Transferring measurements between bikes

Discuss light weight issues concerning road bikes & parts.
wintershade
Posts: 123
Joined: Mon Apr 16, 2018 7:12 pm
Location: San Francisco, CA

by wintershade

Hi -- I am building up two new bikes, and I'm looking for some advice / tips / tricks for transfering my measurements between the bikes. The geometries are all reasonably similar but the finishng kit will be different (e.g., different brand posts, bars, etc). I'm reasonably happy with my fit on the primary bike. I'm fine ordering a couple stems and sending back the ones I don't keep, but I'd like to keep this to a minumum.

Any tips for how to make sure I'm getting the measurements as exact as possible (e.g., using levels, special measuring tapes, etc), without a bunch of trips to my fitter? Is there an "order of operations" here? For example, my plan was:
1) Measure distance from bottom of pedal stroke to top of seat post, set this
2) Measure distance fore/aft of saddle tip to front of pedal stroke (pedal at 3:00) to get saddle position right
3) Repeat steps 1+2 until distances from saddle tip to pedal are the same at all points
4) Measure distance from saddle /bar drop, to determine stem angle and spacer stack
5) Measure distance from saddle top to hood front, to determine correct stem length (I assume this is better than measuring to bar top, since I mostly rid on hoods)
6) Measure discance from saddle tip to bar top and to center of drops, to make sure handlebars are a good fit, make stem changes if/as necessary

Finx
Posts: 31
Joined: Wed Jun 15, 2016 1:14 am

by Finx

Some people are very sensitive to even the smallest change in fit (i'm one of them). I used to do pretty much what you are describing.. or at least very similar.

I finally invested in a Veloangle and Veloangle App. It's a digital inclinometer with some special features and attachments that lets you compare bike fits down to the millimeter.

I'm not involved at all with the company. I'm just a happy customer.
https://veloangleapp.com/index.html

The product is very new, and it can be a bit quirky trying to figure out exactly how it works, and what the software is telling you. I found them to be very responsive to questions via email.

Edit: here is a screenshot of the output generated by Veloangle App (website).

It's kind of hard to see here, but these graphs are comparing three different bikes fit measurements, as taken by the VeloAngle. One graph is relative to the BB. The other is relative to the bike saddle.

Using this, I was able to dial in the fit of all of my bikes, using the one that I liked best as the master/reference.

Image

by Weenie


jfranci3
Posts: 352
Joined: Tue Jul 26, 2016 5:21 pm

by jfranci3

Basically measure everything from the BB Center. I'd put a thin bit of tape directly above the BB on the top tube as an easier reference point.

For the saddle, in this era of short noses, I'd measure from the back of the saddle.

Otherwise, it's also easy enough to line up the two bikes BB center to center if you have all the parts and just adjusting.

If you don't have all the parts, you'll need to know your current stem length and angle as well as your bars width, drop, and reach. Take your current bike's stack/reach and the new one's. Adjust the stem from there. You may also need to size the seat post.

User avatar
dgasmd
Posts: 1447
Joined: Sun Apr 15, 2007 5:10 am
Location: South Florida

by dgasmd

Finx wrote:
I finally invested in a Veloangle and Veloangle App.
https://veloangleapp.com/index.html

Using this, I was able to dial in the fit of all of my bikes, using the one that I liked best as the master/reference.
On your link it shows the cost of the app but I don’t see anything about measuring device they use. Do you have a cost or link to it??

Mep
Posts: 331
Joined: Fri May 28, 2004 4:11 pm

by Mep

It's veloangle.com 200 bucks for the cheaper version of the measuring tool they use
dgasmd wrote:
Finx wrote:
I finally invested in a Veloangle and Veloangle App.
https://veloangleapp.com/index.html

Using this, I was able to dial in the fit of all of my bikes, using the one that I liked best as the master/reference.
On your link it shows the cost of the app but I don’t see anything about measuring device they use. Do you have a cost or link to it??

wintershade
Posts: 123
Joined: Mon Apr 16, 2018 7:12 pm
Location: San Francisco, CA

by wintershade

Finx wrote: ↑
Sat Oct 13, 2018 1:29 am

I finally invested in a Veloangle and Veloangle App. It's a digital inclinometer with some special features and attachments that lets you compare bike fits down to the millimeter.

