Trek Speed Concept front end Instability - Gen 3

Triathlon Forum
1

I’ve had a gen 3 speed concept for 2.5 years or so and the last 1.5 years I’ve had a constant feeling on instability / wobbliness in the cockpit. I do have an aftermarket fast TT setup but it’s been problematic for a while. even sitting up with hands on the base bars, it just feels unstable.

FWIW, I’ve been in triathlons for 16 years, have ridden tri bikes for a long time, have better than average handling skills for a triathlete, and am not a total shmuck.

headset bearings are great, everything is torqued to a T, but it’s just wildly unstable. I’ve been dealing with it but with deep race wheels on and cross winds this is extremely exaggerated.

has anyone else had an issue with this? I really don’t recall the first year of riding the bike having this issue. I’ll likely take it to the trek store about 45 minutes away but they’ve looked at it before and said everything seems fine but I’ve ridding bikes enough to know something is most certainly not right.

anybody have anything here? thanks for any thoughts.

2

Haven’t had a similar experience on my sc unfortunately. Sounds like you have ruled out a lot of things. Have you checked your wheel bearings? Tried different wheels, even at the same depth?

Any issues with iso speed?

Crack in the frame? (You would think the shop would find this)

3

I had similar when there was a hidden crack in my frame near the headset. No adjustments would stabilize it. Your lbs can take a look and make sure you don’t have this bad problem that may trash the frame.

4

we talking the infamous “death wobble” or mere instability like when a truck flies by while riding and you lose your line for a few?

Wobbles are usually:

  • loose headset
  • wheel bearings, wheel balance
  • could be the sealant congealed (balance)
  • crack in the steerer tube or fork
  • crack in the seat or chain stays
  • death grip in the bars
  • bike position, too far over the bottom bracket or front axil causing poor weight distribution.
1 Like
5

It’s with any wheelset. Training and Race. So I feel good about eliminating the wheels and tires

6

Everything is torqued properly. Gotta be a crack somewhere

7

Based on everything I’m thinking it’s got to be crack hidden in headset or fork somewhere

8

I’m suspecting crack too. Have to lbs disassemble to headset and look for cracks. If none, the problem should fix with new bearings etc.

The crack in my frame was small, you would have guessed it wouldn’t affect anything but man that bike became scarily unstable but in an inconsistent way so it was hard to tell if there was a real problem or not. But night and day compared to new tt bike or my road bike which convinced me something was wrong. I had 3 lbs incorrectly just swap out bearings which didn’t fix anything before the last one found the crack and said my frame was dead.