stem riser - how will it affect handling?

clunkychunky

Been having back niggles since i have switched to my winter bike.
checked all the geometry and found the bars are about an inch lower than my race bike (which was set up by precision bike fitting). so figure an adjustable stem could raise the bars to the correct height but not sure how it would affect handling. any idea?

sungod

if the new stem gives aboutthe same reach (horizontal distance from the steerer axis) it won't make a significant difference to handling

whilst you could use an adjustable, if you measure things right you can just use a basic stem with a different angle

in fact, if your current stem is giving some drop, it might be enough to just remove it and flip it so that it now gives some rise

this might help with things...
http://www.brightspoke.com/t/bike-stem-calculator.html
http://www.brightspoke.com/c/understanding/stems.html

gmacz

Just turn the bars so they are an inch higher.
This will tell you if it is the inch drop that is the problem.

cyberknight

Bit of a thread hijack as i was going to post something in this area .

How much do you have to drop your stem by to counteract a reduction in reach of 10 mm to give you the same effective reach ?
The drop is not a problem as my commuter has a bigger drop but a 10 mm longer reach due to length of handlebars.The weekender has the same length stem but i have to hold onto the farthest point of the hoods as the handlebar reach is shorter.
I put a 10 mm longer stem on the weekender to give me the same reach but i have been told that it will affect handling, i do find the bike to be great on comfort and straight line speed but tends to be sluggish on fast turns as it wants to under-steer.Is this from the tyres or the reach?

sungod

if i understand correctly, on the weekend bike you want to increase the distance from your shoulders to the bars by 10mm, without increasing the stem reach, i.e. by using a stem with a different angle, so that the bars are lower

the difference in stem angle required depends on what angle it is at the moment, and where your shoulders are with respect to the bars, so there's not enough info to answer the question

a longer stem will make the steering less responsive than a shorter one - the end has to move further (in absolute distance) to achieve the same change in wheel angle - how much difference 10mm extra would make depends on how long the existing stem is, but the steering behaviour is also determined by frame and fork geometry, some bikes are just less nippy than others

how long is the current stem?

is it angled up or down or straight?

cyberknight

Old stem was 100 mm, new one i put on is 110 mm , both flat

shorter stem...

Longer stem

sungod

tbh 110mm isn't a huge stem, it shouldn't cause handling probems

looks like you've got quite a few spacers under the stem, if extra drop is ok, you could take some out and see if that achieves what you are after with the original stem

if the steerer tube is alloy just move them to above the stem temporarily, then you can try on the road before going all the way and cutting the steerer

BUT: if the steerer tube is carbon, that's not usually wise, as the expander plug will no longer be in the area of tube where the stem clamps, which increases risk of steerer damage/failure

so if it's carbon i'd just try taking out the spacers then *loosely* clamp the stem so you can sit on the bike and test the bar position, but don't ride it like this

cyberknight

sungod wrote:

tbh 110mm isn't a huge stem, it shouldn't cause handling probems


BUT: if the steerer tube is carbon, that's not usually wise, as the expander plug will no longer be in the area of tube where the stem clamps, which increases risk of steerer damage/failure

so if it's carbon i'd just try taking out the spacers then *loosely* clamp the stem so you can sit on the bike and test the bar position, but don't ride it like this

I was not going to cut the steerer as its carbon, i was just going to move a few spacers, this is the bike i ride most of the week so my body is used to this ...I will have to have a play when i get chance .Both of my bikes now have the same 3 contact point measuremenst afaik, maybe it is a tyre issue ? I have read that the boardman`s do suffer a little bit in fast turn speed but are great at fast , straight long distance comfort.

This is what i ride all week...