Fcuking picced off

mb london

Appoligies for the title f this thread, but I have just come back from a gentle ride with my boy, we go around a local lake which has some good terrain for him to improve his skills

However, there is a few jumps which I tend to go off, no more than about four foot high. I have done this countless times on my previous bike but on my new bike (trek ex 9 2012) I have had two pretty Nasty falls. Today as I landed the front tyre which is is tubless blew off the rim the front shox compressed and I went over the bars.

Am I missing a trick?? Should the shox be closed while doing jumps, do I have too much pressure in the tubless tyres 40psi) really really hacked of, especially as I had to walk back about 2 miles to get home :evil:

nicklouse

The fork and shoks should never be locked out when hitting bumps.

New type of bike? Need to learn it again.

Chunkers1980

Sounds like it is not just the boy who needs to improve his skills ;-)

blister pus

Not a lot you can do if your front tyre blows off, you'll lose the front end whatever unless your freakishly lucky. Outside of dealing with that issue sounds like your shock and fork need setting up properly specifically for you and you need some adjusting time.

cat_with_no_tail

It sounds like you might have landed a bit heavy on the front. 40psi sounds a bit on the firm side for me, but shouldn't be out of the acceptable range for most rim/tyre combos.
Out of curiosity, what combo of rim/tyre do you use?

As Nick and blister both said, you'll need a bit of time to adjust to the new bike, it'll almost certainly be a different geometry, different balance etc.

Also, let this be a warning that you need to carry a decent pump, levers, repair kit etc to re-seat the tyre. I've been there before, having to push MILES home because I left xyz spares on the toolbox rather than in the bag. It sucks!

mb london

Cat With No Tail wrote:

It sounds like you might have landed a bit heavy on the front. 40psi sounds a bit on the firm side for me, but shouldn't be out of the acceptable range for most rim/tyre combos.
Out of curiosity, what combo of rim/tyre do you use?

As Nick and blister both said, you'll need a bit of time to adjust to the new bike, it'll almost certainly be a different geometry, different balance etc.

Also, let this be a warning that you need to carry a decent pump, levers, repair kit etc to re-seat the tyre. I've been there before, having to push MILES home because I left xyz spares on the toolbox rather than in the bag. It sucks!

I do normally carry all the essentials when out with my normal riding crew but as I was out for a very gentle ride with my 7 year old I didn't bother (lesson learnt I know)

Here's the thing, the bike was bought new although it had tubless tyres put on it (s-works storm) but the rims are the stock rims - bontrager. So I am wondering that as the tyres are not specific tubless rims could this have been the reason they blew off. As I mentioned above I wasn't dropping off a building but merely a 4 ft drop off.

The back rim has previously blown off and I just put a tube in there, maybe that's the way forward with the front ?

DodgeT

mb london wrote:

The back rim has previously blown off and I just put a tube in there, maybe that's the way forward with the front ?

Think you've just answered your own question.

I dabbled with tubeless a while back, and it was burping / blowing off the rim which I couldn't be ar5ed with.

4ft drop off's, depending what exactly kind of drop your talking about - ie to transition or to flat, and if it is really 4ft at that, as 4ft is not a mere drop (if to flat), so maybe landing technique etc may help.

Anonymous

4ft or thereabouts was enough to put me in hospital. Land to not exactly flat but not that nice, coupled with my stupidity and zero understanding of how to do drops.

Anyway, a drop to flat, wouldn't want lock out on that! I can understand a lock out on table jumps and low impact transitions, but anything with impact something has to give somewhere. You or the bike!

40psi for tubeless - sounds very high. Half the reason for tubeless appears to be to run then at low (20, maybe even less!), for the grip. With tubes I run mine at 30. 40 is too hard for me even with tubes, just skips off everything.

Still, for jumps and drops not so sure.

mb london

It just strange as I have done this drop a hundred times on my previous (lesser) bike with no problems, but on this thing the proxy thing just mangled beneth me. Is is fair to say that the primary reason for this was the tyre blowing on me???

cooldad

Or the tyre rolled off because you landed badly. Who knows.
IMO most bikes are far more competent than the rider.

vala

on the stans website they have this formula to work out what tyre pressure they recommend for an individual's weight

http://www.notubes.com/help_center_tire_pressure.aspx

might be worth seeing what it comes out as for your tyres and adjust to suit.

DodgeT

IMO, if your doing jumps/drops, just stick a tube in, it takes all the tubeless faff out of the equation.

Then, if your still having problems, you need to look at your technique. I'm still doing this btw

bennett_346

Forget tubeless, it's a manufacturer conspiracy to charge more for the sealant which is cheaper to buy than rubber to make tubes out of.

nicklouse

mb london wrote:

It just strange as I have done this drop a hundred times on my previous (lesser) bike with no problems, but on this thing the proxy thing just mangled beneth me. Is is fair to say that the primary reason for this was the tyre blowing on me???

And the lesser bike was a? And the new bike is a?

An HT. and a FS?

The rears kick up more on a fully so you will need to change your riding to suit.

mb london

nicklouse wrote:

mb london wrote:

It just strange as I have done this drop a hundred times on my previous (lesser) bike with no problems, but on this thing the proxy thing just mangled beneth me. Is is fair to say that the primary reason for this was the tyre blowing on me???

