I have a 1987 Schwinn Cimarron LE that was outfitted with a Tange G Master JIS size (30.0mm/27.0mm) headset for some silly reason. Why Schwinn would do this on a bike of this caliber (nice in its day) is a little strange I guess. My question is this. I bought a couple of Tange Passage headsets from Harris Cyclery that were listed as 30.0mm/27.0mm on their website, but when I got them yesterday they were 30.2mm/27.0mm. I promptly emailed Sheldon Brown and asked him about this and he said that in his experience the .2mm difference is not a problem on a steel frame. I respect his opinion but I guess I need a second or third opinion before I install this headset on my bike because I really don't want to damage the head tube since I cannot easily replace this frame, which I like. Has any one else run into this and had success installing a similar headset? I apologize if this has already been addressed in another thread, but I couldn't find it if it was. Thanks.

Well... I've never tried to install a wrong-size headset in a frame. On the other hand, I've found all of Sheldon's mechanical advice ever to be correct

You question a guy who has done many of the thing that he recommends? I'm too lazy to look up tensile strength of steel right now, but given the circumference of the headtube C=2*Pi*r=2*Pi*D/2=Pi*D, it's a difference of Pi*30mm and Pi*30.2mm, which is less than 1% difference, which I'm definite is still well within steel's elastic region. IOW's should be safe to do so. Maybe those with better memory of materials science can confirm.

And, Sheldon, if you happen to view this post, I mean no disrespect. I refer to your website on a regular basis and find the information very helpful. I guess I am looking at this like I would with a medical question. I have the opinion of a well respected physician and want to confirm that with another physician before going under the knife.