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10

To crudely simplify things, a triathlon/TT bike position is much the same as a road position, but basically "rotated forward", so your arms rest atop the very-low-set bars. A consequence of this is, the seat ends up further forward. (source) Using Chris Froome's TT position as an example, noting the hip position versus the bottom-bracket position: ...


7

There are seatpost shims available for a few dollars. You should get them easily in your local shop or online. I use an aluminum shim in one of my bikes with exactly the dimensions you need, it works flawlessly and looks very clean. I got it for about 3.50 € (5$).


6

Any frame can support a range of rider sizes by adjusting (among other things) the seat post and stem. However, as you might suspect, there are compromises to be made. And, there are limits to how big of a rider can fit on a given frame. I'll explain a bit more below to illustrate these points. You can adjust the seat post by making it higher (may ...


5

Triathlon bikes are about one thing, and one thing only. Aerodynamics. Dan Empfield, the creator of the Quintana Roo brand, recognized this early on. Cervelo came along soon after, and their designs basically changed how time trial bikes are viewed, with their breakthrough design of the P3 in 2001 (Company history here.) This P3 design evolved, and there ...


5

There isn't always one size frame which fits a person well in a given model line of bikes (there may be 2 or more - probably 2 if someones on the border of sizes). In some cases, you can get multiple models to fit by swapping out stems and seatposts and saddle and handlebar adjustments or swaps. However, this is highly dependent on the particular model of ...


5

Pull the post and hold it next to the seat tube to see how far it goes in. If it does not go in far enough to be into the seat tube below the top tube you are putting a LOT of stress on the top of the seat tube. Believe that maximum mark on the seat post. A seat post is not that expensive to risk damaging a frame. This is just one (not cheap) seat post ...


3

An up-down movement is perfectly fine – that's what suspension seat posts are designed for! For the side movement it's a bit more complicated. A suspension seat post is basically two tubes sliding into each other with some suspension mechanism. This requires two things: the tubes need a little clearance to move within each other and they need a mechanism ...


3

(this is more of a supplemental answer to Pete's one) The answer is somewhat different if you already have back pain vs if you don't. Simply, if you already have pain it's much easier to make it worse, but if you don't an upright bike is fairly unlikely to cause it. The main factor is likely to be how far forward you lean while stilling on the bike, with a ...


3

The number of comments to your question is becoming quite large, so I thought I'd roll my comments up into an answer (of sorts). You ask whether the seat postures could cause back pains, and whilst I have no specialist knowledge in this area, I'd have to say from a purely empirical viewpoint that the answer must be "no". A lot of people ride a lot of miles ...


3

Penetrating oil (Liquid Wrench). It may take a few days as it needs to work its way down. Or it may free it up in a few minutes. The risk you take with a lot of force with a pipe wrench is you bend the bike or brake off the post or get the post out of round. You should grease the seatpost to help prevent this. If you don't bend the post then I ...


3

What are you are tying to achieve? Is the bike too long for you? Bending a seatpost will weaken it. You can buy offset seatpost. Most people use them to move the seat back I cannot see why you could not use it to move the seat forward. But you are not going to pick up two inches. Two inches would put you almost straight over the pedals - are you sure ...


2

Get 2 spanners that fit. Hold the bolts on both sides with the spanners and turn any one side to remove easily. To put it back alternately rotate each side 1 or 2 turns. Be careful with the tightness, if it's slightly loose you'll experience slight play in the saddle and the micro adjust assembly will soon get worn out. Too tight and you might deform your ...


2

I can't find any other posts, unless they are boutique and don't sell online. However it looks like Thomson, Fox, and Crank Brothers all have posts with 125mm which seems to be the next step down. From there, a few have 110mm and the rest are at 100mm.


2

Nearly. The diameter does need to match, but you also need to consider the materials -- metal needs grease, carbon fiber doesn't, so combining the materials in the frame and seatpost shouldn't be done. Also, note that different seat posts have different levels of adjustability - saddle angle and position, height (which connects to minimum/maximum insertion ...


2

According to Sheldon Brown's site, there are 1987 Peugot Versailles with 23.8mm seatposts (and I have heard of other french bikes with 23.8 mm seatposts, so it is probable that you've measured correctly). The measurement should be done with calipers or a seat post measuring tool, though. One solution I've heard of is buying a 24 mm seatpost and sanding it ...


2

Yes, you can damage the frame if the seat post is too short. I have personally seen someone sit down on an overextended seatpost and fall off the bike as the seat post was wrenched out of the seat tube. The collar went flying and the top of his seat tube was mangled. His frame was titanium and he was able to bend it back. You probably wouldn't be able to ...


1

Yes, it's ok and to be expected. Even expensive dropper posts, which work via the same basic principles as telescoping suspension seatposts, have a bit of side to side movement. For the suspension seatposts, just ensure that the collar at the top of the stationary (outer) portion of the seatpost is firmly hand tight.


1

I have used a couple of these seats over the years - the ones I had did have some movement - noticeable when riding. Although not ideal, you do get used to it. It comes down to cost - it would be more expensive to precision manufacture them with no movement, but at some point people would stop buying, and another point, might as well buy a full suspension ...


1

I'm not sure about structural problems, but the bigger problem is that bending it two inches forward will likely throw off the angle of the mounting clamp more than you can overcome by readjusting it. You'd probably want to put a z-bend in it: two inches forward and then two inches back to level off the mounting clamp. And you don't have enough seatpost to ...


1

I had the same problem. I used vise grips and clamped down very tightly. I hit the vice grips with a hammer, repeatedly. This will jar it loose- it took me about 15 minutes. The bad news: when I did this with my bike, it left deep scratches on the post (the vice grips will come loose and need to be clamped down again).


1

You have to make sure that you're actually tightening the quick release down - it should leave an imprint on your hand when you close it down. If you put a product like frame saver in the frame, you'll need to tighten it down extra since that makes seat posts super slippery. See this thread as well.


1

Traveling long distances on a bike seat is almost always going to be uncomfortable when your body isn't used to it. Give it time. But also, consider taking your bike with you to have a professional make sure the seat and the bike fit you. Some people have managed to permanently damage their blood vessels ( I won't go into detail ) by improperly sitting on a ...


1

In addition to aerodynamics, not yet mentioned is the benefit to your running off the bike. By changing the seat angle, you use your muscles differently and can run faster off the bike than a more traditional seat post angle. As noted in this article, test subjects were about 5 minutes faster in a 40k/10k Brick (stationary bike/treadmill run). There was ...


1

I found that the GMC Denali 21 speed uses an HL Aluminum Micro Adjust 27.2 X 300mm, so I assume your seat is very similar to those found on the Denali. In this case you will need a small crescent wrench that will fit between the guts and the side of the saddle. Some bolts are square and will stay put when loosing the nuts, but some are not and might require ...


1

I found this video, and decided to do like him. He puts some kind of extension on his power drill, and on the end he puts a tiny 1 inch steel wire wheel. He drives the wheel up and down in the seat tube for some time until the rust is gone. I tried hard but never found a wirewheel this small in my country, at least not one that would fit on an extension. ...



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