Having just resiliconed around our bath tub I can verify that the stuff is extremely tenacious. I'd be tempted to fill the well with silicon sealant, let it curefor 24 hours and then put tape over it. The stuff is resilient and dampens vibration, the consistency when coming out of the applicator means it shouldn't be a problem regarding seepage.
Might be worth the experiment?
That is exactly your problem, I ran tubeless on my mountain bikes for years but the pressures were much lower and the rims were designed for tubeless so no holes for the spokes. however I did adapt a standard clincher rim years ago by filling the spoke holes with household silicon, a bit of a bodge but years later it’s still sealed.
Thanks both - I appreciate that this would probably work but I'm less than enthused by the prospect of the associated mess and mass.. plus presumably it's going to find its way down inside the gap between the rim walls and potentially cause issues during removal..?
@Gunk - totally appreciate what you're saying about MTB pressures and this is one reason I'm not bothered by tubeless on the road bike (along with the fact that I've never actually had a puncture on that bike due probably to the more favourable riding conditions and more recently the fact that I never ride it!).
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This is the principal reason this isn't ever going to work, which I alluded to a while back. These are traditional double wall rims with holes thru to the underside of the spoke, to make replacing spokes etc easier.
Tubeless compatible rims don't have these holes (just the valve hole) - which makes replacing spokes a tad trickier as you need to ensure you don't lose the nipple - but does make them virtually airtight bar the tyre seal and valve hole, which the tubeless rim tape & sealant helps with.
You haven't got a hope in hell, especially at Brompton pressures, of keeping these holes
reliably sealed. And if its not reliable, then why go tubeless, you're better off with a tube and a decent tyre surely? Plugging the holes with silicone sealant sounds fraught with unreliability, adding weight and making spoke replacement very tricky indeed.
There is probably a reason no one bothers to manufacture a 16" sealed double wall rim, the higher pressures needed on smaller diameter tyre isn't
reliably compatible with a tubeless system.
If you'd spent the time wasted on pishing around with this on removing a refitting the rear wheel a few times so you're comfortable doing it in the dark on a towpath it would IMHO have been time better spent.
I do admire your tenacity though.....
Granted some tubeless rims lack spoke holes to make sealing easier / more reliable, however I think if you do a bit of digging you'll find that most "tubeless compatable" rims have spoke holes; which is largely what the tape is there for - to seal said holes. For example, the rims on my Genesis are "tubless compatable" and have a traditional double-walled construction with spoke holes in the outer wall.
There's more than one way to skin a cat and it's surely not impossible to seal these holes effectively - the pertinent question being whether this can be done in a way that's viable in terms of cost / hassle / function / mass etc. One option would be to mimic the way the valve seals and plug each of the 28 holes with an individual bung. I also think that a suitably thick rubber rim strip could also work; providing it left enough room in the well for the tyre to seat... or maybe just a different type of tape that's more suited to the smaller rim. Tbh the PVC tape would probably work were I prepared to use enough of it.
I agree that the pressure is also a potentially problematic factor, but then it's comparable to that being used in road tubeless.
In isolation I'm very comfortable with the process of changing a tube; it's hardly rocket science. What I'm not comfortable with is the prospect of having to do so in the freezing cold / p*ssing rain / pitch black of winter, and the associated guarantee that this would make me late for work if it happened on the way.
As previously mentioned, perhaps unlike the majority of Bromptons my example gets used mainly in a harsher environment than city streets; while there's basically no ability to just fold it up, hop on a bus and sort the tyre later in more convenient circumstances.
Maybe I'll succeed with the tubeless conversion, maybe I won't... but I have no intention of giving up until I've satisfied myself that it's not a viable prospect
So it seems that high pressure + double walled rims + tubeless is not a good combination? Surely someone, somewhere has managed it, even if it's not a commercial proposition yet.
In the world of motor vehicles cast wheels and relatively low pressure tyres are the norm so not much motivation for development from that direction.
In the field of adventure touring motorcycles some of the higher end models do have spoked wheels with tubeless tyres. This is done by using "H" section rims rather than "U" section. The tyre is fitted conventionally but the spokes are attached to the inward extensions of the rim. So the spoke ends remain accessible while the only hole in the rim is the valve hole. A little additional weight is less of an issue with motorcycle wheels and although in off road competition spoked wheels can be argued to be more resilient and repairable than cast ones, it's probably more to do with marketing and appearance in modern times. How long, though, before someone manages to come up with a bicycle wheel that has external spoke/rim fittings? After all, probably a major deterrent to cycling is the imagined frequency of punctures, and having tubeless tyres on a high pressure wheel might give an illusion of unpunctureability, at least.
In past times motorcycle competitors did experiment with running tubeless on conventional spoked wheels. They recognised that pressure loss would occur over a period of time but was outweighed by the ability to survive a puncture without an instant deflation. This would be important during a long distance trial or enduro, for example, losing time getting wheels off and wrestling with the tough, inflexible motorcycle tyres of the era. Probably in the mud and rain, too. On the other hand these were the innovators. Most riders just became adept at fixing punctures.
I suppose that most cyclists too have to develop that skill, while we're waiting for the next development. Meanwhile, there's always slime, or aerosol sealants, even if not always 100% effective.
Potentially yes; with tubeless inherently being better-suited to lower-pressure applications. There are however plenty of road tubeless setups that run higher pressures.. while the double-walled rims aren't a problem in themselves; neither are the spoke holes if correctly sealed.
Thanks for the thought about motorcycle wheels - I've happened across some interesting DIY approaches in that field. You make an interesting point about the spoke holes; as mentioned above some bike wheels do already come with only a valve hole; fitting spoke nipples to these must be an absolute nightmare however!
