TTRNO’s Thruxton Cup Bike – Suspension

Racing a bone stock Triumph Thruxton isn’t ideal, not even in the Thruxton Cup, but I made a plan for the season and I’m sticking with it!  I’m only making modifications one at a time so that I know EXACTLY what’s making me faster.  Last race the bike was bone stock, this time suspension was the name of the game.  The best options for the Thruxton Cup, Traxxion Dynamics AK-20 cartridges in the front forks and Gazi Hyper X rear shocks was what I went with.  I showed up to the track the morning of the race with nothing installed… not a good start, but quickly threw my bike on the lift and swapped out the forks and shocks just in time to miss the last practice session.  At this point my first ride on new / un-tuned suspension would be the F2 race against a gaggle of Suzuki SV650s.  The bike felt good but not great, smooth but not planted and quicker but actually wasn’t.  I WAS 2 SECONDS SLOWER!  I got all the trick stuff, but didn’t do any better.  There were 2 things that contributed to this; I didn’t practice and shake off the cobwebs, but more importantly, I didn’t tune my suspension!  Throwing on expensive “go-fast” gadgets is what most motorcycle riders do, thinking that by simply having the things that the fast guys have they will become a fast guy.  Without tuning my performance suspension the bike was just as unruly as with stock suspension, it simply felt better because I was going slower.

About an hour after my first race of the day was the main event, the Thruxton Cup race.  I set my suspension to a baseline setting, that I came up with by jumping up and down on it, then headed out for my warm-up lap.   I lined up on the grid next to Doug Polen, the ‘91 – ‘92 World Superbike champion and ‘93 AMA Superbike champion.  That’s the exact moment when my heart sank.  I was in the presence of a legend, competing with a legend, and on a bike that was stock all except for the suspension, which might as well have been stock.

The green flag dropped and I had a great start, ended up in the middle of the pack and was able to gain a few positions as the turns flew by.  The bike felt a lot more planted this time and I was able to pick up throttle sooner without upsetting the chassis.  When there is someone to chase the laps seem go by faster and with Doug Polen in my sights the race was over before I realized.  I started in 17th position and finished in 4th behind a world champion and two national champions, overall not too shabby.

The results were great, but I needed to get this suspension dialed in if I’m going to collect more gold.  That’s when I turned to my good friend Dave Moss from FeelTheTrack.com.  In the videos below he explains what my suspension baseline settings were after I finished this race:

Now that we know where I am starting it’s time to do some live tuning on the track.  Below is a video of how he adjusted my suspension as I came in from each practice session to end up with the perfect setup for me.

Max Materne’s Thruxton Cup bike settings:

• Forks flush with the upper triple clamp
• Traxxion Dynamics fork kit
• 0.90 front springs
• Preload at zero (all the way counter clockwise)
• Rebound .25 of a turn out from maximum
• Compression 1.25 turns out form maximum
• Shock length at +2mm on ride height adjuster
• Preload with 4 threads showing
• Compression at 10 clicks from maximum
• Rebound at 14 clicks from maximum
• Font tire, Continental Road Attack II Evo
• Rear tire, Bridgestone BT-003 RS
• Cold starting pressures, 30F, 28R

Session 1:

• Ride the bike, assess wet track conditions and get the tires and suspension oil hot. Come in at the end of the session and assess carcass temps and suspension.
• changes shock preload to get some static sag
• change shock rebound as it was too slow
• change fork rebound as it was too slow
• remove 2psi from the front tire
• remove 1psi from the rear tire

Session 2:

• Ride for 4 laps and come in to assess carcass temps and fork travel as the track was drying
• fork travel bottomed out so preload added
• shock rebound still to slow so damping removed

Settings by lunch

• Forks flush with the upper triple clamp
• Preload at two turns in
• Rebound .75 of a turn out from maximum
• Compression 1.5 turns out form maximum
• Shock length at +2mm on ride height adjuster
• Preload with 4 threads showing
• Compression at 10 clicks from maximum
• Rebound at 18 clicks from maximum

Session 3:

• Dry track so focus on braking and flickability in the esses section for 4 laps and come in.
• change fork preload to 4 turns in
• fork compression to 1.25 turns out
• fork rebound to 1 turn out
• shock rebound to 20 clicks out
• lower the front end by 4mm for better turn in

Session 4:

• Push the bike hard on the side of the tire to test chassis stability and be aggressive in traffic
• preload to 6.25 turns in
• fork rebound to 1.25 turns out
• shock compression to 5 clicks out
• shock rebound to 19 clicks out

Session 5:

• Free ride to test the bike at full pace as traffic permitted.

End of day settings:

• Fork height at -4mm from the joint of the cap and tube to the upper triple clamp
• Preload at 6.25 turns in
• Compression at 1.25 turns out
• Rebound at 1.25 turns out
• Shock at +2mm ride height
• Preload with 2 threads showing
• Compression at 5 clicks out
• Rebound at 19 clicks out
• Cold tire pressures, 31F, 28R at 100* track temp

Now that the suspension is finally dialed in, it’s time to race the fastest guy I know… fellow Triumph dealer John Beldock from Erico Motorsports.  Stay tuned for next week’s article on how that went!