What is the first component upgrade to a 105 groupset? do I need to stick to Shimano? The crankset is Oval Concepts 520, forged 6066 arms, 52/36T.
The bike a 2016 Fuji Altamira 1.3, STI 11 spd, brakes are tektro dual pivot. Stem, handlebars and seatpost are entry level Oval Concepts
What are your goals in upgrading?
105 components are already quite good, and the bike is mostly 105. While 105 cranks will probably likely shift a bit better, perfect front shifting rarely has much impact on performance. Front shifting is more of an annoyance than anything. and you would be hard pressed to notice any stiffness or weight differences from the cranks that are already spec'd on the bike.
If speed is the priority, removing drag from your clothing and position will be the first place to start. Skin suits (or form fitting kit) and low drag helmet will be the biggest bang per buck. Next up, wheels can also be a good upgrade, but to be honest you will likely need to spend more than the cost of the bike before you will really notice this upgrade.
If you are upgrading simply to out do your friend or riding partners, well then all that matters is what matters to them. Ask questions and I am sure they will tell you to through your money.
Honestly, the best would be to focus on maintaining the bike, ensuring your clothing and contact points are comfortable and just ride your bike. As it stands you have a good entry level bike. The performance should be quite good, getting that extra bit of performance that remains will be very costly endeavor if you take the upgrade route. When you are ready for a faster bike, save and purchase it outright. Used or old new stock can be a very economical way to go. I would largely avoid the upgrade game as it is often 10% performance, 90% playing with money.
Piecemeal upgrades on a low-middle level bikes is generally not worth it. Each individual upgrade does not buy you very much. The amount you will spend on enough upgrades to make a substantial difference will be more that the cost of a new better bike minus what you can get by selling the old bike on the used market.
The possible exception for mid level bike that has a decent groupset is wheels. Wheel mass has a effect on acceleration than non-rotating parts.
Other ways to spend your money:
Wait until something wears out and replace it with a good quality replacement. Tires, chain, bar tape, cassette ...
Better clothing and gear, especially shoes. Cold weather gear makes it possible to ride more. Computer/navigation units are useful too. A good set of lights also extends riding hours.
Look for deals on Craigslist, EBay and local Facebook groups etc. Sometimes nice condition items pop up.
Perhaps not that obvious but the one component upgrade I would look at is - brakes.
You list Tektro dual-pivot - but from my experience of Tektro budget brakes - I would look at a pair of 105 brakeset. Much stiffer. And braking greatly improved for not much money.
Other things you may consider - simply because they will move with you from bike to bike (making them cost effective) are 1) Wheels 2) Saddle 3) maybe handlebar too
Hope that helps.
