seat height

[TAV]

Ive bought a trek madone 5.5 size 56 but the seatpost comes in two sizes 120mm and 175mm the one that is on the bike is 120mm my last bike fit said that my seat height should be 777mm im 5ft 10 with a 32 inch leg but the seatpost will go to 777mm but its gone past the max seatpost height does anybody think that 777mm is to high for my height,a new seat post is 120 pounds so not good.

 

[mattobrien]

I wouldn't have the seat post above max.

Were you measured when you bought the bike? Was it down to the LBS to make sure it fits?

Without converting inches into mm, I believe it's either 107% or 109% of in step as the measurement from pedal axle to top of saddle.

 

[TAV]

I bought the bike on ebay I had my old bike which was a 56cm frame 777mm is 77cm but for my height and inside leg its seams high but I don't want to hurt my knees.

 

[mattobrien]

I am around six feet tall and have my saddle 940mm from the pedal axle., when the pedal follows the angle of the down tube. 777mm doesn't seem high, in fact it seems rather short.

 

[mattobrien]

Also seatposts are usually around 300mm, sometimes longer. Might be worth sanity checking some of your measurements. Just a thought. You tube may well be your friend here.

 

[Rickshaw Phil]

@TAV, I'm a similar height to you and have just been out and measured my bottom bracket to saddle height - it's about 30 inches (762mm), so I think the figure from your bike fit is in the right area.

I wouldn't recommend running a seat post higher than the max mark as it runs the risk of snapping the seatpost or the frame, so you either need a longer seat post or the next frame size up.

To me £120 seems a lot for a seat post - would any of these do the job?: Link

 

[TAV]

Its a nightmare the only seatposts that fit are the oval bontrager seat post from 2008 looks like im going to have to save up cheers for all the help anyway,

 

[david]

i'm 5-9 and my measurement from top of pedal to top of saddle is 860mm

 

[TAV]

Yeah but you have to measure from the centre of the bb to the top of the saddle

 

[mattobrien]

Yeah but you have to measure from the centre of the bb to the top of the saddle

You don't. Top of pedal axle takes into account the crank length too, whereas top of BB doesn't. It won't be miles different, but I learnt top of pedal axle as it covers everything that will affect you knee extension whilst pedalling.

 

[02GF74]

firstly you are talking road bike. I take 33/34 trouser and seat height from BB is 79 cm. This is on both road and mountain bike, mtb has 174 mm crank and I suspect your road bike will have 170 or 172.5. So I would say you are ever so sightly to high but not way out.

Sit on the bike and whilst wearing your cycling shoes, place your heel on the pedal. Your leg should be near to being locked out, there should be a slight bend in knee. If your heel is not resting with any weight on the pedal and your left is totally straight, then you need to lower your saddle.

You can raise the saddle height by fitting a taller saddle. The seat post on my commute mountain bike is a 8 mm above the mimum and I have been riding that since 1999 and I am probably a lot heavier than you.