I'm not involved at all with the company. I'm just a happy customer.
https://veloangleapp.com/index.html

The product is very new, and it can be a bit quirky trying to figure out exactly how it works, and what the software is telling you. I found them to be very responsive to questions via email.
Thanks Finx. This looks like the ideal option. How straightforward is it to use. At a certain point, if it take 10 hours to figure out how to do this, I might just be better off bringing the bike to the fitter, no?

User avatar
nycebo
Posts: 78
Joined: Fri Nov 13, 2009 8:04 pm
Location: New York, NY

by nycebo

I particularly like how they use the dots to identify where the bars, bb, and saddle are. It seems the purest way to isolate ACTUAL stack and reach. However, can't all of this be simply done with a tape measure? Set the bike up on the floor with the rear wheel on a wall and just start measuring from the wall to saddle back, from wall to stem, from wall to bars, wall to hoods, wall to BB, floor to saddle, floor to stem, etc.

outnumbered
Posts: 170
Joined: Wed Jun 14, 2006 9:59 pm
Location: Reading, UK

by outnumbered

That's what I do... I can't see the need for anything other than a wall and a tape measure.

wintershade
Posts: 123
Joined: Mon Apr 16, 2018 7:12 pm
Location: San Francisco, CA

by wintershade

Problem is what if the bikes have different length chainstays? Seems like a good approach for reassembling a bike averse travel if you know your numbers, but If you’re just measuring from the edge of the back tire, how do you compare across bikes.

cyclingburd
Posts: 2
Joined: Fri Apr 03, 2015 4:31 am

by cyclingburd

I started using a cheap laser level on a tripod. I adjust the position of the level until the vertical line is through the bottom bracket and horizontal is at the top of the saddle. Then measure between the laser lines and various points on the bike. For me the laser level is easier and more accurate than measuring from wall and floor.

Sent from my SM-T700 using Tapatalk


mattr
Posts: 3823
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

wintershade wrote: ↑
Sat Oct 20, 2018 10:45 pm
Problem is what if the bikes have different length chainstays? Seems like a good approach for reassembling a bike averse travel if you know your numbers, but If you’re just measuring from the edge of the back tire, how do you compare across bikes.
Add an offset, bottom bracket to wall for each frame, compare the difference.
I've done several of my own bikes and dozens of customers and friends with a wall, a tape measure and a spirit level.

With a bit of basic trig you can even rotate the position around the bottom bracket for different bikes/set ups/touring/race/mtb and so on. Won't be 100% accurate but it'll give you 95% of a start point.

User avatar
Leviathan
Posts: 1100
Joined: Sat Mar 17, 2007 10:49 am
Location: Mallorca, Spain
Contact:

by Leviathan

Sorry but how do you account for the relative angles between your data points, or you are just comparing points on a locus circle?
Unless you can fix a datum horizontal with a lazer or vertical with a plumb line are you just assuming floor is level?

mattr
Posts: 3823
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Floor and wall are *close enough* to level/horizontal to use as datums.
And it's simple trig. Accurate within the realms of stem length and the adjustability of stem height and so on. If you want to get *more* accurate you'll need to use your body dimensions/angles. Again, fairly simple trig.

User avatar
Leviathan
Posts: 1100
Joined: Sat Mar 17, 2007 10:49 am
Location: Mallorca, Spain
Contact:

by Leviathan

Erm, I understand the maths. What I like about the system they are selling is its independence of floor gradient, if the bike is level, and if your drop downs to the floor are really vertical. Having said that, a laser level would do that better but they are actually more expensive.

by Weenie


mattr
Posts: 3823
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Ah, right, i misunderstood. Sorry.
But what i don't like about it is that it's 200+ dollars, and i have everything i need to do the same job already lying around in the house.

Post Reply
  • Similar Topics
    Replies
    Views
    Last post