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spacers(15 posts)

spacersross
Mar 14, 2003 8:15 PM
I have about 3" spacers between my headset and stem is that to many? and is it safe to have them on top of the stem?
re: spacersrussw19
Mar 14, 2003 9:24 PM
If your steerer is alloy or steel, it's probably ok. If it's carbon, you should check your fork company's website to see if they have a max.

Russ
way too many...C-40
Mar 15, 2003 5:23 AM
Something's wrong if you need that much spacer. It's smarter to use stem rise to raise the bars.
Whatever...Matno
Mar 15, 2003 8:26 AM
Some people like their bars that high. I enjoy having my bars level with the seat (although my current ride has them about 4" below). Unless you have a carbon steerer, using the spacers has no real downside other than a very minimal amount of weight. Countering that is the fact that riser stems look TERRIBLE on a road bike. A lot of newer bikes have such short head tubes (e.g. integrated headsets) that a lot of us NEED to raise the bars quite a bit just to get them to a "normal" level.

3 inches may seem a bit excessive, but if it fits you, do it.
effectively shortens the reach...C-40
Mar 15, 2003 2:25 PM
Another thing to consider about using a lot of spacers is that it shortens the reach to the handlebars. The ratio is approximately 3:1. 3 inches of spacers would reduce the to the bars by nearly 2 inch or 2.5cm. You can end up needing a long stem to restore the reach.
effectively shortens the reach...russw19
Mar 15, 2003 2:40 PM
I just read this and didn't do the math, but wouldn't that ratio only be true if you had a 60 degree head angle? Maybe I am missing something here, but that doesn't sound right.

And even so, reach is one factor in stem position, height is the other.... don't sacrifice one for the other, get them both right.

Russ
effectively shortens the reach...AllUpHill
Mar 15, 2003 4:56 PM
60 degree headangle would make a 2:1 ratio. 2 inches of spacers, 1 inch closer to saddle. The 3:1 ratio would result from a 70.53 degree angle. Remember your trig ? ;-)
effectively shortens the reach...russw19
Mar 15, 2003 7:15 PM
Nope, I don't remember... that's why I said I didn't do the math! ;-)

Russ
effectively shortens the reach...jordan
Mar 15, 2003 9:07 PM
I am not doing math but measuring a 3" rise on my 60cm frame reduced reach by 1 cm.And speaking of math 2"=5.08 cm.
didn't measure right...C-40
Mar 16, 2003 5:49 AM
Don't know how you took your mesurements, but moving a stem up by 3inches will reduce the reach by 2.23cm with a 73 degree head tube angle.
didn't measure right...jordan
Mar 16, 2003 6:44 PM
Stop doing trig that doesn't account for variables such as seat setback.Measure it on a real bike and you will find your reach calculations are not accurate.
Is this a jokeKerry
Mar 16, 2003 7:00 PM
Are you telling us that we can't talk about how much raising the stem moves the bars back because every other positioning factor could change too? Get a grip, man. The point was made that raising the stem that much moved the bars back. It's true, full stop.
totally accurate...C-40
Mar 16, 2003 7:03 PM
If you'd ever worked in a machine shop or designed a machine component, you'd know that trig is vital to manufacturing most of the components of your bike. Trig is 100% accurate.

Seat setback has nothing to do with the effect of moving a stem up or down. It's a simple high school level problem. The stem moves back by the cosine of the head tube angle when it's moved upward. In the case of a 73 HTA the cosine is .29. Should have payed more attention in high school.
totally accurate...jordan
Mar 17, 2003 1:34 PM
Ok guys I did measurements again and it is more like 2cm-sorry for my mistake!
thanks guy I am going with 2"3/4. (nm)ross
Mar 16, 2003 3:51 PM