Commuting - Bike Seat lowers only 4 miles into the ride

So before every ride I jack my seat up a couple inches and then 4 miles later it's down 2 inches. Is there any way of tightening this? I ride a Fuji Crosstown
http://thumbnail.image.rakuten.co.jp/@0_mall/spoke-seya/cabinet/fuji/07crosstown30g.jpg

Thanks!

It appears you have an aluminum seat post. This is a common problem with carbon seat posts. In that case one solution is a special grease that has a granular substance in it to provide grip. I solved the problem on my bike by first torquing the seat post clamp to the recommended specs, and second placing a reflector with a clamp-on collar just above the seat post collar. The extra collar has been just enough assist to keep the post from creeping downward. A taillight with a clamp on collar would probably do the job, too.

Looks like you've got a suspension seatpost. Is it locked out? If you remove the seatpost from the frame, underneath there should be a 6mm slot to lockout the suspension.

With that done, I'd make sure you've got the quick release skewer as tight as possible before clamping down, or consider switching to a non-quick release bolt on the seatpost.

Looks like you've got a suspension seatpost. Is it locked out? If you remove the seatpost from the frame, underneath there should be a 6mm slot to lockout the suspension.

With that done, I'd make sure you've got the quick release skewer as tight as possible before clamping down, or consider switching to a non-quick release bolt on the seatpost.

+1

My wife had the same problem on her new Giant Cypress DX. After the second adjustment on a ride I tightened up the quick release skewer so much I thought I was going to put the clamp through my palm just locking it in. Solved the problem.

consider switching to a non-quick release bolt on the seatpost.

Making it harder for someone to walk off with your seat :)

Making it harder for someone to walk off with your seat :)
True, but i put a cable lock through the seat and rear tire just in case. ANyway, i have the exact same frame and components as the original poster, what i do is just tighten the quick release enough. There is still some slippage, but it's about 1-2mm for 25 miles or so. Also make sure yo lift your ass up from the seat when going through bumps and bar road, your ass will feel better and you won't be pushing the seat down.

Just get a non-quick release bolt and tighten it down until it stops happening.

Just get a non-quick release bolt and tighten it down until it stops happening.

+1 My old Trek had a quick release seat post and I had to readjust it once every week or two, depending on how much I rode. On the flip side, a buddy of mine (and his wife) ride Bianchis with suspension seat posts and have used them on a couple of tours without any problem. Just having suspension shouldn't move the seat down the way it sounds like the OP was having problems with, you just might have to set it up a little higher to take the flex into account.

I had the same problem, but this fixed it.

http://aebike.com/page.cfm?action=details&PageID=30&SKU=ST0001


Despite the photo, the clamp is actually really HUGE

I found that by degreasing the post and such also helps.