There are growing concerns that large groups of dirt bike and ATV riders have moved their illegal rides from the streets of Philadelphia to the suburbs.It's estimated a group of between 100 to 200 motorcycle riders and ATV riders traveled from Philadelphia and moved up Ridge Pike through parts of Springfield Township, Whitemarsh Township and Plymouth Township. The group then stopped just short of the border of Norristown and reversed direction. The riders were first spotted in Whitemarsh at about 7 p.m. on Sunday.Whitemarsh police said it appeared few if any of the vehicles were licensed to drive on public roads.Social media users, who said they witnessed the pack of riders, had harsh words for their behavior, complaining they were driving erratically, sometimes in lanes intended for oncoming traffic and on sidewalks.Whitemarsh police reported two of the riders were injured, including a 31-year-old man from the Olney section of Philadelphia. His injury occurred when his motorbike's chain broke slashing his leg. He was treated and charged with numerous traffic violations. His bike was impounded.Illegal dirt bike riding has long been an issue in cities including Philadelphia and Camden, where there have been fatalities.Chief Ward has been on the Whitemarsh force for 30 years and says what occurred Sunday night was a first in this suburban jurisdiction.