Bicycle Mechanics - Do I need magic allen keys to disassemble the chain set?

I have a 2002 year Trek 4300 Alpha. It seems to have typical four-hole chainrings but I have honestly tried six sets of allen keys (imperial & metric) and none fit. 4.5 mm is the closest I've found but it's not QUITE snug enough on all holes and will definitely strip all the holes. Maybe 4.6 would work or 4.7mm. 5 is too big and will not fit. So then I go to Imperial but 3/16 is too big and 5/32 definitely too small. This is absurd, what the heck allen fits these? I'd drill them out but I'm sure any replacement screw would be off by some miniscule fraction of an inch!

usually it's supposed to be 5mm
I would just use 4.5mm and once they're all out, replace with 5mm chainring bolts and nuts.

but I'm quite sure someone on here knows better than me, so wait around for more posts before doing what I would do.

I have no idea about the bike ok? But just wonder if its not an allen but a Torx?? I have seen some fancy torx that look like allen big time and u need to pay attention really well to see the shape in the bolt. For example a set of campagnolo cranks i have, they come with torxs instead of allen.

are you sure the chrainrings are not riveted on? some rivets are made to look like allen/hex sockets

If you look at pictures of that bike it looks like it doesnt have bolts?? and maybe reptilezs is right?

A Trek at that price level would have bolt on chainrings.

A Trek at that price level would have bolt on chainrings.
Really? $339 is rather inexpensive.

Here's a close-up--and to be clear, I cannot undo these with any allen key now, the closest one to fit will strip the holes. I wonder what a bike store would do, I may just have to drill them out.
http://i897.photobucket.com/albums/ac177/Skoorb100/chain.jpg

Those are rivets designed to look like bolts. Real chainbolts have through holes. When you look at the rear you'll see there's no separate chain ring bot nuts. The nuts are ring nuts with slot grooves on the rim. You won't find any such nuts on this bike. And THAT is why none of the allen keys fit and why you're having such a time undoing them.

But then my momma taught me never to argue with anyone that is capable of mounting a saw to their crankset.... :D

Erased.

added... SUNRACE APEX FLUID Drive, thats the crankset, there is one at ebay if you are looking for a new one.

Those are rivets designed to look like bolts. Real chainbolts have through holes. When you look at the rear you'll see there's no separate chain ring bot nuts. The nuts are ring nuts with slot grooves on the rim. You won't find any such nuts on this bike. And THAT is why none of the allen keys fit and why you're having such a time undoing them.

But then my momma taught me never to argue with anyone that is capable of mounting a saw to their crankset.... :D

who knows, it might just be a 1/8" pitch chainring :innocent:

Wow, thanks guys! Yeah I see that one on Ebay, too, it's "Vintage". Cheap, though.

Making rivets look like allens is annoying but definitely explains this.

The circular saw is mounted on there so that if I hit brush while riding it just chews through it. Adds a bit of weight but works a treat :D

Do you pull a trailer mounted generator or just have REALLLLLLLLLLLLLLLLLLLLLLLLLLLLY long extension cord?

Do you pull a trailer mounted generator or just have REALLLLLLLLLLLLLLLLLLLLLLLLLLLLY long extension cord?The handle bars pump back and forth like an elliptical, so that's how I get the power to the motor.