yongxingfreesty

is it bad to constantly take a seatpost off 1 bike and move to another bike?
i want to share same seatpost/saddle between my two bianchis but not sure if this will damage anything or make the screw loose, etc.

thanks everyone

mconlonx

Should not lead to damage... as long as you're consistent with the seat bolt torque on each bike.

Do they share the same geometry, i.e. seatpost angle? If not, there could be minute differences in fit you probably won't even notice.

fietsbob

Seat tube Bore Smooth So No scratches to be made in the seat post each time its removed abd replaced ?


Not all seat tubes are done accurately to the hundredth of a MM, so even the tenth has a variance .. and they sell in 2 tenths steps ..

yongxingfreesty

i want to swap out my current bars/stem on bianchi pista for some thomsons so I can have thomson everything like my MTB.
then I want to use the same thomson setback seatpost on my bianchi mtb for the pista.

i dont know about geometry. the pista is 53cm and the mtb is 17.5. i am 5 ft 8 inch. i ride recreationally anyway so nothing serious.

cyccommute 

Constantly loosening and tightening the pinch bolt could fatigue the metal...think bending a coat hanger. It might take a while, however. Fatiguing the metal would be worse if you just "guess" at the bolt torque. If the pinch bolt is on a seat collar and separate from the frame, you aren't likely to damage the frame at all. You might wear out the seat collar but those are cheap.

yongxingfreesty

the seatpost goes in real smooth into the mtb, didnt try the pista yet but i know its a 27.2 size as well.
i guess ill just fork out $50 and buy a new seat tube eventually lol

yongxingfreesty

this is what i wanted to know and im afraid of this happening. thanks for chiming in everyone. i googled to see if this question was asked and found nothing so i started this thread.
appreciate all the feedback guys! =)

mconlonx

MTB vs. Pista vs. road bike geometry at the seatpost is very, very different. Buy a dedicated seatpost and saddle for each bike. Do not plan in switching out between bikes.

Phil_gretz

I agree with this. It's not really as practical as it first might appear. Your fit will be wrong or at least compromised on one of the. Why?

FBinNY 

If the frames have integral ears for the pinch bolt, I'd avoid going back and forth too often. These ears are known to fail, either by cracking or by bending until they touch in the back. How much this is a possible problem depends on the seat lug/ear construction and how tight you need to clamp to hold the post.

OTOH- if the frames use replaceable bands for the saddle, the worst that can happen is you break a screw or band, and it's no big deal. Keep in mind that folding bike ownere open and close seat post clamps daily as do many mountain bike riders. So obviously it's possible to do so without consequences.

How it works out for you depends on the specific frame/seat lug details and the fit of the post. If all is right, I'll venture that you can replace posts tens of thousands of times before it's an issue.

rmfnla

My first thought as well, although perhaps using a QR might help if you really want to do it...

Drew Eckhardt 

I wouldn't try. Even a one degree difference in angle is noticeable and you'll probably want a different fore-aft position on the two bikes. Getting those things just right is a royal PITA with measurement difficult due to the saddle's curves.

i dont know about geometry. the pista is 53cm and the mtb is 17.5. i am 5 ft 8 inch. i ride recreationally anyway so nothing serious.



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rmfnla

When I think of how many micro-adjustments I have made getting my position "just right" the idea of changing anything makes me cringe...

CliffordK

If you have a seat/seatpost that you like, it wouldn't hurt to try it on the other bike. They are made to be removed in 99.99% of the bikes... (there are those few "mast" type of bikes).

Keep in mind that set tube angles can change from bike to bike, which would affect both the seat angle and setback.

I agree, one or two tests should be more than enough seat swapping.

However, I think the reason QRs were in used in MTBs (other than lazy shop mechanics) is that some MTB riders like to frequently adjust their seats. So, if an MTB rider can adjust the seat a couple of times a day, a road bike rider surely can do it a few times.

Good point on different seat stay and pinch designs.

cyccommute 

It's hard to see in yongxingfreesty's pictures but it looks to me like the mountain bike has a replaceable seat collar while the Pista's is welded into place. I've only seen a couple of Pistas but I think that is the case for all of them.

FBinNY 

As I said, the advantage of a band is that breaking it costs a few bucks vs. a new frame if an integral ear breaks. But not all integral ears are created equal, and some are very unlikely to fail even id clamped thousands of times, and others barely survive being tightened once. So as with so many things the devil is in the details.

OTOH- others raised valid points about variance in angle, and frame geometry which may cause the Op to abandon his idea soon enough.

hueyhoolihan

IME, it became tiresome long before it became a problem.

fietsbob

the bent for set back seat post (in MTB) may not go in to the other frame because of the bend .. buy duplicate saddle & a different seatpost.