Guide on the Attack Performance Rear Link
I hope this post helps anybody who has questions about what the Attack Performance Rear Link does and how it will affect your rear suspension. I wanted to present actual data (measurements) before and after the link was installed. In addition to the measurable data presented, I also wanted to give my personal feedback on what the differences were after the link was installed.
I own a 2013 675R (2013+ model) so my findings would only pertain to 2013+ 675R models.
Before I purchased the link, I wanted to get as much info as I could to prepare for any additional parts or services needed to compliment the link. After hours of research on the forums, I have found that there was no definitive data about how the link affected the rear suspension of the bike. I found posts where people talked about how the rear-end lowered, others where the rear-end raised, and some that said a higher spring rate was needed while others said that a lower spring rate was needed. I believe all the contradicting points were related to people comparing different suspension links from 4 different manufacturers. This caused too much confusion for me, so I decided to gather the data on my own and share it with everyone.
For reference: My weight is 210+-5 lbs with gear. The bike is track only with full track fairings and stock exhaust. The front forks are also lowered into the triple trees with only 1 line of gold showing. Front and Rear suspension has not been serviced yet and has about 3500 miles on it. The stock OEM measurements below were measured the day I brought the bike home and also before any adjustments were made to change to my preferred sag numbers. The stock measurements and settings were also referenced and confirmed through my service manual.
My preferred rider sag numbers are 37-40mm front and 30mm rear. My tires this season were Dunlop Q3’s. (In my opinion, stick with Supercorsas!! The bike was made for those tires.)
Stock OEM 2013+ 675R Rear Ohlins Suspension Numbers
OEM 675R Ohlins Shock Length – ~294mm
OEM 2013+ 675R Ohlins Spring – 100nm spring – p/n 21141-34/100
OEM 2011-2012 675R Ohlins Spring – 110nm spring – p/n 21141-39/110
Ohlins Spring – 110nm spring – p/n 21040-39/110
OEM 2013+ 675R Spring Free Length – 175mm
OEM 2011-2012 675R Spring Free Length – 175mm
Ohlins Spring Free Length – 160mm length
OEM 675R Spring Length (measured installed on shock without weight) – 160mm
OEM 675R Rear Preload – 15mm
OEM Rear Free Sag – 15mm
OEM Rear Sag with Rider – ~35mm
After installing Attack Performance Rear Link
Full rear suspension droop = same as with stock link (This was measured by lifting the rear off the ground by supporting the foot pegs and letting the suspension droop to its lowest value. This measurement is arbitrary, so I didn’t record the actual measurement. I just noted in my data that it was the same length as stock.)
Naturally, all shock, spring, and preload settings stayed the same after the rear link was installed.
Attack Rear Free Sag – 10mm
Attack Rear Sag with Rider – ~21mm
Attack Performance Rear Link with adjusted sag
Rear Spring Length after adjustment- 162 mm length
Preload after adjustment – 13mm preload
Attack Rear Free Sag after adjustment – 13mm
Attack Rear Sag with Rider after adjustment – ~30mm
After installing the rear link, the rear of the bike was noticeably higher even before sitting on it. Measuring the sag confirmed what I suspected. Installing the rear link changed the sag numbers and kept the rear of the bike 5mm higher in free sag and a total of almost 14mm higher with the rider on the bike. This data shows that the link changed the leverage ratio and provided a different curve in regards to force applied downward vs the amount of shock travel. Needless to say, this would confirm that the suspension linkage does something, and it’s not just a shiny(dull?) piece of aluminum.
In order to get my rear sag numbers back to where I prefer, I would need to back off the preload on the spring. With the weight off of the shock (supported bike on jack stands with rear wheel at full droop) I used my preload adjuster tool (spanner wrench) and backed off the preload about 2mm for a total spring length of 163mm. As you can see by the data, I was still able to easily get 30mm rear Rider sag without changing out the spring to a stiffer one. Although spring rates are a personal preference (after a certain point), the physical limitation of the stock 100nm spring is not reached even with a 200+lb rider.
Some people had changed the rear spring to a stiffer one after installing the rear link. For me, I don’t see a need for it yet as I don’t have enough data to make the switch meaningful. However, I have already done research on that matter and have a few measurements and listed parts numbers above.
