If it seems like there's nowhere to legally chain up your bike in Riverdale, that's because there isn't.

A recent study conducted by Bronx Borough President Adolfo Carrión Jr. found that there is not a single city-issued bike rack in all of Riverdale. The Kingsbridge, Kingsbridge Heights and Marble Hill areas lay claim to 18 racks, however, compared to the borough-wide number -- 426 -- that's still just a drop in the bucket.

The findings have bicycle advocates scratching their heads.

"I have trouble thinking of a neighborhood in the Bronx that has as much going for it in terms of nearby bicycle infrastructure, even though Riverdale itself is bereft of a bike lane," said Wiley Norvell, a spokesman for Transportation Alternatives, a bicyclist-advocacy group.

The Hudson River Greenway, several recreational trails, and the area's comparatively slower traffic flow make it a more bike-friendly place, he explained. "It seems to have a lot more of the basics that we think makes a good neighborhood for biking," Mr. Norvell said.

Called "Bike the Bronx," the borough president's study found that the 18 city-installed bicycle racks in the 10463 ZIP code -- which includes Kingsbridge, Kingsbridge Heights and Spuyten Duyvil -- are concentrated around the West 231st Street subway station, serving the commercial area around Broadway. The borough president's office cites a 2007 DOT survey that found more Bronx bicycle commuters start their route to work in Kingsbridge's ZIP code than in any other.

That's likely why the racks are placed there. Bicycle racks throughout the borough appear to be concentrated where the city agency found more bicycle users.

But bicycle advocates say street parking for bikes is a key element to encouraging bicycle use.

"Citywide, there's one bike rack for every 26 cyclists, which is a pretty low ratio, and the Bronx is definitely at the far end of the spectrum in terms of being even further behind," Mr. Norvell said.

Ubiquitous bike parking on the street encourages more use of pedal power, said Mr. Norvell. "That's why you have bicycles chained to lampposts and subway stations and anything that's nailed down," he explained. "So what's really critical is making bike racks on commercial streets as abundant and frequent as streetlamps."

After reading a recent Riverdale Press story about bicycle commuting, Community Board 8 economic development committee chairman Bob Fanuzzi and housing committee chairman Thomas Durham started discussing problems facing Riverdale bicyclists with other board members. Mr. Durham has asked area bicyclists to help compile a list of good bike rack locations, and the matter will come up at Board 8's Wednesday, Nov. 12 meeting.

The borough president's office also requested that DOT install racks at four locations in Riverdale and Kingsbridge: near Lehman College; at the West 242nd Street subway stop; at the Kingsbridge Community Center on Kingsbridge Terrace; and the Kingsbridge Library on West 231st Street.

Scott Gastel, a spokesman for the DOT, said the city plans to install 5,000 additional racks by 2011. It's unclear if any will be in Riverdale.