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.

Photo: CAMMTB Winter 2022-23 rides have been posted up - please click on the Runs List link..

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Help! Tyre seating issues

Hi all,
I need some help.
I have a tubeless ready Bontrager Jones ACX folding tyre and I have been trying to fit it on to my nuke proof rim. I cannot for the life of me get it to seat properly. I have tried the tricks I know with no success. (over inflating trying to pop it, washing up liquid on the bead, etc.)
It driving me nuts.
Does anyone know what I can do, or what I am doing wrong.
Yours in frustration.
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Re: Help! Tyre seating issues

Hi Ads

I assume you're trying to run it tubeless, using Stan's Sealant or similar?

I spent about a hundred quid and many many hours earlier this year on trying, and in the end gave up. Occasionally I could get a tyre to pop up with a track pump, but more often not, so I bought a CO2 inflator (more money!) which worked OK - but there are lots of mentions online of CO2 softening tyres and leading to blow-outs, tyre damage etc. I found I needed the CO2 because to get the tyre to pop up, you need a really fast hard blast of air.

I found this on whether to go tubeless or not, and on balance they recommend not.

This seems a pretty good guide to how to set it up - but it sounds like you've probably done this...

I was at Grafham Cycles, and asked them why I was having so much problem (after a month or two, I couldn't get the tyres to hold pressure - they'd last for one ride and then in a day or two be virtually flat and need re-inflating), and they said that you need rims in good condition and you need to keep everything really clean. On a mountain bike?? They said if you can't have and do that, don't bother!

The only thing I will say in favour of my experience is that the first time I changed tyres, after riding for a couple of months, I found four or five thorns in my back tyre but it never went flat, and I didn't even notice any pressure reduction. So, it did what I wanted for a while, which was to ride without getting flats on the trail.

If you want to borrow my CO2 gun to give that a go, let me know!

Dom

Re: Help! Tyre seating issues

Aussie Adam
Hi all,
I need some help.
I have a tubeless ready Bontrager Jones ACX folding tyre and I have been trying to fit it on to my nuke proof rim. I cannot for the life of me get it to seat properly. I have tried the tricks I know with no success. (over inflating trying to pop it, washing up liquid on the bead, etc.)
It driving me nuts.
Does anyone know what I can do, or what I am doing wrong.
Yours in frustration.
Ads


Hey Ads,

I'm very familiar (I think) with your frustration, having converted a few rims to tubeless using the Stan's kits. I've always (eventually) managed to get the tyres to seat using a track pump, but sometimes there's been a lot of swearing and cursing in the process.
Are your rims tubeless or converted? If they're UST tubeless rims, then it shouldn't be too difficult. If they're converted rims using a Stans rim strip or similar, then I've found it pays to take the time to make sure the rim strip is well centred on the rim. I've found the Stans strips work really well, but the Joe's No Flat's strips were too wide for my rims, and so I had to cut them (once installed on the rim) with a sharp knive to allow room for the tyre to seat.
Also, if the tyre you're trying to fit is new, I've found it can help a lot if you can put it on a standard rim and inflate it over night so the bead is straightened out (after it's been folded up in the shop for months...). In addition to that, it can help if you work your way around each side of the tyre, pulling at it so the bead moves up and seats better in the rim. That way, when you go to pump it up, there's less gaps for air to sneak out. Soapy water definitely helps too.
Also, do you have sealant in the tyre already as yr trying to inflate it?
Good luck, and let me know if you want any more help.

cheers,
Rich

Re: Help! Tyre seating issues

Hey Dom/Ads,

I'd avoid the CO2, as it can also react with the sealant and prevent it from doing its job when you need it.
The alternative is to drop past a shop with a compressor, and use that to give you a quick blast of air - that'll almost guarantee to get the damn thing to seat

Re: Help! Tyre seating issues

Hi Rich

That's one of the many reasons why I gave up - who wants to have to find a shop with a compressor every time you need to change tyres!!

Happy Tubed Dom

Re: Help! Tyre seating issues

Been running tubeless all winter & some of the summer for the last two years. Great system, love it on normal rims with stans, even running a 26er kit on a 29er works fine. Use liquid hand soap or a silicone spray to seat, never leak, never need pumping up. My tubless ready mavic wheels are a night mare to fit tyres to mmmmmmmmm
Also have had problems where two 29er ACX tyres have not seated very well, one collapsed, blew off & was unusable afterwards. Even ACX tyres on normal rims can be tight as the last person to pay at a CTC christmas dinner. Could well be the tyres, try a non tubeless tyre, rim & stans and it all works very well.

Re: Help! Tyre seating issues

Yup ... certain combinations of tyre and rim work well, while others simply don't work at all - it's can be a matter of trial + error (I bent a set of tyre levers forcing a MAXXIS tyre onto Giselle's converted rims - blasted thing took about 30mins to get on. Then, once i got it sealed, it had a slow leak ... fortunately, it was a super slow leak, so ok to ride on, just needed pumping up every ride. Strangely enough, a few months later and the slow leak has vanished, so the sealant seems to have done its job.
Anyhoo, enough ranting on about tubeless - i'd never go back to tubes myself, as I've been running tubeless for the last 6 years or so, and only get about 1 flat per year that won't seal itself while riding (and that's usually from a big piece of glass or something similar ...). Now that I've said that, i'll probalby get a flat tonight if I'm out riding .....

Re: Help! Tyre seating issues

Thanks for all the suggestions guys.
Running tubeless seems to be like Marmite.
Duncan, I think you might be onto something about these tyres. I tried on Sat for hours to try and sort it. eventually left it overnight. On Sunday the tyre was still inflated (but not seated). I tried on Sunday with just the tyre without all the gunk on the front rim (same make) and couldn't get it to seat on that one either. Expensive bloody mistake to make. I think I will ditch the whole lot and go back to tubes and my old tyres. Maybe saving a couple of flat tyres isn't worth all this frustration.
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