Curtis Bikes' New Thumpercross Steel Downhill Bike - Bespoked Show 2019
Curtis has been hand making bikes in England for nearly 50 years and the latest addition to their range is a total overhaul of the Thumpercross downhill bike.
Many moons ago, the Thumpercross was a four-bar linkage downhill bike, this steel, handmade, single-pivot machine has very little in common with the old one but they liked the name so much they decided to carry on its legacy in a totally new guise.
If you're a fan of brazing, you can't go far wrong with the work of Brian Curtis.
A closer look at his work.
The bike is based on the XR-650 enduro bike that Curtis has been making since 2017 but with a 70mm longer swingarm, a 63° head angle and, of course, travel bumped up to 8 inches (203.2mm).
A simple but effective single pivot design.
Wondering what #Metal Sex Technology is? Well, it's made out of metal and it looks sexy... that's pretty much it.
There's not a machine in sight at the Curtis workshop, every aerospace grade T45 tube is cut with a hacksaw and then filed down to length, they even have a human-powered tube bender. This means that they are capable of making totally custom geometry to suit each customer's needs. How custom you ask? Well, they can even change the thickness of the tubes for a light or heavy version, depending on how aggressively you ride. Want a bike that will take a beating? Go for the thicker tubes and plough with confidence. Want something a bit more svelte and poppy? Curtis can do that. While this bike may look chunky, it's reportedly not too much more portly than the XR650, which comes in at around 32lbs.
Brian has had nearly 50 years of experience to perfect his techniques.
The bike is currently undergoing a 6-month thrashing to ensure it is ready for sale. Expect the frameset to cost around the same as the XR650 (£1,750, no shock), with a full build costing a bit more.
No seat collar necessary on this steel bike.
Even the bike stand was neatly brazed inhouse.
More info.
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I really liked the older Santa Cruz aluminum vs carbon Nomad video.
(which they often AREN'T)
Carbon is extremely strong vs. the stresses it's made to be strong against, which also happens to be the stresses put on the frames in the SC vid. For instance, one of the strongest places on a carbon frame is the downtube/headtube joint, and the downtube is usually pretty beefy too. However, carbon is more susceptible to breaking from impacts on the less prioritized parts of the frame.
Also, the frame is toast after the first whack on the concrete.
They should be. This is a lesson that people that design weldaments have unlearned many times. Often there is the introduction of a new steel alloy, "that does not need post weld heat treat". Later you find out that in the long term it does definitely need to be heat treated.
I personally would not want a steel frame glued together with brass. "should be fiine" for most of of the twiggy ninny pinkbike 9-5 consumerist, and and Dr Bro
Note that Brian Curtis also used to make MX frames out of brazed T45 so I think he’s got his technique sorted.
I'm currently running a $800 china carbon frame, brutally and unapoligetically side loading and bottoming out dailiy (using a shit monarch stand in shock) hitting significant jumps, and i am no more concerned about it failing than any other bike i've had.
just because something is cheap and or from china, doesnt mean shit.
trek, specialized, giant, transition, evil.... they all have had plenty of failures, some of them defects.
Sounds more like you are the ''twiggy ninny pinkbike consumerist'' you are trying to disparage.
Correct, no need for post heat treat after brazing.
Moved to their standard jump frame which I thrashed the s**t out of for years and is still fine (came with a lifetime warrenty in 2007). These bikes are bomb proof.
A friend of mine actually bought one of the very first incarnations of the Thumpercross over 10 years ago. Let's just say this latest version is a considerable improvement- it looks great and the bb isn't 17 inches from the ground any more.
They do use Reynold and Columbus and will ask what you plan on doing to match the tubes up to the style.
Its pretty sweet that they actually offer that flexibility to have it more customised to the way you ride.
No it doesn't. T45 is the material on plans to build reproductions because the original construction materials are very rare and expensive to source due to a lack of skilled labour to produce the wooden structure properly The structure of the original planes was wooden framework box construction for the fuselage and wings with plywood panels around the cockpit, fabric covering the wings and fuselage and an aluminum cowling for the engine. Aside from the machine guns, the engine itself and the bombs, the only other significant use of steel present were the control cables and bracing wires.
factoryjackson.com/2016/03/14/curtis-bikes-made-in-a-shed-2
Great workshop and great craftsmanship.
Son buenos los diseños simples y efectivos como estos
He misses majin although now oxford bikes took the 2008 model as a reference for his production.
The simple and effective designs like these are good
ridemonkey.bikemag.com/threads/majin-frame-i-would-probably-be-a-dealer-but.219227
www.pinkbike.com/photo/1151330
Guess not, I did try cash, want to buy, need to order, etc. LoL