As a project, I'm building a simple single-speed mountain bike from parts purchased on ebay; I bought a cheap new unpainted 20" MB frame that was advertised as manufacurer overstock. So far so good. I plan to use the bike for city riding and so don't need a suspension fork. Instead I bought what was described as a suspension corrected rigid MB fork with a 7.5 inch steerer tube (the longest I saw for a rigid fork). Before I even began to tackle the headset, though, I noticed that the steerer tube is barely longer (just a few mm) than the headtube; no room at all for a headset or stem. Is it possible that I bought a weird frame? (I never considered the length of the headtube an issue.) I looked at cheap suspension forks and the longest steerer tube I saw was 8 3/8 inches, but I doubt even that would be long enough. What am I missing? Thanks in advance.

Proper response:
Nothing wrong with your frame's headtube. Obviously you purchased a fork with a steerer tube not long enough for your frame. Steerer tubes are available in much longer lengths..... :)

Thanks Joker; didn't know children used this site, but live and learn.

Thanks, Fixer. Obviously I should have measured first and was just fooled by the Ebay ads for 7.5 inch steerer tubes as long enough to cut down to desired size. I'll look for longer steerer tubes; much appreciated.

Start at the beginning and quit guessing. Measure your headtube,know your HS stack height,and the stem stack height.Added together,that's the minimum steerer length you need. A bit longer for some spacers won't hurt. too long can always be mae shorter.