Results 1 to 26 of 26
  1. #1
    mtbr member
    Reputation:
    Join Date
    Apr 2018
    Posts
    23

    2017 Top Fuel 9.8 - rear shock knock

    Hi Guys,

    I have a 2017 Top Fuel 9.8 with less than 100 miles on it, and it appears the rear shock (Fox Re:aktiv XC) has developed or has always had a clunking feel / knocking sound.

    The best way to describe it would be a feedback that I can feel through the pedals, like something in the rear end is loose. Most noticeable going through small bumps in rapid succession, inducing a lot of chatter in the rear end. I can duplicate the knock just sitting still on the bike and bouncing on the pedals. I can feel the clunk during initial compression, and again when it rebounds, almost as if there is a worn out shock bushing. Doesn't matter which position the remote lockout is in.

    I've ruled out loose cables, seat post, pivot bolts/nuts, wheels, bottom bracket, and headset. There is no slop in the rear triangle when trying to deflect the wheel laterally. The suspension seems to be working normally, but I am still fairly certain it is the shock.

    Has anyone else had a similar issue with there Re:aktiv XC suspension?

    Planning to take it in to the LBS, just concerned as I have read some stories of older models with the Re:aktiv shock having similar issues that went ultimately unresolved or were considered normal. Talking to them on the phone they hadn't had any experience of the sort on this model, evidently.

  2. #2
    mtbr member
    Reputation:
    Join Date
    Apr 2018
    Posts
    23
    Followed up on this today at my local shop. They hadnt seen it before but got on the phone with another location with a Fox certified technician. He confirmed it was a known issue that Fox would repair under warranty. No formal recall as I guess it effects a small number of units. 3 week turn around time for the shock means I'll be waiting on having it done, but pleased to hear it is a known issue with a fix.

  3. #3
    mtbr member
    Reputation:
    Join Date
    Jan 2017
    Posts
    59
    Hello oab1
    Have they fixed the shock problem?
    I cant believe myself I have bought another Trek after my last 2011 Fuel that was pure crap!
    How do these guys stay in business coming with these gimmicks?
    We have Push, TFT, Vorsprug and some other great tuners and they go to Penske that has nothing to do with bike sus ... oh Trek this is the last time Trek sees my money.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Oct 2018
    Posts
    25
    Quote Originally Posted by adyamg View Post
    Hello oab1
    Have they fixed the shock problem?
    I cant believe myself I have bought another Trek after my last 2011 Fuel that was pure crap!
    How do these guys stay in business coming with these gimmicks?
    We have Push, TFT, Vorsprug and some other great tuners and they go to Penske that has nothing to do with bike sus ... oh Trek this is the last time Trek sees my money.
    So this is not a Trek issue but a suspension company that only has a small number of issues. Penske has PLENTY of knowledge with suspension systems so I think that the tech is there. But it was a pairing with Penske and Fox/RS so they were involved in it together. I think it is a little unfair to blame a brand based on a third party product.

    I assume oab1 got the issue fixed though. This was something Fox was willing to handle and they take care of their products such as Trek does.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Jan 2017
    Posts
    59
    @easterside so Trek has a small number of issues?
    https://www.google.com/search?q=trek...ient=firefox-b
    Even new bikes send for reviews have been plagued with this
    https://www.bikeradar.com/mtb/gear/c...-review-51151/
    Trek even has made some racalls for the knocking Reaktiv shocks
    FOX and RS have proven that have good products to!
    Penske has plenty of knowledge

    ..... so I am beeing left with a turd.

    And this is the reason that in the late years the market has been taken over by companies like Canyon and YT ..... they are not doing stupid "custom" tech that constrain you to be their puppet.
    Trek is doing custom 141 boost, 197 e2e shock(3mm shorter thatn comonly used 200) ABP bearings that have custom size bearings(chineese ones only available from Trek) and so on.

    So by continuing to do this trickery, my expectation for them is ... to go bust and maybe get bought by a Chinese company for pennys.