And the lesser bike was a? And the new bike is a?

An HT. and a FS?

The rears kick up more on a fully so you will need to change your riding to suit.

The old bike was a rockhopper expert 09, and the new on is an ex 9 2012 - which may be finding its way to flee bay before long

styxd

Its not really the bikes fault that you dont know how to ride it properly.

Spend some time learning how to ride before you blame the bike.

bails87

Assuming the forks are set up correctly, if you pulled the tyre off the rim and bottomed out the forks, then it sounds like you nosedived the bike. However, if you're still not sure, pay me petrol money and I'll come and remove the death trap from your property for you.

nicklouse

mb london wrote:

nicklouse wrote:

mb london wrote:

It just strange as I have done this drop a hundred times on my previous (lesser) bike with no problems, but on this thing the proxy thing just mangled beneth me. Is is fair to say that the primary reason for this was the tyre blowing on me???

And the lesser bike was a? And the new bike is a?

An HT. and a FS?

The rears kick up more on a fully so you will need to change your riding to suit.

The old bike was a rockhopper expert 09, and the new on is an ex 9 2012 - which may be finding its way to flee bay before long

Yep. You need to learn how to use the rear suspension correctly. You can not just ride it lik an HT as it WILL buck you off.

What happened is the rear sus extended rotating the bike as it left the drop. Work on what you are doing or go on a training ride session. Have fun.

craigw99

its the bike (you!!) as nicklouse says its the rear sus - he helped me when i started to try jumps and it was all going wrong for me too.. try slowing the rebound on the rear and making sure the sag is 25/30% then take it from there

mb london

I don't think it's me to be honest, I am sure it's the fact the tyre blew off the rim

bennett_346

:roll:

cooldad

I think the bike is rubbish - stick it on Ebay and let some other sucker pay peanuts and find out just how bad it is.

blister pus

This has the potential to be a fantastic thread *fingers crossed*

paul.skibum

Those damn new bikes are death traps - I can't believe a company like Trek with its reputation would dare sell a bike that cant deal with drops. It just seems like it would cause so many problems for their pro riders like Cam McCaul, Shandro, that American fella and Rene Hauslablatterfatter. Surely comeone would have mentioned it to them before now?

Landing on your front wheel from 4ft up will blow through the travel. When the travel runs out it might then puncture the tube/rip the tyre off the rim. My tip is, as they have gone to all that effort to put suspension at both ends of the bike you should probably try and use both sets of suspension when you land.

Apologies for the heavy sarcasm I couldn't think how to reply without it.

bennett_346

I couldn't think how to reply full stop.

bails87

How did ripping the tyre off the rim make the fork bottom out?

The tyre was a symptom of a crap landing, not the cause of it.

mb london

Quite happy to take a bit of sarcasm and being a somewhat newby on a forum happy to be fish fodder for those who little more than these sorts of communities as company in their life.

But, I maintain that this accident must have been caused as a result of the tyre blowing off the rim, I am nothing like an experienced pro rider but the drop/jump was nothing that a novice couldn't take on.

For the people who have suggested my landing was the cause for the tyre blowing off, surly tubless tyres can handle slightly more than that 4ft drop?? Perhaps it's was over inflated (40psi) or the fact it was a non tubless rim. I am sure my landing was not text book but I could not have been the root cause

Looking forward to hear what you think

supersonic

OK, whattyre, what rim? When it 'blew off' did the tyre completetly come off? Just one bead? A bit of bead? Did you land with the wheel crossed up?

4ft drop to flat is quite a bit for a bike like this if you don't land very smoothly.

mb london

supersonic wrote:

OK, whattyre, what rim? When it 'blew off' did the tyre completetly come off? Just one bead? A bit of bead? Did you land with the wheel crossed up?

4ft drop to flat is quite a bit for a bike like this if you don't land very smoothly.

The tyre was an s-works storm and the rim was a non tubless bontrager rythem. The tyre was still on the wheel, just the bead blew and only a bit of. The landing was fairly ok

supersonic

So it was a tubeless conversion? Sounds to me like the combo is not the best (some don't seal as well as others, or wasn't mounted correctly) and the largish drop for what is an XC wheel and tyre has caused it to bend over a little - the high pressure then blew some of the rest of the bead off. With a tube it may have pinch flatted, or bottomed out, but could have survived.

I bet this wouldn't have happened as easily with a tubeles ready/UST rim which locks into place better. Also wider rims can support the tyre better and stop them rolling over.

mb london

supersonic wrote:

So it was a tubeless conversion? Sounds to me like the combo is not the best (some don't seal as well as others, or wasn't mounted correctly) and the largish drop for what is an XC wheel and tyre has caused it to bend over a little - the high pressure then blew some of the rest of the bead off. With a tube it may have pinch flatted, or bottomed out, but could have survived.

I bet this wouldn't have happened as easily with a tubeles ready/UST rim which locks into place better. Also wider rims can support the tyre better and stop them rolling over.

Appreciate your opinion, thanks