PRESTA valve size hole standard on quality rims?

[oldslalomskier]

If you look at Mavic's latest catalogue you will find that all their MTB wheels use 6.5mm holes. Yup - presta. My Deemax's certainly are as are all my other Mavic rims.

 

[JamesM]

I did say all Mavic rims that I've ever encountered, that could have been one second hand Mavic X221 . It isn't though and according their website the Deemax does indeed take Presta as you said and I suspect, but cant be bothered to look, that its the same for most of their wheel sets. However as far as MTB rims go all but the tubless 8 series range have 8.5 mm Schraeder valve holes. I just wanted to emphasise that it's not Presta= expensive high pressure and Schraeder = Cheap low pressure. What type of valves does a Bugatti Veyron use??? I wonder what they use on the landing gear on an A380?

As I said before Presta is light and thin and so better suited to deep V section roadbike wheels, but for MTB's why put up with fragile Presta's when you don't have too?

 

[michael franks]

I've got a pair of Mavic X221s which are presta and other Mavics wjich are schrader and although I don't have a preference for either type, I do wonder why there are two types. :?

Do any rim/wheel manufacturers offer their products in 'either/or' versions?

 

[mcrocker]

Amongst many other things that the company made before they eventually got into bikes they used to make trailers. They also made a kiddy trailer called the Bugger, can't think why it didn't take off in this country.

I know about the little Bugger.

As far as I know, Cannondale began as an outdoor luggage company, making backpacks and bicycle panniers, and bike trailers. Later on they made workstands, and bike racks for cars. I've never heard of a Cannondale boat trailer. Got a link?

The Bugger-Kiddy was not popular in the UK so for a short time Cannondale branched out into making children's string instruments. But the Kiddy-Fiddler didn't sell too well either. Or that's what I heard.

Back on topic: what happens if you put a presta valve in a schraeder rim without the insert? Will it puncture over a certain pressure?

 

[mechagouki]

Back on topic: what happens if you put a presta valve in a schraeder rim without the insert? Will it puncture over a certain pressure?

Nope, I do it all the time at pressures up to 50 psi, never had any problems.

 

[oldslalomskier]

I did say all Mavic rims that I've ever encountered, that could have been one second hand Mavic X221 . It isn't though and according their website the Deemax does indeed take Presta as you said and I suspect, but cant be bothered to look, that its the same for most of their wheel sets. However as far as MTB rims go all but the tubless 8 series range have 8.5 mm Schraeder valve holes. I just wanted to emphasise that it's not Presta= expensive high pressure and Schraeder = Cheap low pressure. What type of valves does a Bugatti Veyron use??? I wonder what they use on the landing gear on an A380?

As I said before Presta is light and thin and so better suited to deep V section roadbike wheels, but for MTB's why put up with fragile Presta's when you don't have too?

Funny you should mention the Veyron. Apparently the regular (schraeder) car valves could not keep the air pressure in the tires due to centripetal force so the Bugatti engineers had to install an extra set of springs inside the wheel to keep the pressure in. Of course a Presta style valve does not have this issue.

And I am not sure where you get this idea that Presta vales are "fragile". Or ho that is even an issue.

 

[JamesM]

Maybe Presta's don't have a problem at 250mph but they still didn't use them on the Veyron. Plus MTB's don't go that fast anyway.

They are fragile, not once your rolling (as someone pointed out they use them on DH bikes) but who's ever broken a valve whilst riding? I ment when pumping them up or fitting/removing the pump etc. It's fairly easy to bend the bit you unscrew on the end if your not being that carefull. Schraeder is far more robust.

So after all that, what is the actual technical downside of using a Schraeder on an MTB? Or is it just that the roadbike world has made Presta's seem classier?

 

[bm0p700f]

I have a set of Mavic X717 rims and they have schreader holes. I again think it is to with schreader valves not being able to cope with high pressures. On narrow rims prestavalves are essential for strength but on wider MTB wheels this is less of a factor.

Just messure the hole edge to rim edge distance on a narrow road wheel and compare that distance to the schreader hole edge to rim edge on an MTB wheel.

I now always use presta tubes as they will fit any type of rim.

 

[JamesM]

On narrow rims prestavalves are essential for strength but on wider MTB wheels this is less of a factor.

Agreed, where the rim is a deep v section type roadie rim!!! I would say however that even on a narrow mtb rim like an XC717 the difference is neglibible. I've never seen or heard of an MTB rim breaking at the valve hole.

I again think it is to with schreader valves not being able to cope with high pressures.

You didn't read my first post on this thread then? If anything they seal better and better as the pressure gets higher. As I said before, at my work we use Schrader valves on accumulators. They are pressurised to over 10,000PSI and then installed on the seabed where they are expected to remain for 25 years without being recharged.

Also I've been spelling Schraeder with an 'e' after the 'a' because I copied someone else, but isn't it actually just Schrader?

 

[bm0p700f]

Well if schreader valves can take 10,000 psi then I have learnt something new today.