Bicycle Mechanics - problem with headset

I currently have a Shimano 600 headset 1" threaded prolly from about 1986. I put it on my new road bike and i know i did it correctly cuz I had 3 other technicians oversee my work when i was doing it. The problem i am having is it keeps coming loose after every 30km and I have to retighten it. My boss took a look at my fork and he suspects that the fork I got was cut about 1-2mm too short for the bike. The result being the headset cant keep its grip to the fork as the fork is too short for the frame. The previous owner had a 105 headset on the bike and it worked no problems tho. I measured his headset and the height of the upper bearing cup (is that the right term) is about 1-2mm shorter than the one on my 600. Would this be the reason why it always stayed tight. I tried removing the spacers from the upper headset but no luck. Any suggestions. If i cant make this headset work, is there a shorter headset that I can purchase. If not and there is no solution I will just purchase another SL fork. I got about 50 of them in the shop.

Brian,
With the headset adjusted and locked down how much space is there between the top of the steerer tube and the lip of the locknut? There should be a very small amount, like .2 mm plus or minus a bit. If there is too much space your steerer tube may in fact be too short. Since the height of the old headset was shorter, this may be the case as you suspect. In such case there may not be enough locknut thread engagement to hold the adjustment securely. The opposite can also be true. If there is no space between the top of the steerer tube and the locknut lip, the steerer tube may be too long. In this case the lip of the locknut will bottom on the top of the steerer tube preventing the locknut from locking down the upper race.

Still another possibility is the bearings. Are they in a retainer? If not you may have too many bearings.

Was there something wrong with the old headset? If the cups and races are in good shape, why not just replace the bearings?
Hope this helps,
Raymond

You could try locktiting it or find a HS with a shorter stack height.Check the QBP catalogue or www.branfordbike.com

nah its the fact that the headset is longer (i think). the previous owner of the frame had an older 105 with no problems. I am using an even older 600. I measured the 2 and the 105 has a shorter stack height. I am going to try and track one down and use it.

You mentioned that you took the spacers out of the headset. Without the keyed spacer, it's not likely that the headset will stay put.

One possible option is to mill the steer tube a little shorter, taking more off the top end if practical. Another idea, if you can't find a headset with a short-enough stack height, is a Chris King Gripnut headset (or a new fork).

hehe i swear to god. i was just gonna ask.. can i use the Chris King gripnut one.. will that fix my problem. and i kept the lock spacer in but its no good.. so will the chris king one work?

Sure a HS will stay adjusted without a keyed washer.If the stack height is too tall,how will shortening the steerer make it better? Sure the CK gripnut will work if it's stack height range falls with the range you need.

i need a HS with a stack height less than 37.6MM so i aint going new shimano i guess. Any recommendations. is the CK meat that requirement. I guess i need 35mm

Their site says 33.0mm to 38.0mm, so it looks like a go. :) CK headset specs (http://www.chrisking.com/specs/headsets_all.html)

aight so if 37.6 is too big for my current fork this will work.

basically since my fork is about 2-3mm was cut too short. this will fix it.

oh . hehe. the site says its built for forks that have been cut too short.. works for me.

For as little as $10 you can get a Ritchey headset. The stackheight is 33. I have one on my mountain bike. Works fine.

Daniel

I had a $10 Ritchey once and threw it away.........Check www.branfordbike.com for other options that are less expensive than the CK. You are in a shop?Don't you have a QBP catalogue?

Here in Cawnada we dont deal with QBP.. I got other catalogues though. Ill read it to see what I can get.

For the record, I just noticed an error I made above: I should have said, you can mill the head tube shorter, not the steer tube. Doh! :rolleyes:

yah that didnt sound like the right thing to do

i searched my distributors and i couldnt find any headset with the stack i need except for the CK. That means I am down about 100-120bux.

My boss still has a million spare columbus SL and SLX forks left from when he had the Miele factory before it became defunct. He said hed sell me them for $120-150. Im now thinking I should just take that one. Should I do that and keep my 14yr old Shimano 600 Headset or search for a new headset instead.

Brian, you work for Miele, the cycle maker?
Too bad they emt out of business...

Yah I work for good ol Jim. And yah. Miele went defunct like what.. 15 yrs ago or something

ok so i found an older Deore XT headset at the shop and I put it on. I had to use 3 spacers/washers which means it had a much lower stackheight. That is a good thing. I rode harder today and the headset is still tight. Finally, no more worrying.