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Old 02-17-08, 08:32 PM   #1
wmodavis
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Steering Column length question

Park's Big Blue Book on page 185 states "For steel and aluminum steering columns, do not exceed 40mm between the stem and headset."

My question is: Does anyone know the rational for Parks 40mm spacing maximum?

On my bike build my headset-to-stem height is closer to 80mm as can be seen in the picture. I purposely left the column uncut until I found out more about fit. I'm resonably comfortable with the handlebar height but would more likely go for higher than lower if I did decide to change and do it by a bar or stem change as I can't afford Parks 'cut-it-longer' tool or their 'column stretcher' tool. Having just come across the Park statement, I am trying to understand the why so I can make an intelligent decision. Anyone have insight on this? Thanks for any input.
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Old 02-17-08, 08:38 PM   #2
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It places a great deal of stress on the steerer tube. Failure would be the concern, and it would no doubt cause a nasty crash.

If you need that many spacer and a high rise stem your frame is probably the wrong size for you.
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Old 02-17-08, 08:45 PM   #3
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I agree 40 mm seems rather restrictive for a steel or Al steerer, even a 1" one, considering Easton allows 50 mm with a 1-1/8" all-carbon steerer.

However the height you show plus an up-angled stem says, as baba noted, the frame is significantly too small for you. That much rise should never be needed.
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Old 02-17-08, 08:49 PM   #4
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Quote:
Originally Posted by barba View Post
It places a great deal of stress on the steerer tube. Failure would be the concern, and it would no doubt cause a nasty crash.

If you need that many spacer and a high rise stem your frame is probably the wrong size for you.
+1

In a few cases with very large riders I've had to search our vendors for very tall stems, especially when a stock-sized frame isn't quite enough.

I can see that the OP is using an adjustable stem, my guess is for more bar height. My preference is to use a riser bar rather than overextending the steerer for those looking for more bar height. With the fight between riders wanting lighter bikes and thinner steerer tubes, there's not much material there left to support the bars, especially when extended past 40mm. Also, using relatively weak carbon spacers adds nothing for support.

Look into a tall city bar, or perhaps a comfort bike if you still feel you are uncomfortable.
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