Old 650b tyres to borrow to check frame clearances. 38-45mm ish wide.

I'm after some old tyres to borrow so I can check clearances for a 650b conversion I'm doing.
Condition / brand / etc doesn't matter as long as I can inflate them.
I reckon 38-45mm would be good so let's start there. The more the merrier, I guess.

Will prob only need them for a few days, in a week or two.

measure your stays and fork 19mm below the current 700c tyre bulge with calipers

622 - 584 = 38

38 / 2 = 19

Cheers!

I get the first bit.. but why divided by 2?
(logic not my strong suit)

Where are you? If my new tyre arrives in time I'll be moving my 50mm Pirelli to the rear of my bike and sticking a 47mm Touraeg on the front, which leaves a 47mm WTB Venture unused ( though I might take it to Scotland as a spare).

Its circumference/diameter logic, to get radius you need to divide by 2.

Its how I did when I converted mine: https://www.pedalroom.com/bike/rychtarski-road-columbus-max-16759#photo179259

Oh cool - I'm in Hither Green, SE6.
Happy to pick up from most places tbh, no need for you to travel.

i've got some used wtb exposures 650b x 42, and a spare new 38mm graveling slick. You're welcome to pick up and try all that

Oh I get it now.
Love that Rychtarski, btw : )

Ah nice one! Will defo pick up the exposures.
Where are you again?

n7 / tufnell park if you fancy riding this north

Ooops, just sent you a pm as well... sorry!
Tufnell park is fine. Won't need them until the wheels are built so no rush... will be in touch in the next couple of weeks hopefully.

: )