Hey!
Essentially my current road bike (EVO vantage 7.0) has a full shimano tourney set. It served fine for a while but last season I was finding myself limited by the speeds (at 2x7, I was overpedalling). Tried finding replacement compatible rear freewheel cassettes in a lower teething (currently 14-28) but to no avail.
I have found a shimano 105 r5700 set for around 300 CAD but it doesnt come with a crankset and so I was wondering whether, using the 105 front derailleur, it would be possible to keep using my tourney crank while the rest of the set is 105? (if I'm not mistaken, my current tourney crankset is the FC-A070)

I've tried cross comparing with the productinfo shimano website but I'm still unsure.

Thanks for your help.

You either have a freewheel or you have a cassette. They are not the same. If you have a freewheel you will need a new rear wheel in order to move to 11 speeds. Your current crank's chainrings are likely spaced too far apart for 11 speeds. Not sure what you mean by "overpedaling". If you mean that your gearing is either too high or too low, more speeds won't change things all that much, but your gears will be spaced closer together

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...I agree with the above, that what you really need to do is to learn more about gearing, and what makes it work well to your own conditions and preferences.

More available cogs won't fix your problem, if cadence is your issue. If by "overpedalling" you mean too high a cadence, all you really need is maybe a larger big chainwheel, and maybe a longer chain to accommodate it. I did not look at your reference, but most Shimano cranks of that era came with 130 BCD chainrings, which are commonly available both new and used.

If by "overpedalling", you mean too low a cadence, thus having to push too hard on the pedals, work backward from that, looking for a smaller small ring in front. This ought to work out cheaper and easier than buying whatever it is you're looking at for 300 bucks Canadian. If the chainwheels on your current crank are riveted, not bolted to the arms, forget I said anything.

I googled the OP's bike. It has a 50 34 compact crank and a 14 28 freewheel
https://cycleactionsport.com/shop/non.../#.YmYX1PPMI7o

Yeah I know currently I have a freewheel. I've already looked at changing my rear hub but its true that cost-wise, doesn't make much sense when its all added up.
As for overpedalling, I mean like 'spinning out'. Like pedaling at an uncomfortably high RPM during sprints. It not that I don't have enough speed, I perfectly happy with 2x7. Its just that when I'm on my 'hardest' gear ratio, I isn't hard enough. So when I push for sprints, instead of reaching my max effort, I end up pedaling faster than comfortable.
Thanks for the help <3

Yeah I meant too high of a Cadence. It rapidly reaches a point where instead of being able to keep pushing, my cadence just gets to a point where its uncomfortably fast. Essentially all I wanted was to **** with the ratio to make it greater (either by reducing the gearing on the cassette or increasing on the crank) but I figured it'd be more expensive to change the crank. Thanks for the input I'll definitely look more into it! <3

There aren't a lot of options in freewheels these days, but a 13-28 would give you a little more top end without requiring major changes to your setup. Hopefully you are already going pretty fast by the time you are pedalling "uncomfortably fast" in your top gear.

There is the DNP 11-28t 7 speed freewheel:
https://www.ebay.com/itm/284202603316
Some people report that the overall width is a bit wider than other freewheels so you should eyeball your current setup to see if there is a reasonable amount of clearance between the end of the freewheel and the frame.