There’s not much detail on the Viper website.
they list a 20″/16″ or 21″/17″ frame without giving any other dimensions.
JRTG, you describe yours as a 19″/16″, so I take it that’s the smaller version ?
I’m not sure that would be suitable for a 6’1″ captain and 5’7″ stoker.
If you were local, I’d ask for a test ride, but we’re about 190 miles away in Worcestershire.
I see Probikeshop have got the same frame for about £380 with postage.
That’s another option, to build one up using parts from my spares box, but I’d still need to buy one or two tandem cranksets and some heavyweight forks.
Which leads on to a couple of tandem build questions;
Could I use two standard triple chainsets with the front chain between the two inner rings, and using the middle and outer ring only on the back for 2×9 ?
If not, could I use a tandem rear chainset, with three rings on the right for 3×9, plus one on left, then a standard chainset on the front round the wrong way to put the chainring on the left ?
Would the pedals keep falling off because the threads are the wrong way round ?
Can I use any air forks and just pump them up harder, or would I need heavy duty DH forks ?
Total rider weight would be around 150kg, 95kg/55kg front/rear.