Thursday, November 25, 2010

New Front Derailer & Brake

Ok, so I replaced the front derailleur with one that I modified with a larger cage. Well, it just didn't work out. The pantograph had too much free play, and the mount is too close to the chain rings to allow the springs to pull the chain onto the smallest chain ring, no matter how sturdy the cage was. Not exactly what I was hoping for. Maybe on another bike, that derailleur will work fine, but not on this one - not enough room to make up for the slop.

I found a Shimano Deore XT derailleur in my parts box, and decided to put it on. The clamp ring is quite a bit larger, so I had to make a pretty large shim, since it's aluminum and I don't have the equipment to weld on a smaller clamp. I think the reason I didn't use it a long time ago is because of the shimming, but I'm glad to go there now. This worked, and the front shifts beautifully.

On to the useless front brake. I measured the lever force at 8 pounds just to get the pads to move, not to mention apply braking force. It was just something about that particular brake (a very cheap one), and cable drag. I found that the cable housing was a smaller diameter (shifter cable housing), so that was part of the drag problem, but even with the correct cable/housing the brake was stiff and ineffective. So back to the parts box I went and viola! I pulled out a Dia-Compe road brake. I'm not sure of the model - something old and discontinued, I'm sure. It has a cam mechanism on the side to multiply the force applied by the cable.

I had to move the mount hole about 1/2" lower, as the Dia-Compe has a shallower throat. A steel 1/4" spacer welded onto the bottom of the fork stem placed a mount hole in the perfect spot. The brake looks good, the new lever pull is under 4 pounds, and I can't wait for the weather to break a little so I can test ride it.


Wednesday, November 03, 2010

Riding on New Wheels

I took a 14 mile test ride Saturday. The new fork and front wheel are awesome. No complaints there, at all. I may trim the front fender back a few inches to prevent heel strike, but it hasn't been a problem yet, so maybe not.

Rear wheel? The used rim I cannibalized was pretty dinged up. Well, OK, it was pathetic and I ignored that because I really liked it. During my test ride, hard braking was downright scary. The wheel locked up too easily, nearly dumping me once. I didn't even try any hills on my ride - just flat cross-town riding.

Monday night I modified a C-clamp by polishing the fixed side of the jaw, and attaching an oak block to the screw side. Then two whole hours were spent, turning the wheel, pinching here and there, measuring, applying brakes slowly, pinching more, marking, (filing the awful seam welds), and adjusting until the rim had a gentle respect for the brake pads.

Today I rode to work (11 miles), then rode home. It was such an incredibly beautiful day (almost 70 deg - this is November, right?), that I decided to take the long way home and rode along the river to the other bridge (an extra 6 miles). There was a stiff wind at my back which enabled a steady 22mph cruise along the path. I really wanted to keep up with that brunette on the rode bike who got on the path in front of me, but by the time I reached the end of the path, she was ahead by 1/4 mile. Dream on.......................................
"Jack, wake up! You're slobbering. By the way who's Natasha?"

Anyway, the rear wheel brakes smoothly now. Odd thing is, now the v-brakes squeek (very high-pitched) and tend to get sensitive after 5 or so seconds of steady application. maybe the rubber has overheated, or is wearing out. I'll try some new pads and see how that changes things. Not a show stopper, ridability is good. I'm happy with the mods.

Only mod left is to fix that dang front derailleur!