pizza_pal

Hi everybody,

I just swapped all my Campy mech from my old aluminum (and two sizes too large) Bianchi onto this 2009 Giant TCR frameset I got for cheap at a swap meet.

I rode it for the first time today and it felt great, although it was apparent that the indexing needs some attention. There was also this kinda chunky rattling sound that I couldn't quite place, I also noticed that my legs were feeling more and more leaden, which I chalked up to a headwind, being off the bike for a month, and running 14 miles yesterday.

But when I got back home and looked over my machine, I was perplexed that my saddle, which was slammed all the way forward (because I'm tiny and ride with an 80mm stem too) was now set back as far as it could go.

I'm just curious how this could happen? The saddle rails were, and still are bolted in there pretty firmly. Like I've done cyclocross and stuff and had my saddle rails get knocked a little loose and this wasn't like that because they're not loose. The frameset didn't come with all the original hardware for the seatpost, so I improvised a little with a 5mm nut.

I'm going to take it into the shop to get a few things fixed up anyways, so I have confidence that this problem will be resolved. But I felt compelled to share this experience because it was just weird, like an alien abduction or something.

Commentary, praise, insults are all welcome.

Edit: backward, not forward

AnkleWork

Why do you ride bikes that are too big for you?

wschruba

A picture is worth a thousand words.

The TCR, for several years now, has come with an aero seatpost with it's own special hardware. Unless you have a saddle with a cutout, you cannot set the top facing bolt to the proper tension in the traditional manner; you need to tighten the top bolt down as far as you can with judicious use of angled pliers/cut down hex key (if it fits), then tighten the bottom bolt to the proper tension (which will, ideally, also tighten the top bolt to the proper tension). It is not a particularly obvious way of doing it, and is not something you get right by doing it once.

Of course, all that assumes you have the correct hardware...we have no idea if what you did was actually sufficient. Ask anyone who has ever had a slipping seatpost, if they thought they made the binder bolt/QR too loose, initially.

Andrew R Stewart 

The usual reason a seat slide rearward is that the post/rails clamp has loosened. The wedge shaped seat between your legs provides the force to make the seat seek the narrowest width between your legs. We see this often at work. One bolt seat post clamps don't get the attention that they often need. Andy

corrado33

My question as well.

The answer to the question is obviously "the clamps weren't tight enough" or "the clamps are bent" or "the hardware you used is wrong and doesn't allow the clamps to clamp tight enough" and now I've argued in a circle.

AnkleWork

Thanks for the clarification. My attention was drawn away by so many tangents, I never figured out what the question is.

pizza_pal

Ok, this explains it - I only finger tightened the top facing nut. I thought this bolt only secured the pitch. It sounds like I probably need the right bottom facing nut too. Fortunately the TCR is ubiquitous enough that it shouldn't be any trouble finding the right hardware.

I ride bikes that are too big because my dad (who is probably in denial about being short) was always repeating some old thing from the 70s about a slightly larger frame being better than a too small frame. I would be better off on a frame with a little less effective top tube length than the small TCR but it's close enough to my fit coordinates, and I have stubby arms so I would be on a short stem regardless of the frame.

Camilo

Finger tight? In other words, it wasn't tight.

I know where that comes from and actually adhere to it myself. Although "bigger" doesn't necessarily mean "too big". And an 80 mm stem is on the short side for sure, but not grossly short, if that's what it takes. Especially if your proportions are odd (you said short arms). I really doubt it affects handling in any meaningful way to anyone but the most sensitive and discerning. People get too hung up on what thngs like stem length "should be". Yea, there's reasons for conventional wisdom on stuff like that, but the reason they make different stems is for people with different proportions.

I can ride a typical 52cm top tube bike or a 54. I have found that I like the 54 with a shorter stem because it's easier to get the handlebars up where I want them, and the overall bikes just feel better to me. But "shorter" in my case means a 90 or 100 mm stem vs a 100 - 110 mm stem. So not really "short". And "standover" works for both, for what that's worth.

It sounds like you're on a budget, mostly a used frame market, and there's absolutely nothing wrong with that. But you might want to try to find the opportunity to try a size smaller top tube frame with a correspondingly longer stem just to see how it feels. You might find that you like it better or you might find that you like the larger frame with the shorter stem better. That would give you some guidance as you move through the used bike market.