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Setting up 2nd bike the same as the other

991 views 5 replies 4 participants last post by  toronto-rider 
#1 ·
I just received my Pedal Force ZX3 it is size 55. My other bike is a Look 585 in size Large (56cm).

Which is the best way to replicate the same fore/aft of the saddle position relative to the BB on both bikes. If I hold a level against the saddle and measure the distance from the BB or the distance from the end of the crank to the level - i should get the same distance for each bike.

The problem i am having is that I cannot get the same distance on the ZX3 as i am 1 cm short. I have pushed the saddle as far as possible back and am using a Thomson seatpost with setback. Do i need to get another seatpost with more setback?

Should the above measurement be done more from dropping a plumb line when i am on the bike, as my position might be fine relative to the BB.
 
#2 ·
Are the seat tube angles on the two frame the same? Because if they aren't, you may have a problem replicating without a post with more setback. The Thomson by the way has very little.

It doesn't really matter how you measure it, there are multiple ways. Not trusting the accuracy of the plumb bob from the knee method, I built a jig that plugs into the BB and allows me to measure the centerline of an imaginary line through the BB to the end of the saddle.

Before that, I put the bike on a level surface and dropped a plumb from the tip of the saddle and just measured from that to the center of the BB. I'd recommend you try that.
 
#3 ·
Assuming:

1.) You are using the same saddle (Which I would recommend) &
2.) Your crank length is the same.

Then on your old bike:

1.) Measure from the center of the BB to the top of the seat up the seat tube.
2.) Drop a plumb line from the tip of the saddle....then measure from the plumb line to the center of the BB.
3.) Measure the distance from the floor to the top of the seat, measure from the floor to the top of the handlebars, calculate the difference between the 2 & that is your saddle to bar drop.
4.) Measure the distance from the tip of the seat to the middle of the bars.


Go to the new bike:

1.) Duplicate the measurement from 1.) above on your new bike
2.) Duplicate the measurement of 2.) above on your new bike. If you can't get the saddle back far enough, get a more setback seatpost. If you can't get it back far enough, get a different bike.:D
3.) Duplicate the measurements in 3 & 4 above using different stems & spacers.

The only other issue you will need to deal with is the reach of the bars and the location of the levers. If you are using the same bars, it's pretty easy...otherwise you have to adjust the measurement in 4.) above for the difference in reach & trial & error on the levers placement.

Len
 
#4 ·
toronto-rider said:
I just received my Pedal Force ZX3 it is size 55. My other bike is a Look 585 in size Large (56cm).

Which is the best way to replicate the same fore/aft of the saddle position relative to the BB on both bikes. If I hold a level against the saddle and measure the distance from the BB or the distance from the end of the crank to the level - i should get the same distance for each bike.

The problem i am having is that I cannot get the same distance on the ZX3 as i am 1 cm short. I have pushed the saddle as far as possible back and am using a Thomson seatpost with setback. Do i need to get another seatpost with more setback?

Should the above measurement be done more from dropping a plumb line when i am on the bike, as my position might be fine relative to the BB.

Forget it and ride. 1 cm won't make that big of a difference IMO.
 
#6 ·
Thanks to those who replied. To answer some questions.

Same saddle, stem, handelbar and crank (UT on new bike, old style on 585)

IT looks like Thomson has only a 16mm offset and on my 585 I am using a Rtichey setback which has 25mm.

I did the 1st 2 measurements that Len J recomended.
 
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