Based on their John Henry 29er, Siren’s new Twinzer uses a curvaceous twin top tube to create a stunning bike that can be built up for mountain biking, cyclocross, randonneuring or, heck, even road riding.
Shown above as a single speed rando bike, the Twinzer name comes from surfing but obviously refers to the dual top tube that runs all the way from the head tube to the rear dropouts. Siren Bicycles is the first to admit there might be slight bit of added compliance and that it adds maybe an ounce of weight compared to their straight or constant-radius curved top tube. The purpose is, well, aesthetic. If you have to ask why, the bike’s probably not for you.
If, like us, you’re thinking “hot damn that bike is sexy”, click more…
The Twinzer frame retails for $1,600 and is steel. The Paragon sliding dropouts come standard, and the seat tube gusset doubles as a handle for hike-a-bikes. It can be upgraded with a 44mm head tube (ID, allows for tapered steerers), an upgraded tubeset and powdercoated finish. You can even add a third water bottle cage mount on the bottom like this one.
UPDATE: Above is the standard Twinzer 29er mountain bike frame, which is what’s currently available. The model below is a different iteration…
This orange one (Bikerumor color scheme!!!) is Siren Bicycles’ owner Brendan Collier’s personal bike and isndesigned with drop bars in mind, so the geometry is different than the standard mountain bike geometry on the black frame. It also shows what can be done to customize any of their bikes. They’re all handbuilt in California, so you can get whatever you want.
The headtube was extended to keep the riding position a bit more upright, and it and the top tube length were adjusted to work with Salsa’ Woodchipper quasi-drop bars. Cable routing is internal and designed around a 1×10 drivetrain of Ultregra STI levers with an XTR derailleur and older SRAM cassette with the orange plastic spider. Brakes are Avid’s road BB7 mechanical discs.
It’s built up with White Brothers’ carbon rigid fork, but Collier says they’re working on their own rigid fork so they can tune the rake and offset to work specifically with Twinzer builds. The best part? He’ll build one just like this for you, too.