Guide on the Attack Performance Rear Link - Triumph675.Net Forums
 
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post #1 of 7 Old 10-17-17, 13:01 Thread Starter
hzhong456
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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.)
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post #2 of 7 Old 10-17-17, 13:24
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Appreciate the detailed review!

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post #3 of 7 Old 10-17-17, 14:43
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Nice detailed review!

One thing you might want to try is lowering the front of the bike. Having the forks at 1 bar showing above the triples, you have effectively raised the front 9mm (each bar is 3mm). That is a LOT, given overall tire diameters are similar to stock.

The main issue with the 675 is the front, having such little trail. The chassis also has a narrow setup window. By raising the front that much, it will cause the bike to run wide on exits, even if you try and compensate with sag/hydraulics, since the chassis will be nose-high. You need that weight on the front tire for proper handling.

I would recommend lowering the front back down to 4 bars showing (stock setting) and give it a try again. While the trail IS short, the bike does work, and somehow manages to stay composed. You only start having issues when you really start pushing the bike at a fast pace or under race conditions.

If that helps, then I would look into getting the Attack Triples if more trail is what you're after.

"It was the kind of situation that regularly sees many of the people who masquerade as motorcyclists and ride every third Sunday up their favourite local road (if it's sunny) to sit at a cafe and make broom broom noises with other pretend-motorcyclist-idiots, crash their brains out."
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post #4 of 7 Old 10-17-17, 16:45 Thread Starter
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Quote:
Originally Posted by mszilves View Post
Nice detailed review!

One thing you might want to try is lowering the front of the bike. Having the forks at 1 bar showing above the triples, you have effectively raised the front 9mm (each bar is 3mm). That is a LOT, given overall tire diameters are similar to stock.

The main issue with the 675 is the front, having such little trail. The chassis also has a narrow setup window. By raising the front that much, it will cause the bike to run wide on exits, even if you try and compensate with sag/hydraulics, since the chassis will be nose-high. You need that weight on the front tire for proper handling.

I would recommend lowering the front back down to 4 bars showing (stock setting) and give it a try again. While the trail IS short, the bike does work, and somehow manages to stay composed. You only start having issues when you really start pushing the bike at a fast pace or under race conditions.

If that helps, then I would look into getting the Attack Triples if more trail is what you're after.
Thanks for the feedback. When I first got the bike and before I even knew about the trail numbers, I noticed the lack of feedback in the front right away. With the forks at stock level (4 lines showing but technically 3 lines showing and 1 line touching the top of the triple), the front kept feeling like it was pushing while trail braking; almost to the point of feeling like I was going to tuck the front every time I trail-braked deep into a corner. This feeling made me change my riding style to slower less U-shaped corners (like riding a 1000cc where the exits mattered more than corner speeds). The only thing that helped was dropping the forks, and I settled on 2 lines above the top triple clamp. As you said, this made the front taller, run wider on exits, and also slower on turn-in but it gave me much more confidence braking into the corner and carrying higher entry speeds. At the beginning of this season, I dropped the forks 1 line more to see if I could get even more feedback from the front. I was not able to fell the difference in front end feedback, but I did notice a very slight decrease in turn-in speed. I meant to put the forks back to 2 lines showing but was too lazy.....for the whole season . Over this winter, I will be raising the forks back to 2 lines showing.

The Attack Triples will probably be my next purchase once I can get over the fact that I need to drill out the ignition on the stock triples.
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post #5 of 7 Old 10-17-17, 17:06
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Quote:
Originally Posted by hzhong456 View Post
the front kept feeling like it was pushing while trail braking; almost to the point of feeling like I was going to tuck the front every time I trail-braked deep into a corner. This feeling made me change my riding style to slower less U-shaped corners (like riding a 1000cc where the exits mattered more than corner speeds). The only thing that helped was dropping the forks, and I settled on 2 lines above the top triple clamp.
This is exactly right, and you are on your way to getting a much better handling bike. Unfortunately, as you know, the lack of trail is the issue, and the only non-bandaid solution is to increase the trail by reducing the triple clamp offset. When you start playing with raising the front, it will lead to other issues, like you have experienced.

The Attack Triples are worth every penny.

Also, don't be afraid of drilling the ignition out. It's quite easy, and you won't be doing any irreversible damage, they are essentially security screws that you drill out. They are replaceable, or you can even replace with standard bolts.

"It was the kind of situation that regularly sees many of the people who masquerade as motorcyclists and ride every third Sunday up their favourite local road (if it's sunny) to sit at a cafe and make broom broom noises with other pretend-motorcyclist-idiots, crash their brains out."
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post #6 of 7 Old 02-19-18, 09:31
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Thanks for the write up.

I wish I had seen your topic sooner.

When I purchase the link from Riders Discount TJ, I also have purchase the Attack performance triples, with a recommended 4 mm offset and a 110 nm springs. When I purchased my weight was 217 lbs (98Kg)

However when I changed, the first thing I felt it, was that I could hold the entry lines, so much better, the transitions left to right were so much faster.

But as soon as I start to apply the throttle, the rear was spinning the whole time. I was not aware if this was how it was supposed to ride now, thought this was how the Pro level riders were riding the whole time, and I should learn to ride it like this. (Mainly because I have never felt it a spinning sensation like this before).

I have even installed a data logger, to check how the wheel speeds difference was. While comparing with some friends, and I was having a huge speed difference over 12 mph (19,2 kph).

Until finally I had it huge a high side.

Tried everything with the 110 nm shock spring, change the preload, clicks to all directions, and nothing, the same feeling as it was before.

I spoke with Dave Moss, and he mentioned that this symptom is called COIL BINDING, and that I should change the springs, before I crash it again.

Back to the OEM 100 nm springs, the bike feel awesome, planted. I was opening the throttle way much sooner in every corner. I end up running a bit more of preload 15 mm, a litte more than I usually run.

My recommendation, is that there is a intermediary 105 nm spring from Ohlins. It would be a much more appropriate step up.

One thing that I like it about the experience was, that I have never felt my bike spinning so aggressive before, now with a proper set up suspension I felt so much comfortable when the bike is spinning. I think that is something everybody should try it. You will not be fast, but definitely you will learn how to run sideways.

My weight is 160 lbs (73kg) and assuming a 182 lbs (83kg) fully with the gear.

Here is how my set up ended:

Front:

Pre load 3 mm
Compression 16
Rebound 16

Rear
Spring 100 nm
Preload 15 mm
Compression 13
Rebound 12

675R
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post #7 of 7 Old 02-25-20, 14:00
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Hi hzhong456,


thank you very much for your detailed report !


There is one thing that I do not understand concerning the Attack Linkage:
Before you installed the Linkage the sag was
15/35 mm which is a difference of 20 mm which I think shows that the spring fits your weight really good !


After installation of the linear link without altering the RSU, the sag was 10/21 mm which is a difference of only 9mm!
This shows a much stiffer rear end and should require a softer spring to get the right behaviour, and this cannot be achieved just by lowering the preload.


Why does anyone recommend a firmer spring to be mounted in combination with the linear linkage, when the rear end get stiffer with the attack linkage?


Can someone explain the context to me please?


Best regards
Dirk
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