Inside the British Motorcycle Industry: Renthal

Renthal handlebars

When Honda build a new CRF450 motocrosser in Japan, the handlebars they fit are made by in the UK by Renthal. That is an impressive reach for an 80 strong manufacturing plant in Stockport, just outside Manchester. Commercial Director Rees Williams (35) takes up the story...

“People buying new CRs complained about the cheap steel handlebars. Honda approached us about supplying them direct. We knew we would perhaps lose a few sales as a lot of owners bought our bars for their new bikes anyway but we thought if someone is going to supply Honda, we’d rather it was us.”

Kawasaki, Suzuki and KTM also use Renthal products in production. It is a big achievement and shows how much global respect Renthal commands, but aftermarket sales not OEM (Original Equipment Manufacturer) are the company’s main source of income.

Ree Williams

As we have seen so often while visiting firms in the UK motorcycle industry, the Renthal business was started by enthusiasts who wanted better kit for their sport. Andrew Renshaw and Henry Rosenthal were trials riders and they were fed up with replacing handlebars that bent too easily in the spills of competition. Henry’s aunt, who ran a metal distribution company, had some high tensile aluminium alloy tube left over from an aircraft contract in the exact 7/8" diameter needed for a handlebar. That was 47 years ago, in 1969. In 1975 They moved into proper premises, and expanded into the USA in the Nineties.

In October 2000 a fire destroyed the Renthal building. It was an opportunity rather than a setback. A new factory with up to date tooling and facilities was built on the same site. The business grew steadily at home and overseas.

Investment in lean manufacturing helped Renthal survive the financial crash of 2007-2008 without shedding jobs. Already huge in the motocross market, and with a strong presence in the road bike sector, Renthal expanded into the bicycles in 2010 making handlebars, steering stems, chain wheels and other components.


Sprockets, handlebars and bicycle components are all made in the Stockport factory. A three storey warehouse section houses several million pounds worth of stock and the dispatch operation, where you can see orders being prepared for delivery to the 50 plus countries to which Renthal exports. They have 117 distributors worldwide.

Handlebar grips are made on another site in the UK while chains are produced in conjunction with an Italian manufacture, and arrive ready greased in large reels packed in wooden crates.

Most of the research and development work is carried out on site. A well equipped office with CAD (Computer Aided Design) stations and 3D printing facilities shares space with the team which manages production. A separate room in the factory houses an array of testing and measuring equipment which is used to test raw materials, verify finished products and also to check components as they are developed. A pair of hydraulic jaws pull pieces of tube apart to evaluate shear strength. There is a bank of three machines to measure material hardness. A purpose built rig examines fatigue resistance. A precision measuring table can check component dimensions and alignment to thousandths of a milimetre. A digital measuring arm is also used  

As part of the quality control process, the metals used by Renthal are from traceable stock. If a component fails quality checks, Renthal know what batch of raw material it was made from and they can double check everything made in that batch, or even scrap whole runs if necessary. The metals are all EU sourced. Engineering graduate Rees Williams told me that it is the best option in terms of quality control. Rider's safety depends on the stuff Renthal makes. There is no room for cost cutting or short cuts.

However many times you experience it, there is always something magical in seeing raw materials arrive and following them through to finished products, packaged and ready to ship. We started a tour of the factory with rear sprocket making. Blanks are plasma cut from huge sheets of aluminium alloy. They are mounted in batches in a gear planer for the teeth to be cut with the final drilling and machining being carried out on CNC mills. Anodising is done by a local specialist outfit after which they are returned to Stockport for packaging.

Every Renthal rear sprocket you buy, road or off-road, has a small PVC badge attached. The shape of the badge is machined into the surface of the sprocket so it looks better that if it were just stuck on.

"It's a bit obsessive," say Rees Williams, " But it looks just right."

You have to love that sort of attention to detail.

Blanks for engine sprockets arrive cut to size. Teeth are cut on gear hobbing machines, the splines are formed by broaching tools and CNC lathes take care of the final finishing before the parts are sent off-site for heat treatment.

Rees also walked me through the stages of handlebar production from lengths of aluminium tube to finished products. For the constant diameter bars, the blanks arrive at Renthal having already been heat treated to the final specification. The more complex tapered Fatbars® undergo a swaging process to create the tapered sections, after which they need further heat treatment which is done on-site in Renthal’s own furnace. The finished bars go off-site for anodising. The final process is to laser etch the bars, which again, is done on-site. During the production process the bars are scanned inside and out to check for any irregularities which could affect their performance.

Unusually for a UK based manufacturer, Renthal’s biggest market is the USA. They have a big presence in the motocross and supercross scenes over there and are the second biggest selling chain brand, with only DID above them. They are big in the UK too, but over here, 40 per cent of their motorcycle component sales are for road bikes, with off-road accounting for the other 60 per cent. Overall, sales of bicycle components account for 20 per cent of the business.

Lean manufacturing has played a big part in Renthal’s success and will continue to do so. That does not mean full-on automation of all tasks. For example, the handlebar bending process is only semi automated. Batches need not be huge to be economically produced, which give a flexibility which cannot always be achieved by a CNC process. Renthal have not compromised on quality even in the face of cheap goods from The East. They have remained profitable by maintaining their reputation for quality rather than going for the lowest price.

It’s a very British approach, and it works.

Renthal components are distributed in the UK by B & C Express:

Completed Renthal sprockets