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Traxxion AK-20 vs GP suspension 25mm

16K views 62 replies 12 participants last post by  jd41 
#1 ·
Looking to upgrade forks for next year. Riding intermediate track pace. Fairly happy with the stock re-sprung forks but some a traditional traction and front end feel/ confidence would always be nice.

I spoke with GP suspension and another suspension provider and they didn't recommend re-valving as it is not doesn't make much of an improvement over the stock damping for 13+ zx6r's.

I have a Penske triple shock and have looked into either the AK20 or GP25 cartridge kits. Any recommendations?
I do like that the AK20's are modular so they can be installed to a future bike and it's also the least expensive option. Both products seem solid but some feedback and suggestions would be much appreciated.

Local suspension guy is Dave Moss and he works on any brand.
 
#4 ·
JD, are you happy you upgraded the rear suspension first instead of the front or do you feel you should have done it the other way?

I'm in a similar situation, intermediate pace looking to continue getting faster...trying to decide which component I should focus on first. Right now I'm just running re-sprung front and rear stock suspension, with an additional adjustment nut for rear ride height. Haven't necessarily had any issues yet, but I'm guessing as I get faster one piece or the other will reach it's limits.
 
#5 ·
There are expert racers and top of advance group guys who run stock suspensions, on shittier bikes than a new gen ZX6R. You won't reach the limits of those parts anytime soon. It's all in your head. I used to think the same. Spent like $2k on suspensions, offset triples, switched to slicks. Guess how my lap times changed....hint: insignifcant.
 
#8 ·
Suspension tuner didn't show for some TD's and I hadn't been able to figure out some issues but finally had it improved last week at Buttonwillow. The front kept raising a bit too fast making mid-corner stability whack. On the plus side it really made me concentrate on throttle input's to keep it stable. lol. I'm thinking I took a lot of weight off the bike after converting it from street to track only.

Front sag is 25mm with 1/2 turn preload. I'm currently changing the spring rate down to 9.5N and hope to see an improvement.
 
#12 ·
While I can't comment on the quality of the stock suspension in a zx6r, I do have a few thoughts to throw into the mix:

1. Cartridges require maintenance more often than standard suspension. I recall the Ohlins NIX 30 forks need service every 10 hours of use, where the old school R&T forks that I have can go 20 hours. With the amount of track time I am getting, that is the difference between twice a year and once a year for service.

2. On the other hand, especially if you have a good trackside suspension tuner, you will always benefit from using better equipment. So the argument that you have to be riding at a certain pace to get value out of better equipment is debatable. I disagree that you need to be at the fast end of the advanced group to see a difference.

3. On the other other hand, $1500 buys a lot of track time that you could use to improve. One of the guys at the pointy end of Amateur Open in CVMA was on an R6 with stock suspension, regularly beating guys on well built 1000s. His strategy was to spend his money on coaching.

4. I was talking with a local suspension tuner who was saying that the K-Tech stuff just wasn't quite as developed as the Ohlin's stuff (Kyle Wyman's BrotoGP interview backs this up). However, the same guy had good things to say about GP carts. I rode an MV with the GP carts and thought they were fantastic. Long story short, most of these brands are good, but Ohlins just has more development and it is easier to find someone who knows how to set them up.

I know saying this stuff does little more than cloud the waters further, but I just thought I would throw my $0.02 in the mix.
 
#14 ·
Appreciate the input. I heard that podcast as well. The only reason I wouldn't want to get ohlins is because I already have a Penske and it's much cheaper to buy ohlins as a set than cartridges only. Good to hear good things about GP suspension. I've had some coaching form Pridgemore CLASS and plan to do some more but it is by no means "cheaper" than a fork upgrade. CA superbike school is $2750 for two days!

I understand that it's not "necessary" to upgrade suspension to be fast, but it's not a coincidence that all Racers recommend the same things: track time, tires, suspension, coaching. (not necessarily in that order)

All the aftermarket cartridges are far superior in every way to the oem generic trash thrown at bikes.

quality control is far better, tolerances are way tighter and the polish and assembly is superior.

comparing an oem cartridge to an aftermarket one is like comparing what your suspension works like at all the max settings to what it works like on all the minimum settings........... it is night and day difference!

Can you make oe parts work better, yes....

