Custom frames with loads of headset spacers

buckles Posts: 694
edited October 2013 in Road general
I wonder if anyone with frame building experience could answer this. I've always been curious as to why a custom road frame would need a tall stack of headset spacers (or any spacers whatsoever, for that matter).

I know standover height could be a reason and I can imagine if for example the bike has a higher than usual bottom bracket and/or the rider has short legs, the toptube would have to be made lower. But is there any other reason, e.g. those touted by compact frame makers (lower weight / greater stiffness etc)? Or have they just cocked up and made the frame the wrong size :lol: ?
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  • Wirral_paul
    Wirral_paul Posts: 2,476
    I'd suggest your final point would be kinda right - more likely the owner wanted a tiny headtube length to keep the stem / bars low, and then realised they couldnt ride in that position rather than the frame designer getting it wrong!!

    Saying that though - i've just ordered a custom winter / audax style frame with a 120mm headtube - very short as i ride a 54cm frame size. External headset and taller forks to give space for 25mm tyres and guards mean its putting me in exactly the same position as my other bike (with a 5mm spacer) though
  • Strith
    Strith Posts: 541
    Peoples position and requirements change with time, there are no set in stone rules for how you should fit on a bike.
  • I guess most custom builders use a standard head tube to match the rest of the geometry. What they SHOULD do, of course, is increase the headtube length and adjust wheelbase to stop the handling from becoming squirrelly if the customer wants/needs an increased femoral/trunk angle or a higher position.

    I'm not sure how much of an issue that it is, but Zinn's road bike maintenance recommends a short stack and angled stem rather than long stack (to decrease leverage on a carbon steerer).
  • napoleond
    napoleond Posts: 5,992
    Enigma seem to do this a lot.

    It ruins the look of many a frame, reduces front end stiffness and puts increased strain in the fork steerer.
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  • giant_man
    giant_man Posts: 6,878
    I don't think Enigma do it more than other manufacturers quite honestly. If you are going for a custom frame, you should have some idea as to how you want your frame built, esp headtube imo
  • Seems to me that headset spacers are a cheap, quick and easy fix to get the right position.

    But in an ideal world, you shouldn't have any. You should just have the right size frame/stem in the first place.
    APIII Posts: 2,010
    I had a 5mm spacer specced on my build as insurance, (in case my flexibility deteriorates). Any more than that just seems wrong. Ultimately, the customer is the one who signs off the build spec, so some people must be happy with a lot of spacers.
  • alan_sherman
    alan_sherman Posts: 1,157
    I think zero spacers looks a bit odd. Most forks recommend no more than 25mm. So there is a small window for the sweet spot before angled stems kick in.

    I think I run a 5mm spacer with a 73 degree stem as I run a horizontal top tube. I think anything other than a 73 degree stem looks wrong with a horizontal top tube. However - the trade off is less seat post showing. Getting a balance of all these things is what I would want from a custom build. Some people want to look fast - so want a small frame and a lot of seatpost. Usually this means a number of spacers!
  • buckles
    buckles Posts: 694
    I don't like the look of 'slammed' stems; I have a 10mm spacer underneath the stem on my race bike. I think the top cap is pretty tall compared to a standard top cap so really it's equivalent to 20mm spacers.

    My training bike is the largest size of the model available, yet I need 35mm of spacers under the stem... Would much prefer 25mm longer headtube and 10mm spacer...

    The custom bike that inspired my curiosity has 5 x 10mm spacers under the stem!
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