Yes I decided to leave the 11x8mm (and others) for later, otherwise I fear the first post would have been too long - I can ramble on about hoses and fittings all day reallyOriginally Posted by fgw
But you are right: 11x8mm PVC, with 1,5mm sidewalls are a good compromise also. This hose started seeing use, as a result of the problems I mentioned with the standard 10x8, which has only 1mm walls, and collapses much to easily. There is a Tygon 3603 which is 11,2x8mm and that has some succes over here, but is too expensive I think, and you need special 11mm compression nuts for the fittings - you can't just use standard cheap 10/8mm Push-ON fittings like you can with 10x7mm tubing (which is available in a very nice Clearflex version).
We have also been selling (and using) this 11/8mm combo, but personally I still prefer the 10/7mm for 3 reasons:
1. Fittings and hose are cheaper.
2. The hose has a smaller bend radius.
3. The flow advantages of the slightly larger 8mm ID are probably marginal at best, as the fittings used are still only about 6,9mm ID (as also shown by Cathar's graphs) - where as with the 7mm ID, there is hardly any ID flow restriction going through the fittings.
BUT 11x8mm PVC is sure much better than 10x8 PU or PVC - so not a bad choice at all.
As the hose ID gets larger, the sidewall thickness also needs to increase to still have a good bend radius, so something like a 12x8 with a Push-On fitting with ID of 8mm would be really great. (and guess what diameter Zalmans blue hose is.. yes 12x8mm exactly. Sometimes the big companies do get it right!) Only problem is that sourcing the fittings and hose for this size is not easy. I have only been able to find suitable fittings in plastic, and we really prefer nickel plated brass (with o-ring sealing).
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