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Planet X Pro Carbon - Flex and Wobble

HebdenBikerHebdenBiker Posts: 787
edited November 2014 in Workshop
Hello all,

I bought a new PX in August. It's done under 100 miles.

I haven't ridden it for a couple of weeks, but got on it yesterday and instantly noticed "flex" in the rear end, which made the bike feel like it was made of spaghetti, or articulated in the middle, if you know what I mean.

I thought maybe I was imagining it, but I tried again today, and the same thing.

When I spin the wheels they seem true (ie don't catch on the brake pads), and there are no outward signs of damage to the carbon. QR skewers are tight, tyres inflated to 100PSI. I weigh 80kgs and am no Marcel Kittel.

Obviously I will return it to PX if I need to, but it's a faff and I want to explore any obvious causes before I do this.

Anyone?

Cheers.
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Posts

  • diamonddogdiamonddog Posts: 3,351
    Something wrong there, mate of mine has had one for about 18 months now and no problems at all and he weighs in at 85kg. Also I have had one for a few years as well without any problems at all although I am only 51kg, TBH I enjoy the ride as much as the more expensive bike I have, very lively ride.
    I would give it a thorough check over especially the wheels etc. and if you can't sort it get off to PX.
  • sigorman85sigorman85 Posts: 2,536
    What's the seat post hight? If to high this maybe the problem
    When i die I just hope the wife doesn't sell my stuff for what I told her I paid for it other wise someone will be getting a mega deal!!!


    De rosa superking 888 di2
  • JSCLJSCL Posts: 1,259
    We call their bikes Planet FleX. I've seen even a light less powerful rider manage to flex a PX frame at the BB area when riding.

    You have to remember though, you aren't buying stiffness. You're buying an entry level carbon frame. Rear end flex is strange though. What wheels do you have in?
    Follow me on Twitter - http://twitter.com/scalesjason - All posts are strictly my personal view.
  • natrixnatrix Posts: 1,111
    Try taking both wheels out, checking them over then putting them back in and trying the bike again. Years ago I had an axle snap, the wheel stayed in place because of the QR, but it made the bike wobble.

    I've got a PX pro carbon and get on really well with it (prefer it to my steel framed road bike)
    ~~~~~~Sustrans - Join the Movement~~~~~~
  • heavy_ratheavy_rat Posts: 264
    I sold my PX Pro Carbon earlier this year and replaced it with a Giant TCR. The difference in stiffness is quite significant although more noticeable at the front end. I never had an issues out back.
  • natrix wrote:
    Try taking both wheels out, checking them over then putting them back in and trying the bike again. Years ago I had an axle snap, the wheel stayed in place because of the QR, but it made the bike wobble.

    Best suggestion so far - thanks. I'll check and report back!
  • OK - neither axle bent or snapped.

    On close inspection, rear wheel a few mm out of true - but can't believe that would cause such huge handling issues.

    Will borrow a friend's wheel and try with that...
  • diamonddogdiamonddog Posts: 3,351
    OK - neither axle bent or snapped.

    On close inspection, rear wheel a few mm out of true - but can't believe that would cause such huge handling issues.

    Will borrow a friend's wheel and try with that...
    Wouldn't think that the wheel being not true is the problem as when my PX rear wheel was out of true I didn't notice any handling problems and only found it was out when I checked the wheels when cleaning after a ride, but hey it's worth a try.
  • tehtehtehtehtehteh Posts: 103
    the only time I've felt this on a bike is when the chainstay snapped, but I also heard a knocking where the snapped ends were hitting together, give them and the seat stays a close look, it can be suprisingly hard to spot when you're off the bike as they close up
  • JamesFreeJamesFree Posts: 703
    They are notoriously flexy I couldn't believe the difference when I got on any other bike other than my old Planet X even a cheapie carbon Dolan was loads stiffer!
  • diamonddogdiamonddog Posts: 3,351
    Not IME or others I know that have them, no more flexy than my other far more expensive bike.
  • MatthewfalleMatthewfalle Posts: 17,571
    Agree - never heard a bad word about them. Cranks etc all still attached ok?
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • deswellerdesweller Posts: 5,271
    Sounds like some sort of location issue. I would check for bearing play; wheels, crankshaft bearings, pedals, headset. I know the sensation is from the back, but you can get some misleading messages from the frame if there's lots of play where there shouldn't be.
    - - - - - - - - - -
    On Strava.{/url}
  • natrixnatrix Posts: 1,111
    desweller wrote:
    Sounds like some sort of location issue. I would check for bearing play; wheels, crankshaft bearings, pedals, headset. I know the sensation is from the back, but you can get some misleading messages from the frame if there's lots of play where there shouldn't be.

    Agreed, go through the 'm' check http://www.cyclinginstructor.com/Bicycle_m_check checking bearings for play and that all bolts are tight.
    ~~~~~~Sustrans - Join the Movement~~~~~~
  • I think if there's any issue with these framesets that has merit it's the slightly noodly tracking, which is a fork issue rather than at the rear end. So it sounds like something is wrong. I write as a former owner.
  • bondurant wrote:
    slightly noodly tracking, which is a fork issue rather than at the rear end.

    Yes! I went for a short ride the other night and I did think to myself "it's the steering".

    Tell me more about "noodly tracking" and how to resolve!
  • Manc33Manc33 Posts: 2,157
    My PX is flexy around the BB. Over rough roads you can get a "boing" out of the rear end over bad bumps or, some weird rhythm of bumps. No metal framed bike ever did that lol.

