First time custom hardtail question

[Partsbike]

I am in the process of cutting and custom hardtailing my xs650 Special. My question is, when setting up the frame ride height without the wheels and tires in hand can I use the tire manufacturer's overall diameter specs to determine where to put the axles? I have the wheelbase figured out just not the ride height.

For instance, my front tire is going to be the Speedmaster 3.00x21. The tire is listed at 27.2" overall diameter. My thought is to affix the front axle at 13.6", half the tire diameter. Is this a good idea or am I way off? I'd appreciate any feeback. Thanks!

 

[shitsnack]

Keep the swingarm intact, make it level, measure from there.

 

[Partsbike]

You're saying level the swingarm, then use the tire dimensions as I described earlier to set the height? My plan was to set the frame height first then adjust the axles in relation to that which in my case leaves the swingarm slightly angled. If I level the swingarm the frame ends up slightly higher than I desire.

Thanks for the reply and sorry if I am not understanding correctly.

 

[shitsnack]

I guess you would just leave the swingarm at whatever height you wanted, and it doesn't have to be level. You can figure how much drop you have from there.

 

[Partsbike]

Thanks again. Yeah. I got all that. I know where I want the frame to be but setting the rear axle height without the wheel and tire is the issue. I just want to know if using the manufacturers tire specs as a substitute is a good idea or not.