It seems fairly common to use tubeless sealant inside tubes; the problem being that it eventually dries out and writes off the tube. That said, I wonder if a water-based sealant could be re-activated by the addition of some more water, or whether it's more complicated than that...?
So... onto more mundane things. This week saw a return to the usual commute, and with it increasing dread about the changing weather.
Despite my legs still aching from the weekend's activities, Monday's ride in proved unexpectedly pleasant - with mild temperatures and sun. I also found that a stretch of tow path near Yarnton had finally been cleared; revealing a lot more tarmac than I'd assumed was there; although I picked through the remaining debris warily given the persistant punctures I'd picked up in this area recently..
On account of the nice weather and my reluctance to once more find myself at home, the journey back ended up as a long meander in / around the city; as usual bitter-sweet as I love being here, but know that (for the moment at least) this remains transient.
While there's still plenty of green around on the trees the dead leaves are starting to accumulate on the ground..
Yesterday's commute in was more of what I was expecting; ominiously dark skies with sporadic (thankfully) light / fine rain and a relatively stiff headwind, which further taxed my aching legs. This was completed in the usual base-layer and lightweight walking trousers, although any colder and I think I'd have had to crack out the fleece.
Despite the conditions I did still manage to blag a sausage-stop, ate like a horse throughout the day (due I imagine to ongoing sleep deficit and leg-recovery), had a decent evening in the pub and a pleasant meander home - although again there was a distinctive autumnal chill in the air. Once home I was asleep pretty much as soon as my head hit the pillow; sleeping uncharateristically all the way through until 7 this morning when the alarm signalled that it was once more time to drag myself out of bed and climb back into the hamster wheel..
This morning's weather was a lot more pleasant; still overcast but brighter, fairly still and with little prospect of rain. It was a struggle to get up and out however - last night's allergens to thank for a fuzzy head and puffy eyes, with legs still aching from their continued hammering and arse sore - not sure if the Brompton's saddle is to blame or whether this is again due to sheer amount of riding on relatively bumpy terrain.
Nevertheless the ride in was still very nice; with generally-pleasant fellow-commuters and lots of sights to behold - quite a few other Bromptons today plus some nice other assorted steel including the nice grey Croix de Fer being ridden by an asian girl on the tow path; her bike got a compliment as I passed but I stopped short of extending this display of appreciation to the equally impressive bits of the rider that were perched directly atop the bike..
Today was nothing remarkable however I did stop for one picture - note the static red wagon on the distant A34; a fate I'd also be enduring had I chosen to continue the journey in the car..
Monday will mark the 40th commute on the Brompton. Changing seasons and punctures notwithstanding it's all seeming pretty familiar and manageable now, with the few remaining problems slowly being ironed out where possible.
Clothing remains somewhat problematic, both in terms of effective waterproofs and the opposing requirements of stuff that's comfortable both on the bike and in the office. The current middle ground is lightweight walking trousers, base layer and fleece as required on the bike, then once at the office a quick swill around the key areas in the sink and change into a T-shirt and comfy jumper to make me feel less like a sweaty, shrink-wrapped mess throughout the working day. If the weather's good (so the bike remains outside) the sweaty bike-garms get draped over its bars to dry in the breeze..
The morning routine has settled around a 7:45ish departure and pretty consistant journey time meaning I typically get to work between about 8:50-8:55.. one benefit of missing the traffic being little variation in how long the whole process takes so less requirement to leave a lot earlier than would be necessary in ideal circumstances.
Bag contents are also pretty stable; and while still sub-optimal in some areas and the requirement for a little tweaking its contents generally accommodates most needs and brings peace of mind - although I still sometimes get a sudden feeling of panic that I've forgotten my rucksack..
There are a lot of things to be kept on top of - items to be remembered and electricals to be charged, but the bike has its own set of peripherals (spares, tools, meds) and the bag keeps most things together while the tidier home environment (in some areas at least) helps me keep tabs on the essential that can't live in the bag all the time. While typically disorganised and demand-avoidant, it's nice to have some manageable logistical hurdles to overcome in the name of necessity, and rewarding to find the least-worst solution to situations and make life easier for future-me.
The bike lights are now a permanent fixture due to their requirement more often than not - going on by default in the early morning murk while also being required often on the way home if I don't head back straight away. The rear light has new (Eneloop rechargeble) batteries so should last a very long time; the front much less-so being brighter and only taking a single AA - the current example being old and pretty shafted, so something else that really requires replacement when I can pull my finger out. So far however it's lasted for the week, while I always carry spares and the excellent head torch takes the lion's share of actually allowing me to see where I'm going in the dark.
Meh, anyway it seems I'm rambling again. While viewing the descent into winter with rightful trepidaction, commutes currently remain pleasant and beneficial, while I think the bike has currently offset in the region of 12% of its total associated outlay through saved fuel.
Many jobs remain to be done, and I've finally pulled my finger out and spent proper money on a proper chain (rather than a potentially squiffy one off
ebay). Having heard suggestion that the original-fitment Sram items are poor quality (and having found it to have so far worn at an alarming rate) I'm looking forward to getting the new KMC item on there; although I'm not sure whether to run them side-by-side in the interest of chainring / sprocket longevity, or just to run the original one into the ground before swapping to the KMC chain full time..
I probably also ought to look at some spare sprockets for the rear as I hear these wear quickly too (1:1 with the chain being a common suggestion) although I can't seem to acquire just the sprockets without associated bits that presumably don't wear out..
I also have a couple of spare innertubes on their way since, while I carry puncture repair gear I don't like not having a new tube in the bag for emergencies.