Frame fit question

That's a start point and nothing more. You probably won't want further forward than that, you may need further back.

The ideal is to have your seat at a position that supports your weight on the bike, optimises peddling efficiency and minimises weight supported on your hands.

Variables including frame size and geometry, stem length, and rider weight distribution, (your relative upper body mass) come into it.

Millimetres can make a big difference so take your time and experiment.

Jay.

otherworld said:

That's a start point and nothing more. You probably won't want further forward than that, you may need further back.

The ideal is to have your seat at a position that supports your weight on the bike, optimises peddling efficiency and minimises weight supported on your hands.

Variables including frame size and geometry, stem length, and rider weight distribution, (your relative upper body mass) come into it.

Millimetres can make a big difference so take your time and experiment.

Jay.

very true...in fact it isnt even a start point...it is a no no....

have a full fit, from some one who doesnt use string...you need to have your physiology examined, your physical peculiarities mapped , look at the type of riding you want and your long term aspirations....

then have the fit results applied to your frame.....it is useless to just buy a bike with standover height and drop a piece of string...at best you will save some bucks, at worst, you will have an injury from riding that will put you off your bike for ever..... dont chance the string......ever.

your frame must have dimensions and geometry to match your physiology...most production bikes these days are too upright, ie the seat post angle is too vertical, the head tube too vertical, the trail of the bike too short, and the wheelbase too short....( as a result of everyone tring to ride Tri bars position forward....you cant do this for long, it makes a bike unstable on the descent, too rigid in corners, too shimmy shake and unsafe)...for any ride over an hour you will have a strain in your back, neck, wrists or hips that may build to a life long riding career ending outcome.....typical of this type of bike are Cervelo...bad news, they cant use all the rear cogs on a tri-version, the chainstay is too short and the angle of the chain distortion too acute to allow the derailleur to work the full range....they are hopeless on a descent and unstable at speed.....

look at the long standing tour bikes of Greg Lemond, Eddy Merckx, Lance Armstrong, Phil Anderson...they all rode bikes with seatposts set at between 71 & 72.5 degrees, rarely 73..., they had long chainstays, usually at least 415 out to 440mm mm not the standard 400mm on most stock production mass produced bikes ( its cheaper to make a mass output of chainstays across a range...to hell with safety)...

They all had head tubes angled at around 72.5 degrees or less and they had trail that handled....

its not about weight....its about fit....Rassmussen ( and Basso) in the tour on stage 20 is/are a fine example/s...he (both) had an ill fitting TT set up, too vertical, too rigid, too unstable, to shakey...it refused to handle and tossed him (Rassmussen) off into a ditch, he lost it on a round about, along with his confidence to ride it ( as well as Basso), they replaced it with 5 twins ( quins) throughout the race and all were the same...useless...he (R) only managed to salvage his postion by guts and power on the flats.....( like Basso)

get a fit...forget the string...get a custom with serious angles that work....