New posts

drilling out 321's

Aug. 18, 2006, 11:14 a.m.
Posts: 1818
Joined: Nov. 27, 2005

i have the old, greyish mavic 321's
the old vavle holes only big enough for presta.
But id like to run schredar, (sorry bout spelling)
some guy said i cant drill them, or i'll crack the rim?
the rims are pretty new, i havent been running them for eyars..
actually only a couple months.

Cove Peeler For Sale, cheap.

http://buysell.nsmb.com/showproduct.php?product=2717&cat=13

Aug. 18, 2006, 11:17 a.m.
Posts: 827
Joined: Sept. 10, 2005

i think it will crack…

Aug. 18, 2006, 11:20 a.m.
Posts: 1489
Joined: Dec. 19, 2002

why would it crack?

:high: :.:.:.:.:.:.:.:.:.:.:.: :high:

Aug. 18, 2006, 11:23 a.m.
Posts: 827
Joined: Sept. 10, 2005

i was just thinking it wouuldc crack while drilling through, and i wouldnt want to risk it. sorry if im wrong. I just wouldnt want to take the risk of ruining my rim over a type of tube.

Aug. 18, 2006, 11:28 a.m.
Posts: 14534
Joined: Dec. 16, 2003

I've drilled out a few rims with no problems, I don't know why the 321's would be different unless you're drilling with a hammer and chisel. How do you think the first hole got there?

Aug. 18, 2006, 11:49 a.m.
Posts: 1489
Joined: Dec. 19, 2002

if u wanna be careful just use some coolant while drilling the rim.

:high: :.:.:.:.:.:.:.:.:.:.:.: :high:

Aug. 18, 2006, 11:55 a.m.
Posts: 3874
Joined: Sept. 23, 2005

if im not mistaken, he is refering to the rim being weakened AFTER being drilled. As in, maybe after a few rides since the hole is bigger, the rim could crack because there is less material there. I dont think hes worrying about the rim cracking DURING the drilling. Maybe he is…. idunno. Just doesnt seem logical to me.

thinkin bout bikes

Aug. 18, 2006, 11:57 a.m.
Posts: 0
Joined: June 1, 2006

I did it before on a " Weinmann Safety Line " Rim that came stock on the DS500. It worked fine.

Aug. 18, 2006, 12:11 p.m.
Posts: 1489
Joined: Dec. 19, 2002

chunk, either way it shouldn't crack… unless u know a reason. the rim should be the exact same no matter how they drilled it for whichever valve. just make sure u drill it bang on the middle as much as possible and use a good sharp drill bit.

:high: :.:.:.:.:.:.:.:.:.:.:.: :high:

Aug. 18, 2006, 12:13 p.m.
Posts: 3874
Joined: Sept. 23, 2005

chunk, either way it shouldn't crack… unless u know a reason. the rim should be the exact same no matter how they drilled it for whichever valve. just make sure u drill it bang on the middle as much as possible and use a good sharp drill bit.

hahah!! i didnt even say anything about wheather or not i thought it would crack. I was just trying to help sysco get the message accross.

But while im typing… Yea, it shouldnt make any difference at all. Your friend is probably doing the pinkbike thing where they see one failure of a product and assume they will ALL break the same way :lol:

thinkin bout bikes

Aug. 18, 2006, 2:25 p.m.
Posts: 17792
Joined: Oct. 28, 2003

I've drilled out a few rims with no problems, I don't know why the 321's would be different unless you're drilling with a hammer and chisel. How do you think the first hole got there?

It got there in a professional machine shop with excellent tools.

I drilled an extra hole in an aluminum windsurfing boom once. It worked with "no problems". After two years the boom cracked. Guess where!

When you drill a hole you put a stress concentration area into material. It will naturally be weaker at that point.
When you drill a bigger hole, you make a larger stress concentration.
When you drill a hole with jagged burrs - you bet - it gets even weaker

Don't do it.

Aug. 18, 2006, 3:35 p.m.
Posts: 3598
Joined: Sept. 27, 2004

I drilled my D521's and they have lasted on my hardtail for 3 years without a hitch.

"X is for x-ray. If you've been bikin' and you haven't had an x-ray, you ain't goin' hard enough." - Bob Roll

Aug. 18, 2006, 3:38 p.m.
Posts: 0
Joined: May 7, 2006

go ahead,no prob,i've been doin it fer years.

Aug. 18, 2006, 3:39 p.m.
Posts: 1489
Joined: Dec. 19, 2002

use a SHARP drill bit and a decent steady hand and don't worry about any stress from it.

:high: :.:.:.:.:.:.:.:.:.:.:.: :high:

Aug. 18, 2006, 4:18 p.m.
Posts: 0
Joined: Dec. 4, 2004

The problem with drilling, if not done properly is that you can introduce stress if the bit "hangs up" usually occuring just before the bit finishes the hole. Two ways to over come this is to drill the hole with a drill press and hold the rim with a vise. If this is not an option try a Carbide Bur in a hand drill working from the tire side towards the hub stopping often to check the size of the hole.

"The Attention Deficit Disorder Association's Book of Wild Animals of
Western Eur- Hey! Let's Go Ride Our Bikes!"

Check out my pipes at www.thomasjlipspipeworks.wordpress.com

Forum jump: