Handlebar position between bikes

[jambee]

Hi there bike fit experts,

I've been wondering if there is a rule of thumb one can use to set handlebar height between bikes.

I have 4 different bikes. Three of which use 650B wheels with tires ranging from 42mm to 55mm. I also have two rides that use 700c wheels with 44mm.

When I built the largest tire size bike, the framebuilder explained to me that he set the headtube to a shorter value than the smaller tire bike. He shared that the goal is to end up at the same height of the handlebar between the bikes.

If that is correct, does it mean that for the same riding position,if I were to measure from the floor to the top of the handlebar, the measurement should be the same or very similar?

Looking to be educated.

[cabriggs]

You want the bars to be the same height relative to the bottom bracket, not the floor. So you would measure floor to bars, then measure floor to bottom bracket center, and subtract the second from the first. This is the value you want to be (approximately) the same across bikes.

It's entirely possible you have bikes with the same bottom bracket drop, and therefore with the same wheels/tires, the bars would be at the same height relative to the floor.

Alternatively, you can measure bar height relative to saddle height. You should end up with the same result because your saddle height is set from your bottom bracket.

[Point Grey]

3CC4E87A-16C4-4525-9C65-5BBE7E23F029.jpg
Find a shop with an XY Tool to get an exact measurement from bottom bracket to handlebar between bikes

[Peter P.]

You want the tops of the bars the same height difference as from the ground to the saddle on your other bikes. Use a tape measure.

This will take in to account differences in fork length, headset stack, BB drop, and anything else I forgot.

[Nomadmax]

Saddle to ground, bars to ground = difference. (making sure reach to bars and hoods are the same). I use the measured mid-point of the saddle as the reference point.

That cuts out the whole BB height issue.

[whatshubdoc]

Use this tool: www.bikegeocalc.com

I plug in the bike that "fits" first. Copy the URL and save it somewhere. The URL contains the coordinates to your fit.

Then I copy and paste the URL into a new window/tab; modify it to your other bike (Bike A, B, C. etc.)

Once it's all fixed up I make sure that the following are correct (in this order):
- Saddle height (assuming crank length is the same)
- Saddle setback
- Saddle tip to bar center
- Saddle center to bar center

Then I install the right spacers and stem to get the right reach/stack.

If you notice, the trainer bike is 4mm longer than the main bike. I use a 79 reach bar on the main bike, and a 75 reach bar on the trainer bike, which gives me the same effective reach. They do have different groupsets on there from different brands, so you'll have to take that into account as well.

But anyway, this tool has been 99% spot on for me when transposing fits. PM if you have questions.

[jambee]

Thanks for all the recommendations. I finally did some measurements and came out to some interesting results:

Handlebar from ground | Bottom Bracket Middle | Delta

Bike 1: 975 | 275 | 700
Bike 2: 965 | 265 | 700
Bike 3: 990 | 290 | 700
Bike 4: 970 | 270 | 700

Seems to be extreme luck or am i missing something here?