  6. #6
    mtbr member
    Reputation:
    Join Date
    Oct 2018
    Posts
    25
    There are not too many posts regarding it but I do understand it was on certain Fox shocks. And have you not been to your LBS? They have the means of replacing the damper which Fox sends out (then you're not left with a turd unless you want to make it one).

  7. #7
    mtbr member
    Reputation:
    Join Date
    Apr 2018
    Posts
    23
    I have not attempted to have it fixed yet. The bike is actually riding really well, so I don't find that it is more than a nuisance. I would certainly like to have it fixed, but i'm waiting I wont mind the 2-3 week downtime.

    I also agree it seems to be a Fox issue, and perhaps not even unique to the "re:aktiv" shocks as I have read some others have similar issues with their DPS units. I will admit the re:aktiv tuning isnt so noticeable to me on this bike, and i tend to use the lockout anyway, but it was a pretty staggering improvement riding the re:aktiv shock on the Fuel 9.9.

  8. #8
    mtbr member
    Reputation:
    Join Date
    Mar 2007
    Posts
    691
    Quote Originally Posted by adyamg View Post
    @easterside so Trek has a small number of issues?
    https://www.google.com/search?q=trek...ient=firefox-b
    Even new bikes send for reviews have been plagued with this
    https://www.bikeradar.com/mtb/gear/c...-review-51151/
    Trek even has made some racalls for the knocking Reaktiv shocks
    FOX and RS have proven that have good products to!
    Penske has plenty of knowledge

    ..... so I am beeing left with a turd.

    And this is the reason that in the late years the market has been taken over by companies like Canyon and YT ..... they are not doing stupid "custom" tech that constrain you to be their puppet.
    Trek is doing custom 141 boost, 197 e2e shock(3mm shorter thatn comonly used 200) ABP bearings that have custom size bearings(chineese ones only available from Trek) and so on.

    So by continuing to do this trickery, my expectation for them is ... to go bust and maybe get bought by a Chinese company for pennys.
    Cool you can use google. You realize how many bikes Trek sells right? I bet the issue rate is below 5%.

  9. #9
    mtbr member
    Reputation:
    Join Date
    Oct 2013
    Posts
    82
    Sent my reactive shock from my topfuel to Dirtlabs in colorado. My shock had a bit of resistance off the top and I could feel it slightly while on the bike. Explained this to the guys at dirtlabs and they said they know what I was was explaining. They overhauled it and turned for better small bump compliance and it came back awesome! Felt totally different while still have an excellent pedal platform. I highly recommend them.

  10. #10
    mtbr member
    Reputation:
    Join Date
    Jan 2017
    Posts
    59
    Quote Originally Posted by josh8 View Post
    Cool you can use google. You realize how many bikes Trek sells right? I bet the issue rate is below 5%.
    If they have 5% just on this issue I would say it qualifies for a recall. As for your statistical guess is a loosing bet anyway, the problem is so well known by Trek users, official Fox services and unofficial Fox services that calls for help!

    As for you irony attempt what can I say ... you are doing your best, that is all that matters.

    @1lawnman I would be so curious what have they done to the shock effectively.

  11. #11
    mtbr member
    Reputation:
    Join Date
    Mar 2007
    Posts
    691
    Quote Originally Posted by adyamg View Post
    If they have 5% just on this issue I would say it qualifies for a recall. As for your statistical guess is a loosing bet anyway, the problem is so well known by Trek users, official Fox services and unofficial Fox services that calls for help!

    As for you irony attempt what can I say ... you are doing your best, that is all that matters.

    @1lawnman I would be so curious what have they done to the shock effectively.
    Recalls only happen on safety issues, not because your shock makes a noise.

  12. #12
    mtbr member
    Reputation:
    Join Date
    Jan 2017
    Posts
    59
    Josh, just cut it ...
    Trek bicycle store Bezons 95-La Défense paris- velo trek route, VTT, VTC et accessoires de qualité - information SAV
    Use the uber cool Google mentioned by you and translate it if french is a no go.

  13. #13
    mtbr member
    Reputation:
    Join Date
    Mar 2007
    Posts
    691
    Service bulletin ≠ recall. Very different things. One involves the government, one does not. You can find that on google too..

