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I recently purchased a bike with Fulcrum Racing 6DB wheels and Kenda Flintridge tires. They came tubed, and I'd like to convert them to tubeless.

However, in a manual on their site, Fulcrum list that only certain Schwalbe tires are compatible:

Only SCHWALBE tyres of the TUBELESS EASY type for E-Road, Road and Gravel applications (only the products in the tables on page 6) have been tested and approved for Tubeless Easy conversion with the Fulcrum 2 Way Fit Ready profile. Any other type of Tubeless and Tubeless Ready tyre is not allowed.

How serious is this warning practically speaking? I could get different tires, but my current tires are basically new so I'd rather not change them yet. Both tires and wheels fit well when running with an inner tube.

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  • It is official and it said "any other ... is not allowed". It looks like it is an abnormal wheelset. So you should be better to ask manufacturer the reason and confirm if there is any thing so special. – Cray Kao Sep 29 '20 at 10:46
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    @CrayKao no, that's Fulcrum's entry level wheelset for endurance road bikes and gravel. They ship with many new bikes. Comming from one of the biggest players in that market they are as conventional as it gets. This makes this question all the more relevant. And it will soon provide the OP with new data. Cause most will ignore this advise, when we do not hear of many incidents it would show that switching tyre brands is reasonably safe. – gschenk Sep 29 '20 at 12:26
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    Cray may have meant that Fulcrum is abnormal in (officially, as pointed out in @gschenk's answer) requiring that only one manufacturer's tire be used on their wheels. This is not standard practice among wheel manufacturers, hence it's abnormal. If that's what Cray meant, then I agree. However, there is nothing unusual (that I know of) about the construction of Fulcrum's wheels, and as pointed out they are a common OEM spec. – Weiwen Ng Sep 29 '20 at 13:10
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    "Tested or not tested" or "verified or not verified" is what I used to read in the manual and website. "Any other is not allowed" is abnormal. Especially, it is written in an official manual. This is a very strong warning. Thus, it is better to confirm with the manufacturer but not depends on someone's experience or judgment who does not represents the manufacturer. – Cray Kao Sep 29 '20 at 13:38
  • For Campagnolo and Fulcrum it's normal to have a ridiculous set of limitations, probably in order to avoid warranty claims. The question is, is this more serious since there are actually different tubeless systems that may be incompatible. – ojs Sep 29 '20 at 17:38
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A bit of an update, looks like Fulcrum have removed their strict "Schwable only" requirements:

2 way fit ready

2 way fit

and instead insist on a Fulcrum rim tape and refer to a wheel tyre width/pressure compatibility chart. Am I correct to interpret this as any tubeless tyre suitable for hooked rims would be fine?

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  • Hi, welcome to bicycles! It's great to get updated information, thanks! But if you want an answer to your last question you should probably ask it separately. – DavidW Dec 28 '20 at 2:20
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I'll attempt to offer a bit more nuance than the other answers. On road bikes, the downside of a poor tubeless fit is that the tire could burp, i.e. you hit something and the bead comes loose from the rim momentarily, while you're at high speed. Given the high pressures involved, a burp could mean that you lose a lot of pressure instantly. This would mean a loss of control. On a gravel or cyclocross bike, a burp is never a good thing, but you shouldn't lose all your pressure, and moreover you're probably traveling slower and on loose (and softer) terrain. The lower pressures may mean that wider tires are inherently harder to burp as well.

Normally, I'd take a manufacturer compatibility list very seriously. Some examples follow. Note that this paragraph refers to hookless rims, which the OP does not have. Enve tested a wide range of tires on its current hookless rims, and they produced an explicit list, including tires that are specifically not approved, and another list that are specifically recommended for its wheels. Zipp instead says that tires must be compatible with hookless rims, and encourages riders to check with the tire manufacturer. They say that these tire manufacturers explicitly said to them that their tires are compatible with hookless rims. Continental, on the other hand, has explicitly said that the Grand Prix 5000 is not compatible with hookless rims in general, and thus Continental tires appear on Enve's not approved list. Cadex merely has a short list of tires that are known to have failed their testing (NB: they also have transitioned to hookless rims).

However, at least Zipp and Cadex appear to have tested a range of tires. Fulcrum's compatibility information is a lot more terse, and it's unclear if they even tested any manufacturers apart from Schwalbe. (NB: see @gschenk's answer; Campagnolo Germany may have told some German forum posters they only tested with Schwalbe.) Thus, I would assume that more tires than just Schwalbe are tubeless compatible on Fulcrum wheels. The problem is that we don't know which ones might fail. Riders should remember the very considerable downside to a poor tubeless fit on road wheels. Additionally, I personally use tires with latex tubes on the road. They provide similar rolling resistance benefits to tubeless setups, and they are actually more puncture resistant than butyl tubes. They are trickier to mount than butyl tubes and they do require daily inflation, but they enable you to forego the hassle of tubeless initial setup (albeit that's a once and done deal unless you change tires). Because I don't face frequent punctures, I don't see the benefits of changing to tubeless. If the OP does need that puncture protection, then at least Schwalbe is known to make good tires as well.

