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Gixxer 4 ever
27th June 2004, 21:27
Quick question. How often do those of you that change your own tyres replace the valves in the rims? "tubeless tyres" And those that have it done at the shop?

Holy Roller
27th June 2004, 21:31
The shop puts new ones in when changing the tyre.

Question?
Does anyone know if there are 45 or 90 degree valve stems or attachments? I find it differcult to inflate the tyre with most air lines at the service stations, usually have to bend the filler pipe stem just to get it onto the valve.

pete376403
27th June 2004, 23:50
There are 90 degree stems (guy at work has them in his Speed Triple) and I wanted TTS to put one in my wheel when they put on the new tyre. They said the old GS wheels are not suitable so sold me a 90 degree adapter that screws onto the standard stem. Handy and only $5

Motu
28th June 2004, 07:48
It's a pain trying to get air into tyres with what is supplied at the service station - a 90deg valve is a good idea....but at speed it will bend and weaken the stem where it goes into the rim,of more concern to criminals who speed,but over time the stress will still weaken it.

scumdog
28th June 2004, 08:29
It's a pain trying to get air into tyres with what is supplied at the service station - a 90deg valve is a good idea....but at speed it will bend and weaken the stem where it goes into the rim,of more concern to criminals who speed,but over time the stress will still weaken it.

Yep there are enormous centirfugal (sp?) forces at work when a wheel is spinning at speed, avoid the 90deg fittings if you can, use a longer valve stem and you might get more flex out of it to get the service station fitting on to it a bit easier.

Years ago a drag racing team couldn't figure out how it was that after a fast run the front tyre went flat, they discovered that the wheel was spinning so fast that the centrifugal force was causing the centre of the valve to get flung outwards enough to let the air out (just like when you push it in with a nail)but when they stopped it was back in position - valve caps was the cheap fix

curious george
28th June 2004, 15:46
Jeez scumdog, I thought that old hooey about centrifugal force and flat tyres died out years ago!!! To get anything like that effect, you need to spin the wheel at about 20,000rpm or something! It just aint gonna happen. Ever.

What about those little valves which can spin on its insertion point? Anybody used them before? They look neet, and a lot easier to inflate at the garage

scumdog
28th June 2004, 16:05
Only quoting what I read in the write-up on the dragtster, funnily enough the problem went away when they started using valve caps though.

Maybe some physics geek could weigh the centre out of a tyre valve and then calculate how fast a rim would have to spin for the spring to be overcome? :Offtopic:

vifferman
28th June 2004, 16:32
Maybe some physics geek could weigh the centre out of a tyre valve and then calculate how fast a rim would have to spin for the spring to be overcome? :Offtopic:It's not just the spring - doesn't the air pressure also work to push the valve shut? Or not?

Big Dog
28th June 2004, 18:59
It's not just the spring - doesn't the air pressure also work to push the valve shut? Or not?
That and the valve opens the other way. the centre needs to go in.

Milky
28th June 2004, 20:55
On a slightly related note, I know you can put tubes into tubeless tyres on the BM - 4.00/18 style tyre, I guess that means 100 profile... is it possible to do the same to lower profile tyres?

Motu
28th June 2004, 21:16
No problem with that,but I've found sometimes they won't seat with a tube in them - just yesterday I saw a guy beating a 4.00x18 on his TLR200 to death with 60psi in it,but no way would the bead seat...that's a trials tyre though....

Milky
28th June 2004, 21:25
where there's a will there's a way my friend.....

Gixxer 4 ever
29th June 2004, 06:51
,but no way would the bead seat...that's a trials tyre though....
A good wetting with a soapy dish water or if that will not work I use CRC over the water. Now do not shout at me as the CRC will not affect the rubber. (plastic or what ever they are made of) Read the label. I have used it from time to time for years and had no tyre rubber problems. Also use this to fit tyres to alloy rims on the wife's car. Hate them alloys.

Motu
29th June 2004, 07:14
Let's get into a rageing debate - I say use WD40,it's much better..beleive me,I've tried everything and they don't seat,ever.

F5 Dave
29th June 2004, 12:19
Let's get into a rageing debate - I say use WD40,it's much better..beleive me,I've tried everything and they don't seat,ever.


How about using Probe? :buggerd:

It's water based & claims not to affect Latex

Gixxer 4 ever
29th June 2004, 12:27
Let's get into a rageing debate - I say use WD40,it's much better..beleive me,I've tried everything and they don't seat,ever.

So you ride with them like that? Never I hope.They do go on but you have to be patient and deflate use more soapy water. Apply with a 25 mm clean paint brush. I apply the soapy water to the tyre before I put it on the rim because it is hard to lub the inside wall of the tyre once you have it on the rim. If this does not work pop the beads on the side you are having trouble with relub and try again. They will go on but you got to spend time. Only inflate to 40 psi when trying to install.

Motu
29th June 2004, 14:57
Yes,I ride with them like that - on my trials bikes.No,they don't seat,but you are welcome to come up and prove me wrong.When I got the TLR200 ready for it's first season I got a new tyre fitted and tyres swapped from KT250 to TLR at Cycletreads - oh,you won't get the front tyre to seat said I....no worries mate,we know what we're doing.After destroying a rim lock and bursting a tube he said I might have to ride for a bit to get it to seat.18mths later it's still not seated - do you think I should take it back?...

Please don't respond with more how too's,I have my own tyre machine with motorcycle adapters,done a few tyres in my time I have....

F5 Dave
29th June 2004, 15:26
Aww c’mon I thought you wanted a rageing debate.

