This is the latest version of my steel Diamond frame and Unicrown fork first introduced in 2010. I want to talk about some of the details, the thought that goes in to my work. People might think this is a ‘standard’ steel frame and forks. It isn’t. It began as an exceptional frameset but this one’s better’er!

The frames and forks are made in small batches – 100 at a time. Each is hand-made by excellent craftsmen in a small shop. The alignment, with all the Quality Control during production, is superb. The finished product is the best steel frameset I’ve yet offered. The (rigid specific) geometry is virtually identical to the last version but the frame is now lighter than before and revised tubing specifications and forming have improved the ride.





The welds are excellent, very smooth with perfect penetration – the same people build the steel frames as build my Titanium frames. All the cable guides and bottle bosses are brazed on – this is a process with a much lower temperature than TIG welding and does not melt or warp the steel tubes and creates a very strong connection. This is particularly good as the guides and bottle bosses are mostly at points on the tube where the wall thickness is thin from butting.





The new steel Diamond frame is 0.4 pounds (about 180 grams lighter) than the older (Merlin made) version. Both the seat tube and seat stays are now a smaller tube diameter – this delivers a better ride and saves weight.





Crucially the frame and fork are designed as one unit (it’s a frameset after all) so the ride, the geometry is everything I want it to be – no compromises.





The fork is 435x55mm rigid specific. It exceeds the EN test standard for a mountain bike fork. The fork has been placed in a test rig and hydraulically flexed and impacted for hundreds of thousands of cycles. We haven’t had any failures. It’s a very good unicrown fork. And it is not suspension corrected (as a good rigid fork / bike should be). The frame and H-bars® pass their respective EN tests too.





The fork steerer tube is now a one piece machined 4130 cromoly tube. It is machined with varying wall thickness and a built-in crown race. This is not a stock steerer tube or just a piece of straight gauge tubing. Previously (and with many forks) the crown race element is a sleeve weld or brazed on to a straight gauge 1 1/8″ tube. My new steerer starts out as a very thick 4130 tube and is then turned/machined down to my specifications with a thin (walled) upper section that tapers to a thicker section down where the lower headset is and where forks need more stiffness and strength. The crown race support (for a 1 1/8 headset) is also machined into the tube. The steerer tapers perfectly to provide a thicker, stronger section for the crown race and (crucially) the bottom section of the steerer (where the fork blades are welded on) is left at a larger diameter with greater wall thickness – this delivers additional strength at the very part of the fork where forces are greatest when you’re riding. It costs more to make but it’s way better.





The fork blades are custom butted. Fork tubing was previously only available in certain wall thickness and it wasn’t ideal for rugged off-road, fat wheel riding but this new tubing is unique to the Jones forks and is butted to my specifications. The wall thickness is greater at the top, thinner partway down and then thick again at the drop-outs and brake mounting. It is, overall, a little heavier than before (as the legs and steerer tube are more substantial) but it rides much better – less fork chatter and stronger. And because the fork is rigid specific, it is not longer (heavier and weaker) than necessary like rigid ‘suspension corrected’ forks are. The (135mm) wide Jones front hub stiffens up the front end and can provide the foundation for a very strong wheel. The dropouts are new – they are CNC’ed 4130 cromoly and very much considered in three dimensions. There is less material in several places where it could be reduced without compromising function. They have a really big area for welding the fork legs to – much stronger than before.





The brake mounts (disk tabs) are designed to transmit the braking forces across a very large area of the fork and designed such that these forces are carried all the way down and into the drop-out itself. The dropout design provides much more substantial tubing to weld the brake mount to, as does the thicker fork blade butting at this point. The Jones brake mount ‘anchors’ to the drop out and attaches to the fork leg at three other points. It handles braking forces very well and minimizes fork-flex and vibration when braking. The rear brake version on the seatstay is similarly designed to provide a strong mount and dissipate braking forces.





I’ve been using forward-facing dropouts since 2003 or so. It’s now very much a standard approach for quick release front wheels. It ensures braking forces drive the wheel in to the dropout, and not in a direction that might have the wheel ‘eject itself’ from the fork. There’s a 40° chamfered section on the dropouts to make getting the wheel in that little bit easier. It guides to wheel in.





Although the fork is designed to pair with a Jones frame it might work with other frames so do contact us for more information.








The chainstays are formed for more tire clearance than the previous version (and this clearance is better positioned along the stays). The new tube ovalization improves the side-to-side stiffness.








The inside of the bottom bracket shell is machined after welding. This is the best way to ensure a true cylinder. It’s crucial that the Eccentric Bottom Bracket (EBB) fits precisely inside the shell and then expands against a large surface area. The machining is such that the EBB fits at either end but not in the middle of the bottom bracket so it can’t rock and creak. The best EBB currently available is provided with each frame.





The rear dropouts have, like those on the fork, been improved – and they have the same chamfers as on the fork is used to make getting a wheel in easier. The gear hanger is ‘industry standard’ (#103 from Wheel Manufacturing) so more readily available should it need replacing. Each frameset is supplied with one gear hanger insert and one single speed dropout insert so gears or singlespeed is an easy option.





The headbadge is 25 gram lighter than before. Since this is my one concession to fashion (not function) it’s good to get the weight down. It is plated copper. It might well be an indulgent stowaway but I have to say it does look good.

ED coating – the ‘paint job’ – electrically deposited black material as an undercoating to begin with, then powder coat on top of that. So a good finish to begin with then a excellent finish on top of that. And then a clear powder coating as a third finish to deliver a beautiful frame and fork with a more durable finish than regular paint with the decals between the two coats of powder.

It’s an excellent frameset that builds into a wonderful bike. A joy to ride.