How To Measure Seat Tube Length?

How to measure seat tube length – Seat tube measurement. Simon Bromley / Immediate Media Seat tube length is the straight line distance between the centre of the bottom bracket and the top of the seat tube. Again, it’s trickier than it sounds: some bikes like the Trek Madone have a considerable extension of the seat tube above the top tube junction while others use a seatmast, so it’s difficult to compare with an alternative’s dimensions.

How do you measure the length of a seatpost?

To figure out the right size, you first need to find your top tube length. This is the horizontal tube that connects both your seat and your handlebars. It’s generally measured from the center of the bottom bracket to the top of the seat post clamp.

Is frame size seat tube length?

1. The road bike frame size guide – This is your most important consideration. Frame size is related to the seat tube length. For example, a 56cm frame will have a seat tube that is 56cm long. Here’s our definitive road bike frame size guide to help you.

What is the seat tube size?

Diameters – Seatpost diameters generally range from 22 mm to 35 mm in 0.2 mm increments. The most common size is 27.2 mm (1.07 in) for most bikes, especially for the higher-quality models. BMX bikes commonly use 25.4 seatposts. In some modern bikes with thicker alloy or carbon tubing, larger diameters such as 30.9 mm are used.

How do I measure my top tube length?

Top tube length – Top tube length is a key sizing measure – but beware, there’s more than one way to measure a top tube. Immediate Media The most important consideration to make as you decide which frame to go for is the effective top tube length: the distance from the head tube to the seatpost on a bike with a sloping top tube, or simply the length of the top tube on a road bike with traditional geometry.

Are all bike seat posts the same size?

While there are any number of post diameters out there, most modern road and MTB bike frames accept a seatpost of either 27.2mm in diameter (‘standard’), 30.9 or 31.6mm (‘oversize’).

Does seat tube length matter?

Seat tube length doesn’t matter at all for fit. It matters a bit for weight and ride quality, but the geometry of fit depends on the relative position of the bottom bracket, saddle, and the top of the head tube (or the brake hoods, to measure a different way).

Why do pro cyclists ride smaller frames?

Don’t miss a moment from Paris-Roubaix and Unbound Gravel, to the Giro d’Italia, Tour de France, Vuelta a España, and everything in between when you join Outside+, Editor’s Note: VeloNews tech editor Nick Legan is a former ProTour mechanic who most recently wrenched for Team RadioShack at the 2010 Tour de France and elsewhere.

His column appears here every Thursday. You can submit questions to Nick at [email protected], and be sure to check out Nick’s previous columns,Q. Hi Nick, Reading your recent answers got me thinking about tubulars and their overall “place” in riding and racing. I started riding a little over two years ago and immediately fell into it completely.

At almost 45, I feel like I wasted so many years on other athletic pursuits that were so lacking compared to cycling. However, I digress. While I feel like the ride of my Zipp 303 tubulars is akin to skimming along on a cushion of air (which it is literally, but I meant figuratively), one of the real joys I find with tubulars is the process.

People think I’m crazy, but I find the whole effort to carefully apply glue over several days and then get the tire to seat just right before going out to race it a very zen-like experience. I really do feel a connection to the tires and road knowing that the contact I’m making with the road is something I had a part in creating.

I also love knowing that the tires I ride from FMB were painstakingly made by someone who has a vested interest in the experience rather than a clincher spit out by a machine. The last part may be Pollyanna, and I do ride clinchers for most of my training, but to me tubulars provide a connection to my bike that is extremely gratifying and dare I say, spiritual.

1. Cheers, — Ted Culotta A.
2. Ted, I hear you.
3. Tubulars have played such a wonderfully, storied part of cycling’s history and culture.
4. Mounting and riding them shows just how much someone appreciates the finer things in life, even if there is a bit more work involved.
5. Eep calm and carry on, my friend.Q.
6. Nick, I was intrigued by your recent response on tubular roadside flats.

You mentioned you bring along a pre-glued tubular. My question is this, and probably shows my ignorance on tubulars: if it’s pre-glued, does the glue dry, or does the tire stick together when you fold it up, or does the glue simply always stay tacky and you can unfold it without it sticking together? – David Ward A.

1. David, When gluing tubulars, you let the glue dry between layers of application.
2. Only the last layer on the rim is left wet, then the tire is mounted.
3. So a pre-glued tire is dry to the touch.
4. The base tape surfaces will stick together a little bit when they come in contact, but not enough to be a problem.

In fact, when I carry my spare, I roll the tire so that the base tape is protected. You don’t want road grime hitting your base tape. Here’s a great series of photos on the way I was taught to fold a tubular. I use Arundel’s Tubi bag, as I mentioned last week, to keep the tire protected.

What size bike should a 5’9 Man ride?

Road bike sizing chart

Rider Height (feet/inches)	Rider Inseam (inches	Bike Frame Size (centimeters)
5’4′-5’7′	28.5′-30′	52-54 cm
5’6′-5’9′	29.5′-31′	54-56 cm
5’8′-5’11’	30.5′-32′	56-58 cm
5’10’-6’1′	31.5′-33′	58-60 cm

How long should your seatpost be?

Most seat posts have a “minimum” insert of 3 to 4 inches. But this varies with the material and the thickness of the post, and the weight of the rider means the minimum might still be too little. As a tall rider I frequently have my seatposts up to maximum, and have bent several over time, and have fractured one frame.

