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Changing Headset Stack Height Affect Geometry???
Hello... This is my first post so hello to everyone in this forum. Honestly, I don’t know where to ask this question and I think this sub-forum is the best place to ask. I only find thread about lowering headset stack so I really have no idea about this because I want to add my headset stack height. I want to upgrade my current headset. It is a standard threadless external bearing EC 1-1/8 upper and lower. It is a FSA TH848 that have 24.6mm total stack height (upper 13.3 + lower 11.3) according to their catalogue. Let’s say, I want to change it to Chris King 1-1/8 NoThreadSet that have 31.4mm total stack height (upper 17.7 + lower 13.7) does it change steering geometry? Should I lowering my stem angle/height to get same body position? Is it safe to add bottom stack height? Every bike manufacture have headset recommendation that can not be change? I look up at bikegeocalc.com and messing around with headset stack section and every measure is change when changing headset bottom stack height. And because there are another EC 1-1/8 headset that really fascinated me like IRD Double Roller Drive, Tange Fatty MX2, or Reset Racing Headset that have longer bottom stack height so any response will really help. My bike is Kona Sutra. |
Upgradring a headset ain't going to make a noticeable difference unless.the old.one is worn out.
If you have rhe new headset and tools , try it and see does it work. 40 min job. If you don't have the part or tools just leave it alone. |
The 2 mm change between your current headset and the CK will have a negligible effect on handling and rider position. That said, what is the incentive to "upgrade" your current headset?
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Only the lower stack will affect the geometry if it changes, and as noted, it's unlikely to be a very significant change.
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Does the bike have a suspension fork? Slightly decreasing the fork's sag will do the same as increasing the lower stack. Or mounting a slightly smaller profile rear tire again will do the same. Andy
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Originally Posted by blamester
(Post 20719189)
Upgradring a headset ain't going to make a noticeable difference unless.the old.one is worn out.
If you have rhe new headset and tools , try it and see does it work. 40 min job. If you don't have the part or tools just leave it alone.
Originally Posted by HillRider
(Post 20719215)
The 2 mm change between your current headset and the CK will have a negligible effect on handling and rider position. That said, what is the incentive to "upgrade" your current headset?
Originally Posted by JohnDThompson
(Post 20719231)
Only the lower stack will affect the geometry if it changes, and as noted, it's unlikely to be a very significant change.
Sorry I mean it is just to keep peace in mind because already one year after I purchase it. Not have problem with my current headset it is still spin correctly. Maybe for my next build....If the factory bike spec have a complete FSA TH848 headset, is it safe to change different type of headset that have longer stack height? especially on the lower cup...
Originally Posted by Andrew R Stewart
(Post 20719357)
Does the bike have a suspension fork? Slightly decreasing the fork's sag will do the same as increasing the lower stack. Or mounting a slightly smaller profile rear tire again will do the same. Andy
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Changing the lower stack height does change the geo angles of the of the bike in the same way a different length fork will. However, 2mm is so small a change as to be essentially irrelevant. It aeems pointless to me to replace a working headset as a preventative measure. A headset usually lasts last many many years. If it is still turning smooth with no play, leave it. |
Originally Posted by Kapusta
(Post 20720468)
Changing the lower stack height does change the geo angles of the of the bike in the same way a different length fork will. However, 2mm is so small a change as to be essentially irrelevant. It aeems pointless to me to replace a working headset as a preventative measure. A headset usually lasts last many many years. If it is still turning smooth with no play, leave it. better to leave it... thanks. |
Wheelbase say a metre, other side of the triangle 2mm, the angle is 0.11 degrees.
So you're looking at something like half a degree per centimetre you change the height of the lower cup. Pretty negligible in most any scenario. |
Originally Posted by Kimmo
(Post 20722814)
Wheelbase say a metre, other side of the triangle 2mm, the angle is 0.11 degrees.
So you're looking at something like half a degree per centimetre you change the height of the lower cup. Pretty negligible in most any scenario. |
Originally Posted by JohnDThompson
(Post 20723004)
… and well within the range you'd encounter running different tire profiles and/or tire pressures.
I forget about running different tire profile... thank you again! |
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