Valves, tyres, inner tubes and how to feel an utter plank

[m1ks]

Having recently asked about 8.5mm fitment valves for tubeless rims and been advised that early zed alloys were for tube fitment and not finding info to the contrary I passed on the bolt in 8.5mm valves, (the only ones I could get) and got tubes.
Fitted the rear today and on getting ready for the first run out i gave the tyre a last quick pressure check, at this point I noticed in bloody big casting lettering on one fork, 'tubeless', bugger, did I feel like a plank!
Still never mind I have tubes for them and all seems OK, i assume running tubes in tubeless rims is OK, I know of this being done before.

On another note, on removal of the old rear tyre and tube I found the tube fitted is a 3.00/3.25 - 18, far too small, on a 120/90 - 18 it needs a 4.50 - 18, certainly a contributing factor in the tyre blowing having been inflated way beyong it's intended use and the additional weight of a pillion passenger.
On inspection it had a pinhole on the inner curve where it's contacted the rim, (some corrosion there) and a split across the outer section which seems to have occurred through stress.

Initial ride had me feeling like something wasn't right with the front but after a little running around it didn't seem so bad.
I guess a combination of recently riding the ZXR and having lower bars on to replace the others added to which i'm looking for problems which may or may not be there has an affect on it.


There are still some bits to fettle but it's definitely getting there and I feel better that it's been out on the road again.

[Pigford]

Surely, fitting a 3.00/3.25 tube in a 3.50 rim should make bog all difference The dirt bike riders & long distance chaps often only carried one size to fit all.

If you've ever blown one of them tubes up out of a wheel... They expand enuff to fit a 8" rim... (300 tyre ), so I really can't see a problem.

Before you all slate me off, I know its not 100% as per the book, but in the real world..... How many 4.00 section tyres have been fitted to 3.50 rims.. etc

This is just my warped opinion...

[m1ks]

All I can say on that is that the old tube had split across the width and it was a clean split, no sign of perishing, scuffing or contacting so this can only be due to the stress of over inflation with the additional weight of a pillion, I tend to find that things are designated for a reason and 3.00/3.25 is a far cry from 4.50, it's even smaller than the 3.50/3.75 - 19 designated for the 100 section front tyre.

[hillbilly]

i dont see any problem with fitting the smaller tube in a wheel,as pigford said they do go big when blown up outside of tyre.we once blew a M***D tube up ,i bet you could have drove a d8 bulldozer through it.and it wouldnt blow out.

[Jon]

Yeah technically a smaller tube will stretch, but they have different tube sizes for a reason. A smaller tube stretching that extra couple of inches diameter will have a significantly thinner wall section than the right sized tube. Certainly aint ideal anyway, even if it would do the job for years in 90% of cases Id personally rather be 100% sure when blatting along at 120-odd through some twisties.

Better fitting right sizes especially since Miks just had a rear end blow out recently almost wiping him n my wife out in process. Better having that peice of mind really after something like that. Proper tyres/tubes, etc worth the expense for peice of mind in long run.