1. Now I always buy a 450 mm or 500 mm post and almost always reinforce it with an insert tube up the middle.
2. I will not ride a seat post without 5″ of frame insertion.
3. Since you sound like a MTB kind of rider, consider a dropper post rather than chopping ruthlessly through your seat poles with a hacksaw.

These are intended to go at a good height for normal efficient riding, but you can turn the interlock and they slide down ready for low-seat technical riding. I understand you can do it one-handed while rolling too. Once you’re done you can raise the seat again without stopping.

Can I get a longer seat post on my bike?

Pretty much all you can do though is put a longer stem, possibly raise and lower it, use wider handlebars and adjust the saddle angle+ position a bit further back (which may be easier with a different seat post). The biggest things you have to do are get the effective top tube right.

What is CC seat tube?

Seat Tube Length ‘Centre to Centre’ or C-C is the length from bottom bracket centre to the middle of where the top tube meets the seat tube.

Is reach or top tube length more important?

Reach is more constant. Consider a rider who is 6′ tall with two bikes; both bikes have a listed ETT of 610mm, but they have different seat angles.

Why does seat tube angle matter?

Frame angles – Seat tube angles range from about 70-75 degrees. A steeper angle moves the saddle forward while a shallower angle moves it back. Steep is fine for racers. It allows them to ride hard in an aero crouch, as the more open hip angle doesn’t constrain breathing or power transfer.

1. It’s not so good for more relaxed riding as it transfers more of your weight from your backside to your hands, which can cause aches and pains.
2. You can change the effective seat tube angle by sliding the saddle forward or back in the seat post clamp, or by fitting a different seat post with more or less ‘layback’ (the distance the clamp is behind the seat post centreline).

Head tube angles range from about 66 degrees (gravity-oriented mountain bikes) to 74 degrees (razor-sharp road bikes). Other things being equal, a bike with a steeper head angle with steer more sharply and a bike with a slacker head angle will be more inclined to travel in a straight line.

What size seat clamp do I need for a 27.2 seatpost?

Seat Clamps – Seat clamps for road and MTB bikes fulfil the same function as BMX seat clamps and are typically made of the same material (aluminium), often CNC-machined and anodised for extra resistance to damage. However there are a couple of considerations to take into account when replacing a seatclamp, the foremost being internal diameter and quick-release or bolt closure.

• Diameter: The internal diameter of the seat clamp must correspond with the external diameter of the seat tube – too big, and the seat post may move in the frame, with the risk of cracking; too small and the collar can’t fit on the top of the tube (and you might damage your frame in trying to force it on).

There are five standard seat tube diameters on the market: 28.6mm, 30.0mm, 31.8mm, 34.9mm, and 36.4mm, so once you know the size of your seat tube (measure with a calipers or check your manufacturer’s specifications) make sure to buy a seatclamp that matches.

1. Note: The seat clamp diameter needs to match the diameter of your seat tube rather than your seatpost, which is a little smaller.
2. For example, a 27.2mm seatpost (a size commonly found on road bikes) fits inside a 28.6mm diameter seat tube, so it’s a 28.6mm clamp you need.
3. Quick-release closure: A quick-release or QR seatclamp uses a small lever to close the seatclamp collar, as with QR wheel skewers allowing the mechanism to be easily opened and re-closed without the necessity for tools.

This is useful for riders who wish to frequently raise or lower their saddles, as with MTB bikers who might want to drop the saddle for better body positioning on a technical descent, and raise it again for pedalling efficiency when going back up the hill.

However QR seatclamps have fallen a little out of favour in recent years, owing in part to their sometimes less-secure grip (making post slippage a problem) and also to their propensity for being inadvertently knocked by knees. Additionally, many commuters have long bemoaned the fact that QR seatclamps make saddles an easy target for thieves.

The advent of dropper posts for MTB riders has also eroded their appeal. • Bolt closure: These use a simple, short bolt with a hexagonal head to close the seatclamp collar. Bolted collars have long been favoured by gravity riders for their secure grip but are also now more often seen on road bikes as the advantages of a rock-solid grip (once the optimum saddle height has been set) outweigh those of the QR collar.

What size is a specialized seat post?

All models use a 34.9mm seat post and a 38.6mm seatpost collar (S184700004).

What is the size of giant seatpost?

Jonny Sprockets Bike Shop –

#8

t said: 30.8 and 30.9 doesn’t sound like much, but it’s the difference between a post that slips and one that doesn’t. Older giants used a 30.8,which was a stupid giant only size. recently they switched to 30.9 which is a pretty common size. I used to run 30.9mm posts on older giants without problems and vice versa.

1. Not with a QR though, and I wouldn’t dare on a carbon frame.
2. The problem is that most seat posts arn’t what they say.
3. Cheap posts can be as much as 0.2mm off.
4. When we stocked giant I rember having a very tight 30.8mm seat post in a giant, I took a 30.9 from a specialized and it was almost loose.
5. I then installed the giant post on the spec, where it was a nice fit.

Crazy. Worst yet I’ve had a few oval shaped seat poles, as in- not round. In any case I’d be getting a 30.9 as its the most comon size and from my past experience should fit, even if it is an older giant with 30.8. If not, get it honed at the LBS.