Headset stack height - help please

[kingoffootball]

I've read through all the threads that came up on the relevant searches I tried, but really just after a few opinions on this specific question.

I'm looking for a replacement threaded headset for my '91 Karakoram Elite:
http://www.retrobike.co.uk/forum/viewtopic.php?t=181205

The existing headset is a tatty Tioga one, which I'm very confident has a stack height of 33.5mm.

Having been offered an LX headset with a stack height of 37.6mm my initial instinct was to try it and hope 4.1mm wouldn't make too much difference, but I then recalled when I'd previously considered replacing it Rob Atkin had advised me that when he tried to do something similar on his 92(?) Tequesta the Shimano headset was too high.

So my questions are:
1) Is that likely to be too much difference in stack height to attach securely to the fork?
2) Is there any way to check for sure, without refitting the dirty/greasy old headset to my painstakingly degreased frame and forks?

Thanks in advance for any help/input.

 

[MiniNinjaRob]

I got a Ritchey logic headset in the end from the US, but I think CRC have them now. Pretty cheap too - not as nice a quality as Shimano but ok if packed with plenty of scrummy grease.

I remembered that I had replaced the original one BITD with a Ritchey one so I just double checked the stack height and it was fine - in fact it worked PERFECTLY.

If funds are tight I may be pursuaded to let you have the one on my Tequesta as it's not being used and the bike was only ridden once due to it being too small.... :cry:

 

[hamster]

One trick with the Ritchey is to cut an inch section of old inner tube and fit it around the top of the forks before assembly. You can then use it as a sealing boot around the lower race. It's ugly but effective for the winter.

 

[FluffyChicken]

- Measure the length of you steerer, from where the crown will sit, up to the top.
- Measure the headtube length of the frame.

- Take one away from the other and that is the stack height you have to play with.

No need to worry what the old headset's stack was as you now know what you maximum is.

 

[FluffyChicken]

I have no idea which Tioga Avenger your bike used.

But in 1992,
Avenger DSL, DL, ST and RX had 33.5mm
and CR 31.5mm

So assuming it's cut at that with no additional spacers like cable hangers. it'll be 33.5mm like you think you need.

 

[MiniNinjaRob]

I have no idea which Tioga Avenger your bike used.

But in 1992,
Avenger DSL, DL, ST and RX had 33.5mm
and CR 31.5mm

So assuming it's cut at that with no additional spacers like cable hangers. it'll be 33.5mm like you think you need.

The Ritchey Logic one I bought has a 33mm stack height - which with your info proves why it fitted so neatly.

This one is mine (before fitting)

 

[kingoffootball]

Thank you. I wasn't sure whether measuring the steerer and headtube would give me accurate enough measurements, but to the nearest mm I get 170mm and 140mm respectively, which would mean I needed a 30mm stack height .... which is really going to reduce my options and definitely rules out the LX one.

Hmmm, maybe I'll have to attempt smartening up the Tioga one at this rate. Not 100% satisfying, but it might end up being my best option.

 

[kingoffootball]

But then looking through the relevant Tioga catalogue none of them appear to be less than 31.5, which at least suggests a little error in my measuring.

 

[jax13]

This one is mine (before fitting)

are you sure thats 'before fitting'!!!

 

[FluffyChicken]

But then looking through the relevant Tioga catalogue none of them appear to be less than 31.5, which at least suggests a little error in my measuring.

You have taken the crown race off before measuring ?
Unfortunately you need to be accurate when measuring as you're only talking mm here and there.

you can loose a mm or two in the top lock nut if needed but not the best thing to do, especially as these are original parts :?