In contrast, you can sometimes ignore manufacturer compatibility warnings entirely. Campagnolo's (which is Fulcrum's parent company) component instructions frequently warn that mixing and matching with other company components can result in mechanical failures, and possibly even injury or death as a result. That warning is meaningless; I've used third party chains, chain quick links, chainrings, and cranksets, and even a competitor crankset, on a Campagnolo drivetrain. I've exceeded the stated rear derailer capacity for both Shimano and Campagnolo. Fulcrum's tire compatibility warning has to be taken much more seriously than Campagnolo's component compatibility warnings. The issue is that we don't know precisely how much more seriously, and it is difficult for consumers to find out which tires may be incompatible.

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    Road tire pressures are way to high for burping, which can you get when pushing the lower end of pressures (e.g., cyclocross and gravel). Bigger concern is the higher pressures mean the tire bead could climb on a bad rim/tire combo which could lead to a failure. – Rider_X Sep 30 '20 at 5:32
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Don't know abut your jurisdiction, but this warning means that if you ignore it and wheel will malfunction in anyway, resulting with accident that will put you in wheelchair and destroy some property, it will be legally your fault, and only yours, and all the associated costs will be yours to pay.

Even if the risk of this actually happening is small, I'd still prefer a wheel / tire combination that manufacturer takes some responsibility for.

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    Right, that's another point to consider: warranty and liability. – Carel Sep 29 '20 at 11:43
  • fwiw the LBS that sold me the bike is willing to do that conversion with the existing tires, so this might not be an issue (my warranty is through them) – cwj Sep 30 '20 at 5:51
  • @cwj warranty is one thing, liability is another. You wouldn't be able to sue wheel manufacturer for any damages and if you have any liability insurance on the bike, it would probably be void. In the case of a road accident that may have been caused by the wheel / tire, like loss of traction, it would make it easier to find you guilty of it even if it would be a total BS (in my country it is default to assign guilt to the one riding vehicle that's not 100% up to codes and specs). I would hope nothing like that would happen at all, but just in case... – Mołot Sep 30 '20 at 8:11
  • Good point, thank you – cwj Sep 30 '20 at 8:42
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I'd stick to the advice, you don't want to risk a front wheel shedding off a tyre due to incompatibility.

Once the tyres are worn out go for the recommended combination

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    Normally I would agree totally. Enve tested a large number of tires, and posted recommendations that specifically exclude one popular performance tire (Continental GP 5000). However, it’s not clear which tires Fulcrum tested. For all we know, they tested only Schwalbes and then decided that it was too difficult to test others. – Weiwen Ng Sep 29 '20 at 11:36
  • Now in 2020 road tubeless tyres, wider rims, hook-less beads are all so new that it is good advise to be very careful and follow the rim manufacturer's advise. In a few years, if the market has settled then, the answer may, or may not, be different from now. – gschenk Sep 29 '20 at 12:22
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In this case it might be a good idea to contact Fulcrum's representative in your country, or Fulcrum in Vicenza.

Others did as much and were told informally that it is ok to use other tyres that stick to tolerances (cf. forum post in German). However, Fulcrum tested only with Schwalbe's range and can only confirm compatibility for Schwalbe.

Such a course of action may be prudent on Fulcrum's side. There have been issues with fit of tubeless tyres and rims and no proper standard has been established so far. At the moment (2020) a de-facto standard from large tyre manufacturers seems to form, where difficulties mounting tubeless tyres become less.

Testing a tyre manufacturers range is demanding if done with rigour. Before one even starts it has to be established if a tyre manufacturer is consistent in their tyre's tolerances.

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  • That fits with what I was thinking. The issue is that it may be impossible for consumers to know which tires stick to tolerances. This is something we may be able to deduce via word of mouth, but that is vulnerable to all sorts of biases. Additionally, if you know a certain tire had a blow off, that means that someone had to find out the hard way. – Weiwen Ng Sep 29 '20 at 13:08
  • Tubeless tyre and rim standards have changed over the last year. They've gone from hooked to hookless which eases the fitting but imposes tighter tolerances.in manufacture. – Carel Sep 30 '20 at 8:12
  • i agree, this is simply a way to say "don't use tubeless tyres that are non standard" – Vorsprung Sep 30 '20 at 13:21

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