WANTED: 1" Headset, with caveat

[n9viw]

I got started (sorta) on my Bandito last night, at least as far as getting the forks off the respective donors, a Schwinn Sierra MTB and a Schwinn Aerostar BMX bike.

While cleaning the headset, I found that the lower bearing cup for the MTB frame I plan to use is badly cracked... seems the PO was fond of jumping maybe? I tried brazing the cracks, but the heat distorted the thin metal of the cup and warped it.

"No worries," says I, "I'll just put the lower cup from the BMX bike (fork donor) in there." NOT! The head tube of the BMX bike has a bigger ID than that of the MTB, so the BMX cups won't fit! The ID of the BMX head tube is 1.275", the ID of the MTB is 1.175", a 0.100" difference. Large enough to cause a problem, since it's too much to take off the BMX cup or the MTB head tube, since any milling would make either one too thin.

So, all that said- does anyone have a 1" headset for a 1.175" head tube they'd like to sell me? I really don't want to have to cut the BMX head tube off and try to reweld it to the MTB and keep it straight! The only other option would be to scrap the MTB frame and get a different one, not an easy or cheap option here in the 'burbs in the winter.

TIA!

[TheKid]

They're pretty cheap new. You just need to know your race ID - 26.4mm, or 27mm. Here's a few links:

http://www.ebikestop.com/Items/004-hd1040?sck=12257306

http://www.ebikestop.com/Items/004-hd1041?sck=12257306

http://www.ebikestop.com/Items/oc-hd1040?sck=12257306

[n9viw]

See, the funny thing is, NONE of those address the ID of the HEAD tube, only the ID of the race for the STEERER tube (the tube on the fork). I need to make sure the headset is going to fit the FRAME before I can fit it to the FORK! I don't know why they don't include that.

I think I'll call the LBS and see what they have. Hate to pay the extra I'm sure to, but if that's my only option for real solutions, guess that's what I take.

[TheKid]

It sounds like you need the smaller cup, which is for a 1" headset. The BMX (larger tube) takes a 1 1/8" headset. BTW, headset parts of the same size aren't always interchangeable. Cups and races have different shapes, and the bearings from one headset may not seat correctly in another. You're better off replacing the entire headset if you need parts, just to be sure of a correct fit.

[n9viw]

Okay, that makes sense. The headset in the BMX bike must be an oddball, because if the cups are 1-1/8" as you say, the rest of it is 1" - the steerer tube, threaded cone, and fork cone. The bearings are the same diameter (I think) as the MTB's.

I'll call the shop and ask them to mic the neck on a 1" headset, and go from there.

[n9viw]

Just called my shop, and had one of the techs mic a cheap Wald threaded headset (actually, the only 1" threaded headset they had). That one measures out at 1.3"!

So, is the Schwinn Sierra an oddball, or what? Looks like for want of a bearing cup, I have to scout out a whole new frame! Stupid Schwinn! :mad:

[n9viw]

Well, it pays to have more than one LBS. Called Mikes Bike Shop in Palatine, and they have a Shimano 1" threaded headset for $25. The guy measured the headset necks for me, and it came out to 3cm on the nose... 1.18", which is close enough to 1.175" for me!

The cost is a bite in the butt, but at least it's the right size the first time. I'm gonna pick that up on the way home tonight, and hope it's the most expensive single part of the build.

[n9viw]

Ah, Sheldon... he was a wealth, wasn't he? <snif>

As it turns out, it is a Shimano STX headset with sealed cartridge bearings (yay!), and the crown race did fit the fork just fine. The cups, OTOH, were a PITA to install- I think the head tube is bent just a bit, which would explain the cracked lower cup.

I gave it a wallop with a rubber mallet on Saturday, which put it back in round enough to install the lower cup, but not yet the upper. I may not get to it this week, as the wife's b-day is this weekend and I'm making crazy plans.

[myride]

I got started (sorta) on my Bandito last night, at least as far as getting the forks off the respective donors, a Schwinn Sierra MTB and a Schwinn Aerostar BMX bike.

While cleaning the headset, I found that the lower bearing cup for the MTB frame I plan to use is badly cracked... seems the PO was fond of jumping maybe? I tried brazing the cracks, but the heat distorted the thin metal of the cup and warped it.

"No worries," says I, "I'll just put the lower cup from the BMX bike (fork donor) in there." NOT! The head tube of the BMX bike has a bigger ID than that of the MTB, so the BMX cups won't fit! The ID of the BMX head tube is 1.275", the ID of the MTB is 1.175", a 0.100" difference. Large enough to cause a problem, since it's too much to take off the BMX cup or the MTB head tube, since any milling would make either one too thin.

So, all that said- does anyone have a 1" headset for a 1.175" head tube they'd like to sell me? I really don't want to have to cut the BMX head tube off and try to reweld it to the MTB and keep it straight! The only other option would be to scrap the MTB frame and get a different one, not an easy or cheap option here in the 'burbs in the winter.

TIA!

I had a like problem. I cut the bearing housing and let it expand enough to fit , and I quess you could cut out a little piece of bearing hlder to put it in a smaller race. good luck

[John Lewis]

Yep, There are a few oddies like that to catch you out. another is the pedal thread size on one piece cranks.

maybe you can get one from your LBS. Either new or from the scrap bin.

My problem was the crown race. Couldn't get one the right inside diameter. I ended up using brass shimms and green loctite. Seems to be holding up so far.

I'd be concerned with splitting the tube as you might end up with an alignment problem.

John Lewis