Ok well changing the tack (if not the tire <_< ) my Beta had a tubeless Rear rim & they had just inversed the spokes & had a rim with a shoulder for the spoke ends. On My GasGas they use a normal rim with straight pull spokes & just fill the centre with Goo to seal the rim to make it tubeless.

So my question is why not the front as well?

Motu
29th June 2004, 17:07
Aww c’mon I thought you wanted a rageing debate.
?

CRC is absolute crap,WD40 is the reals mans lube,CRC is just perfumed kerosine - WD40 is...um...perfumed kerosine,but smells waaaay better! I like Vegemite too,Marmite is for CRC lovers.

I don't know if it's only trials tyres,but the tubless ones just won't seat with a tube.A lot of the modern bike riders will move a part worn tyre onto their twin shock,or sell them to a twinshock rider,some will seat,but they all have problems. I normaly buy a tubed tyre for a tubed bike on the road.

F5 Dave
29th June 2004, 17:13
What about that Wynns stuff Viscolene? I was given some & it makes a good cable lube.

Pepsi vs Coke, Stella vs Becks

Though if you saw that telly program on marketing apparently all beers taste the same it's just an image you buy.


(the test was a bit flawed though)

Gixxer 4 ever
29th June 2004, 19:40
Please don't respond with more how too's,I have my own tyre machine with motorcycle adapters,done a few tyres in my time I have....
That was not my intention. You have done all that can be done so I have to accept your comments. I started this thread to find out how often people pull and replace the valve steams on their road bike tubeless tyre rims. Can you comment on that? I have never changed one and have no problems but some people replace them with ever tyre. How hard are they to put in? Cheers

Kickaha
29th June 2004, 20:49
That was not my intention. You have done all that can be done so I have to accept your comments. I started this thread to find out how often people pull and replace the valve steams on their road bike tubeless tyre rims. Can you comment on that? I have never changed one and have no problems but some people replace them with ever tyre. How hard are they to put in? Cheers

They should be replaced every time the tyre is changed,they flex as the wheel rotates and they start leaking around the base once they get old,this may not ever happen but it's only got to happen once to ruin your day (and tyre)

Any good tyre fitter will replace them each time without being told,I also recomend using metal valve caps instead of plastic,they have a better seal and will contain the air if the valve does crap out.

Gixxer 4 ever
29th June 2004, 21:37
They should be replaced every time the tyre is changed,they flex as the wheel rotates and they start leaking around the base once they get old,this may not ever happen but it's only got to happen once to ruin your day (and tyre)
metal valve caps instead of plastic,they have a better seal and will contain the air if the valve does crap out.
Thank you. That's what I was after. I felt this was the case but if no one has ever had a problem I would just leave it the way it was. Your right about the flat being a pain. One of the bikes I rode with to Paeroa this year had one. Big job to selvage. I now have a repair kit. Think I will change the steam when I do this tyre next month. Thanks

Motu
29th June 2004, 22:24
they flex as the wheel rotates and they start leaking around the base once they get old,this may not ever happen but it's only got to happen once to ruin your day (and tyre)

Yep,I had long stems on my 'Coon,with 6 on board and fully loaded for an Easter trip away when the stem broke on Good Friday,no way to get it fixed and just had to return home.

Relacing them every tyre change is a bit anal,but I wash my hands at least 20 times a day so have no right to comment.

Big Dog
30th June 2004, 06:52
On a slightly related note, I know you can put tubes into tubeless tyres on the BM - 4.00/18 style tyre, I guess that means 100 profile... is it possible to do the same to lower profile tyres?
Anecdotaly, from what I have heard around the traps over the years a tube can go inside a tubeless. Most tyre typews advise against this as it can cause balance problems at speed.

Once when I could not afford a new tyre after running over a screw so the pro's put in an inner tube on a tubless tyre on the Falcon. All good till about 90kms then it got a little funky in corners, And at 120 it was real funky on the straights.

Gixxer 4 ever
30th June 2004, 17:02
Once when I could not afford a new tyre after running over a screw so the pro's put in an inner tube on a tubless tyre on the Falcon. All good till about 90kms then it got a little funky in corners, And at 120 it was real funky on the straights.
I am no expert here but I remember putting tubes in tubeless tyres when I was hard up as well but the radial tyres moved around so much they soon leaked and went flat. Could have had something to do with the shingle roads and being young. :bash: :Oops:

Kickaha
30th June 2004, 18:45
Anecdotaly, from what I have heard around the traps over the years a tube can go inside a tubeless. Most tyre typews advise against this as it can cause balance problems at speed.

Once when I could not afford a new tyre after running over a screw so the pro's put in an inner tube on a tubless tyre on the Falcon. All good till about 90kms then it got a little funky in corners, And at 120 it was real funky on the straights.


A tube is able to be used in a tubless tyre and If the tyre is rebalanced after the tube is fitted it will not cause any problem, a good tyre fitter will also use tyre talc in the tyre before the tube is fitted to stop the tube chafing on the inside of the tyre,some tyre companys used to recomend a downgrade in the tyres speed rating due to extra heat buildup though.

And if they put a tube in your tyre after running over a screw they certainly weren't pro's,amateurs is the word I would use.

scumdog
30th June 2004, 19:00
Make sure the tube is the correct one, mate of mine had heaps of punctures caused by low profile tyre with regular profile tube, it was on a cage so maybe it is an unlikely event on a scoot.

Motu
30th June 2004, 19:20
Tubed and tubeless tyres can have different internal construction - the tubeless is less finished and often had ribs inside,a tubed tyre will be smooth inside - as Kickaha says use talc on the tube to stop chaffing,down grade in speed rating for sure.Fit a tube only if there is rim or bead damage causing leaks.