TriVelox were the beneficiaries, and also the victims, of a peculiarly British fixation with chainline. In the 1920s and 1930s many British cyclists shunned derailleur systems because they involved running the chain out of line on the extreme sprockets. British cycle magazines of the time railed against this obscene practice, denouncing it as the engineering of the devil.

And in some ways they were right. Roller chains are designed to run in a straight line. Although British cyclists were wrong to think that chains run with dramatically higher frictional losses if you run them out of line, they were correct in thinking that they do wear out significantly faster.

And then there was the issue of cleanliness (which is, of course, indistinguishable from godliness). This was an age when chains were expensive, and meticulously lubricated and cleaned. Many bicycles of the time had their chains running inside oil-bath chain cases - something that was not possible with a derailleur.

The British cyclist expected his or her chain to last not just for years but for decades - and as any modern cyclist knows, this is not the way of the derailleur.

TriVelox responded to this challenge with a gear system in which the chain ran in a straight line through a fixed ‘derailleur’ arm. You changed gear, not by moving the derailleur and bending the chain, but by sliding the freewheel block sideways on the hub. And it worked, Walter Greaves rode a TriVelox system for 45,383 miles in a single year and used only two chains and two sets of sprockets. Try getting 23,000 miles out of a single chain on a modern bicycle!

However the Trivelox system also had its down sides, it was humungously heavy and it required a very wide rear axle to accommodate the sliding freewheel block. As far as I am aware it never developed beyond a three-speed system because this would have required and even wider hub.

In the 1950s, when it became clear that lightweight derailleur systems were reliable and practical, the market for TriVelox gears shrank back to a small number of tandem riders and finally disappeared all together.

The history of TriVelox as a brand is a trifle complicated. Some elements of it might be:

• TriVelox’s 1937 catalogue claims that they had introduced their revolutionary gear system seven years earlier - therefore in 1930.
• In 1931 two gentlemen called Alec Shuttleworth and William Hill from Keighley in Yorkshire, England, applied for a patent (eventually UK Patent # 382,104) for a system, as described above, in which the freewheel block slid sideways on the hub etc.. Their patent agents were Walford & Hardman Brown of Coventry, the preferred patent agents of the Triumph Company Limited a bicycle manufacturer (and, of course, more famously a motorcycle manufacturer). It appears that Alec and William were working with Triumph on their cunning wheeze - and that the ‘Tri’ in TriVelox refers to Triumph, not to three speeds.
• In 1935 Val Page, the legendary motorcycle designer and head designer at Triumph, applied for a patent (UK Patent # 451,722) for a more refined system along the same basic lines. The Triumph Company Limited (not TriVelox) is listed on the patent.
• In 1936 Val Page applied for a US patent (US Patent # 2,117,116) to match his UK one. This time the patent was assigned to Tri-Velox Gears Limited. This is the first mention of TriVelox as a separate company that I have found. TriVelox Gears Ltd. shares the address of Triumph in Coventry.
• 1n 1945 TriVelox may have parted company with Triumph. It changed its name from TriVelox Gears Limited to TriVelox Gear Company and claimed to have a head quarters in Manchester Square in London.
• By 1949 TriVelox Gear Company was based in Spennymoor, County Durham.
• TriVelox products do not appear in the 1939 edition of Holdsworth’s Aids to Happy Cycling, do appear in the 1949 edition, and have disappeared again by the 1954 edition. This may suggest that TriVelox went out of business in the early 1950s.

In terms of derailleurs their history might be:

• In 1930 they may have introduced the rather crude design design featured in Alec Shuttleworth and William Hill’s patent (UK Patent # 382,104). This used a cable-operated plate to shove the freewheel block from side to side. Spares for this system can be seen on page 20 of the 1937 catalogue. Spare part no VG11 is the plate that shoves the freewheel block.
• In 1936 TriVelox introduced the more sophisticated design design featured in Val Page’s patent (UK Patent # 451,722). This moved the freewheel using a toggle chain and indicator rod running inside a hollow axle, in the style of a Sturmey-Archer hub gear. The toggle chain entered the axle through the non-gear side, making the gear low-normal. They renamed this signature gear, with the sliding freewheel block and static derailleur, as the ‘Model A’. They now offered it in 4 variants, one for each of the combinations of solo or tandem, and with or without hub brake.
• By 1937 TriVelox had also introduced the ‘Model B’ and ‘Model C’, these were bell crank operated derailleurs much like Simplex Rigidex models, in which the freewheel remained laterally fixed and the derailleur moved sideways - in the conventional way. The ‘Model B’ used a freehub system and the ‘Model C’ used a screw-on freewheel.
• Around 1945 they redesigned their Type A system so that the toggle chain now entered the axle through the gear side. This is shown in a 1945 UK Patent. This makes the gear top-normal, and probably improves the change as the human is doing the hard work of getting the chain up onto the bigger cogs, while the spring only has to do the easier work of moving the chain onto the smaller cogs.