Converting spoke wheels to tubeless

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TUBELESS MOTORCYCLE CONVERSION
A COMPREHENSIVE ONLINE RESOURCE

Updated October 2023

You can convert your spoked, inner-tube motorbike wheels to run tubeless tyres. But after 15 years of doing it and writing about it, for a travel bike here’s my advice:

  • Buy a bike with stock tubeless wheels. Spoked or cast, OEM tubeless wheels ought to seal reliably
  • DIY or getting it done, you must use ‘MT‘ tubeless rims (more below)
  • Consider proprietary sealing applications, like CWC Airtight or BARTubless
  • Fir tubeless tyres which are less porous/leak prone
  • For travelling (as opposed to dirt day rides) Tubliss™ is not the answer
  • Initially at least, I also recommend fitting TPMS to monitor leakage

On this page:
• Tubeless Tyres are a Good Thing – Fact
Why do some bikes have spoked wheels and others alloy?
• Differences between tubed (TT) and tubeless (TL) tyres
• Conversion: Is it safe?
• TPMS – It is safer

Other pages:
• About tubeless tyres and rims
Spoked tubeless rims
• Tubeless: professional (proprietary) rim sealing
DIY sealing ideas (sealants, tapes)
DIY sealing a Yamaha Tenere (2008)
• BARTubeless sealed rims CB500X RR
Tubliss and similar spoke-sealing cores
CWC Airtight vulcanising band seal
Mounting Tubliss™ liners to my GS500R
Why Tubliss™ is not suited to overlanding
• The short-lived Golden Tyre FTS system
• DIY sealing an Africa Twin (2020)
• DIY sealing Honda 300L (2023 – in progress)
Tested: rechargeable £20 tyre pump

Related
Changing TL alloy wheel sizes
TPMS: full article
The best do-it-all ‘adventure’ tyres

82~up-creek
Up a creek; southern Algeria 1982

Tubeless Tyres are a Good Thing – Fact

Inner tubes are an anachronism. Cars and any modern road bike with alloy wheels have been tubeless for decades. Even bicycles are doing it. Running tubeless wheels presents major advantages to motorcycling; all the more so when overlanding.
My overarching motivation for converting spoked travel bikes to tubeless has been to avoid a scenario pictured above: lost and alone up a creek in middle of the Sahara in 1982. It happened again several times on a ride to Dakar a few years later, until I had to ride on and ruin a flat tyre. And, of course, it’s happened many times since and always will.
If you ride alone in the remote areas you want to avoid inner tube repairs. They’re never easy, especially if you’re stressed by heat, insects, onlookers, sandstorms, dangerous radiation levels or marauding bandits. Tyres have got a lot better since the 1980s; on a 2018 trip in Algeria; 12 bikes x 2 weeks x 2000km = 0 flats.

Gluey string plugs; as used on the Dakar, 2023

If you can’t do a tubeless roadside repair (like above), chances are your tyre or wheel (or you) are well and truly buggered. I’ve had trips where I’ve crossed borders on two flat tyres for want of an unobtainable tube. With tubeless, all I need is a pump, a plug, the spike and 10-15 minutes – all available in any outback tyre shop in the Adventure Motorcycling Zone.

Safer: punctures deflate slowly and controllably, unlike a tube bursting, followed by the tyre collapsing instantly. This is the main reason to go tubeless
Easier: punctures can be plugged and reinflated by the roadside in a few minutes. Not over a laborious hour, up a creek in the middle of nowhere, as above
Less hassle: A nail in the tyre (especially in a groove) need not mean an instant flat. You can keep topping up for days until convenient to fix properly
Better mileage: with no tube/inner tyre friction, they say TL tyres run cooler and so last longer
Lighter: less unsprung weight
No need to carry bulky tubes or even tyre levers, but should you have a problem, a tube can be fitted
Even some OEM tubed rims have the recommended safety lip (see below), though not always on the front wheel

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Why are some wheels spoked wheels and others one-piece?

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In the late 1970s ‘alloy’ (cast, forged, mag, composite) wheels came on the scene: a cutting edge, maintenance-free and a cool-looking progression from old-fashioned spokes. Whether they actually saved weight was doubtful, and certainly some early BMW alloys were notorious for cracking. Around 1977 Honda’s riveted Comstar wheels appeared on their CX500 and Dreams (left), but while the CX was the first production bike to come tubeless (afaik), the Dreams still ran inner tubes.

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Tyre technology progressed and just like car tyres, alloys were well suited to tubeless tyres. Running a spoked wheel with no inner tube, air will leak out where the spokes screw into the rim via the nipples. With tubeless, the valve stem and the tyre/rim interface are the only points of leakage. Tubeless valves (right) have rubber seals, and tubeless tyres have special beads (edges) to seal in a suitable ‘MT’ rim.

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Fashion being what it is, two decades into the second millennium in the midst of an off-the-shelf retro revival, spoke wheels now signify rufty-tufty adventure. But knowing that tubeless is safer, some manufacturers have revived the innovative idea on Honda’s mid-1980s XL600M (top of the page): make spoked wheels (cool + rufty) tubeless (safer + better). Now your top-of-the-range, fully spec’d ‘adventure’ version of some BMWs, KTMs, Triumphs and others, come with spoked tubeless wheels while the lower-spec road-plodders’ version will have boring old alloys (left).

