Homemade topcap, 5mm spacer, bolt ~2g total

Discuss light weight issues concerning road bikes & parts.
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v3d
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Joined: Thu Feb 21, 2019 12:05 pm

by v3d

3d printed, and then the threads tidied up with a die.

Equivalent to a topcap, 5mm spacer, and a bolt.

This isn't strong enought to get the bearing preload but once the stem bolts are tightened it replaces the usual ensemble.

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by Weenie


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FIJIGabe
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by FIJIGabe

Very impressive. I wonder if something like this could be made from Ti, and if so, how much it would weigh. That might be strong enough to put the required preload.
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Klaster_1
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by Klaster_1

Very clever idea and cheap, maybe I should try that too. On the other hand, 5mm UltraSpacer and Hypercap are 3.74g and can be used to preload. Might as well not bother with top cap at all. On the other hand, your dust cap looks heavy, probably somewhere in 10g range, I'd try to 3D print a replacement. Actually, I already have a 3D printed cap (1.6g) and plan to print my own version of Ultraspacer.

hannawald
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by hannawald

I swapped Ultraspacer back for carbon spacer. Very light but it deformed so it didn´t look that well and on my 2,5cm of spacers it has permanently deformed by mm or 2..so i think it may not be good for front end stiffness..

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Klaster_1
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by Klaster_1

hannawald wrote:
Sat Mar 02, 2019 4:30 pm
I swapped Ultraspacer back for carbon spacer. Very light but it deformed so it didn´t look that well and on my 2,5cm of spacers it has permanently deformed by mm or 2..so i think it may not be good for front end stiffness..
Oh man, that' sad to hear, I wanted to ask around for Ultraspacer feedback as I learned about the product and there it is.

v3d
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by v3d

Those extralite parts are interesting. This is really a fun project that I did for a ligher non-structural part. I have a feeling that this printed in Nylon with an SLS printer (rather than an enhanced PLA on a home printer) might be stong enough to get preload. But I've never actually needed to do that on the road, and other than if my stem bolts came loose I can't think of a reason why I'd want to, so it isn't a priority for now. Something like the Shapeways 'strong and flexible' might be enough.

Another alternative I tried was threading a thin (M2) bolt inside the plastic bolt. This made the bolt strong enough, but the top cap part would bow before achieving enough preload.

I have actually done a top-cap spacer combo before, but I decided not to use it in a position where if it crushes a little bearing pre-load is lost, since FDM prints can sometimes crush between layers. It probably would have been ok, but didn't want to take the small risk for a 7-8g saving.

Marin
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by Marin

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Last edited by Marin on Mon Mar 04, 2019 8:28 am, edited 1 time in total.

by Weenie


Marin
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by Marin

If you just want to have something light with no function, use a black condom?

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