alexbike

I'm a bit embarrassed to ask this question because it seems like it should be a no-brainer, however I did a ton of research and I can't figure it out. I probably don't use the right vocabulary hence no good result come out.

So I recently purchased a new Bianchi Infinito XE and I am trying to swap the original saddle for my own. On my previous bike both bolts holding the seat clamp together are down facing, i.e. accessible from below the saddle. On the new Bianchi one of the two bolts is facing upward and only accessible through the saddle cutout. This is fine when removing the original saddle however my saddle does not have a cutout, so I have no way of tightening that bolt. There is not enough clearance to get an Allen wrench in there. There is a knob-like thing on the front bolt, but I couldn't dream to tighten it to 1 Nm, let alone the 8-10 Nm recommended.

I would go and ask the LBS but they are so busy right now they can't help anyone (some are downright dismissive when asking for help).

Any help, suggestion or reading material would be appreciated. Reading up I learned about offset seatposts, which this Bianchi Reparto Corse seems to be, but I can't seem to find examples that are bolted from the top and bottom...

PS: I have photos but new account can't post pictures.

Thanks

SoSmellyAir

I understand what you are trying to describe. The Cannondale C3 seat post that originally came with my bike has the same design. The front bolt can only be tightened from the top by tool (through the saddle cut out) or by hand (via the knob). The theory is that you tighten it past the desired angle by hand (although I used a pair of needle nose pliers), and then tighten the rear bolt to the specified torque and the forces acting on both bolts would more or less balance out. I hated that and bought another seat post in which the heads of both bolts point at the ground.

alexbike

That's an interesting design choice. Thanks for the insight, I will try to figure out the size of the seat post and swap it out. Looks like it's slightly D shaped so hopefully that's standard and I can find something compatible.

Meanwhile I will try this, if I'm lucky the saddle won't slip when I ride.

SoSmellyAir

That design "works" in that the saddle does not slip if the bolts are tightened properly. It is just a huge pain to make fine angle and/or fore/aft adjustments.

I was shopping an Infinito CV and the seat post is definitely a feature in the "con" column, and that was before I even realized (from your post above) that it is not a round post.

Motorazr

I only use saddles with a cutout (because I need that) but I recently had to try what you're describing (tighten front/downward bolt first by hand ) and that worked fine - minor hassle. I'd rather find a new saddle than to replace a bespoke D-shaped seatpost. On the other hand, yeah, having a proprietary seat tube shape is a negative for me too in any frame design.

SoSmellyAir

I can live with its cross-sectional shape, but the Infinito seat post has (1) that whack design we discussed above; AND (2) the head can be removed and installed backwards to change the offset, which just seems unnecessarily complicated and fragile for my 200 lbs. Look at the photo on the left at the bottom of this article:

Bianchi Infinito CV Disc in review | GRAN FONDO Cycling Magazine (granfondo-cycling.com)

CliffordK

@alexbike's album:
https://www.bikeforums.net/g/user/539489
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CliffordK

What a pain. The vintage Campagnolo seat posts also have a bolt on top (long before cutouts existed). But, one could usually squeeze a wrench up there if one persisted. Worse if the vintage seats have full sides on them.

Many of us have a few custom tools in our toolbox made for a one-time use like this.

What I'd probably do is take an Allen Wrench and cut off a 3/8" to 1/2" piece. Just long enough to fit into the hole and stick up a bit.

Now take a 12 point box-end (combination) wrench and tighten the stub.

This will depend a bit on the size, although I am finding a couple of mini wrench sets including "SPEEDWOX Small Metric Wrenches". The quality doesn't look great, but hopefully it is good enough.

In some cases there might be a reason to modify the handle on a wrench, by cutting, bending, or welding a cheater on.

Gresp15C

One idea is to replace the allen head bolt with a hex head bolt and washer so you can access it with a regular box wrench. Or, a stud and a nut.

dsbrantjr

I find that inexpensive tools from Harbor Freight excel for this type of modification; I wouldn't dream of taking a torch, grinder or welder to any of my Snap-On or vintage Craftsman tools, but HF cheapies or garage sale finds, bring 'em on!.

CliffordK

Another option along the same line of thought above...

get a 1/4" to whatever Allen head you have. Very common... HF has a zillion "security set" that would have it.

As above, cut either the 1/4" end, or the Allen end to meet your needs.

Then there should be a good selection of 1/4" wrenches that you could use.

For example, find a 1/4" ratcheting box end wrench. There are some that are offset, some with flex heads.

CliffordK

It would work. But, in the photo above, the head is probably recessed. There is a long precision shoulder, and whatever threads.

I suppose the precision of the grind depends on whether the bolt just provides tension, or also controls lateral movement of the saddle.

You probably won't save a lot of space over using some kind of allen wrench stub + wrench.

alexbike

Thanks for linking my pictures CliffordK and thanks everyone for the advice. I think I'll start by trying the fiddly method of tightening the front bolt with my fingers and if it doesn't hold I'll find a cheap Allen 5mm that I can hack. I just really need to get that one off my bike because it's very uncomfortable. Also I don't necessarily want to change my saddle because I'm comfortable on the one I have and I don't know the first thing about finding a saddle that suits me.

jon c. 

I have one of those and it is possible. You just need to find a wrench with a very small L end. It was a struggle, but it did finally get the thing off.

Replaced the ancient unicantor with a cutout saddle so there was no problem.

alexbike

I didn't realize it was proprietary when I read the reviews it was mentioned that it's a bit too big (so stiffer than it needs to be). These days though if you need a bike you can't be too picky given the bike and part shortage going on. I'll just hope that in the future if I need to replace it these parts still exist, would be a shame to have an unusable bike because of an odd shape seat post.

Kimmo

This is a big fat meh - you don't need special tools, just use the thumbwheel and a bit of trial and error to set your angle.