Serotta Get Fit Help Needed

[Ramjm_2000]

New guy here needing some help with a recent custom frame and the subsequent Serotta fitting I received prior to ordering the frame (Lynskey Level 3). Well as it turns out, the turn around time for my frame is about 7 weeks so I'm setting up my other bikes to mimic as closely as possible the fit results. My issue is the actual fit data, they are somewhat different than I'm used to. I'd normally just go into the shop I had the fit done but it was a surprise Christmas gift and was done in my wife's hometown. We live in DC so I'm having to do this solo until I can get back down to Nashville. Here are the measurements that I need more clarification on:

1. Saddle rail to TT: I suspect this only applies to trad. frames. Also given the differnces in saddles, does this really tell me anything important? Also where on the rails should one measure?

2. Saddle to Stem drop: best way to measure this?

3. Saddle Tip to C of BB: Top of saddle, middle. or bottom?

4. Saddle Tilt: best way to measure

Also, there seems to be some proprietary measurement data X, Y, etc.. listed. I know there is a special serotta T-square device that these are used for, can this data be extrapolated?

Thanks in advance.

JR

[pdxmech13]

what's a lynsky #3
should i go into the basement

[Ramjm_2000]

what's a lynsky #3
should i go into the basement

Hope this helps :D

http://lynskeyperformance.com/

[Needs Help]

1) Saddle rail to TT....does this really tell me anything important?

Not that I'm aware of.

2) Saddle to Stem drop: best way to measure this?

One way:
Tie a piece of string to the rails. Run it under the seat and up the back of the saddle, over the top of the saddle, over the nose, and extend it towards your handlebars. Get a broom and lean it upright against the center of your handlebars and tie the end of the string around the broom handle. Tilt the broom handle away from your bars so the string is taught(maybe lean the broom against a chair so it won't fall over). Adjust the string so it is level. Measure the distance from the string to the top of your handle bars.

3) Saddle Tip to C of BB: Top of saddle, middle. or bottom?

It shouldn't matter. It's a horizontal measurement. You need to drop a plumb line that bisects the BB. Then you measure the horizontal distance from the seat tip to the plumb line. Be aware that some saddles, like a Fizik Arione, have longer noses.

4. Saddle Tilt: best way to measure
One way: a level placed along the full length of the saddle.

[David Kirk]

2. Saddle to Stem drop: best way to measure this?

The easiest way to do this accurately is to measure from the top of the saddle to the floor, then measure from the top of the handlebar to the floor and then.......subtract the bar number from the seat number and viola! you've got bar drop.

Dave

[Ramjm_2000]

Thanks for the help guys!

David,

Why didn't I think of that? Makes sooo much sense!

Needs Help,

Thanks as well. All good advice.I'm still curious about the purpuse of the saddle rail to TT measurement and it's significance. As for the saddle tilt, I normally do use a level and generally try to keep the saddle 90 degrees with maybe lowering the tip just a hair (the bubble still remains in the "level" range). My fit sheet says -2.9 degrees any words of advice on measuring this?

As for the X,Y, etc.. measurements anyone?

[Singlespeed]

Your saddle tilt was measured using a digital level and that's certainly more of a preferential setting. If you know that you like to ride with the saddle a touch nose down, set it appropriately.

As far as the X Y coordinates, you are correct that they come from the Serotta X Y tool. The purpose of these numbers is to quickly and easily locate the coordinates of the handlebar and seat relative to the bottom bracket (without taking several measurements). This tool makes easy work of comparing the characteristics of two different setups (i.e. differential and reach).

[Dave]

Thanks for the help guys!

David,

Why didn't I think of that? Makes sooo much sense!

Needs Help,

Thanks as well. All good advice.I'm still curious about the purpuse of the saddle rail to TT measurement and it's significance. As for the saddle tilt, I normally do use a level and generally try to keep the saddle 90 degrees with maybe lowering the tip just a hair (the bubble still remains in the "level" range). My fit sheet says -2.9 degrees any words of advice on measuring this?

As for the X,Y, etc.. measurements anyone?

Specifying a -2.9 degree angle isn't very valuable information for the rider. I use a 9 inch long "torpedo" level to adjust the saddle angle. Over a 9 inch length, the nose of the saddle would be 9 x tan2.9 = .46 inch lower than the tail. That assumes that the angle was measured across the entire saddle from tail to nose. If the fitter placed a small level over a shorter length, the angles is probably worthless to you. Some saddles kick up at the tail, which would alter the angle.

Measuring the amount of drop on the nose is easy. Just place the bike on a level surface, place the end of the level on the tail of the saddle and hold it horizontal (level bubble). Then measure the drop at the end near the nose.

[Ramjm_2000]

Good stuff. Thanks! Just a couple of other quick questions (I'm inquisitive by nature, sorry :) ) The fit was based on the assumption that I was going to use a 6 degree stem with a 120mm length with a TT length of 54mm. In reality the stem is eight degrees not six. Using the stem in the - not + position, will the 120mm length be appropriate or should I be using a 110?

Also, I'm curious about that saddle to stem measurement, like the rail to TT one, does this really tell me anything? shouldn't saddle to HB drop be more important? It's not even listed on my specs.

I guess my plan is to get the bike set up based on the fit and translate those measurements to ones I'm more familiar with. Thanks for helping.

JR

[Dave]

Good stuff. Thanks! Just a couple of other quick questions (I'm inquisitive by nature, sorry :) ) The fit was based on the assumption that I was going to use a 6 degree stem with a 120mm length with a TT length of 54mm. In reality the stem is eight degrees not six. Using the stem in the - not + position, will the 120mm length be appropriate or should I be using a 110?

Also, I'm curious about that saddle to stem measurement, like the rail to TT one, does this really tell me anything? shouldn't saddle to HB drop be more important? It's not even listed on my specs.

I guess my plan is to get the bike set up based on the fit and translate those measurements to ones I'm more familiar with. Thanks for helping.

JR

The change in stem angle has no significant effect on the stem length (.7mm longer), but it will 4mm lower, requiring more spacer.

Saddle to handlebar drop is very important. If it's not listed, you have a major piece of information missing.

A saddle tip to center of handlebar measurement (taken diagonally) is what I use to monitor small changes I make to my saddle position or to insure that a new stem really produces the reach I desire. This dimension is often shown on a drawing as a horizontal dimension, but this would be extremely impractical to measure. A tape measure from the tip of the saddle to the center of the bars or the edge of the split between the stem and face plate is much easier.