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Spoked wheels do still have a place on motorcycles, most commonly on proper dirt and rally bikes where it’s said they’re lighter, stronger, repairable and flex rather than crack. I’m not sure about that, they can crack too under a heavy, loaded bike on the edge of an African pothole. Tube-type tyres are thinner-walled and more flexible (good for dirt traction) and lighter too (good for racing). But rally racers usually replace tubes with mousses (left) or similar solid foam inserts which are puncture immune and said to have an equivalent pressure of just 10-15psi. Otherwise, if you get a flat running tubes you just DNF and push the bike back to the van. It’s not a drama like it can be on the overland.

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But even for dirt racers, mousses have several negatives and are not suited to road use; even firmer ones. Because the set pressure is still low, on a hot day the tyre flex and heat generated by a loaded bike at highway speeds will see the foam break up or even explode (left). And tyres run at soft pressures will wear out much quicker. On long rallies like the Dakar, mousses get changed along with the tyres every couple of days. Disregarding the notorious difficulty in fitting mousses without special equipment, they need to be kept lubed and are clearly ill-suited to long-range motorcycle travel. A mousse discussion.

Differences between tubed (TT) and tubeless (TL) tyres

If you’re going tubeless, should you use tubeless tyres? Yes. The man from Michelin told me a tubeless tyre’s inner carcass is coated with butyl to be totally non-porousTube-type tyres may not have this coating. They also have a different bead profile which was never intended to create an airtight seal.
Also, broadly speaking TL tyres tend to come in 17-inch sizes for larger bikes and tend to be stiffer; 18s are more common for dirt bikes where spokes and tubes (or mousses) are the norm.
Rim manufacturers also have no need to ensure that the metal in tube-type rims are not porous. If you do use TT tyres on your TL conversion (most likely due to tyre-size limitations or preferences), adding Slime or a similar sealant (right) will help reduce slow leakage (as well as punctures). As mentioned below, whichever tyre type you use, having a rim with the ‘MT ‘safety hump is important and TPMS is a good idea too.

Is It Safe?

A few die-hard Flat Earthers once vehemently proclaimed that sealing a spoked rim to run tubeless could not be done. The fact that they’re clearly wrong doesn’t help shake this devoutly held belief. I’ve yet to read any direct experience, even second or third hand, but some nevertheless claim it’s lethal. When actual reasons are given, the possibility of a tyre coming off the rim at high speed is cited (or perhaps the sealant unpeeling). But were that possible, how is it any different from a tubed blow-out in the same circumsyancese?
It isn’t.
Know this: a tubeless tyre deflates slowly, because the air can only escape around the [typical] nail pushed through the tyre carcass (or through poorly sealed spoke nipples or a bad rim seal). When the same happens to an inner tube, the ‘balloon’ bursts almost instantly as the tube collapses and the tyre with it. Sounds lethal and bikes being bikes, I’m sure it can be, but even in all my years of tubed riding I’ve never crashed a bike as a result of a tube puncture (others have).
It’s also possible the DIY element puts some off,
 but there are proprietary wheel sealers now and to me, DIY has always been a part of what’s now called ‘adventure motorcycling’, long before you could outfit an overland bike from an online catalogue.

Think about it. What’s the worst that can happen compared to an inner tube blowing out on a 100mph bend on Kilimanjaro? After a DIY conversion, you may get an annoying slow leak from an imperfect seal which, if unmonitored, may lead to pressures dropping low enough to cause rim damage on a rocky trail or a highway pothole. And when the rim gets dinged you lose the tubeless seal until that dent is knocked back out. I know because this all happened to me following my first DIY conversion on my Tenere.
Meddling with tyres is understandably seen as a risky practice, but how many of us have ridden long highway miles on ‘road-legal’ knobblies like Michelin Deserts or MT21s and actually felt safe on fast, busy, wet roads? It’s not something I like to do anymore because I suspect emergency braking on such tyres could have much more lethal consequences than sealing spoked rims to run tubeless tyres.

TPMS – It is Safer

Read the long version.
Short version: you can now buy a TPMS for your motorcycle for just £35 on eBay. A tyre pressure management system is composed of two replacement valve caps with sensors communicating wirelessly with a display mounted on the bars. 
Result: real-time tyre pressure monitoring. Many people find that DIY or other conversions like Tubliss and BARTubeless gradually lose pressure. This is one gadget I wish I’d had on my Tenere back in 2008, if not all my desert bikes over the years.

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Jebel Saro, Morocco 2008. First DIY tubeless experiment…

4 thoughts on “Converting spoke wheels to tubeless

  1. Ken Gillett

    First Honda Comstar wheels we saw in the UK (and probably Europe) were on the CB250/400 Dream and CX500 and most definitely tubeless. I have only heard of some original GoldWing Comstars using tubes, but never saw that over here.

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    1. Chris S Post author

      Hi Ken, I had a new CB400T in ’78 (just long enough to sell it) and a CB400AT in 1980. I had the auto long enough to get through a tyre or have a puncture. I am pretty sure they were both tubed although this American pdf http://davestestsandarticles.weebly.com/uploads/4/8/4/5/4845046/dbmay78comstar.pdf states the CX500 and CBX were indeed tubeless. I also read this on SuperDream forum; “To keep it even simpler, just stick with this and you’ll be fine: Standard Comstars use tubes. Reverse Comstars are tubeless”.
      The ‘spokes’ may be bolted to a flange on the rim making the rim airtight, but it would still need the MT safety lip inside. I see on ebay the CB900F and similar fours are definitely Comstar MT, but other used Comstars lack the MT lip which a TL tyre sits and seals in. You could go TL but it would be risking problems (as I found to my cost on the XT660Z).

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