Bicycle Mechanics - Is this rim safe (Mavic Aksium)

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.




View Full Version : Is this rim safe (Mavic Aksium)


the_don
07-31-10, 01:04 AM
I went to a bike shop and they said it was fine, but I am not so sure....

check the photos and let me know what you think please.

http://farm5.static.flickr.com/4106/4845871360_33f156288c_b.jpg

http://farm5.static.flickr.com/4109/4845871528_e40168f4fb_b.jpg

http://farm5.static.flickr.com/4126/4845252977_a9e2413be0_b.jpg


rat fink
07-31-10, 02:12 AM
That's a crappy butting job, but it should be safe.

Torchy McFlux
07-31-10, 03:40 AM
That is not safe, and not fine. The seam is out of alignment and will cause stuttery and dangerous braking.
The braking surface is very clean. Are the wheels new? Mavic should replace the rims at no charge if they are.


wrk101
07-31-10, 05:50 AM
+1 Not safe.

rat fink
07-31-10, 07:41 AM
I guess safe is relative. I agree that if the rim is new, they should replace it. But if it is not, I'm not sure I would call it a ticking time bomb or anything. I've run worse, and never any significant problems next to annoyance.

mrrabbit
07-31-10, 01:14 PM
You folks would be amazed at how many millions of entry and mid-range rims have gone out on the market in the past 20 years with misaligned seam butting without graveyard popping up alongside your local highways and byways.

If it wasn't a recent development - and you are confident the pins are intact...then you are probably fine.

I bet you hear and feel a "tick" when braking though?

You should be able to slightly bend in the one spot using a crescent wrench covered with electrical tape...but that's about it. You can't do anything about the butt overall that resides within the body of the rim.

=8-)

KDC1956
07-31-10, 01:24 PM
I for one would not use that rim at all.I would get a new rim and start to rebuild my wheel.Or take it back to where I got it and get a new wheel.
My 2 cents for FREE lol.

FBinNY
07-31-10, 01:36 PM
I guess safe is relative. I agree that if the rim is new, they should replace it. But if it is not, I'm not sure I would call it a ticking time bomb or anything. I've run worse, and never any significant problems next to annoyance.

+1, if new and unused ask for a replacement, but I doubt it's a material safety issue.

Pinned clincher rims are prone to mis-alignment because the joint is supported in the hollow area and twisting forces can bring the unsupported flanges out of alignment. It's far less of an issue with tubulars which don't have flanges extending out. The wheel won't collapse or anything, but some careful file work is warranted to smooth out the joint and improve brake modulation.

If the rim is fairly new, but too used to warrant free replacement, the seller should be willing to file the joint smooth for you.

merlin55
07-31-10, 09:57 PM
perfect example of why rims with welded joints are better

davidad
08-01-10, 05:39 PM
perfect example of why rims with welded joints are better Only because it is easier and cheaper for the manufacturer.
The wheel is safe to ride because the total tension of the spokes on the rim hold it together at the joint with over 3000 pounds of force.

mrrabbit
08-01-10, 06:16 PM
Only because it is easier and cheaper for the manufacturer.
The wheel is safe to ride because the total tension of the spokes on the rim hold it together at the joint with over 3000 pounds of force.


One problem with welded joints is that for dishonest manufacturers, the machining operation to finish the job is used as an opportunity to hide joint defects. Some manus will even purposely not bother with joint quality at all and simply use the weld and machine process as the end-all period.

It'll look like a good straight-joint rim - but it really isn't. Sidewall thickness will suffer and you'll end up with a soft hole/eyelet that becomes a tensioning problem.

Pinned and sleeved keeps it honest...

=8-)

ultraman6970
08-01-10, 09:16 PM
Hammer it until aligned then put duct tape to it and sell it :P

Now seriously, did you try hammer it to get it back in place?

Bezalel
08-01-10, 10:08 PM
How far is the alignment off after a tire is mounted and pressurized?

the_don
08-02-10, 05:47 AM
looks better when tube and tire are pumped up.

I guess the consensus is towards the it's safe. I might try bending it true again, I don't care too much about the irregularity in braking. It is not bad!

A new wheel is pretty cheap, so I might just order a new one and keep this as a backup, or give a friend who rides brakeless and doesn't care about it being slightly off

alaska
08-02-10, 11:16 AM
if you bend it, then you are stressing the aluminum and increasing the chance of failure.

it's fine as is so long as the braking surface is smooth. if not, you'll get a brake tick and yr pads will wear down incredibly fast.

FBinNY
08-02-10, 11:30 AM
if you bend it, then you are stressing the aluminum and increasing the chance of failure.

Minor bending if done right won't hurt, but may not stay. If you shore both sides of the area with strips of wood, metal or plastic, and gently squeeze it right at the seam, it may improve, but there's no assurance that it won't shift back.

As for the brakes, the tick may be minor, but depending on the direction can rapidly shave brake shoes. It's your call, but a bit of file work will help.

fietsbob
08-02-10, 12:31 PM
Doesn't appear to be much of an offset..
If you are confident of your metalworking , the corner of the end of extrusion could be smoothed.
and the seam where the 2 ends of where the extrusion meet,
to not feel the seam when you brake.

jeweler's files are short, small ones., mill files ar a foot or more long.