tyre valves, 8.5mm and 11.5mm holes

[m1ks]

Having had recent incidents i'm replacing both tyres and also fitting new valves at the same time, (not optional as it currently has tubes in but i would be regardless).
Now, it would appear that the standard snap in rubber tubeless valve is commonly available in 11mm and 16mm, (for cars and seemingly modern bikes).
Having had a friend just fit me a new front valve in my ZXR it would appear that that one is an 11.5mm hole as the valve was from a local tyre fitters.
now i've just measured my Z650 holes and they are 8.5mm, (alloy rims), I can get screw in type valves at this size, at a heftier price and don't look so nice but no snap in rubber ones, (bloody annoying as I can get a bag of 100 for less than £20 of the 11.5).
Now the bod at my local tyre garage has suggested drilling out the holes to 11.5mm, now personally i'm not sure I like this idea though in theory theres no reason it wouldn't work.
Has anyone done this before? alternatively does anyone know of a good source of 8.5mm rubber snap in valves or cheaper screw in valves?

Thanks

[lta01]

Hi there, first to say I'm not an expert on Z650 models, so someone might be along later who knows better.

Are you sure that these rims are suitable for use without tubes ? many of the early alloy rims on Japanese bikes had rims which still needed tubes.

Often the rims are marked "suitable for tubeless tyres " or you can tell by looking at the inside or the rim profile. Tubeless rims have a pronounced Bump or ridge on the sealing surface nearest to the centre-line of the wheel which is there to retain the tyre if pressure drops a bit. Rims needing tubed tyres just have a flat smooth sealing surface.

hope that's of help.

[Rich]

If you are using the original kawa cast wheels they are not for tubeless tyres.

[m1ks]

Thats good to know and something I wasn't aware of, thanks guys.
So looks like i'll be needing a pair of inner tubes and rim tape instead of valves as well as the tyres. They are, (to my knowledge), the original Kawa cast wheels which replaced the spoked ones on the 81 on models.

I've already ordered the tyres, (Avon Roadriders), just hope they are suitable for use with tubes. Anyone know?

[m1ks]

OK, new tyre ordered for the ZXR front so whilst at it I ordered a pair of tubes and rim tapes too for the Zed, the Avons arrived this morning, looks like good softish grippy rubber and i like Avons, regardless they should beat the pants off the cheap crap Cougars that were on.
Soon as I get the tubes and tapes i can get them on and test ride the zed and see if it's OK

[Pigford]

Do you really need "rim tapes" on a 'mag' wheel....... I thought that was only to protect tube from spoke ends Won't hurt I suppose

[m1ks]

In theory no, as you say they'refor spokes to protect from the spoke ends, however given recent events and the obscene cost of £1 per tape I thought, bugger it, can't hurt to have a bit more protection from the rims, I do know that theres some ally corrosion in the rear, only minor and will clean em before mounting the new stuff but going with a full belt and braces approach on this one and running the new tyres in steadily.
Impressed with the look and feel of the avon roadriders i've got for it, we'll see how they perform on and will update.

[m1ks]

On another note but related this thread came in handy for my neighbour having just had a tubeless tyre fitted to his trike front which is losing pressure over a few days, when i mentioned it we realised that'll be the problem with his.

[Pigford]

......I've not really got on with Avon tyres in recent years..... Had some Azaro's (or sumink like that) back a fews ago on me Gixxer.... They were sh*te

....But, just had a set of Avon Viper Sports fitted on me Z1000 & they are really good.... I am using modern running gear (17" 120 & 180) but they seem to be the business..... Had to run them in on the York rally (670 miles) and they haven't "squared-off" - so pleased with that