatible, but at your own risk, because the tires without the “TR” mark have also a misleading max. air pressure imprinted (well above the max. 5.0bar).
Zipp, Giant and Enve – TSS rim manufacturer
Especially the manufacturers Zipp, Giant and Enve have commited their entire product range to Tubeless Straight Side. Practically all products are manufactured here only without rim flange. This means for the consumer to be especially careful in the setup. The tire must in no case exceed the 5.0bar (72 PSI) specified as maximum by ISO. No matter what is written on the tire as max. recommendation may be printed. This is because there are still manufacturers who produce products that comply with the TSS and TC standard, but use a misleading max. specific air pressure.
Of course, there are many other great combinations out there. It is important that you make sure when buying that both parts – tire and rim – comply with current tubeless standards.
Make sure the tire you choose makes an official statement about TSS or TC. Either on the website or in the installation manuals.
Tips for mounting tubeless tires on road bike
Not all tubeless tires are the same. Already in my first post of 2020 I got a lot of comments that this is all a piece of cake. One had already put on a tire himself and was through in a short time, without any problems. Absolutely – this can and should be the hopeful outcome today! I have now put on many combinations of rims and tires with tubeless on my road bike. There are two scenarios.
Scenario 1: New tire and rim. If the tire and the rim is clean, then the tubeless setup is usually simple. Often a road bike wheel comes with a tubeless rim (without the need of rim tape at all) or comes from the factory with a tubeless rim tape already installed. Everything is clean and tight, the tire just needs to be mounted. A short burst of air (with compressor or reservoir on the floor pump) and the tire sits. In the “worst case scenario”, you may have to apply a little mounting fluid (water with dishwashing liquid) to the tire bead, so that the tire slips better into place.
But it can be night and day. Scenario 2:
It may be necessary to seal the rim first (apply tubeless rim tape). The tire is possibly already broken in or used, maybe you need to refill the sealant or just want to change tires for season.
Or it happens that the new tire sits extremely tight, does not want to hop on the TSS rim (where the rim shoulder is ever so slightly oversized for safety by the rim manufacturer). The tolerances for TSS and TC were chosen extremely narrow by the ISO. And it can be that the tire manufacturer makes the tire extra narrow and the rim manufacturer makes the rim extra large (but still, both within the tolerance range) to avoid a – worst case – tire blow off.
There it remains for me to wish good luck and a thick skin! Now you have to be strong and get all the tricks out of your repertoire if possible. Spit in your hands, roll up your sleeves, and have a LOT of patience.
In general, it is recommended to take at least 24 hours to mount tubeless tires. And not to plan with an immediate ride just right after installation. Even if the tire sits directly, it can lose air much faster in the first time. Until all the small holes are plugged with sealant. This is generally always true for tubeless tires, not only for road bikes.
Best Case Scenario Assembly:
In the best case (which is mostly true for MTB and gravel tires) tubeless mounting is not difficult and follows these simple steps:
- Mount tire on rim on one side and install the valve.
- Pull the second side of the tire onto the rim and at the same time pour in the sealant on the tire sidewall. Then pull this side of the tire completely onto the rim.
- With a floor pump try to boost some air quickly into the tire, usually the tire jumps directly on the rim with a very relieving “pop”.
- Now all you need to do is to distribute the sealant within the inner tire (by rotating movements of the wheel) and check whether the tire holds the air, possibly re-pump. All good to go.
Worst Case Scenario
If everything goes wrong, then the process looks much more complex. Heaven and hell are sometimes so close… The following steps will give you a rough idea of what it possibly can be. In detail, the steps and photos follow right after.
Below the following instructions you will also find a link to a post, specifically on tubeless mounting (including “stubborn tires” and tips).
Tip 1: Let the tire settle into the rim shoulder and stretch
For tubeless to work out the air seal must be kept tight. To do this, the tire must fit extremely tightly on the rim. Accordingly, the tires can only be fitted to the rim with a lot of skill in the first place. Do not use force but try to move the tire ever so little into the rims inner bead. And once the tire sits well you will have to pump up the tire up to max. allowed pressure. In my case, according to DT SWISS these rims are up to max. 5.0bar (72 PSI) allowed. According to Schwalbe, however, the tire is released up to 6.5 bar. So the limit of 5.0 bar applies in this scenario (with conflicting max. pressure information on rim and tire).