Can you ever make them work as good as aftermarket, not for the same amount of money you can't


AK20's for the win!
cheaper than the others, more readily available, easier to service and clean (DDS requires some disassembly just to bleed, may be a bike specific issue?) and I have had the same set of AK20's in my bike for damn near 75,000 miles and they still work fantastic! (I change the oil on them annually is it)

I have seen locals here drop 2-3 seconds off lap times with suspension upgrades....... So saying it doesn't or won't improve lap times is really a vague general statement (and I am sure for some people it doesn't...... just like some people don't get faster or better form attending trackdays and getting "instruction")

I liken the correct suspension and function of high quality products as to aiding in your confidence and making your tires work less hard so you then can push them further to improve times.......
This is the feedback I was looking for. Thank you. I'm not trying to validate a purchase, I simply want to know how much of a quality product it is and which one would be a better option. I also like their modular approach to transfer to future bikes.
 
#13 ·
All the aftermarket cartridges are far superior in every way to the oem generic trash thrown at bikes.

quality control is far better, tolerances are way tighter and the polish and assembly is superior.

comparing an oem cartridge to an aftermarket one is like comparing what your suspension works like at all the max settings to what it works like on all the minimum settings........... it is night and day difference!

Can you make oe parts work better, yes....

Can you ever make them work as good as aftermarket, not for the same amount of money you can't


AK20's for the win!
cheaper than the others, more readily available, easier to service and clean (DDS requires some disassembly just to bleed, may be a bike specific issue?) and I have had the same set of AK20's in my bike for damn near 75,000 miles and they still work fantastic! (I change the oil on them annually is it)

I have seen locals here drop 2-3 seconds off lap times with suspension upgrades....... So saying it doesn't or won't improve lap times is really a vague general statement (and I am sure for some people it doesn't...... just like some people don't get faster or better form attending trackdays and getting "instruction")

I liken the correct suspension and function of high quality products as to aiding in your confidence and making your tires work less hard so you then can push them further to improve times.......
 
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#16 ·
If your dead set on upgrading. I would go for the GP 25mm kit. From what I remember reading its a exact copy of Ohlins popular 25mm kit that they don't make anymore that they bought the rights to it I can remember correctly. Ohlins then came out with the 30mm kit that they took somethings internally to make it cheaper to make. From some of the fast guys I know don't like the feedback of the 30mm kit ohlins has now and go for the GP 25mm kit. My friends from TSE in Wisconsin push that and Penske. I also have the GP cat front /Penske rear and it's a nice combo. My buddy Tony has the Gas cart set up but he is stupid fast and says he notices the difference but then again. He is up there fighting for podiums. I would spend the money but I like wasting money on cool things even though I don't really need em just because I enjoy modding stuff so why not.
 
#19 ·
I forgot about race tech cartridges. Any positive experiences with them (G2-R 25mm CARTRIDGE KITS)? Like the AK-20's, they are also modular and able to be installed on multiple bikes.



---

Getting in my new springs today. Can't wait for my next TD. Glad that Buttonwillow just added a day in December! :D
 
#20 ·
Lots of...."interesting" responses on just this thread alone. Here's trends that I've seen over the years across a few hundred different riders and bikes...

- People don't take the time to set up their bike properly in the first place

- People compare unserviced, old, and incorrectly setup OEM suspension and slap on new stuff then say "Errr mah gawd the stock stuff is trash!"

- People tend to throw money at the bike instead of fixing the problems (themselves) first

- Typically on the internet, those that talk about the "night and day" differences that aftermarket suspension does compared to OEM are not even fast enough to truly extract the advantage of said aftermarket suspension

First thing that came to mind when I saw you talking about the front "coming up" mid corner is probably because you're not trail braking enough.

Getting bumped to Advanced at the local track day org is a big deal for sure and I don't want to undermine that. But I hate to admit, the real learning begins once you get to that group. Once you are at that point, generally speaking, it's an indicator that you're a consistent rider with a decent set of skills under their belt.

Up until that point, assuming someone has a serviceable bike with suspension tuned for them, that money is FAR BETTER spent on a riding school to improve the loose nut behind the bars.
 
#21 ·
Wow. You're completely right. I stopped trail braking as much after having a low side. Greatly appreciate the advice. Going to get my current stuff sorted out and refreshed. I'll get cartridges once I actually need them. :bigthumb:
 
#33 ·

I thought this was a pretty informative video by Dave Moss. Basically comparing two methods of settling the chassis and increasing the front contact patch in turns. Each method, " brake-turn-gas(trail braking) vs Brake-gas-turn" is useful depending on the type of corner.


