Sun Mach 4 mtb rims * impressions?

Quoted message said:

Looking to build an mtb wheelset & curious as to the quality &
durability of rims. Other posts have mentioned tire mounting problems
with Suns. I'd appreciate any feedback on the Mach 4.
Thanks,
JB

Not on the Mach 4 specifically but we have built 3 wheels recently,
people bringing the Sun rims/hubs to us, we build and these 3 rims were
really crappy. All new but not impressed. Soft, very diffecult to make
round, VERY hard to keep true as it was stressed before the build was
finished. Reinforced my feelings that these are 'not great' rims.

Quoted post said:

Looking to build an mtb wheelset & curious as to the quality &
durability of rims. Other posts have mentioned tire mounting problems
with Suns. I'd appreciate any feedback on the Mach 4.

Tire mounting is not an issure with the Mach 4s. There's one set of Sun rims
that inspired me to get slime tubes. These are pretty easy to mount tires on.

These, I bought as a prebuilt set with LX hubs from Cambria for about $100. The
wheels needed complete retensioning and truing after a few hundred miles, but
they were a bit slack to begin with and I knew it was coming. Even with that bit
of knowing neglect, the rims have held up nicely and returned to true well.
These are not premium rims by any means, but I prefer them to anything Mavic has
at similar prices. I ride aggressive, mostly-flat cross country as a 220 pound
50yo so you're mileage will vary.

Now I'm going to go ride 'em.

Ron

Quoted post said:

Looking to build an mtb wheelset & curious as to the quality &
durability of rims. Other posts have mentioned tire mounting problems
with Suns. I'd appreciate any feedback on the Mach 4.
Thanks,
JB

A friend and I chose a pair of Mach 4's for her bike that we were
building up as a commute/tour bike. She weighs about 100 pounds, and at
their published weight of around 400g these rims in 26" are about
equivalent to a typical light road rim in 700, so we figured these
would be about right. That part of the plan has been working out fine.
As is pretty common with Sun rims, the wheels are holding up well
functionally but we couldn't get as close to no compromise between
radial truth and tension balance as is possible with more up-there
brands. However, one of the rims she built up ended up having a weird
little abscess in the transition corner between spoke well and sidewall
that somehow neither of us noticed until we were on tour. We're worried
about it ending up acting as a stress riser, but no cracking yet. It's
a bizarre thing I've only ever seen on these rims... which may or may
not be indicative of anything. These *are* down there in price and also
in weight, which is sort of weird.

As for rim/tire tolerance problems, my friend's are fine but it's
perfectly possible with any Sun rim. Normally you can live with it and
it's just a pain in the ass.

PS: If this is your first wheelbuild and you want something that will
build up well and be a really good rim, get Velocity Synergy's with the
OC version in back. Sun rims pretty much make less sense for a
beginning builder, not more.