To settle a tight fitting tire it is recommended to inflate the tire with tube inside first. This is for three reasons:
a) the tire adapts to the rim and stretches (it “sets”), for this the tire must rest best at least 48 hours with tube and maximum pressure;
b) Misalignments can be detected and compensated (if the tire is not seated correctly in some places); This was the case in my assembly, see pictures of the Schwalbe tire below.
c) In the subsequent tubeless mounting, one side of the tire is already on the rim shoulder and the conversion to tubeless is easier.
The tire must fit perfectly all around the sidewall. In my example it does not, see the picture below the paragraph. Therefore, the tire must be deflated again and rubbed with a water solution on the sidewall. In this way, you reduce the friction and the tire gradually jumps completely on the rim on the second try and some “massage”.
Now the tire remains at least. 48 hour to rest in this position to stretch. I additionally adjusted it further to the rim with a 25km ride, re-inflated to maximum pressure and let it rest again for two days.
Tip 2: Tubeless mounting
So now that the tire with inner tube has now adapted somewhat to the rim, you can proceed to the final step. Remove the inner tube again and fill up the tire with sealant, either through the valve or by the inner side wall. If everything looks good it is now time to again to boost some air into the tire. Now if the tire jumps in and holds the air tight, you will still need to have a look and check the tire pressure. As follows the steps in detail.
After this explosive accident, I was not in the mood to continue making photos for some time. It was time for a break. So in this first attempt it took still awhile but at some point it worked out finally – no more tubes on my road bike.
With all my experience over the last years I now even conducted a summary of tips on tough tubeless projects that you can find here:
Advantages of tubeless road bike tires
Finally, talking about motivation may not be optimal at this point – but I didn’t want to skip the actual part of “but why”. The primary point and goal of this post is to educate on tubeless for road bikes – from a point of view of failure. As I assume this is where we can learn the most. What exactly are the motivations to convert a road bike to tubeless at all? From the perspective of the road “racing” cyclist.
I weighed my wheel before and after tubeless installation. The difference is very small and should usually count only slightly “pro” tubeless. If you compare tubeless with a TPU bicycle tube, then tubeless is even minimally heavier.
Meanwhile, it is considered set that tubeless tires play in a league with latex and TPU tubes. At least I could not find a final study or conclusion which system should have the lowest rolling resistance.
Lower air pressure:
In principle, a pro-reduced inflation pressure movement is forming for bicycle tires, stating that tires with balanced inflation pressure roll faster than blanket pumping of tires to maximum recommended pressure of tire/rim manufacturer. However, a somewhat “medium” air pressure is just as well possible with inner tubes. Only the argument that you are better protected against “snake bite” punctures with tubeless, is practically not valid for road bike. Since this issue usually occurs only off-road.
Puncture protection overall:
Lastly, the most important aspect of the tubeless system. The sealant in the tire prevents minor punctures on the tube, which would otherwise have led to a flat tire. So who had to deal with frequent problems with flat tires due to already sharp stones or broken glass on the road bike will love Tubeless.
Conclusion and recommendation
Would I recommend tubeless for road bike tires?
Yes, but with limitations. It is conceivable that the conversion will work well. But this is not the rule. It can go perfect or be your worst nightmare.
Tubeless technology for road bikes has made great strides since 2020. Thanks to clear standards and better products, it is now easier and safer than ever to make the switch. So if you’re looking for improved performance and fewer punctures, now might be a good time to try tubeless!
Limitations apply in that there can always be unexpected mishaps:
- If the tubeless setup does not work out, then the fall is quite steep, as it quickly becomes a mess.
- You might get lucky with the first setup – no mess, everything worked out without a hitch. But at the latest in 6-12 months you will have to refill the tire or have a puncture. Plan well ahead, familiarize yourself with tubeless patches.
- Be careful with the max. Pressure of 5.0 bar (72 PSI) – best for both TC and TSS rims ALWAYS stay below the limit.
Stay safe and enjoy the ride!
For those who are undecided, TPU bicycle inner tubes are a good idea: