Hello. As I built my first fixie and rode it for a good 35Mi, I felt pretty tired. I've rode many BMX bikes and with the same ratio felt more resistance on others. Can it be that my chain is so tight that it is making it hard to pedal? I am running 44/15...it's a nice drive but it does tire me more than usual. Just wanted to know if my chain is TOO tight.

the chain should move vertically by about 1cm if it's properly tensioned.
if it's too tight it won't budge at all.

also there will be a tight and loose spot depending on the position of the cranks because the chainrings aren't perfectly round.

First off, your FG has larger wheels than your BMX, so you are actually running a bigger gear. With a 44:15, you are running nearly 80 gear inches, which is a pretty high ratio for the street. As to your chain tightness, you need to learn how to tension your chain. There are threads on this forum on the topic of chain tension adjustment.

Once you go slack you'll never go back.

Thanks a lot. My chain is very tight then. All I have is a little wiggle room on any given chain position. I'm not putting it back
As long as there isn't a HUGE amount of ware...which there isn't, I'm not that worried. Just a little hard to push.

This is where you're going to have to do some thinking and decide if 80GI is actually what you want. "Just a little hard to push" isn't really a good first impression of your bicycle, especially when it comes to your drivetrain and how that relates to your body. You only have one set of knees.

This isn't my first time riding a bike though. I just don't know if the ratio is causing the difficulty rather than the tension.

Pluck your chain and find out.

Thanks for the help. Just a question though. GI means what, and what is a "good" training ratio? My friend, the owner of a large bike store hooked me up with this ratio and said it would be nice. After riding it a few times I'm pretty used to the ratio. It's got a 15t in the back, vertical dropouts. If anything I'd need to get a 14t...I think that will fit a 700c wheel(to fix the tension problem).

So you have two problems- your gearing is too tall for anything but riding flat country and not stopping much, and your chain is way too tight. Because you've got vertical dropouts, you're stuck trying to find a "magic gear" where the chain divisions happen to give you a good tension. I'd say your best option is to add a link back into the chain, install a cog that's either one or two teeth larger, and roll with that tension.

First things first. Your problem here is that you have vertical dropouts, and it is quite difficult to get proper chain tension because you can't adjust the wheel axle position. You can mess around with different chainring/cog combinations, a chain half link, an eccentric axle hub, and eccentric bottom bracket and even filing the dropouts, but this is both complicated and expensive. Personally, I'd just try to find another frame with either track dropouts (rear facing) or horizontal dropouts (forward facing). Maybe you can either sell or trade your current frame with the vertical dropouts.

As to the subject of gear inches, it is a number computed as follows: (number of crank chainring teeth) X 27 / (number of hub cog teeth), and is just a number that is used to determine gearing. A higher number means a higher (harder) gear and a lower number means a lower (easier) gear. I'd recommend a starting gearing of about 70 GI, such as 44 X 17. Remember that a smaller rear cog equates to a higher gear, so if you went from a 15 to a 14 you'd end up with an even higher gear than you have now.

Thanks a lot guys! Hopefully a 16 or 17 will work...but even if i replace the link that i took out, the single speed 16t still requires a tensioner.
I've learned a lot. Thanks to all.

It should be this tight