The stock springs for OEM Ohlins Daytona Shocks are not mass produced Ohlins parts and are made to Triumph’s specs. Through my research I have found that the only (?) difference is the spring length. OEM Daytona 675R Ohlins springs measure about 175mm and regular Ohlins springs measure 160mm.
If you are changing out the spring to one that is 160mm in length, you do not need to shim the shock as the shock length will always be in the ~294mm range regardless of spring length. You can not the reduce the shock’s shaft’s full uncompressed travel by changing a spring. You would just need to wind down the preload adjuster up to 15mm lower to compensate for the 15mm difference in spring length. This only applies to the OEM 675R Ohlins shock as I do not have or handled a TTX36 shock.
If you need to go to a higher rate spring, the easiest would be to use the spring from a 2011-2012 67R. it is the same spring length but has a higher rate of 110nm; that is if you can even find a loose spring without the shock.
After setting my rear sag back to my preferred 30mm, I left my rebound and compression settings the same as before I installed the rear link. The front sag numbers were also checked just for consistency. I did not want to change too many variables before going to my last track day of the year. I had a baseline of how the bike felt 2 weeks prior so it was still relatively fresh in my mind.
The last track day of the year for me was on Wednesday 10/11/2017 at NJMP Thunderbolt. The morning was wet from rain but the afternoon temps rose and quickly dried the track after 11AM. In comparison, my previous track day prior to installing the rear link was on 9/24/2017 at NJMP Thunderbolt and was warm and dry the entire day. The air and track temps were within 5 degrees between each day so it was a good comparison.
I always had issues with rear grip or running wide on hard exits, and I was never able to compensate for that with preload or compression changes. For me, adding more compression took away from the feeling of the rear, which led to more slides, and removing compression added more feeling of the rear but caused me to go wider on exits. It would always feel like the rear would squat and then stop as if there was no more shock travel.
On 9/24/2017, I had issues with rear grip coming out the 2 left hand turns (there are only 2 of them at NJMP Thunderbolt) and 1 of the right hand turns. Every time I tried to get on the gas early, I would get micro-slides. These micro-slides ultimately became a huge slide of the rear tire while coming out of turn 5 which sent me straight into the outside curb and in to the grass. Coming in hot from the pits, I checked my tires to make sure it wasn’t tire related, but I didn’t find anything abnormal. The tires were within correct psi range and was not overheated or under-heated. I backed off the early throttle inputs and was fine for the rest of the track day.
One of my goals for my 10/11/2017 track day was to push the bike the same exact way to see if the rear grip issue came back, and I waited until the afternoon sessions to do so. At the same corners where I had micro-slides, they became corners where I consistently went wide. However, this was not a bad thing. I was going wide because the rear was gripping and pushing me away from the line I was used to instead of sliding. In other corners, the bike was holding a tighter line into the apex and was making me early apex. The next session, I adjusted my tip-in points to be a few feet later and it solved my early apexes and wide exits. After getting used to how the bike handled, I started to push it even further to see if I could recreate the micro-slides out of apexes. The only way I can describe it is that it made my rear tire feel like a Supercorsa. I was able to get on the throttle so much earlier than before and with no unsettling of the rear tire. It just gripped and pushed me to the outside curbs on every exit!
By changing the rear link, the feeling of the rear has also improved for me. I can feel the rear end squatting under hard exits but it doesn’t stop squatting as if it hit its limit. It feels like it has double the shock travel!! Even on the edge of the tire, I can feel the suspension and tire flex. Before the rear link, I couldn’t feel how much grip I had at the rear, and I only noticed it when it stepped out on me.
If anyone ever needed a definitive and analytical reason to buy this link, I hope my documented experience would help in your decision. In my opinion, there is no question on whether this link actually does anything or is worth the money. It is absolutely necessary to get the rear of the bike behaving controllably and consistently.
If you have read through this whole post, congratulations!! You are probably as neurotic as I am in needing to understand how it changes the rear suspension of 2013+ Daytonas. Now go buy one!
(If there is any misleading info please let me know so that I can test, confirm, and correct what I did wrong.)