Bottom bracket refacing
5 min read
Asked by: Steven Carter
Why would you face a bottom bracket?
Facing is just as critical for press-fit bottom bracket bearing alignment. It also ensures the lip of the bottom bracket cup fits evenly and squarely against the face of the frame to hopefully eliminate clicks.
How do you face a bottom bracket shell?
Quote from video: Apply cutting fled to the Rhema this will prevent it from overeating. And facilitate the flushing out the deborah's rotate the bottom bracket facing tool clockwise.
Does changing bottom bracket make a difference?
In other words, bottom brackets do different significantly drag-wise in terms of percentages but as far as actual watts are concerned, we’re talking relatively small numbers here that most general cyclists aren’t likely to notice.
How often do bottom brackets need to be replaced?
Your distances seem a bit low. 3,000 miles would be incredibly short life for a bottom bracket cartridge. 100,000 would be normal. Cup and Cone axles do wear quicker but that’s more due to water ingress causing damage rather than wear from straight usage.
How long does a bottom bracket last road bike?
Properly maintained, an average entry-level hybrid or street bike bottom bracket from a reputable parts company should last indefinitely, or for at least 100,000 miles.
How long does a MTB bottom bracket last?
As for a bottom bracket, on the low end, maybe 5000 miles. The basic Shimano one most people use (UN51/55/similar) can reasonably expect 10k+ miles. But sometimes you get unlucky and get a bottom bracket that lasts maybe 500 miles.
Is BB92 the same as PF92?
The frame’s bottom bracket shell inner diameter is 37mm. A bearing with an OD of 37mm is pressed directly into the frame. Trek is moving away from the BB90/95 system to what they call PF92, which is the same as a BB92 (41mm ID shell and 92mm width).
Can you Rethread bottom bracket shell?
Most bottom bracket shells have an internal thread to accept bottom bracket bearing units from numerous manufacturers. If these threads are not in acceptable condition, they may need preparation. Threads may need realignment, or may have weld splatter from manufacturing that prevents the threading of the bearings.
Can you face a carbon frame?
That said, carbon is a material used throughout the world for many applications so there’s absolutely no reason why you can’t face a carbon frame using the same process you would for a metal frame.”
Do ceramic bottom brackets make a difference?
The Bottom Line: Quality hybrid ceramic bearings are better than steel bearings in a bicycle bottom bracket application because they have rounder balls for lower resistance, better races for lower resistance, and are grease-efficient in low RPM, low heat environments for lower resistance.
Will ceramic bearings make my bike faster?
The short answer is yes, quality ceramic bearings do offer a performance increase. They roll smoother and with less friction creating less resistance. “Faster” is relevant though; they will not knock 10 minutes off your next Ironman but they may get you across the finish line seconds faster in your next time trial.
Is ceramic bearings better than steel?
A ceramic bearing is also harder than steel bearings (up to 30%), which improves durability, and they also don’t rust so less maintenance should be required. Most sealed ceramic bearings are actually hybrid ceramic bearings, which combine a steel race with ceramic ball bearings.
Is a sealed bottom bracket better?
A good bottom bracket is a “fit it and forget it” deal. A sealed unit is what’s current and popular because it doesn’t require any servicing. They last a long time and can easily be replaced if they wear out.
Why do bottom brackets fail?
The fail by water and grit entering the bearing and causing the cartridge bearings to get loose. This is felt by poor shifting or chain rub, and finally the bearing can get very stiff if the balls jam up inside. External bearings can be cleaned and adjusted. Most have some sort of seal that can also be replaced.
Do I need to grease the bottom bracket?
Quote from video: Похожие запросы
Is threaded bottom bracket better than press fit?
After a decade or so of press-fit bottom brackets being the dominant system on high-end road bikes, there has – to almost universal acclaim – been a notable return to threaded bottom brackets in the last few years.
How do I make my bottom bracket smoother?
Quote from video: So not only will having a spacer eliminate side load and quiet your creaky bottom bracket it will also make for a smoother pedaling.
Do press fit bottom brackets creak?
The reality is pressfit has nothing to do with creaking. There are many areas of a bike where bearings have a pressfit and there are no problems. For example, wheels, freehubs, pulley wheels and some headsets are pressfit yet they don’t generally creak.
What does a low bottom bracket do?
In this sense, a lower bottom bracket improves stability in much the same way as a longer wheelbase. Counterintuitively, a lower bottom bracket also makes the bike more agile when turning. When a bike leans into a corner, it pivots around the roll axis (the line connecting the two contact patches along the ground).
Why are MTB getting longer?
A longer reach and wheelbase means a more stable place to climb – well, as long as the seat angle is sufficiently steep to keep the front from lifting – and if the bike is stable then you’ll need less of the moving about as on the saddle as you attempt to find traction.
How high should my bottom bracket be?
With 170 mm cranks, a 10 ½ inch bottom bracket height is a good starting point. Road racing will require a slightly higher bottom bracket due to the need to pedal through some turns. 10 ¾ inch bottom bracket height is a good starting point if you are using 170 mm cranks.