700c Thorn Disc Steel Fork - Blue Imron

Our Thorn 700c Reynolds 525 Steel Disc Forks have an ISO disc mount, direct fitting stainless mudguard bosses, stainless open brake line guide and stainless bosses for lo-loader carriers. The L1 dimension (centre of axle to crown race seat) is 383mm. They're suitable for use with mudguards, using tyres up to 40c and they're available in 46mm or 52mm fork offset in 5 different colours. They have a high quality cast fork crown and weigh 1255g with the 380mm steerer (the steerer may be cut down to suit, which also reduces the weight by 1.03g per mm).

They've been designed to fit our Rohloff equipped Thorn Mercury and/or our derailleur equipped Thorn Club Tour MK4 but they'll also be suitable to retrofit to many non-Thorn frames - check the required L1 and offset.

Until now, we've resisted having such forks made because we knew that it would be impossible to make a steel fork, with disc brakes, which was both safe and comfortable.

The reason for this is because the forces, exerted by disc brakes, differ from the forces exerted by rim brakes - even at an identical rate of retardation. Unless the blades are large enough in diameter and thick enough in gauge to absorb these forces, the LH blade will be taken beyond its yield point under braking (i.e. it bends permanently). This happens under moderate braking, at very low speeds, both with Competition and Super Tourist gauge blades. During our tests, under emergency braking from speeds below 10mph on an unloaded solo bike, without the rear wheel coming off the ground, even tandem gauge blades failed to resist these forces. Any cyclist may have to make a similar emergency stop - at any time!

In order to make the Thorn steel disc fork fit for purpose, we've had to use blades which are significantly heavier gauge than tandem blades. We've also had to increase the tip diameter. Our Thorn disc forks are safe to use on road-going solo bikes, even with 5kg of luggage each side.

Our Thorn 700c steel disc forks are more comfortable than any alloy disc fork, and no less comfortable than any other manufacturer's steel disc fork - they're more comfortable than some, many or most other manufacturers' steel disc forks - but they're certainly not and never could be, as comfortable as our V brake 700c touring forks.

- Steerer: 1 1/8"
- Offset: Choice of 46 or 52 mm
- L1 (Axle to Crown): 283 mm

WARNING:
- For sealed and unsealed solo road touring use only
- NOT suitable for stunts, jumps or serious off road use and abuse
- Max. Rotor Size: 183 mm
- Max. Load: 5 kg per side
- Max. Rider Weight: 130 kg
- Check carrier mounting carefully (especially if not using Thorn MK5 Lo-Loaders)
- Lower carrier mounts need spacers to clear rotor
- NOTE: ISO disc mounts may require facing
- INSPECT REGULARLY