Bicycle Mechanics - Should my front rim/wheel be replaced.

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cyclezealot
01-19-04, 10:57 PM
While riding my older road bike, I thought I felt a slight wobble when applying my front brake..Headset ok. Tight. Wheel seems in true.. No bulges on front tire.
Looked closely. there seems to be a weld where a seam comes together? Very slight roughness and uneveness about the seam... Is this what is causing my wobble upon braking..And do I need to replace my rim or front wheel...
When does a rim need be replaced..Wear from outside of rim does not look too bad...


dexmax
01-20-04, 05:27 AM
maybe it just needs a little truing.. Or perhaps some spokes have loosened making the rim somewhat uneven. I have seen rims(mavic, sun, alex) in the shelves show a little bulge, but it dissapears after truing the wheel.

Can you post a pic of the rim?

cyclezealot
01-20-04, 08:34 AM
maybe it just needs a little truing.. Or perhaps some spokes have loosened making the rim somewhat uneven. I have seen rims(mavic, sun, alex) in the shelves show a little bulge, but it dissapears after truing the wheel.

Can you post a pic of the rim?
The bulge is very minor..Looking at wheel is seems trued.the point abut the bulge. It is at the seam and the bulge is really uneveness of the two sections with the ridge being a little rough. Sharp point does not seem to be tearing apart my brake pad yet. Dexmax..Don't have a digital camera yet..Put my pictures on CD's ... The bulge is fairly even, just the two sections somewhat uneven and sharp...


Michel Gagnon
01-20-04, 10:11 PM
The answer is a definite "it depends". The best sign of rims that need to be replaced is when the rim surface is concave (i.e. rounded in, caved in) instead of flat. On a well used up rim, you will see a nice, smooth well-polished groove that goes all around the rim. No dent, no fine line (unless there were a few rocks grooving their way), but rather a groove that looks like ruts on some forest roads. At some point, the groove is deep enough that the rim isn't thick enough and will split apart. The minimum safe thickness depends on tire pressure and some rims have a wear indicator in them.

In your case, it's either a severe bump that flattened your rim or an improperly made rim junction. Or maybe your rim is so worn out (see paragraph above) that the seam is the only section that's rigid enough. In the latter case, replace the rim ASAP. In the two other cases, it's your judgment call.

BTW, there are some techniques by which one "de-bulges" a bulge with pliers and a block of wood, or sands a rough section, but in my humble opinion, these are at best temporary stop gap measures that are fine on a tour, but nothing else.

Regards,

Rev.Chuck
01-20-04, 10:36 PM
Does the rim look like this? )( If so, the time is come. Either lace up a new rim or get a new wheel.

cyclezealot
01-21-04, 02:09 AM
Does the rim look like this? )( If so, the time is come. Either lace up a new rim or get a new wheel.
It still seems to feel flat..I will keep an eye out for the )(.thanks.

Phatman
01-21-04, 01:01 PM
I'm thinking that you are talking about the seam on the rim? all rims have this seam, because the rim was formed out of a single piece of straight metal bent into a circle. when they are joined, it is called a pinned joint. some nicer rims are machined to smooth down the seam, and some mavic wheels are welded on the seam to produce a "seamless" joint.

have you not ridden this bike in a while? maybe you have just forgotten that the seam is there? I suppose that rough use could theoretically (cant spel today) put the seam out of alignment, and make it stick out.

the bottom line - with a piece of equipment like a rim, if you don't feel safe on it, then replace it, but your rim is probably fine though.