Suspension

The race suspension for the Seeley is conventional to stay within the vintage racing rules, but that does not mean it is ordinary. Luckily, we have Cosentino Engineering right next to Spannerland!

Chris Cosentino started the race development program for a vintage fork kit a few years back using Kenny’s original 1962 Featherbed Norton race bike as the test bed. The concept was inspired by a more basic conversion done by Kenny Dreer. The result is a cartridge damping upgrade kit for Norton Commando Roadholder, post ’73 Triumph T140 and T150, and Ceriani Roadrace forks.

The Upgrade kit replaces the stock damping assembly and springs with a modern Showa unit incorporating adjustable compression and rebound damping circuits and a custom internal single rate spring with adjustable pre-load. To comply with the rules of most US vintage racing organizations (AHRMA,WERA, USCRA) all adjustments are hidden from view, but easily accessed though a custom designed cap. We could have gone with external springs for a more vintage look, but then we would have lost pre-load adjustability.

Chris starts with a modified Showa Cartridge Damping unit. Each cartridge uses shim-stack based technology for high and low speed compression damping and rebound damping. He then adds his own custom internals to locate the damper and internal adjusters and support the internal spring.

The complete assembly, including the spring, is one unit that drops right into the existing fork tubes with no modifications required. You don’t even need to take the forks off the bike!

The Cosentino race setup for the super light Seeley uses 25-30 lb/in springs along with Redline fork oil. The 5W oil gave good results during the original testing at Daytona so there was no reason to deviate.

After the upgrade there will be several improvements:

  • more controlled bike pitch motion during braking
  • better bump absorption
  • no clunk under hard acceleration as the fork tops out.
  • better performance at full compression
  • ability to tune suspension for varying loads, road surface, track style, etc.

This conversion should be on any ultimate vintage race bike setup as it provides a huge improvement in front fork performance without affecting external looks and brings the fork technology more in line with the updated tire rubber compounds and constructions that are used. Similar to the short stroke “vintage” engines that are available, this gives you internal performance in line with modern design and manufacturing technology and external looks suitable for inclusion in any concours bike show.

The rear suspension was more straightforward. Again, there are limits as to what can be used in vintage racing. There can be no external reservoirs. We went with Works light weight alloy shocks made in the U.S.A.

Cosentino Engineering products can be purchased directly via his website except in the UK where they are available though Minnovation Racing.

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