Rim Magnetism?
 

A little while back when I was soliciting advice on pads and levers to improve my braking (went with Koolstop Salmons at pretty much everyone's advice), I seem to remember someone saying that the salmon Koolstops don't work well with steel rims.

So this morning while waiting for my water to boil, I took a refrigerator magnet to various parts of my bike. The magnet was lightly attracted to the rim, but nowhere near as strongly as to the spokes, fenders, or frame. I mean you could feel a light pull but it wasn't strong enough to keep it stuck to the rim on the top of the wheel (the magnet is heavy, but it stuck to the spoke without problem).

Does this mean the rim is just a not-so-magnetic steel (if there's such a thing), or it's an alloy with some steel in it, or some third possibility I can't think of right now? If it helps at all, the rim said it was an ARAYA HE VP-20.

On a related topic, the braking surface has lots of black streaks on it from the hardened old shimano pads I just took off the bike. Should I try to clean that off somehow? How?

On an unrelated note, I have two sets of lightly used bar tape. I'd thought of putting them both back on the bike to give some extra padding (so double taping it). If I do that, do I wrap them both the same direction or do clockwise-then-counterclockwise for one side and the opposite for the other? Or should I just single tape it.

thanks.

You got yourself there some of that fancy aluminum alloy stuff.

I had an early 90s Trek 830 with the same rims. Almost 95% sure they were aluminum alloy.

hmm, I wonder why it still (lightly) attracts that magnet. I guess I don't know enough about magnetism. Maybe being in contact with the steel rims does something.

Maybe it's wire bead in the tire underneath the rim?

Probably because there's a spoke running through it, about half of it anyways.

alcohol may help clean the rim surface for braking but I guess my question to you is do yo uhave trouble stopping your bike? regarding bar tape, I can't imagine it would come out looking very good. I would invest in padded gloves. Also if you are putting so much pressure on your hands as to make them that uncomfortable, perhaps you have a fit issue with your bike or just really crappy cheapo bar tape?

No real need to double up the bar tape, I just have the second roll and thought if one layer was nice and plush, 2 layers would be even better.

I got new pads and levers because I didn't have anywhere near enough stopping power fully loaded going down a hill with my old setup (old hardened shimano pads and cheapo dia-compe brakes with suicide levers), so I did have problems stopping, but hopefully I won't when I get my new brake cables run (switched to ergo levers and interupters). I just didn't know if cleaning the braking surface would help more while I'm doing everything else.

I have two rolls of (lightly used tape) because less than 100 miles before I decided I needed to rip everything apart to have a new braking setup, I had drop in bars which are extra long and needed two rolls to cover it all. Now I have new bars and stem, but thought I'd keep the tape because I liked the feel and it was hardly used. If doubling up won't make it feel supernice (yes I have padded gloves), then I don't need to do it.

Drink a glass of wine, then clean rim. If brakes are not perfect yet, start again.

Trust me, the magnet is not attracted to the aluminum rim.
Scotchbrite pads can be helpful in cleaning a rim.

The weak magnetic attraction, as suggested above, is due to the steel wire beads in your tires and/or the spokes. If the rims were steel, the magnet's attraction would be very obvious, as it is on the known steel parts, not weak.

Yes, there are non-magnetic "steels". The 300-series stainless steels (304, 316, etc.) are non magnetic but NOBODY ever made rims from those grades of stainless steel.

Incidentally, most good quality spokes are 304 stainless steel and are also non-magnetic. Lower grade spokes are galvanized or cadmium plated carbon steel and are magnetic.