I'm almost done with my bike. I installed my new rear wheel with a Formula Flip Flop Hub with both a Freewheel and Fixed gear installed on the wheel. I was told that the chainline needs to be straight when using the Fixed gear. I was also told that the chain cannot be pulled to either side and the chain alignment needs to be straight with the gears. Is this true? What about when using the Freewheel, does the chain alignment need to be straight?

I know that you can purchase shorter bottom brackets, but can you flip the bottom bracket so the slightly longer end (the drivetrain side) is in the oppsite side of the drive train? This way it will bring the Cranks closer to the seat tub and align better with the gears on the rear wheel. Do people do this? Please let me know. Thanks!

How do I measure for the chainline? I want to ride this thing. W will post pictures too.

I'm no expert, but I think they recommend spacers on the hub to push the fixed cog outward. I am sure fixedgeargallery.com/forum has this discussion somewhere. My fixie has a pretty straight chainline ... if it's not straight you will get bad "vibrations" from the chain whether in freewheel or fixed mode.

You can ride it with a chainline that is off a little. But it will be noisy and vibrate some. I don't think you should flip your bb. There is a definite R & L side which assures you won't rub the frame with the cranks, chainrings, etc. It's easier to put spacers at the hub to move it a bit.

If you have 120mm rear spacing, most likey you'll need a 107BB if you are using a converted road double crank. Otherwise, check out www.sheldonbrown.com. There is a bb and crank database and a big section on determining chainline. You can also use the search function on this site. There have been several chainline discussions in this forum.

And yes on the pics. Always good to see more bike pics!

It's easier to put spacers at the hub to move it a bit.

Won't it make my wheel off center with the bike if a move around the spacers? The Wheel is perfectly center now. I am using the original bottom bracket which is not a cartrige bottom bracket. I looked at the spindle and it looks like it is only 4-5mm longer on one side. If I measure the distance of my crack arm to the rear chain stay and divide it by 2, if the number is shorter then the length of the shorter side of the botton bracket spindle, shouldn't it work if it's flipped? I looked at the spindle and its not as long on the drivetrain side as others I have seen. Like I mentioned, about 4-5mm, but I am going to measure it to be 100% sure. This bike is using the Sugino Cranks that came with the bike with an english botton bracket. I was told that a 110mm spindle is usually the common size for a single speed conversion. Any idea?

I also looked at www.sheldonbrown.com and I am trying to fully understand it.

I've flipped the spindle before with no problems. Just make sure the chainring has enough clearance on the chainstay

Ok...so I took the measurement of the space between the inside of the crank arm (drivetrain side) and the chain stay, right where they meet. It measured 18mm. I then took the measurement of the bottom bracket spindle and it measured 119mm. So, I divide 18mm by 2 and get 9mm. I then subtract 9mm form 119mm and get 110mm. So, I should install a 110mm spindle, correct? I was told by a machanic at Sheldonbrown/Harris Cyclery that the common size spindle to convert to a single speed for bikes of my year (early to mid 1980s) is a 110mm. Has anyone else heard of this? If this is correct, where am I going to find a 110mm spindle?

I also decided to flip the spindle. It's is fairly close to being straight, but when I pedal the bike (on the bike stand) you can hear the chain. I also notice that the chain will get tighter and looser on the freewheel cog when I am pedaling it. Is there something wrong with my freewheel?

Nothing wrong with the freewheel. Your chainring is likely off center. Do a search for it, it's been discussed on this board before.

Switching to a 110 mm spindle will only move the cranks 4 mm inboard, but is likely the best solution. To make sure, though, you'll have to measure the chainline on the rear hub.

she's ALIVE! I am noticeing that the freewheel makes little nioses, is this normal?

check it out: http://forums.roadbikereview.com/showthread.php?p=805652#post805652

I'm right in the middle of this job myself. Heres what I'm doing. I believe its the way to go. First dial in the chainline to be straight as possible, by adding/removings spacers or washers on the left/right side of the axle as needed. I just eyeballed the chainline and then made sure that the chain tracked the cog and chainring smoothly when turning the cranks. Now, you may find that the rim is too far left or right. Redish the wheel as needed in order to center the rim between the chainstays. Im sure sheldon brown or some other web site has redish instructions. If anyone has more tips or advice please send it on. Have fun!