Why are the rear wheels locked up on my toddlers schwinn tricycle?

One of these may work. Measure distance through hub and diameter of hole, then call to confirm compatibility. A Schwinn dealer will be able to order but may cost more.
WheelMaster Alloy Rear Trike Wheel 24x1 75 Wei As7x Silver 36H

Northern Industrial Tools Tire Wheel 26in Spoked Pneumatic Spoked Wheels...

I’m happy to help further over the phone at https://www.6ya.com/expert/donald_f2ed37026a3ac881

Problem with bearing or axle, no way to be more specific. Have someone comfortable with mechanical items or a bike shop look at it. If fairly new refer to place purchased.

I’m happy to help further over the phone at https://www.6ya.com/expert/donald_f2ed37026a3ac881

No known replace source is available.

through your local bike shop. You may find these parts to be more than the price of a replacement

The Schwinn Meridian Trikes use a different type of axle than others such as Sun Bicycle Trikes. The center of Schwinn & Sun Trikes are the same and measured diameter at 17mm, but differ on the threaded ends... Sun Trikes continue with 17mm to the axle ends, but Schwinn Trikes taper down to 12.5mm axle ends to fit their custom size wheels. This Schwinn tapered reduction in axle diameter may be part of the reason why Schwinn axles seem to bend or break more easily.

It seems that Schwinn requested these custom parts size to lock consumers into having to purchase solely high-priced Schwinn wheel/axle parts.

As of 2022, buying replacement Schwinn Wheel/Axle replacement parts is a real pain because Schwinn will not sell direct to consumers, will not disclose Schwinn part numbers, and Schwinn Customer Service tries to redirect public parts inquiries to "authorized dealers".

The problem is most local bike stores no longer carry Schwinn bikes or parts and the retailer "big-box" stores such as Walmart, Target, or Dick's Sporting Goods will only sell Schwinn parts for bikes they stock or have sold to you at that store.

After complaining, to Schwinn Customer Service several times, they finally allowed me to order direct from Schwinn.

http://stores.ebay.com/biketony007sbikeworld

this guy has schwinn 12" fenders

http://www.schwinnbikes.com/support/owners-manuals

http://www.schwinnbikes.com/skin/frontend/schwinn/default/pdf/Schwinn-Roadster-Trike-Manaual.pdf

Lists the parts so you can convey what you need to a supplier.

Page 1 has the number to call. 800 626-2811.

Search engines work better than postong and awating an answer.

search for >>> inner tube 10" bicycle

http://www.schwinnbikes.com/media/uploads/blog/files/Schwinn-Meridian-Manual_Mar2011.pdf

This might help...

http://www.schwinnbikes.com/media/uploads/blog/files/Schwinn-Meridian-Manual_Mar2011.pdf

The rear brake may be locked up. Page 26.