Eligibility: Swing arms

GP Originals at the Algarve Historic Festival

TZ350 swing arm update

Since this survey was completed Bora Specialised Fabrications have produced a small run of eligible TZ350 replica swing arms. These units have an excellent period look with improved strength and chain adjustment. Made by one of the UK’s most respected fabricators and eligible for every post classic race series including GP Originals.

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Another recent update has arrived from Bill Simpson Racing. BSR is now offering a chain adjuster using a period design to complement their swingarm for the TZ350

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Eligibility for swing arms has been the debate over the off-season. GP Originals is very much a collective and we value our rider’s opinions. To finalise our stance on what should be eligible going forward we compiled a very simple questionnaire. The survey was completed by our large grid of riders at Brands Hatch Round one.

The questionnaire was anonymous and only provided to members riding in the Series to ensure collection of relevant opinion only. There were 36 completed surveys, as you will see the results were decisive on every question.

This survey reflects GP Originals only and does not encompass any other racing club or series.

Existing replica swing arms

GP Originals aftermarket replica swing arms

We asked how riders felt about the aftermarket replica swing arms that are already in existence for TZ350s. Specifically, Harris, Bill Simpson (BSR), Maxton, Spondon. These are widely used and have been available for many years. Most of these products use modern block style chain adjusters, a form of which were available in-period but not on 350 machines.

New aftermarket swing arms

GP Originals and modern swing arms

Question two asked about the newest version available from Fondseca. This swing arm is not described as a replica and has been developed over many years. The main non-period feature being the front box section which does not use the sloped or K-shape found on an original item or many of the other period aftermarket options available in the day.


The future options

GP Originals making new aftermarket swing arms

We next asked what our rider’s criteria would be when choosing a replacement in the future. This question does not affect eligibility but we felt this was useful information for fabricators potentially making a new product for post classic racing.


Existing ineligible items

GP Originals ineligible swing arm

We asked for opinions on how to approach a rider with an item deemed ineligible. We are delighted to announce that the very small number of riders with the modern swing arms have voluntarily replaced them already in support of the concept of GP Originals. Currently we have no machines with ineligible swing arms registered with us.

Time to stop typing and go racing

  • No GP Originals rules have changed
  • No riders or teams have been banned
  • Please get in touch with your questions before buying expensive aftermarket parts