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Sun Venus better than Mavic CPX33?(6 posts)

Sun Venus better than Mavic CPX33?Bicygoth
Nov 7, 2001 11:57 AM
I'm rebuilding my rear wheel and want to use a Mavic CPX33 rim but since my Local BS doesn't have one in stock, they offer me a Sun Venus rim, Somebody know how they compare, this is just for a training wheel.
Sun Venusburdiman
Nov 7, 2001 1:01 PM
I bought a set of Sun Pro Race wheels which are built around the Venus Rims and they were nothing but trouble.
I sent the wheels to Sun for replacement because the eyelets were pulling out of the rim (including cracking around the eyelets).

They rebuilt the wheels with new rims and they did the same thing within a week. It took 3 1/2 months for them to service the wheels by the way.

I will never buy there rims again but like the Sun hubs.

Just my experience but it was not favorable.
re: Sun Venus better than Mavic CPX33?Jofa
Nov 8, 2001 5:26 AM
Unless the outgoing rim is entirely unsuitable in design, or unavailable, I'd replace it with one the same or that is at least the same depth, so you don't have to replace the spokes as well. Old spokes are to be treasured since any that were going to break will already have done so.

I also have heard of these rims breaking around the sockets, though I've never used them so can't report from first hand experience.

Jofa
I call Bull****!jw25
Nov 8, 2001 7:55 AM
I'm with you on re-using spokes, up to a point. Eventually, they will start breaking, depending on how high the tension was during their lifetime, and the conditions they were ridden in.
Spokes break far less often nowadays then even 10 years ago, thanks to advances in metallurgy, but stainless still has a fatigue life.
So, feel free to reuse spokes, but when doing so, remember that once one breaks, generally all are approaching their fatigue limit, and will start breaking in the near future. Besides, spokes are fairly cheap.
Spoke lifeKerry Irons
Nov 8, 2001 7:22 PM
Good spokes in a well built wheel don't break except in accidents or in the "freak failure" mode (defective spoke, there always will be some). However, they didn't break 10 years ago, 20 years ago, or 30 years ago either. Perhaps your experience reflects that there was less knowledge about what constituted a good spoke, but they have been around for a long time and spoke breakage with those brands in well built wheels using good components has not been a problem for a long time.
bullwho? winkle?Jofa
Nov 9, 2001 4:06 AM
If a wheel has made it through a few thousand miles then this phonomena you report, of multiple successive breakages, is one I haven't seen, except in the cases of external damage like a chain causes when it drops behind the sprockets.
If many spokes are breaking in newish wheels then it means something is wrong: invariably, the wheel hasn't been properly stress-relieved.

Jobst Brandt has put it nicely: (to paraphrase)- if we could snap our fingers, so to speak, to make the spokes in a newly built wheel turn into threads, which would trace the straightest path between hub and rim. and then snap them again to return the spokes to metal, then we'd have our ideally stress-relieved wheel.

We can't do this, so must approximate it, by individually overtensioning the spokes so as to equalize their internal stresses, and by manually straightening the spoke- line. These processes are the best we can do and are mostly successful but may have a small failure rate, which combined with the (now thankfully rare) ‘rogue' spokes, will manifest itself in broken spokes earlier, not later: spokes which make it through the first few thousand miles probably won't break ever, unless they are caught up in debris.

Jofa