  14. #14
    mtbr member
    Reputation:
    Join Date
    Apr 2018
    Posts
    23
    Quote Originally Posted by 1lawnman View Post
    Sent my reactive shock from my topfuel to Dirtlabs in colorado. My shock had a bit of resistance off the top and I could feel it slightly while on the bike. Explained this to the guys at dirtlabs and they said they know what I was was explaining. They overhauled it and turned for better small bump compliance and it came back awesome! Felt totally different while still have an excellent pedal platform. I highly recommend them.
    Oh wow, that is good information. Thanks for chiming in. Nice to know someone other than fox may be able to repair/improve it.

    Can you elaborate a bit more on the symptoms you had? Did it feel sloppy or clunky off the top at all? Mine feels like a bit of free play, both in the initial stroke and again when transition back from compression to extension.

  15. #15
    mtbr member
    Reputation: DethWshBkr's Avatar
    Join Date
    Nov 2010
    Posts
    2,111
    Psh. What does Penske know about suspension? They are only one of the most well known premier developers of suspension systems on the most sophisticated race cars in the world.

    Stupid Trek.

  16. #16
    mtbr member
    Reputation:
    Join Date
    Jan 2017
    Posts
    59
    @DethWshBkr ya ... maybe thats why in race cars they are using this on the rebount circuit and on bike shocks are using it on the compression circuit, ya for bike anything will do.

    The highlighted spring and shims are probably the culprit for the clunkines
    Attached Thumbnails Attached Thumbnails 2017 Top Fuel 9.8 - rear shock knock-screenshot-2018-11-06-09.47.09.jpg  


  17. #17
    mtbr member
    Reputation:
    Join Date
    Oct 2013
    Posts
    82
    Oab1, shock didn't clunk or make noise audible. It was like it stuck very slightly anywhere in the travel. Example..I would lean over the bike and place my torso on the seat and use downward force to compress the shock. It did not at all very gradually and fluidly move. It was like it would reach a point and the all of a sudden release tension on the stachtion and move. Did this anywhere within its travel. The newer treks and other models did not do this. Dirtlabs told me that there was probably a valve tune change on newer models. Mine was an early 2017 9.8. Anyway they knew exactly what I was describing and told me they would tune for small bump compliance. Came back way way better. Still same great pedal platform with no pedal bob. I highly recommend you call them. They are super cool to talk and work with.

  18. #18
    mtbr member
    Reputation:
    Join Date
    Oct 2013
    Posts
    82
    Oh it had always done this even when new. Kinda concerned me early on but thought that was the way it was designed being "reactiv"

  19. #19
    mtbr member
    Reputation:
    Join Date
    Apr 2018
    Posts
    23
    Hey 1lawnman, thanks. That sounds very similar to mine. Started from new, and I noticed it is in fact sticky from anywhere in the travel. The transition from stuck to moving is the sensation I'm calling clunky. Mostly notice it on the initial hit, and again when changing direction to return to sag height.

    I sent DirtLabs an email. Will gladly go that route if they can do something similar for me. What was the turn around time for you?

    @adamyg, that very well could be. Where did you get that diagram? It certainly looks like the reactive valve, but I'm not too familiar with it. and if that is the case, are you essentially converting it to a DPS unit by "fixing" it?

  20. #20
    mtbr member
    Reputation: DethWshBkr's Avatar
    Join Date
    Nov 2010
    Posts
    2,111
    Quote Originally Posted by adyamg View Post
    @DethWshBkr ya ... maybe thats why in race cars they are using this on the rebount circuit and on bike shocks are using it on the compression circuit, ya for bike anything will do.
    Hmm. I wonder why they would use a valve like Re:Aktiv in the compression circuit of a mountain bike rear shock instead of the rebound.

    Absolutely baffling!

  21. #21
    mtbr member
    Reputation:
    Join Date
    Jan 2017
    Posts
    59
    Quote Originally Posted by DethWshBkr View Post
    Hmm. I wonder why they would use a valve like Re:Aktiv in the compression circuit of a mountain bike rear shock instead of the rebound.

