JonM

Hi Guy, The rim is old but as clean as I can get it. It's been rubbed over with emery, wire brushed and Dremel polished with an abrasive. Any burrs or edges I took back and smoothed. The tyre not seating occurs at different points around the rim, as opposed to there being one 'problem area'.

Given up and ordered Michelins! When they arrive next week we'll know if it's the tyre or my technique. BTW. I'll still have this Vee Rubber rear so if anybody gets any ideas feel free to share!

Thanks, Chris. The tyre (& rim) is lubed with Putoline tyre soap, applied generously and was heated with a tyre warmer used for racing motorcycles. It's been bounced, hit with a mallet and left overnight at 60psi. I've trimmed the rim tape to ensure the tyre bead isn't binding on that and done my best to get it positioned 'square' before inflation to offer the best chance of the bead getting over the inner rim lip and out to the wall. I'll also add that before starting I lightly sanded the rim with emery paper to remove any oxidation, then wire brushed and finally gave it a going over with a coarse polishing wheel on the Dremel. I'm not totally green when it comes to this, but am totally stumped- hence wondering is it just a bad tyre?

Thanks guys. The valve core is still in place and I'm using only a foot pump, but as there's a tube I didn't think that'd matter? (my understanding is that a compressor blows in enough air to force the bead to seal whilst inflating tubeless. Because this is tubed I wouldn't have thought inflation speed/rate mattered?)

I worked up to 60psi over various cycles of inflating, deflating, using levers to encourage the bead over the inner lip & repeating. Inevitably I just end up 'chasing' the unseated part around the rim.

I'm afraid I need to resurrect this thread! After everybody's advice I decided to fit a tubeless tyre on the back with a tube, and because I'm trying to keep costs down I bought... ..Vee Rubber. (I can hear laughter already). So b**ger me, the rear is tight. I ended up putting it in my race bike tyre warmer and using copious amounts of Putoline tyre lube. Once on, however, it won't seat. Probably a quarter of the tyre won't meet the rim wall, it stays in the centre channel. If I deflate and lift the bead out of the channel, it then pulls 'tight' elsewhere and that part of the bead drops into the channel. Am I doing something wrong or is it my budget Vee Rubber tyre?

Chris, I agree on the sealing and also on the logic. The bike is rough and with a full rebuild won't be anything but that. I'm not averse to renovation (my R1 has had a top end rebuild in 2019 and I took the engine out. I also rebuilt the calipers, changed the rad, thermostat, starter relay, rear shock, master cylinder, clip on's and countless other things). I did it because it was fundamentally a good bike and deserved it. (see pic) This Gasgas doesn't! Plan is to ride it and enter a few trials. I have road raced and raced motocross, so have intentions of taking it further. I could cut my losses and sell it, but the engine seems good- starts well, no nasty noises, no smoke etc. I'm a set of tyres and a few spokes away from having a rideable bike. (fingers crossed)

Thanks, Greg. I'd still need the Morad rim sealing strip as that has valve, or do you advocate fitting a separate valve (like we do in cast wheels) and sealing tape? Tbh I'm siding with a tube in a tubeless at the moment. It's £20 for a sealing strip and I have neither a compressor not fitting mousse to properly mount a tubeless. I'm also concerned that more spokes might yet ping and I'll need to replace them, so an adhesive sealing strip would be ruined by me lifting it to replace a spoke.

Option 3 sounds good! I understand running a tube inside the tyre is going to reduce the compliance of the tyre a little, and that I also won't be able to run quite as low pressure but with what I've got it seems the most cost effective solution. A Waxoyl type product is a good shout. As for riding, I'm looking forward to getting more involved. I've dabbled with different two wheel sports with & without engines, so hoping there's a bit of crossover.

I'm only replacing the spokes I have to, which is probably 8 or 9+? (two broken/missing + loose spokes which are seized and can't be tightened). If I replace rim + full set of spokes I'm looking at c.£200 on a wreck of a bike. Regrettably I don't have £200 but even if I did, I wouldn't spend it. This is my first trials bike and I need to see how I get on. If I decide to take things further I'd either sell the bike 'as is' or break it for spares. I need to be pragmatic and given the overall state of the old girl, she just doesn't warrant the kind of money required to make her competition worthy. I'm ever so grateful for all the help, though, so to recap: 1) Fit a tubeless tyre with a tube. 2) Fit a tubeless tyre, get hold of sealing strip and look to find a low acidity silicone sealant so I don't do any further damage. Option 1 or 2?

In principle I agree but in this instance I just don't think it's worth the cost and effort. When I picked the bike up I could see it was well worn but with eBay I do believe you have to 'suck it and see'. I could see it was rough but that's the game. I picked it up in December before lockdown and repacked the mid/end silencers, changed plug, air filter & gearbox oil. Forks are f**ked but have had seals + bushes replaced anyway. The back wheel had two missing spokes but plenty more loose, and of course they're all seized. Nightly for a week I oiled them with penetrating fluid and took a blowtorch to them. Some freed, most didn't, so I'm £40 into new spokes + nipples. Guess what I'm saying is I bought a wrong 'un and I'm just throwing money into a pit. I'll do what needs to be done but no more, as it'll only ever be a tired 20yr old bike.

Woody, thank you so much. Everything answered and so my best course is to buy a tubeless tyre and run it with a tube. (The tyre I took off was actually a tube type tyre, so a bit naughty.) I've cleaned the rim with abrasive brushes and emery cloth but still looks like this:

I'm sorry for asking but I'm a bit lost and usual methods of getting answers aren't working... I've recently bought a heap of a 2001 250 TXT (eBay, and yes, I should've walked away) and last week removed the cracked, nasty rear tyre. I couldn't get the bead off on one side so ended up cutting it off. It was a Barum tyre with innertube, but I thought it odd no rim lock? So question 1- In 2001 did the TXT have tube front & tubeless rear? Question 2- the rim is nasty and corroded inside. Could this be a reason for running a tube (because it wasn't sealing well?) Question 3- if it's a tubeless rim but I choose to run a tube, is it better to buy a tubeless tyre or tubed tyre? Just thinking about rim wall shape. I think the old tyre had the bead glued on one side to stop rotation (which makes sense if no rim lock) but I'm lost as to whether I should be tubed, tubeless and how to best achieve an outcome?

Hi Guys, the last few weeks I've found myself on this forum almost daily looking for answers so I'm afraid I'm another one who can't offer ANYTHING but needs help! Background: My dad rode trials in the 70's (before moving onto Motocross) and has recently restored a '71 Bultaco Sherpa T which he's taken to a few local trials centres. I've just bought a complete shed of a Gasgas from a typically neglectful owner and I'm finding problems at every turn. I've got general motorcycle experience but nothing specific to trials so apologise in advance for many stupid questions. Cheers!