Squirrel Like Front End

[Mr_Price]

I'm busy tweaking the suspension on my Trek Rail. It came with a Zeb Select+

The damper was completely locked, wouldn't open or close. I couldn't find a new RockShox damper so took the plunge and got a Push HC97.

It was 160mm stock but always sat at 150mm. So I put a 170mm air spring in while I had the fork open. This raised the "bottom bracket" by 10mm so I decided to try the bike in the "low" (mono link) setting which put the "BB" back to my normal height. I am aware I have made the bike super slack.

I've only had two rides so far on it and it's absolutely night and day different. So good. A little more tuning needed but really happy with what I did. The proof was in my Strava times.

The last 100m of my ride is smooth tarmac and I was really over steering when I noticed how reactive the wheel now felt and not in a good way. Like a squirrel in a washing machine. To be clear, it could have been that I was not weighted over the front wheel.

I have a dangerously limited knowledge of contact patch and "cast," as I procrastinate at my desk before I can ride again, I'm wondering if the change in HA made the bike feel this way.

I'm not going to make any drastic changes again straight away. The obvious one is try the bike back in "high" setting and steepen the HA again.

Anyone got any thoughts on that? It might have been like that before and I just didn't notice.

@Rob Rides EMTB went back from 170mm to 160mm on his Zeb. I wondered why?

 

[Mteam]

None of what you have done should result in oversteering, assuming you put it all back together correctly.

You haven't by some chance put the fork lowers on backwards have you? That would make it feel awful.

Have you got a photo of the bike now?

 

[Gary]

Mtb tyres at super low pressures and in super soft rubber compounds can behave like this on tarmac.

 

[Mr_Price]

None of what you have done should result in oversteering, assuming you put it all back together correctly.

You haven't by some chance put the fork lowers on backwards have you? That would make it feel awful.

Have you got a photo of the bike now?

Photo is coming soon. Couple of more tweaks!! I did have to swap the disc brake over... would that count???

 

[Mr_Price]

Mtb tyres at super low pressures and in super soft rubber compounds can behave like this on tarmac.

Ohhhhh!! I like that! 4 rides ago I went to Cushcores. This ride was my lowest PSI yet, went down to 18!! Cheers Gary, that might be it.

I was wondering if the new "contact" patch of the tyre had been changed which can apparently impact steering cast or something.

 

[Gary]

You're asking about "trail"
Most riders barely actually notice much difference in handling at all when they slacken out a bikes steering by fitting a new headset, bushings or increasing fork travel. Or altering "trail" by swapping the entire fork for an offset a whole 4mm shorter.
They just like to go on and on about how amazing their bike now is after spending money changing something. As mentioned above the changes you've made to the fork wouldn't have anywhere near as dramatic an effect to your bikes handling as you're describing.