How come bikes come with 53's on the outside and smaller rings on the inside? If the cassette was reversed, wouldn't it work just as well with the big ring on the inside? Is the reason mechanical? For looks? Did it just happen that way?

Just guessing, but I would think that mounting the crank spider on as large a bolthole circumference as possible would be a good idea. And it also seems like a smaller possibility of interference with the rings is ensured with the big ring on the outside.

Plus an inverted cassette (big cog on the outside) would just seem wrong.

If you look at the clearance between the chainrings and the chainstays it becomes clear that putting the large ring on the inside would require a much wider spindle to get the needed chainring space.This would put the feet further apart while pedaling, which would cause some people much difficulty.

Assuming it's a 53-39 and a 12-25, there's no reason why someone would be in a 53/25 combination, so having the larger ring on the inside is useless.

Nahhhh jlin, what I meant is why isn't everything reversed, as in the 25 would be on the outside while the 53 would be on the inside. The gearing would be the same, but would be physically reversed on the bike.

Oh, well because the 25 ring wouldn't have enough clearance from the frame.

And it would be much easier to drop the chain into the spokes.

Because the derailleur doesn't have to adjust as much for different chain lengths. Also, you want to be able to have the biggest combination, and if the big chainring was inside, then to get the biggest combination, you'd need to have a bad chainline.

Nahhhh jlin, what I meant is why isn't everything reversed, as in the 25 would be on the outside while the 53 would be on the inside.
You would have interference with the chainstay at both ends.

Part of the reason may well be that while a higher gear, say 52-12 is faster, a lower gear, say 32-25 has significantly more torque. Greater torque applied to the outside end of the cassette would have a better chance of pulling everything out of alignment.

Besides it's just more aesthetic with the little stuff on the outside on the rear and on the inside in the front.

Take a look at your Double or Triple Chainrings as they sit on your bike. Now imagine replacing the small ring with your BIG ring on the inside and look at your seat stays.

A LOT of frames couldn't do it...The big ring won't fit. My wife has a triple and her small ring probably clears the seatstats by 10mm....no chance of putting a big ring closer to the frame.

.....and the bike would go backwards not forwards and it would look very silly there and then something wouldn't fit proper...................................................

M-E-C-H-A-N-I-C-A-L-L-Y C-H-A-L-L-E-N-G-E-D **********

Because if the big ring was on the inside, as you move to a higher gear the chain would be bending to a worse and worse angle. As it is now, the small chainring is roughly in line with the larger rear cogs, making for smooth low gearing, and the large chainring is roughly in line with the smaller rear cogs, making for smoother high gearing. If you flipped the front chainrings, at your absolute highest gear the chain would be a good 1.5" out of alignment from the front to the rear, grinding away like crazy. The problem would be further amplified with a triple.

Is this an attempt at winning "The Original Cycling Related Material Post Contest" that was up here earlier this week?

I actually think it's so that you only have to scrub one grease mark off of your leg instead of three.

Nah, I was hiking yesterday and I started thinking about biking

If the rings were reversed, (i.e.: small ring on the outside and the large ring on the inside), and the cassette left as is, (i.e.: largest gear inside, smallest gear outside), and you did not want to cycle with the chain running from the inside ring to the outside gear, nor the outside ring to the inside gear, you would lose the use of your lowest gear combination and your highest gear combination. I for one want to use those two gear combinations!

Ride on! -Spoke

How about put one ring on each side of the BB shell, the 39 on the left, the 53 on the right. Then split the cassette with the climbing gears on the left, and the higher speed gears on the right? Two chains two smaller freehubs, double chains that freewheel, and dual acting ders working together? How's that for engineering?

Now you can have even dish in your wheel. There, dish problem solved.

Dang it! I thought maybe you were going for the win I think about stuff like that sometimes when I'm out walking the river trails. I've wondered why cranks and cassettes are all on the same side of every bike. Then I thought, the cost of manufacturing the front, and rear derailleur to operate in the opposite direction would not be very practical. I'm sure there are other mechanical and gravitational issues in there as well.

'Damn your Vulcan logic.'

Ohhh man....now i thought of another one.

How come nobody has made a bike where the drivetrain goes to both wheels?!

Kinda like what patriot was saying (Thanks for the idea ), put dual double rings on the bike, one on each side, and have dual cassettes, one for the front wheel and one for the rear!

Edit: oh yeah, ya gotta be able to steer!!!!

How the heck would you steer?

hmmm...... Sounds like a good engineering problem to solve.

I just hope weight is not a factor.

The simplest solution is most often the correct one.