Sent from my LG-K371 using Tapatalk
 
#40 ·
That's awesome JD, he is a great guy and an even better suspension tuner. I like the way he actually teaches you about suspension as he is tuning your bike. I should have brought a notebook with me when he worked with me during a round this season.

Sent from my LG-K371 using Tapatalk
 
#43 ·
The afternoon session was way better after Dave Moss set up the suspension but I haven't been able to get the bike to steer properly since changing out the steering stem bearings. It keeps veering to a side and has heavy handling. I feel really frustrated with this bike. I also had a couple of headshakes at turn 1 at Laguna Seca and while braking into turn 2 and turn 7-8.

I'm going to inspect the races and bearings, loosen up the collar just enough to make sure there isn't any play, check rear wheel alignment and swap out the triples if it doesn't improve. Wheels are straight. Rotors are straight.
 
#44 ·
Andreani Revalve Kit

I installed my revalve kit yesterday. Instructions are in Italian which only has the stack specs so no problem. The valve compression side has drilled holes on the sides while the rebound is solid. Measured everything and put it in order.


ANDREANI MODIFICATION KIT FORK FOR FORK KAWASAKI ZX6R 636 2014
 

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#45 · (Edited)
Rebuilt my forks today and installed the new spring and valve kit. Oil was filthy! Previous fork sag was at 20-22mm without preload. It used to be fine with the 9.5N spring in street trim but switching to track fairings made them too heavy. Now I can adjust it to 25-30mm with the 9.25N spring.

Also had to readjust my steering stem bearings. They were still to tight at 5ft-lb. These needle bearings have to be hand tightened to get the proper play. I didn't like them. Using OEM ball-bearings next time.

I'm confident this will resolve my suspension issues. Thanks to everyone for the suggestions and saving me 1k$.

:cheers
 
#47 ·
Currently at buttonwillow. I have to say that the respring and revalve exceeded my expectations. Unbelievably stable and turn in is better that I've ever felt it. I also finally understand how to adjust the suspension and what each change will do. Now I need to learn how to adjust the rear properly.
 
#49 ·
I won't give advise, but I'll relate my personal experiences regarding a handful of different sportbikes:

The suspension is there to be your 'instant on personal coconut telegraph.' The main participants in this dialogue are (in no particular order):

1) Your brain, your butt, your hands, your feet, your knees/thighs, and your eyes. Any of them at any given second of any given minute can feed your brain significant information.

2) The tires (& wheels), these lovely black rubber/silica doughnuts dance on a ≈ 2.5" X 2" interface between you, the rider and the tarmac. The information they supply is ever changing by mere fractions of a second. Many factors affect the ultimate flow of data.

3) The suspension & chassis I'm gonna lump together, only for the sake of simplicity. Yes, they are separate, yet joined entities. Stating the relative obvious fact that in the vast majority of cases one is not going to be altering the chassis, but it is a very real possibility, none the less.

Most people I believe, place too much emphasis on twiddling the fork. Yes there are gains to be made there. Likewise most people neglect the rear end of the bike. Why? because it's not glamourous. Few see the bling when tuning forks and shocks. Personally, I think getting the shock dialed in is a 'must do.' Why? The shock affects every in./mm from the head stock back - that's most of the bike; it's also where the rider is. The front suspension takes its cues from the rear suspension/tire/spockets, etc.

I have learned the hard way where to invest mods on a sportbike, that doesn't mean I haven't performed purely adornment mods early on it the mod(s) phase. I certainly have. And some are done early in the relationship to accommodate my aging body, as well as my vanity. But no one makes suspension changes for their vanity - unless it's to keep their pretty face & the rest of their body (& the bike's) pristine.

On a street bike that maybe sees a little track time with a track day/school, but is otherwise used for pleasure/sport/transportation, etc., no non-sport bike rider will ever noticed you dumped nearly $12,000 on a set of Öhlins FGR300 (I used the most extreme for dramatic affect), or a cool eleven hundred dollars for a nice, but not top the line, but still used by factory/privateer racers, Öhlins TTX RT shock. But I think a mid-tier shock by K-Tech, Nitron, Öhlins, or Penske is a wise move for an upper 'B Group/A Group' rider. If you don't know that means leave your bike stock and enroll in a track day school ASAP. Also save your money on rebuilding your stock shock. They are not as rebuildable as aftermarket - no not even as stop gap. I've gone down that rabbit hole.

