Bicyclists carry a variety of things on a road trip in case of a breakdown.

But a 3-pound roofers' magnet isn't among them.

The magnet, used to clear driveways and lawns of nails, pieces of flashing and other sharp objects, would have come in handy Monday along an old railroad right-of-way between State Route 89 and Gynden Road in Sparta Township, Crawford County.

State trooper Daniel Rexford's report explains what happened: "Actor[s] arrived at the above location and deposited small tacks in an attempt to sabotage a bicycle ride. There were numerous bicyclists that rode over the tacks and sustained damage to their tires."

How many of the more than 300 bicyclists participating in the Fourth Annual Pennsylvania Greenway Sojourn got flat tires?

About 150, said Katie Magers of the Rails-to-Trails Conservancy in Washington, D. C., which is sponsoring the six-day ride. The riders were en route to Titusville when their tires were flattened by an unknown number of carpet tacks. Fortunately, everyone was able to keep their bikes under control when the punctures occurred. No one was injured.

Tom Sexton, director of the Northeast Regional Office of the RTC, said local residents went out of their way to help the stranded sojourners. They transported the riders and their bikes. "They were really great," Sexton said.

That's also an apt adjective for the local and regional bicycle shops who sent bike mechanics to Titusville to repair the flats.

The organizers of the 200-mile trail and road trip, which I wrote about last Friday, hope the rest of the trip will be flat free. The riders are scheduled to arrive today in Cabot in Butler County.

For more information about the RTC and the Greenway Sojourn, visit www.railtrails.org or call 717-238-1717.

Anyone with information about the trail sabotage is asked to call the state police toll free at 800-922-1975. That includes anyone who sold a large number of carpet tacks in recent weeks.

If the jerk(s) who did this are arrested, tried and convicted, I have a suggestion for a suitable punishment. Give them a roofers magnet and make them walk the length of the affected trail.

In their bare feet.

More on flats

Flat tires and how to prevent them has been a popular topic on the message board of a news group hosted by Yahoo.

"Betsy" asked about a front tire that kept going flat. David Micklo suggested a plastic insert that lines the inside of mountain bike tires and keeps them "pretty much puncture resistant."

"Rich" said spoke nipples are the cause if the hole in an inner tube is on the inside toward the rim. "If that is the case, you need a new rim strip from your bike shop." He said he has used cloth tape from his first aid kit as a temporary measure. He also has Kevlar tires, a material used in bullet-proof vests.

Paul Wiegman said inner tubes deteriorate with use and disuse and should be changed on a regular basis. He also suggested tires manufactured with Kevlar bands built into the treads or with silica in the tire webbing to make them puncture resistant. He also said he uses "slime," a liquid that is poured into the inner tube and seals small punctures.

Wiegman, a botonist, said the sizable woody thorns of black locust trees that grow along some sections of the Great Allegheny Passage can easily penetrate a bike tire. Watch for thorny twigs on the trail after a storm.

Betsy thanked everyone and decided to go with a slime liner. "Although it adds weight to the bike, my biceps may benefit each time I have to put it on the rack."

To exchange information about the passage at no charge, go to groups.yahoo.com/. At Find A Group, type in Great Allegheny Passage. The search results bring up Great_Allegheny_Passage and on the right side of the screen is a button to "Join This Group." Click the button, give yourself a name and password and you're ready to go.

For more information about the Allegheny Trail Alliance, go to www.atatrail.org or call 1-888-282-2453.

A quartet of rides

The Monessen Amateur Radio Club is sponsoring a four-distance ride -- 30, 50, 70 and 100 miles -- on Aug. 14.

Those pedaling the longer distances may leave from Elizabeth between sunrise and 8 a.m. The others may depart between 8 and 10 a.m. Food, water and rest stop facilities will be available on each route. Radio-equipped sag wagons will patrol each course.

The cost is $15 for those whose entry fee is postmarked by Aug. 10 and $18 thereafter. Add $8 if you want a T-shirt. Send your check to the Monessen Amateur Radio Club, 133 Main Street, New Eagle, Pa. 15067. The club provides vital communication links during emergencies, especially those that are weather-related.

For more information, e-mail grilli@verizon.net or call 724-258-2798.