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Difficult Handling 29er

pma73pma73 Posts: 116
edited September 2019 in MTB workshop & tech
Hello

I've got a cube reaction 29er xc and have just switched to a rigid carbon 3t fork.

First ride last night on the new fork, on road with 60psi speed king rs tyres.

On the road I found the front wheel was tracking in line and was difficult to adjust direction at anything above around 15 mph. Also when out of the saddle climbing on road it was difficult to adjust direction with the bike travel affected alot by the climbing action.

The headset was over tightened initially but the bars turn with ease whilst static.

I'm running 720mm flat carbon bars, 80mm stem and quite alot if steerer tube still as I need to get it cut.

I'm puzzled by the really bad handling.

could it be:

60psi speed kings on tarmac?
narrow bars?
over tightened top cap?
long steerer?
something else or all of the above?

any advice would be gratefully received.

thanks.

Posts

  • robertpbrobertpb Posts: 1,866
    Is your new fork sag compensated, if not it's changed the geometry. Also if you are only riding on the road 60psi is way too much even for that, I'd start at 40psi and go up and down 5psi to find out what works, also put 3-5psi less in the front.
    Now where's that "Get Out of Crash Free Card"
  • pma73pma73 Posts: 116
    SAG only relates to suspension forks right? I've switched to a carbon fork.
  • figbatfigbat Posts: 680
    Yes, but have you got the axle-to-crown length on the new fork to match the sagged measurement on the old fork or the fully-extended length?
    Cube Reaction GTC Pro 29 for the lumpy stuff
    Cannondale Synapse alloy with 'guards for the winter roads
    Fuji Altamira 2.7 for the summer roads
    Trek 830 Mountain Track frame turned into a gravel bike - for anywhere & everywhere
  • Likely you have a short axle to.crown length which has made the head tu r steeper. Also if you have a fork with shorter trail that's makes everything more twitchy. 60 psi in speed kings is alot ut thats more the reason for not being able to control direction. Modern mtbs dont take to steeper head angles. To use a short axle to crown fork you need an older bike.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • veronese68veronese68 Posts: 22,991 Lives Here
    Always hard to tell remotely but your description sounds like the headset is too tight. That would make it follow the line it wants making steering difficult. Does it turn completely freely with the front wheel off the ground? It might feel free on the ground but there is still some resistance.
    Forks being too short would make it twitchy, so it would change direction too easily if anything. Too long would make it slow steering.
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