I also found that having my OEM forks re-built with new internals is a savvy move. This will get you to the 80-90+ percentile. But this would be a little on the back burner, because there are other things to sort out prior. Or another way I look at is, this is a nice to have, and not a need to have... until your riding abilities come up quite a bit.

A track only bike, also benefits from a mid-upper tier shock. I still think for a lot of 'A Group' riders can get by with new fork internals. Or at least until one becomes a contract rider for one of the major suspension manufacturers. What I found made a noticeable difference with bike transitions from little chicane wiggles to full left-full right; decreasing radii, off camber to off/on camber transitions are... wait for it... hold your breath... aftermarket wheels.

Now, this is a big-ticket item that really is over kill on the street, but on a track, at speed, they make quite a worthy asset to have. My experience was like I was on a completely different bike, so much so that I had to re-programme my brain to ride quite a bit deeper into the turn, otherwise I was turning in way too early. Sometimes clipping the inside of the turn that I was/and did come off the track a few times and on to the kerbing/rumble strip. But they are damn nice to have, and oh-so bling! Shwing! Beautiful.

Do I have aftermarket wheels on my ZX-6R? No! It's a street, mostly bike; me & my body are just to old. It sees the occasional track days, but that's it. I'd probably spend similar money either on track days, or on taking my 636 to the Rockies for two weeks, or ride down the California Coast, and back up through the Sierra Nevada/Cascade Ranges. (Though not right now with the tragic fires.)
 
#51 ·
I didn't know Dave Moss recorded everything. lol I'm at 2:16. Dave Moss does great work. He took the time to help me understand what the issue was.
I have some questions and comments lol

1. Why do you have 42 on the bike but you're JD41, and everywhere on the forums is all about 41?

2. You don't look like a JD

3. If I knew nothing about you and I randomly saw you in the paddock I would think "Yep...definitely a Lorenzo fan" lol

4. That's cool that you got to work with Dave Moss! Does he charge for all of that, and if so how much?
 
#54 · (Edited)
Suspension is dialed in. In retrospect, my biggest problem was geometry. The front had little weight on it and stock rebound adjustment was insufficient. This all happened after I crashed about 2 years ago and switched from stock trim to track plastics. I should have taken into consideration the weight that shaved off. Additionally, the tank cover was transferring unwanted energy to my GPR damper and causing a weaving effect on the steering which was resolved after swapping to an ohlins/ graves mount. I should have also reset the engine mounts sooner. The revalve and spring swap helped to correct fork adjustment. Now feel is restored to the front and it has great stability where before it felt like a nervous twitchy wreck and was wheelie prone.
 
#55 ·
The tank cover was pushing but not the tank itself? Aren't they screwed into the same location and sandwiched over top by the GPR?

My bike is the opposite of a wheelie machine, I think I have the back up to high now that I'm running a 60 profile. Places it used to pop a wheel several inches it literally won't come up lol
 
#59 · (Edited)
I agree with Michael Castro at GP suspension that it's not worth the time playing with the stock big piston forks, honestly they kinda suck. I just rode another team's ZX6R in the AFM 600 races this weekend and it had stock suspension supposedly re valved by super plush, and had stiffer springs put in. I got the bike a lot better after the whole day but it never really got that good. In that video I posted on my IG you can see the front end chatter and rear bouncing in T2. I'm super happy with my Ohlins and from what I've seen the GP kits are equivalent. A few of the top 5 guys in AFM are running GP Suspension forks.

Edit: Whole saturday practice, qualifying and 3 Sunday races .... bleh. I could see them working fine through advanced group trackday pace but they will really limit you eventually
 
#60 ·
Intermediate Rider Here.

Stock 13 ZX6R.

I've set up the suspension to text book sag, then made some rebound/preload adjustments based on what I was feeling while out on track. Overall I'm satisfied with the bike.

However, I am a heavier rider (230-235 No Gear). I notice the front end getting light frequently, especially corner exit which causes understeer and lowers my confidence.

I'm interested in hearing opinion on only re-springing the front and rear to better suit my weight.

Side note: I'm signing up for YCRS in 2020 which I know will help.
 
#61 ·
You need to fix geometry as well. You probably would benefit from stiffer springs. Are you maxed out on preload? My rear is raised and front is lowered compared to stock
 
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