LIGHTWEIGHT 25.4mm BICYCLE ALLOY SEATPOST SADDLE STEM 300mm LONG

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One (precise) measurement is often better than a thousand expert opinions”– author’s expert opinion. 🙂

Measuring a seat tube diameter is often necessary before purchasing, or changing the seatpost. How should one do that? Three methods will be explained here, but one can always be creative. 🙂 Finally, the suggestion that a less than 0.2mm difference in seat post diameter would make the post too small to fit snugly in the seat tube is laughable. Any halfway decent clamp should easily account for 1mm error or more. It might take time to source the particular needed combination, but Google and local bicycle shops are a way to go.If the current seatpost is a well-fitting one, and it is 30.9 mm, I’d look for a 30.9 mm dropper seatpost. Standard outer diameter dimensions were important so that derailleur clamps etc. could be made in exact matching sizes (derailleur clamp inner diameter needs to match the seat tube’s outer diameter). Higher quality frames are usually made with thinned down tube walls to reduce the weight of the frame. This meant that a wider seatpost diameter usually meant a higher quality (and lighter) frame. So high-quality frames with 1 1/8″ seat tubes usually had 27.2 mm wide seatposts. Also, at several parts you refer to Vernier calipers, but none of your images have Vernier calipers. You show just plain old digital calipers that don’t have a Vernier scale. Look up what a Vernier caliper actually is. Most seatposts are a lot wider than 15.75 mm. Machining the sidewalls down would weaken them tremendously in my opinion. It is easiest to measure the existing seatpost outer diameter – if there is a well-fitting seatpost on the bike. In case there’s no seatpost, we would need to measure the seat-tube’s inner diameter (using calipers, and minding to measure the tube itself, not the seat-clamp’s inner diameter).

Measuring the circumference of the post and dividing by Pi is a good method. There are even circumference tape measures to do it.Ritchey company used to be quite good, but I haven’t bought anything from them for a while – and they don’t seem to be making any 25.4 mm sized ones. However, if seatpost is to be extended by more than some 20 centimetres, I would look for a well matching seatpost, not use an adapter – because adapters are usually not very deep (long), so won’t offer much of a support for the seatpost. Hope I’ve explained well what I mean. Painting, or chrome plating could also be done – just take it into account when machining to not have the new seatpost too narrow, or too wide. Having said that: going a bit too narrow can be fixed with some DIY shims from Coca-Cola cans (that’s one thing that drink is good for 🙂 ),

It can be seen from picture 2 that the seatpost is marked as 31.6 mm wide (and 410 mm long), while it really measures only 31.42 mm. This means the seatpost will probably not fit firmly enough to stay in place inside a seat tube meant for 31.6 mm wide seatposts. Always measure! 🙂 The same brand is also responsible for bringing dropper seatposts to the road audience: the Specialized Diverge, in its S-Works form, features a 'Command' dropper post. The theory is that those riding the adventure road bike, like mountain bikers, will want to be able to adjust their saddle height to suit the terrain.Rear lights can be a bit of an issue when it comes to an aero post, although many brands now offer adaptors that allow for the shape. Ok, so it's not cheap - but Canyon's VCLS seatpost is designed to offer superior vertical flex/compliance whilst maintaining lateral stiffness. A floating seat clamp means that saddle tilt is not affected by the comfort providing flexion. It works a treat. You get two upper clamps so you can run 7x9mm carbon rails or 7mm round alloy rails. The lower clamp can be reversed depending on your desired saddle angle in relation to your frame’s geometry. Once the saddle rails have been inserted in between these two clamps it's just a case of tightening the titanium bolts with a 4mm allen key. Micro adjustments are possible once the saddle is pretty much in place: tightening the front bolt will lower the saddle, while tightening the rear will raise it.

I’ll be honest, when it came to Enve, there was a time when I wondered what all the fuss was about. Then I rode a set of its gravel wheels. My expectations of its products were forever raised by this syrupy smooth set of hoops. I had high demands for the seatpost. If you use a carbon seatpost, make sure to fit it using a thin layer of carbon paste as this stops it slipping. Pay attention to the quoted torque at which you should tighten the bolt - overdoing it can cause it to snap. If you don't own a torque wrench already, here you can find our recommendations for the best torque wrenches for bikes. Seatpost diameters are usually a multiple of 0.2 mm (but not always, as tables 1 and 2 show). If a measured value differs and most closely matches a value that is not a multiple of 0.2, there is a high probability that the closest multiple of 0.2 mm size will fit. For example, a measured 25.5 will most probably fit a 25.4 mm wide (nominal and measured width) seatpost. A rule of thumb is that the widest post that slides in without being forced (other than pushing or twisting by hand) is the right one. If it drops in, with play, before the pinch bolt is tightened, the seatpost is probably too narrow. There's plenty more options available - just make sure you opt for one in the correct diameter and with sufficient length for your riding position. Seatposts: All you need to knowMethod 1: if the frame already has a mounted matching seatpost – one that attaches firmly enough so it doesn’t slide, while being narrow enough to allow easy mounting and dismounting – then it is sufficient to measure its outer diameter, as was explained above in the section –“How to measure the seatpost diameter?”.