Skip directly to content

GSD Giant Sportive

Giant 100 miles - British Cycling Grade 4
Spirit  50 miles  - British Cycling Grade 2
Demon 30 miles - British Cycling Grade 1


The GSD Giant sweeps through the picturesque lanes of West Sussex and Hampshire in support of a locally-based charity, the AGSD-UK. Setting out from The Petersfield School. The route circumnavigates the South Downs National Park between Petworth in the east and the Meon Valley in the west; passing through some of the prettiest villages and hamlets in the South of England. Cycling by green rolling pastures, ancient woodlands, river valleys and wetlands within one of Britain’s most accessible breathing spaces you’ll experience an exhilarating and challenging sportive.

  • Free start and finish photographs
  • Individual rider timing
  • Web results service
  • Full Route Marking
  • Mechanical Support
  • Rider public liability insurance
  • Drink and snack food stations
  • Emergency support
  • Post-event Massage
  • WC and showers
  • Pick-Up Wagon
  • Event centre facilities and parking
  • Event Photography
  • On site catering
Registration Opens       8.00am

Start Times (for guidance only)


Giant                      8:30am to  9:00am

Spirit                      9:00am to   9:30am

Demon                  9:30am to 10:00am


Entries for the Giant route are asked to start within the times quoted. However every effort will be made to keep timing equipment enabled until the last rider returns.


Petersfield Weather forecast ©

Sportive Entry

Online entry is now available here:



Terms and Conditions of entry


Free start and finish line photos

Available to download after the event





Sportive fee


















Raise £200 to earn a FREE GSD Giant Jersey!

The entry fees must be paid in advance and sponsorship can be collected online using Virgin Money Giving or paid to the charity directly beforehand or on the day. As a charity sportive the pricing structure is very simple, we charge a standard registration fee to take part and we suggest that riders set a target just £1 per mile in sponsorship from family, friends and colleagues. Whilst fundraising is very important to us (its our only source of income), we welcome anyone away who simply wants to pay the entry fee and enjoy a fabulous sportive around the South Downs.

On the day entry

On the day entry carries an additional fee of  £5 per person; we would encourage online pre-entry which will save you time on the day, allowing you to pick up your registration pack from the 'Pre-entered collection point' and avoid having to queue.


Raising the suggested sponsorship should not be very difficult, but you'd be surprised how much you can raise using an on-line webpage. You can set one up in a few minutes here:


If you'd like to make a donation to the AGSD-UK, please use the button below. We'll get another 25% through gift-aid if you're a UK tax-payer.


Donate to the AGSD-UK through Virgin Money Giving

Join our Strava Group




GSD YouTube Channel


Glycogen Storage Disease and Sports Nutrition

This Paper on Superstarch examines how a food supplement developed for people with Glycogen Storage Disease (GSD) might be used as a better source of energy for endurance sports; its especially good for several reasons:

  • No spikes in blood-glucose and insulin 
  • Provides sustained energy for several hours
  • Promotes fat-burning in preference to glycogen and muscle protein
  • Much kinder to the gut during an endurance event


New to Sportives?

Many people who take part in cyclo-sportives are experienced cyclists, but there are many others who don't cycle on a regular basis and may benefit from some advice on preparation. have recently written a handy guide on how to prepare for a charity bike ride, view it here for advice on the following topics:

Fitness Bikes
Clothing & Footwear Sponsorship & Publicity
Safety Bike Gear
Food & Drink Route & On the Day

School Report 

On Sunday 23rd September, 2012, my parents and I took part in a 44 mile charity bike ride around the undulating hills of the South Downs. The aim was to raise money for a charity close to my heart, the Association for Glycogen Storage Disease. It is close to my heart as I suffer from this condition; so does my sister.

Basically I don’t have an enzyme that helps to break down stored glycogen in my body for energy, so I have no back-up supply of energy, only the energy I get from the food and medication I take. This affects my blood sugar levels.

We trained for the ride as much as we could incorporating as many hills as we could. This made us fitter, or so we thought.

The course we cycled was described as having some undulating hills, but there seemed to be an endless amount of hills, we would just recover from one to find the next hill just around the corner. It took a lot of will power and plenty of snacks to get through it. My main challenge was to balance my sugar levels, with my intake of food and the extra energy I was burning up very quickly whilst riding. I stopped to have a snack and drink every hour, to minimise a severe drop in my blood sugar levels.

It took me 5 hours and 48 minutes to complete the distance, my parents finished a few minutes later. We raised an amazing £2500 between the three of us; we intend to do the bike ride again next year and hope to improve on our times by training more intensely. 

Trushal (Class 8)

Article kindly reprinted from Trushal's school newsletter