Info on tire for a rookie

[Cheetah]

Hi everyone,
My wife and I are new to the world of tandem. We bought a used Roland for not much money. The bike was in pretty good condition. The only thing I add was a new set of wheels. The original bike had a 130mm rear axle but it is now running (rolling) with a 145mm model. After looking a bit on internet to find out what size tire we should be using for our total weight of 350 lbs. This include Pilot, Stoker, Bike, Bottle and Tools, I end up choosing a 28mm tire. In the LBS around I was able to only find Armadillo tire (Specialized). I don't know if these are a good choice but may be you will tell me. The problem is that the bike slowdown quickly when we stop pedaling. Also the downhill speed is not faster than when I am riding my single roadbike. Is it possible that the rolling resistance of this tire is so high that it is slowing down the tandem that much??? The tires are inflated at 125 psi. Reading all messages related to tires I just realise that many are riding on 25mm tire. I am not sure if I could install 25mm on my wheelset since the rims are Mavic T520. The tandem is actually use more for fast ride but for sure we are going to travel a bit with it. If we travel, we will probably use a trailer to carry the luggage, so almost no more weight will be add on the tandem's tires. So, is my Armadillo tire good or not? If not what should we be using for 28mm tire? And if it is possible to install 25 mm tire, what model should I install?

Thank you all for your help. It is well appreciated.
Have a nice day,
Michel

[TandemGeek]

The Armadillo is considered a good tandem tire relative to durability and puncture resistance, but it doesn't deliver the smoothest ride of the various tire models available. As for the tire's impact on your downhill speed, at 120psi it wouldn't be that much "slower" than most other tires in that size and at that psi rating. I would be more inclined to make sure your wheels are spinning free and true, including your cassette and a check of your rear wheel alignment in light of the respacing.

Other "good tandem tires" to consider would include the Continental Gatorskin in 700x28 & Avocet's FasGrip K20's in 700x28. Of the three, the Avocet FasGrip "seem" to have the best road feel but also wear out the fastest. I"m not sure I'd recommend the 25's for use on the T520's. If memory serves, the inside width of the T520 rim is just about too wide for a 25mm tire.

[Cheetah]

Thanks for the answer. The wheels are straight and are turning freely. The only thing I will recheck is the 2 rear dropout to be sure they are parallel so the rear axle is not bending when the quick release is tightened. But because the rear wheel is turning freely I think the dropouts should be straight. I am now wondering if there is a good difference in performance from 25mm to a 28mm tire. I am taking as comparison my road bike, but this one ride on 23mm tires.

Any more comments will be greatly appreciated.
Have a nice day,
Michel