Hi,
I am new here and also very new to bike mechanics.

I have been given a very good Giant composite frame, juste the frame, no fork. I was thinking of buying an old Empire road bike and swap the frame. I was wondering if both bikes were compatible.

Giant frame looks like 18"
Empire bike has 21" wheels (55cm)
Pictures: imgur(.)com/a/ZRxRR


Thank you for your help!

Too little detail to answer. But probably no.
And 21" is not a recognized wheel size. Try again.

It's possible that some of the components might swap over, but the Giant is probably designed for a wider, more modern rear hub that the Empire has. Depending on the Empire's rear axle, this may be as simple as adding spacers to the present axle, or replacing the current axle with a longer axle, but may also require replacing the whole hub, at which point you may as well buy a new wheel. Is the Giant a bare frame, with no fork? The Empire's fork almost certainly won't swap over, so you'd be looking at buying new fork. Without knowing the head tube specs on the Giant, I can't say whether this would be a threaded or threadless fork. So you're probably looking at a new stem and handlebars as well. The Empire has down-tube mounted shift levers, but the Giant has no mounting bosses for those, so new shifters as well. This is just what I come up with off the top of my head; there may well be more pitfalls.

I wouldn't consider it to be worth pursuing.

Best thing to look for is a modern bike with a cracked frame if you want to do all this work.

I wouldn't be surprised if the Giant had some sort of press fit BB.

add the Front Derailleur, seatpost, headset & seat clamp to the list of incompatibilities, it gets long very quickly...

The list of what might fit is shorter:
seat
pedals
cables
valve caps

Unless that Giant is something really special, you would likely do better buying an already built bike than trying to build it up.

Things to consider would be the rake and stack height on the fork you are trying to replace with. You go buy a "donor" bike with the wrong fork and you set yourself back...take a look at off the shelf carbon forks from Enve, etc.

IF you were going to try to do this, I suggest trying to find a cheap bike with the group you like on somewhere like Nashbar, BD, etc and do a part swap. You likely will still need some small items to make the change and make sure (as above) to pay close attention to the fork specs on what is supposed to be on the frame for compatibility.

I looked at both bikes and nothing is compatible so I have to agree with everyone above it is a no go. For others who may be interested here are the two links.

Imgur: The most awesome images on the Internet

Vélo de route Empire | de route | Ville de Montréal | Kijiji

I'm thinking the Giant appears to be some kind of TT frame.

Is that a clamp on top of the seat post mast? Perhaps some better photos of that. You may not need the seatpost, but it will make fitting the frame more complicated.

Can you estimate your bike fit before starting? Do you have a road bike that you can measure the bottom bracket to seat rails? It looks like the Giant seat can be lowered about 2", and perhaps raised a hair. A TT bike might raise the seat slightly more than a road bike. But, it is a non-starter if you can't get close to fitting your legs.

I don't think I would pay $120 (even Canadian) for that Kijiji bike, to ride or for parts. For a parts swap,there would be much better bikes to start with.

I'm not saying that the swap is a bad idea, but as others have mentioned, look for a more modern crashed donor bike. Or, sometimes one will find something like a 10 year old bike that is underpriced for what it is (brifters, etc). Maybe low end brifters?

Being a TT bike, how do you want to build it up? Road drop bars? Bullhorns? Modern TT bars? etc? That will dictate a lot for your ultimate build.

Expect to hemorrhage some money on the build. $500 in parts (and skimping at that). Do you have a local bike co-op/recycler that would have a chance of having some nice parts?

Don't bother. You don't know what you are doing.

I think that is a little harsh of an assessment.

Anybody can learn about bikes. And there is no better place to start than with a bare frame and a pile of parts.

But it will be a steep learning curve jumping from $100 department store bikes to a Carbon Fiber TT bike.

I wouldn't really start with a TT frame for one's first quality road bike either. Put that frame in the closet, and look for something more standard.

Mixing the two bikes the OP found would create a very odd Frankenbike. Choose the lightest frame possible plus the heaviest components possible... to arrive somewhere in the middle?