denada

after putting a new front fender on my '19 trek fx 4, it seems like there is more space between where the fork meets the main frame. i think this happened as i was tightening the screw that attaches the top of the fender to the fork (in second pic). loosening the screw doesn't do anything and i don't think i made it very tight in the first place. any ideas? i kinda wanna take it into the shop because if my fork came off while riding i would die or worse.

thanks

dsbrantjr

I seriously doubt that inserting that screw into the back of the fork had anything to to with the gap between fork and head tube. I suspect that you just noticed the gap.
Lock your front brake and push the bike back and forth with the front wheel on the ground. If there is no play in the fork you shouldn't have anything to be concerned about. If there is play you will need to adjust the headset: https://www.sheldonbrown.com/headsets.html#threadless (assumes a threadless headset which is likely)

joeruge

My first impression from looking at the photos is that you're imagining something. But, I'll take you at your word that there is more space. If that is true, in my mind there is only two ways for this to happen; 1) your stem somehow slipped upward, no longer compressing the the headset bearings. This would mean that the stem wasn't sufficiently tightened in the first place - a very dangerous situation. If there is now more space, you should notice some movement in the fork when you hold the front brake and rock the bike back and forth against the ground. By placing you finger at the junction of the fork and frame you will be able to feel even very small movements, indicating that you have to release the stem and tighten down on the cap bolt to specified torque and re-tighten the stem to compress the bearings. Make sure the stem is proud of the steering tube by about 3-4mm before you start tightening down the cap bolt. Recheck after doing the first compression if it's close. Most caps have a a ridge a couple of millimeters deep to allow them to center in the stem. I recently got a new bike from a dealer and after doing the above test, i noticed that, because of this ridge, the cap came to rest on the steering tube and was not sufficiently compressing the headset. A 3mm spacer fixed that.

Or, 2) for some reason your steering tube slipped out of the fork crown when you put the bolt in to hold the fender on. (maybe putting the bolt in pushed the steering tube around?) This seems extremely unlikely, but if this is the case it would be very bad. And if this is what happened - you're lucky to discover it this way!

If putting the fender bolt on caused this new situation, something is wrong and you probably should take it back to the shop to get it checked out.

denada

no play. looking at pics of the bike online there is a little gap.just seems bigger than i remember it.

yeah i didn't made any sense to me how that screw could affect that space since i can see with a flashlight right where it goes (no where, just into the hollow space in the top of the fork).

thanks.

denada

yeah again i can't notice any play, but is hard to tell because when you push the bike back and forth it of course the whole bike rocks a little bit. i might take it in just to compare it to another fx 4 they have on the floor. while i'm there they'd wander over and ask whats up and i could ask. if there is something wrong, all those fixes are beyond me. putting fenders on was super easy; adjusting the stem might be beyond my skillset.

denada

took it in. bike shop say it's normal. you all say it's normal. still don't feel 100 percent about it, but i guess it's normal. would there be any early warning signs if it wasn't? or when my face hits the pavement will i know?

if anyone else with the same bike would take a pic of the gap on theirs, i'd love to see. would put my worried mind at ease.

Andrew R Stewart 

denda- You need to meet my wife. She also often doesn't believe what I tell her is correct. Andy

Bill Kapaun

Did you look at any similar bikes to compare?

denada

^yes. they all had gaps. same size as mine? i don't know. mine was back at the service station for the 15 seconds i took to look.

if her frontal lobes depend on your opinion, in understand her skepticism.