    I might even try to build up a cheap FS MTB for "comfort" rides. :oops:
  • diamonddogdiamonddog Posts: 3,351
    Manc33 wrote:
    My PX is flexy around the BB. Over rough roads you can get a "boing" out of the rear end over bad bumps or, some weird rhythm of bumps. No metal framed bike ever did that lol.

    I might even try to build up a cheap FS MTB for "comfort" rides. :oops:
    I thought you had a Holdsworth Stelvio or Trentino from PX not a Pro Carbon.
  • diamonddogdiamonddog Posts: 3,351
    bondurant wrote:
    slightly noodly tracking, which is a fork issue rather than at the rear end.

    Yes! I went for a short ride the other night and I did think to myself "it's the steering".

    Tell me more about "noodly tracking" and how to resolve!
    The more you ride it the more you get used to it, eventually it feels normal and TBH I don't even notice it now. I fitted a slightly longer stem as I needed one and it didn't seem quite so twitchy on the front end but that could be the fact I am just used to how it rides.
  • rafletcherrafletcher Posts: 1,391
    bondurant wrote:
    slightly noodly tracking, which is a fork issue rather than at the rear end.

    Yes! I went for a short ride the other night and I did think to myself "it's the steering".

    Tell me more about "noodly tracking" and how to resolve!

    Fit a stiffer fork, which is what I did to my old PX carbon frame.

    I used a Deda Black Fin..

    http://www.ribblecycles.co.uk/sp/road-t ... edaforr600
  • diamonddog wrote:
    bondurant wrote:
    slightly noodly tracking, which is a fork issue rather than at the rear end.

    Yes! I went for a short ride the other night and I did think to myself "it's the steering".

    Tell me more about "noodly tracking" and how to resolve!
    The more you ride it the more you get used to it, eventually it feels normal and TBH I don't even notice it now. I fitted a slightly longer stem as I needed one and it didn't seem quite so twitchy on the front end but that could be the fact I am just used to how it rides.

    Thanks.

    I did spec a 90mm stem as opposed to the 100mm on their standard build, as I have a short reach. However, given that the bars are compact anyway, now I've ridden the bike I could do with a longer stem. This would improve the handling I'm sure.

    And yes - I'm getting used to it. Time will tell whether I can live with the wobble.
  • rafletcher wrote:
    bondurant wrote:
    slightly noodly tracking, which is a fork issue rather than at the rear end.

    Yes! I went for a short ride the other night and I did think to myself "it's the steering".

    Tell me more about "noodly tracking" and how to resolve!

    Fit a stiffer fork, which is what I did to my old PX carbon frame.

    I used a Deda Black Fin..

    http://www.ribblecycles.co.uk/sp/road-t ... edaforr600

    That's great - thanks. Over time, if I really can't live with the "wobble", I'll do this.

    Basically I'm satisfied now that there is nothing mechanically or structurally wrong with the bike. It's just the characteristic of the ride, which I can choose to live with or change.

    Thanks everybody.
  • I've read about others that have reduced their spacer stack to stiffen things up, but that may not be an option as it could compromise your fit of course. Could try flipping your stem to help keep things close to what suits.
  • ravey1981ravey1981 Posts: 1,111
    Never had a problem with mine and I've taken it as quick as dare on the descents... I'm on a medium frame with stock forks, 110mm stem and 25mm of headset spacers, stem in the downward position (as it should be)
  • Manc33Manc33 Posts: 2,157
    diamonddog wrote:
    Manc33 wrote:
    I thought you had a Holdsworth Stelvio or Trentino from PX not a Pro Carbon.

    I have but its the same shop, the same frame material and similar pricing.
  • deswellerdesweller Posts: 5,271
    Manc33 wrote:
    diamonddog wrote:
    Manc33 wrote:
    I thought you had a Holdsworth Stelvio or Trentino from PX not a Pro Carbon.

    I have but its the same shop, the same frame material and similar pricing.

    PX like to pick up end-of-line and liquidation stock. Hence the Holdsworth and SAB frames.

    They did also memorably make a big song and dance about picking up Jimmy Savile's ex-race bikes after he died, then went strangely quiet about it when news of his midemeanours broke!
    - - - - - - - - - -
    On Strava.{/url}
  • Manc33Manc33 Posts: 2,157
    Some sicko out there will want to buy Jimmy Savile's old bikes. Seen that documentary on YouTube about him being a wizard? Its something you'd laugh at, but should we really be laughing?! How come everyone hated and loved him at the same time? The guy was an expert hypnotist, which explains why so many victims won't ever come forward. Also he was one of the only people to be able to waltz in and out of Buckingham Palace without security checks being done.

    In fact as far as I know he was the only person not a member of the Royal family allowed to do that!

    You have to wonder then, who was this guy? He seemed pretty bloody high up in the scheme of things to me.

    He was some sort of expert con artist, but he was a wizard man I know it, stuff like "now then now then" well you can't have now and then at the same time. Again he is just confusing you. Its the subtlety of it that makes people universally say "Oh come on, a wizard, don't be silly" even though all the evidence is there.

    Sorry I know that doesn't tie into Planet-X bikes but I didn't mention Jimmy Savile first. :P If someone mentions him, I have to say something.

    Who next though, Noel Edmonds? Cliff Richards? Wogan? Phillip Schofield?
  • ravey1981ravey1981 Posts: 1,111
    :shock:
  • if it has replaceable dropouts, I would also check those are tight. Would suspect they would make clunking noise rather than vagueness, but worth checking anyway.
  • bompingtonbompington Posts: 7,028
    Manc33 wrote:
    ...get the tinfoil hat on...
    I suspect that Savile was one of those lizards too.
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