Cam MTB - the Cambridge Mountain Bikers' Forum

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DISCLAIMER. MOUNTAIN BIKING CAN BE DANGEROUS. YOU JOIN US AT YOUR OWN RISK.

SAFETY BRIEFING.

  • Wear a helmet. Despite recent advances in medical science, brains still cannot be mended nor replaced.
  • Wear gloves or mitts. Hands often hit the ground first. Cuts and grazes invite infection and a hospital visit.
  • Wear eye protection, it only takes a twig or thorn to lose an eye. Crud catchers are a good idea in mucky weather.
  • When downhilling, for your own protection, allow plenty of space behind the rider in front.
  • Bring a bare minimum emergency tool kit and a spare inner tube.
  • Breakdowns are a bore. Plan not to have any by ensuring your bike is in perfect working order.
  • Punctures are also tedious. You can minimise them by fitting latex tubes, slime tubes or running tubeless tyres.
  • Don't ride too close to the person in front. If they crash into a badger, you'll need time to swerve.

Photo: CAMMTB Winter 2024 rides have been posted up - please click on the Runs List link.

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John and the Great Tubeless Debate...

After having a discussion with John, Uncle Tom, Ali and others about the various merits of going tubeless for the winter, I can now state categorically that it's a benefit.

John, Ali and I spent a long journey home from Barrington replacing tube after tube in John's rear wheel until we ran out and had to start fixing them. John would ride a couple of hundred yards, then have a major blow-out. Nothing obvious wrong with tyre or wheel, but the rim tape was worn into the spoke holes to such a point that it couldn't handle the pressure. Odd that it should only happen after we stopped at the pub (the extra weight of beer and snacks maybe)?

I take my hat off to John for not only remaining calm, but then running with his bike down Cantelupe Road all the way to Grantchester. Good effort!

There must be some sort of award due. I reckon at least 5 blow-outs in less than 2 miles, but I wasn't counting.

Anyway, I was home by 1-30am so not too bad...

John and the Great Tubeless Debate...

ok, so assuming some of us may want to dabble with the tubless option, which variety of liquid goo....and how much for a 26" or 29" wheel is best.

also any type of tyre to avoid?

pat.

Re: John and the Great Tubeless Debate...

Just to be an annoying arse I've been running tubeless for the last three winters(not summer) even small cuts can be sealed by stopping & rotating wheel so cut is at bottom, wait 30 secs, add a tad of air & off you go.
It's a yes

Re: John and the Great Tubeless Debate...

Soz guys, feel real guilty for leaving you to it-assumed with 3 of you there it would be o.k. --perhaps my spare tubes may have helped. Been running mud X's tubeless for a couple of years now with no problems-just bog standard rims with Stan's rim strips & sealant. Only problem I had was when I did a completely incompetent high-speed attempted bunny hop & twatted the rear wheel,burping the tyre-took several pump-sessions on the way home (Oooeeerrr missus)but sealed again eventually.
Always carry a tube though.
As for tyres, both Tom & myself have tried to seal Conti's & failed but Tom did suggest more rim tape may help seat the bead initially.

Re: John and the Great Tubeless Debate...

Try Continental Revo Sealant. It's ammonium and protein free, so won't chemically corrode the tyre (unlike some brands of sealant).

It's an enhanced version of the stuff they've been using to mend car tyres...

Re: John and the Great Tubeless Debate...

is it also lactose free, if so what flavours do they do?

Re: John and the Great Tubeless Debate...

I've run tubeless for about 3 years now. Its generally great, the improved traction is noticeable and the lack of punctures is nice.

However the system is not infallible. If your running low pressures and dick about jumping, 180 endows etc it’s pretty easy to burp / rip the tyre off the rim.

Also you need to remember to top up the sealant every month or so, otherwise the tyre will go dry and wont seal new punctures.

I've also had homemade valves (cut from an old inner tube) come apart (stem breaks away from the rubber). Spend the cash on pucker valve stems.

Conti tyres are pretty tricky to seal, however they do eventually. You have to use a compressor. I run / ran speed kings and mountain kings. The Kevlar speed kings are particularly hard to seal, its best to leave them inflated for a bit with tubes to stretch them out.

For the last couple of years I’ve used stans 355 and crest rims. These rims have a lower profile and so I get less pinch flats (cuts in the tyre itself) in rocky parts.

One problem with tubeless is the feeling of infallibility it gives you riding through rock gardens, however you soon find its pretty easy to cut the sidewalls of the tyres if you really hammer into a sharp rock. A piece of heather stuffed in the hole usually fixes it!
All in all I think it’s worth the extra hassle and would never go back to tubes.
Chris

Re: John and the Great Tubeless Debate...

It all sounds so complicated and so much faff! You will all have to persuade me it is easy and cheap in the pub.

Re: John and the Great Tubeless Debate...

Getting UST tyres over UST rims is a b1tch, though.

Last week Uncle Tom told me a trick to use, i.e. always leave the tyre around the valve until last. (Is that right, Tom?) Unfortunately I don't have the UST rims anymore.

Maybe I'll try the Stan's conversion route at some point, though I always thought there must be an advantage to using UST.

Re: John and the Great Tubeless Debate...

It's more weight, if you ask me. Thicker tyres, fluid slopping about all over the place, compressor in the backpack (already in there if you're Pat...)

I might try tubeless one day, but I get on well with the latex tubes so I'll stick with them until I don't.

But I'd never go back to butyl tubes, no.

PT

Re: John and the Great Tubeless Debate...

I am a tubeless virgin! so far so good. the bike came with tubeless summer tyres + tubes! The tyres fitted for winter are Maxxis Beavers (not officially tubeless). The weight is marginally less. 100g of slop and a valve + tape in exchange for 150g of tube.

The tricks for fitting tubeless tyres are as Riaan says to remove them starting at the valve, and put them on finishing at the valve. Doing this means the opposite side can be sunk into the well of the rim, making it much easier to get the last part of the bead on. You cannot fit a motocross tyre ubnless you do this. My thoughts so far, are that it is the way to go for the winter. However for summer I will probably revert to Latex tubes, as tubes make it simpler to swap tyres should it rain at a race. There are plenty of videos on youtube showing how to do it. One thing I did after watching the videos., was to hang the wheel from a bike stand. this makes sure the tyre is round and fits the rim closely.

ps bad luck John and Mark that sounds like a nightmare trip home

Re: John and the Great Tubeless Debate...

What happens to the older fluid? Does it cure and build up in the tyre?

Re: John and the Great Tubeless Debate...

Now you are just messing with my mind! I will no longer believe there are any other Clare/Claire/clair people until I see them with my own eyes.

Re: John and the Great Tubeless Debate...

Sorry, that was my fault for not clearing the nom de plume I used the other week, when I was messing with your mind.

But the question still stands...what happens to the old tubeless fluid if you have to keep topping it up?

Am I making myself clare?

PT

Re: John and the Great Tubeless Debate...

It's mostly water I believe, so I guess it evaporates. If you let the tube dry out you get rubbery deposit on the inside of the tube. The tyre tends to wear out before it's a weight problem.