9 posts / 0 new
Last post

For the purpose of fitting I measure fore/aft and effective body extension from the sweet spot of the saddle (widest point of the saddle).  Is there a set dimesion that rcognizes this protocal and if not how do I create one (other that the right click start a new dimesiont option).   In other word I want a standard dimisention and calcualtes the changes in reach and fore/aft when adjsuting saddle height, stem length, spacers... and so on

Effective body extension

You've described where you want to take this measurement from in the back, but it's not clear to me where you want to take it to in the front. If you want to measure to where the handlebar attaches to the stem, you can use the Rider compartment dimension shown below. If the reference point on the saddle is not quite where you'd like it to be, you can tweak that using the Saddle reference point fields.

Where are those dimensions

Where are those dimensions located?  I looked under Rider and tried all of them but could not locate the ones in the pic above, I create a Mid-Saddle to HB center and Mid-Saddel to Grip Hoods Tip dimension using the right-click method but find that when I make changes to other parts of the bike, my custom dimensions do not adjust automatically. So it would be good to use the RIder compartment ones if they do just that.



Rider compartment

Rider compartment is found under Components >> General.

Thanks Brent once again, you

Thanks Brent once again, you're awesome!


Brilliant!   This tool is amazing and you just made my day.  Thank you Brent.  Was fiddling with the saddle reference points but didnt quit understand how to manipulate to my standards (for fitting purposes).   Have a great day!



saddle Refernce point and Saddle Height (saddle to DS pedal)

Hi Brent,


now that you have cleared up my roadblock with fore/aft I am curious if you know how to keep the saddle reference point (-40 for the current bike I'm working on) and the normal dimension for saddle to drive side crank (i.e. top of saddle through center seat tube to drive side pedal).  Case in point I make the saddle reference point changes for fore and aft but this changes the measurement for saddle height (as previously mentioned) - I need the saddle reference point for fore-aft and the normal saddle height measurementThoughts...




PS – how do I change tire size (working on a CX bike now and want to show knobbie tires)




Saddle reference point

In response to a few requests, BikeCAD now includes various dimensions that go to either the tip or the tail of the saddle. Beyond that, all other dimensions going to the saddle are taken from a common reference point which can be tweaked using the Saddle reference point (X and Y) dimensions. I hadn't anticipated the need for more reference points than this. For now, all I can recommend is that you set the Saddle reference point (X and Y) values to suit the Saddle height dimension, once you've generated a drawing for that dimension, you could tweak the Saddle reference point again to display the Rider compartment measurement.

As you've pointed out, if you change the Saddle reference points after having established your saddle height, your seatpost is going to slide in or out of the seat tube moving the actual height of the saddle. You could overcome this by noting the length of seatpost exposed when Saddle height is first established. This dimension is available under Components >> Seatpost. After the saddle height changes when you tweak the saddle reference point, you could change the input value for Saddle height until the new value for Length of seatpost exposed is equal to what it was before.

Although I can't think of how you could have both standard dimensions displayed in a single drawing, you could effectively accomplish that by displaying one of the two dimensions as a user dimension.

As for CX wheels, there are various standard wheels available in the standard wheels menu. You can add more of your own wheels to this menu as described at: bikecad.ca/standard_parts_library. If you are configuring your own wheels in the Custom wheels menu, you'll want to change the Tire ∅ dimension (tire diameter) and W (tire width) dimensions. You may also want to change dimension M which controls the squareness of the tire cross section. When entering tire dimensions, be aware of the comments at: bikecad.ca/tire_diameters.

Thanks for this > tire

Thanks for this > tire diameters

Thanks Master. ;-)


Best regards Dave

Log in or register to post comments