I assume you mean size so that’s what I’ll answer for since I don’t know what “sixe” means. I have a 26" Nimbus frame on a 24" Profile Wheelset. Since the frame is cheap, I’m not the least bit hesitant about drilling into or welding onto it.
Other people may have different opinions and additional knowledge, but so far my experience has been: for the fat DH (and Coker) tires it’s basically hydraulic or V-brakes. V-brakes can lead to leg clearance issues. However, if you want a drag brake, there is no current hydraulic drag brake solution.
For the 29er with a narrower rim and tire it’s a different story; see here .
Yes I make them for the public. This one was a prototype to test out the overall configuration and Ben, after training and racing, says it’s great. There were several untested ideas and luckily they all worked out just fine. I haven’t worked out the cost yet for a generic configuration but if you PM me with what you are looking for I can work up a quote for you.
Most of the configuration is standard or standard GB4 parts now but there still is some custom work on the frame and the air seat which adds to the price. It’s not cheap but this is absolutely top-of-the-line everything, including some parts that are not available elsewhere.
I will need to know if you want a tiltable saddle and what your bottom-pedal-to-top-of-saddle saddle distance is. I will also need to know your braking hand unless you specifically want the handle to be ambidextrous.
In the local mountains here in Santa Monica there’s a lot of single tracks that skirt long fire roads, and there’s 50-200-foot sections of these tracks that are quite steep. I’ve found a Magura brake to be required gear on this steep stuff if you actually want to ride instead of back-pressuring the cranks at every half stroke (sans brake), which results in a super jerky kind of spasmodic descent (that cooks my knees). Riding/feathering the brake on this steep terrain is an art I’m just getting used to. One good trick is to cover the brake lever with rough athletic tape to improve grip – with the regular surface (slick plastic) my finger(s) kept slipping off when jouincing over ruts and rocks.
The Magura has very fluid action and has a narrow profile. V-brakes, while cheaper, are not as smooth and are usually pretty fat – but cheaper. Also, on long gradual descents, I can actually go faster with much smoother action when I’m lightly feathering the brake instead of back pressuring to keep the speed managable. You gatta know how to go without the brake, and you often need far less braking than when you first start out (I did, anyway), but some stuff is just flat out impossible with no brake–a well known and accepted part of mountain biking.