Recumbent - Best way to choose new tire for a tandem trike

We have a Tandem Terra Trike we bought used last fall, it had around 1000 miles on it, we put another 300 on it before winter settled in. It currently has Schwalbe Marathon tires on it, but they are very worn. (explains why we didn't do well on gravel roads last season.) We ride mostly paved, but would like to add a 2 mile stretch of gravel to one of our courses. We haven't bought tires for a trike before, so we aren't sure what to look for. Is it normal on a trike to replace all 3 tires when there is only 1300 miles on them? Any input is appreciated. Thanks.

My experience is that the tires that do the braking and turning (front on a tadpole) wear much quicker than the rear tire. The other factor is that the sidewalls may give out before the tread is gone on a rear tire. It helps to keep them properly inflated to give the longest life.

It wouldn't hurt to check the toe in on your trike. I realize it's a tandem, but marathons are long wearing tires. I am surprised you didn't get a little better life than 1300 miles.

We're running Marathon "Plus" on our Rans Screamer, and the same on my Catrike. You should be seeing many more miles IMHO on your tires on your tandem trike. +1 on checking the toe in and pressure. If the toe in is out, you can wear tires down pretty quickly with "scrub". Tires will also wear more quickly if they are under-inflated. Mike

Thanks for the replies, being rather new at this, I'm not sure what toeing in is or how to check for it. Could you please elaborate? Thanks.

Toe in refers to the degree of parallelism of the two front wheels when viewed from above (birds eye view). A toe in of zero means they are parallel. A positive toe in measurement means the front of the wheels at the elevation of the axle are closer together than the back of the wheels are at that same elevation.

Quoting Greenspeed here:

"Steering alignment should be done once a year or when excessive tyre wear is noticed. The front wheels should 'toe in' between zero and 1/16" (0-2mm). That is, the measurement across the front of the wheels should be between 0 and 1/16’ less than the measurement across the back of the wheels, at axle height.

A check can be made with a tape measure, and adjustment made by undoing one of the steering connections (eg steering arm on kingpin) and screwing one of the rod ends (ball joints) in or out half a turn at a time. Note you will notice that the rod ends have a jam nut (lock nut) to prevent them unscrewing and to eliminate movement on the thread. This will have to be loosened first before the rod end will turn and locked up again before each measurement is made.

A more accurate way is to use a trammel. A trammel has two pointers on a bar, which sits at the back of the tyres at axle height. A mark is made on the tyre with a pen, the trike rolled forward half a wheel revolution, and the marks compared against the trammel pointers. This method eliminates any inaccuracies due to wheel run out etc. All measurement should be done with rider on seat if possible as this helps flex and preload everything into position."

You adjust the toe in on a TTT by adjusting the length of the tie rods - the rods that connect the handlebar assembly to the kin pins.