CHICAGO (CBS) — Out in the western suburbs, Christmas came a day early for one little boy with special needs.

The smile on Owen Payton’s face said it all Saturday.  The 5-year-old could hardly believe he was riding his very own bike for the first time.

The sight had his parents fighting back tears.

“It’s almost indescribable, to be honest,” Christopher Payton, Owen’s father, tells CBS 2’s Mai Martinez.

His son has a heart condition and cerebral palsy, which make it almost impossible for Owen to ride a regular bike — something he’s always wanted to do.

But specially modified bicycles can cost about $3,000 — beyond the family’s means.

The bike Owen received was a gift from two complete strangers: 12-year-old Riley Christensen and 9-year-old Tommy Antonson. They just want to help kids with special needs get bikes.

Riley came up with the idea three years ago and teamed up with Project Mobility out of St. Charles. Tommy joined the cause after his sister, Rosie, was given an adaptive bike of her own in 2009.

“It’s just wonderful. It’s wonderful giving kids who don’t have a bike or can’t ride a bike freedom,” Tommy says.

Owen particularly likes the yellow color of his new bike.

In the three years Riley and her supporters have been doing these Christmas Eve surprises, they have given away nine adaptive bikes worth between $2,500 and $3,000 each.

They’re not done. Another child will be surprised on Monday, and they’re already collecting donations for next year’s gifts.