Monday, February 1, 2010

New Rims

Tax time is upon us, and the first twelfth of the year has gone well, so I decided to succumb to a little upgradenitis.
I was debating if I should get a Niner carbon fork and drop 600g from my Swift, or replace the Sun EQ21 rims on my wheels with Stan's new Crest29 rims for an estimated 240g savings.
The fork would be an easy and quick way to drop some weight, but the rims would be half the cost.
Myth was, or is it a (sub) urban legend that with Stan's rims you can air up a tire with just a floor pump. If that was the case, the long term benefits of the rims might be more valuable than the instant weight loss of the fork.
Life being easier won out and I got the rims, which you probably already figured out by the title up there.
Also, I really love the fork on the Swift, and not sure if I want to mess with a good thing.
When I got them they seemed well made; other than a spoke hole that wasn't completely punched out, I'd say perfect.
I decided to be all scientific for blog sake and weigh stuff. The rims weighed 370g each.
My old wheelset, with rim strips, velox tape, and rotors weighed 2180g, just the wheels w/ out skewers weighed 1660g.
Back when I used to do bicycle repair and got parts wholesale, I wouldn't have thought twice about taking the bolt cutters to the wheels and extricating the hubs, replacing the spokes and nipples with bright shiny new ones, but seeing I had just spent about double what I had ever spent on rims before, such luxuries would not be afforded to me.
I Used the old tape the new rim to the old wheel trick which worked famously. I wish I had used this technique in the past, as it really didn't take much longer than starting from scratch.
All said and done, the new wheels with out skewers weighed 1530g. Nice.
Now lets put the yellow tape, valves, and rotors on...and the weight is 1790g! A weight loss of 390g!
Ah, wait a second, something doesn't add up. I dig the old rim tape out of the garbage, and weigh it and the old rim strips separately and get 160g.
I must have taken my first weight with skewers.
So much for being scientific!
290g net difference.
Now for the moment of truth; would they air up with a floor pump?
Not a chance.
BUT... Ignitors, not the easiest tire to set up tubeless, aired up without Stan's liquid with a resounding pop, with valve cores in. Plus it took a decent effort to break that bead to put the sealant in the tire. Usually I use 120ml of sealant, but with how secure the bead locked onto the rim, I went with 60ml (I probably have lost almost 60ml just trying to bead up tires before, so I guess I save another 120g).
Do I notice a difference?
There's three inches of snow on the ground, how would I be able to tell a 290g difference?
What I did notice was the almost 4mm wider rim really makes a difference with the profile of the tire. I think the short thin sidewalls really accentuate this, because I've had 24mm wide rims before, and hadn't noticed this much difference.

Sun rim
Stan's Crest 29

Can you see the difference?


the original big ring said...

love those rims - just need money and the justification for getting them (more for my wife than me) and will order me up a pair


Anonymous said...

Thanks for measuring the rims. Just ordered crest 29s, have ztr 29s.
Sheesh, I completely missed the fact that I am going to have a wider tire footprint than my ZTR 355's (inner flange width increase of 10%) pretty much neutralizing the reduced rolling resistance I would get when dropping 15% rolling weight with the crest rims.
So I have a more flexy rim compensated by wider casing stabilization, but thus really wider tires which I don't want in this case.
Thanks for post.