Wheel Sizes

Here is a list of the rim sizes used up to now, together with a (fat) tire to give an idea of the size of the wheel. The typical WB and Trail are gleaned from the Python Projects Survey.

As you are going to have the wheel positioned between your legs it must not be to large so you can't reach the bottom bracket. For that you need to know your Inseam Length.

						minimum inseam for crank
	ERTRO	Tire Width	Wheel Diameter	Typical Trail	Typical WB	145mm	155mm	170mm
16" big apple 50	345	50mm	445mm	-170mm	880mm	N/A	N/A	N/A
20" big apple 50	406	50mm	506mm	-140..-170mm	950..1200mm	N/A	N/A	N/A
24" big apple 50	507	50mm	607mm	-240mm	1140mm	79cm	80cm	81.5cm
26" big apple 50	559	50mm	659mm	-250..-300mm	1070..1380mm	81.5cm	82.5cm	84cm
27" big apple 50	-	50mm	-	-270..-310mm	1200..1380mm	?	?	?

Another point to remember is the BB-FWA distance. When this gets below 40cms you will get in trouble when using a derailler. The chainline gets so extreme that the chain tends to fall off. You could get around that problem by:

• increasing the height of the BB, possibly increasing the seat height too, to have a comfortable seat-BB height difference (+15cm -> +25cm seems to be a good value).
• taking smaller cranks
• using smaller wheel sizes.