    Absolutely baffling!
    Maybe this was the only way to get that dreaded clunk?
    Or maybe it wouldn't be Trek if they would have done it wright?

    @oab1 guess what, Fox use to have a TSB regarding this issue and some parts in the piston where re-manufactured, but guess again FOX being FOX is not producing the re-engineered parts anymore so the turd is on us the consumers!

    And guess again ..
    Fox - makes great products
    Trek - makes great products
    Penske - makes great products
    .... but join these 3 together and you get the worst threesome ever.
    Last edited by adyamg; 1 Week Ago at 12:23 PM.

  22. #22
    mtbr member
    Reputation:
    Join Date
    Oct 2013
    Posts
    82
    48 hr turnaround. Not included shipping time to and from

  23. #23
    mtbr member
    Reputation:
    Join Date
    Apr 2018
    Posts
    23
    Quote Originally Posted by 1lawnman View Post
    48 hr turnaround. Not included shipping time to and from
    Well unfortunately it is true that the parts needed to repair the issue with the re:aktiv shock are no longer being produced by Fox. So there is no fix available anymore. I was recommended moving on to the DPS shock.

    I notice the 2019 models come with a DPS with trunion mount. I might try to get the bike shop to source me one of those.

    Otherwise, Im not sure why you couldn't use a metric shock (165mm x 40mm is only 2mm more travel, maybe you can change the bump stop in the shock?)

  24. #24
    mtbr member
    Reputation:
    Join Date
    Jan 2017
    Posts
    59
    So the BIG famous super brands called FOX and Trek have pulled the plung on us!
    Anyway, as 1lawnman said, Dirtlabs seem to be really nice and very supportive but unfortunatley they cant source the Reaktive re-engineered parts.

    So as I said before, the turd is on us, Trek belivers.

    Now I know why all my friends ride on YT's an Canyon's. Here in Europe Trek is almost disappeared.

    Also, how could you go to a DPS, as the eyelet bulkhead of the DPS doesnt fit.

  25. #25
    mtbr member
    Reputation:
    Join Date
    Oct 2018
    Posts
    25
    Quote Originally Posted by josh8 View Post
    Service bulletin ≠ recall. Very different things. One involves the government, one does not. You can find that on google too..
    BINGO. You get a cookie for telling the mans right.


    Quote Originally Posted by DethWshBkr View Post
    Hmm. I wonder why they would use a valve like Re:Aktiv in the compression circuit of a mountain bike rear shock instead of the rebound.

    Absolutely baffling!
    You sir are fantastic.

  26. #26
    mtbr member
    Reputation:
    Join Date
    Jan 2017
    Posts
    59
    The smartassnes on this topic is over the bars.
    But this is much appreciated coming from fellow riders ... I just hope you get the same giz when you'll need it!

    Anyway, Dirtlabs are working on a replacement for this "discountinued" 1 year old shock so maybe we'll get some good news. I dont know if its a completley new shock or maybe just a new piston.

    Also regarding replacing this with a stock DPS there might be a problem with a raised BB witch is allready a bit high.
    A 3 mm on the eye 2 eye will translate in a 8ish mm like BB raise, and this is considerable. Also the HA will get close to a XC machine.

Similar Threads

  1. Knock knock..
    By DIRTJUNKIE in forum Fifty+ Years Old
    Replies: 109
    Last Post: 06-28-2016, 11:02 PM
  2. Knock..knock
    By DIRTJUNKIE in forum Off Camber (off topic)
    Replies: 85
    Last Post: 11-15-2014, 07:54 PM
  3. Knock, knock... new guy alert.
    By ricksride in forum General Discussion
    Replies: 18
    Last Post: 12-07-2013, 04:21 PM
  4. Knock knock
    By dogonfr in forum Haro
    Replies: 3
    Last Post: 04-11-2011, 01:19 PM
  5. Knock Knock....
    By misteremanca in forum 29er Bikes
    Replies: 3
    Last Post: 01-08-2011, 03:04 PM

Members who have read this thread: 71

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

mtbr.com and the ConsumerReview Network are business units of Invenda Corporation

(C) Copyright 1996-2018. All Rights Reserved.