A replacement for Mavic 'Open Pro' rims.

[JohnW]

Lots of food for thought here - I hope members continue posting. Experience is the best guide.

[mig]

is it possible that the latter day open pro is made from a different, possibly reclaimed metal? in a different facility?

a retired car mechanic friend thinks that most car brake discs are now made from low grade, reclaimed metals and are only specced to last 10,000 miles of mixed driving. is the same happening with cycle wheel rims?

i've had good experience with ambrosio rims through some pretty hefty mileages & weathers. i used to think that they were expensive but, looking at some of the prices quoted now for rims, they no longer seem that way. soon rims will be as expensive as the lower end factory built wheels. i think that they will increasingly become a niche product when sold on their own (not helped by high transport costs i would think.)

maybe the time is nigh to seek out some stocks of the ones we all like and buy 'em up. i have a few, but not many.

[JohnW]

...............maybe the time is nigh to seek out some stocks of the ones we all like and buy 'em up. i have a few, but not many.

Whilst I have neither knowledge of, nor contacts in, any of the relevant trades, what you say does ring true and make sense mig.

Your pro temp solution is good. About 35 years ago, when we were about to start a family and my wife stopping working, I faced a problem of shortage of funds for cycling for the then foreseeable future, and I bought quite a lot of G40 and later Open CD rims. This was a good investment and between them they lasted me for over 25 years. It was a policy that worked. When I eventually needed more rims, the mileage offered by the 'Open Pro' was in real sharp contrast to what I'd been experiencing with the G40s.

Why do manufacturers do this?

[Brucey]

just yesterday I unlaced an (unworn) open pro rim that had been in a prang. I found that I could quite easily bend it across my knee. Now, I've bent lots of cheap rims (of similar cross section) and many of these moved a lot more easily than that. But I have also tried to move rims like MA40s and these don't move at all easily by comparison, so I think that recent Open Pros are softer than they could (or should) be. [On the plus side after a few minutes of such bending antics I had a perfectly straight Open Pro rim in my hands.... ]

I also think that small changes in how the rim is machined can make a huge difference to the way the rim wears. Firstly machining rims at all is probably a stupid idea; if the rim is made well (like Mavic rims used to be), it won't really benefit from it. Also the microstructure of the extrusion surface is different from that of the core, probably stronger and more wear resistant. So in addition to the obvious thickness reduction, you are likely 'machining the best bit away'. Thirdly a machined rim surface will throw out trapped swarf into the brake block (almost any brake block) when it is first used.

The last of these may be something that really catches people out; you may have ridden thousands of miles on the old rims without picking up any aluminium, but the new rim might be half-way worn out before you notice what is going on.

cheers

[mig]

for a higher 'churn' of product at a perceived lower risk of dilution of the brand? if mavic is seen on enough cars at the TdF then it's got to be good stuff right?
i suppose that the open pro isn't the best example of a rim not being built to last in that the manufacturer could still claim that they are built to be lightweight. i think that they have been 'lowered' out of the 'racing rim' category and into a 'training rim' one by dint of that fact that pretty much all 'racing rims' are aero carbon affairs now. box rims are no longer seen on race days in the main. hence open pros feature on training irons and aren't up to the hammer.
having looked at the prices of NOS mavic and ambrosio kit out there i think that any rims i buy in the future will be bought on the basis of them being a cheap consumable and being replaced whenever needed.

[JohnW]

...............a machined rim surface will throw out trapped swarf into the brake block (almost any brake block) when it is first used................

..................and with current 'Open Pro', for the whole of it's life - in my experience.

[mig]

IIRC the machining was given a name (SUP?) and made to seem beneficial? i think it was to make rims quieter under breakng when new as older ones often had high and low spots and made a chuffing noise under breaking until worn in? more especially the coated ones. i remember 'on-off 'patterns' of wear on the tracks in older mavic rims.

[Brucey]

a retired car mechanic friend thinks that most car brake discs are now made from low grade, reclaimed metals and are only specced to last 10,000 miles of mixed driving. is the same happening with cycle wheel rims?

somewhat OT but everything metal you buy now will contain a proportion of recycled material. It doesn't automatically make it 'bad' in any way; the chemistry should be controlled within certain specifications, so basically someone has to screw up before you start making absolute rubbish.

However I can see how someone working in the car trade might think what he thinks; relatively speaking brake discs have never been cheaper and nor have they ever worn so quickly.

However in this case the blame lies pretty firmly with the brake pads. All car manufacturers now specify brake pads that stop the car quicker than they used to. To achieve this (along with all the other things that are desirable), in most cases they simply use brake pad compounds that are far more abrasive than they used to be. These pads wear the discs very much more quickly than older formulations, and if the discs last even two sets of brake pads, you are doing well.

It isn't all bad, BTW; abrasive pads also make rusty/contaminated discs clean up better.

BTW I suspect that OEM bicycle brake blocks might do something similar to modern wheel rims, too.

cheers

[mig]

in this time poor age are we perhaps guilty of cleaning rims less?

[Keezx]

IIRC the machining was given a name (SUP?) and made to seem beneficial? i think it was to make rims quieter under breakng when new as older ones often had high and low spots and made a chuffing noise under breaking until worn in? more especially the coated ones. i remember 'on-off 'patterns' of wear on the tracks in older mavic rims.

SUP (Soudé Usine Process:Factory Welded ) refers to the welding and not to the machining.

[mig]

'tis true.....it's UB control that is the machining.

[Ross K]

I've pranged my Open Pro rear rim and want to replace it and keep the spokes/hub.

One rim not mentioned in Brucey's (and others') comprehensive lists is the DT Swiss RR411, available in asymmetric for better rear bracing angles. ERD is 602 (Open Pro 602) but I understand that this is measured with PHR washers and Squorx alloy nipples. I want to use brass nipples but cannot find any resource that tells me what the effective ERD is with brass nipples, of the non-Squorx variety.

I have a pair of wheels built with the sister rims, the RR511 (32mm semi-aero section but otherwise the same as the shallower RR411), on my TT bike and they seem very good, my wheelbuilder liked building with them, they are very true and easy to fit (non-tubeless) clincher tyres despite the urban myth that all tubeless-ready rims are a bugger for fitting normal tubed tyres.

Can anyone advise on the feasibility of the RR411 being a straight swap for Open Pro with existing spokes and standard brass nipples?

Many thanks.

[Brucey]

Well the first problem is that the ERD of Open Pros is 605mm, not 602mm. Mavic quote 602mm but this is Nipple Seating Diameter, not ERD.

The rim you want to build has a quoted ERD of 601mm (with the washers); they say you can use brass nipples instead (but still with the washers) but I have not BTDT. Anyway it looks to me as if your spokes will be about 2.5mm too long, and a bit more than that on the NDS if you use the asymmetric version.

A slight problemette is that RR411 is only available in 20, 24, 28 drillings. The asymmetric version is available in 24, 28, 32.

cheers

[Ross K]

Thank you for your advice, Brucey!

[Tenor]

I have two sets of wheels with Ambrosio Excellence and have also used Open Pro. They build into very strong wheels, but I couldn't comment on comparative life. Easy tyre fitting. Available in silver and black.