It also clearly depends on the weight of the rider and his or her position on the bike, which determines what percentage of that weight is resting on the handlebars.
Another critical dependency is how long the stem and handlebar are, as greater leverage puts greater stress on the steerer. The shape of the stem clamp and sharpness of its lower edge also affects the stress on the steerer. Finally, the spacer height that can be safely used depends on the type of riding the bike will be subjected to.
If the rider pedals it gently on smooth roads, the answer will be different than if he rides it into curbs and big potholes or off of semi-truck loading docks. I have a philosophy on this that is colored by the fact that I design and build both custom and non-custom bikes for very tall, and often very heavy, people. Only then am I confident enough to use a tall spacer stack on the fork steerer.
Tall riders who do not have a custom frame that fits them often have a big spacer stack of as much as mm under their stem in order to get their handlebars high enough.
Breaking a steering tube is a guaranteed crash. I made this post, because I am just curious about your aesthetic criterion. Well, as for my opinion, I don't like zero spacer below the stem.
I like 5mm spacer above the stem, so for the balance, at least, I prefer 5mm or more spacers under the stem. Anyway, thank you again, all of you. Maybe my original post might not have given enough explanation about my intention, cause I'm not good at English. I hope I could return with some other useless? Last edited by Aya on Tue Jan 16, am, edited 2 times in total. Post by gewichtweenie on Mon Jan 15, am a little nub above the stem is okay. Post by pdlpsher1 on Mon Jan 15, pm Can't help but notice the old style Di2 external junction box.
Why aren't they using the handlebar junction box? A maximum stack height of 2cm is allowed below the stem and a single 5mm spacer must always — always — be stacked above.
All questions can be answered here. If it can't, it's not worth asking. The most important part of this component set is the seal. The design provides an internally mounted threaded sleeve which winds up or down as you rotate the outer casing. Turning the outer casing to the limit achieves the full 7mm extension. The edge at the base of the cone is burred; getting a grip with greasy or sweaty hands is not a problem. Yes, you could adjust your spacer and stack height out on the road. You have to know the correct technique to make use of this feature though.
We show how it all works in the remainder of this article. The headset on this bike is a OEM version of a First integrated headset. This type of headset has a rubber gasket just below the top of the seal which forms a firm seal to the steerer.
Pulling the fork down presses the seal against the head tube, easily sliding it a few centimeters up the steerer. You then slip the fork back up into position. Wiping away old grease and dirt from the bearing seats, top and bottom. Then coating those same surfaces with a light smear of grease. Once you move the bearing seal flush over the bearing and compression ring, you can decide how you are going to make use of the adjust mechanism.
Ideally, of course, you have planned this in advance: it all depends on steerer height. If you are a racer with a zero, or near-zero, stack height, then follow the procedure here to the letter—your steerer will be cut near flush to the top of the stem.
You need to calculate a ball-park stack height to work with. Does the cyclist require a default 5mm spacer, 10mm, or even 20 or 30mm stem height above the top of the seal? The calculation can be made with the 7mm in mind: you could extend the sleeve all the way out for the initial installation, which allows for adjustment of 7mm down to 0mm.
The illustration shows a 2. Making use of the full 7mm ie. Too far. Post 8 of 19 views. Post 9 of 19 views. What fork is on the bike. If it was say an Easton carbon fork, it would be 50mm max under the stem. If it was say a Reynolds fork then it would be 40mm. If it is say a Profile Design fork the it would be 20mm.
Just figure out what for you have and if you need it at the max so be it. Who friggin cares what the ST style police think. Ride what is comfortable and within spec. At least you are still riding with a bad back. Good for you. Post 10 of 19 views. The two things that should be guiding you are as follows: 1. If you have an excessive number of spacers - you may be on the wrong size frame, or the wrong brand or style of bike for you. Fork manufacturers have limits as to how many spacers or ho much you can stack up above the head-set or the frame.
For full carbon forks with carbon steerers it's about an inch and that's it. Otherwise you are voiding the safety limits for the fork. Aluminum and steel steerers can be stacked up much higher - but you should re-read 1 if it's much more than an inch. Steve Fleck stevefleck Blog. Post 11 of 19 views. I was at about an inch until my back went. I havnt even really rode my tri bike this year bc of it, I have been sticking on my road bike. Since it has started to feel better recently, I want to try and get back on my tri bike but it is just too low.
I have 4cm and didnt want to go any higher but I wanted some opinions on if it was safe. I also have an orbea aero fork that came with the bike but I cut the steerer tube last season.
Post 12 of 19 views. I remember reading somewhere that for carbon steerers, the height of spacers should not exceed the diameter of the steerer tube i. Post 13 of 19 views. It varies by manufacturer, and considering different wall thicknesses and layups I can't really see using a rule of thumb.
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