"Interested in fitting Progressive Springs. What is the cost to supply?"

The front forks also have problems with too fast a dive rate, spring too soft, rebound too soft and again, a harsh feel. If you want to fix the front end problems, we would strongly recommend a new spring and our Provalve kit. This will give you a plush ride, very controlled dive and we match rebound settings to the new spring.

Front:

• Provalve Service Set-up and spring

Rear:

• Ikon shocks including spring and damping mods

"Thanks. I'm looking for progressive fork springs - I think your reply is referring to Shocks, am I right?"

Fork springs will support the weight of the bike and rider, this is approximately 1/3rd of the equation for your front forks.  To get the best out of your forks you must consider upgrading compression damping (gets you to 2/3rds of the equation) and rebound damping (to get to 3/3rds - everything working properly).  That's why we recommended the other parts.

When you fit a bigger spring, whatever damping there is will be overworked.  The Thunderbird is already too soft damping with a too soft spring.  So when you fit a bigger spring it will not solve all the problems with the Triumph's front end.

Progressive springs have two spring rates combined into one spring, however, there is a crossover point when the soft and hard rate combine, so your already soft standard damping has to not only contend with the normal compression rate from the spring but a heavier rate too, it doesn't create the most stable conditions for your bike. Hope this clears it up for you.