What’s wrong with my Reverb?

I recently got a broken reverb from my friend.
He said that it had had some sag and finally it totally collapsed.
I of course was interested if it could be fixed.

The post could be compressed by hand and did not hold the position.

First I noticed that it was lacking almost all of the pressure.

Continue reading “What’s wrong with my Reverb?”

Checking the bearings on Specialized Hi-Lo hubs

I have reused the original hubs from my 2011 Specialized Enduro Comp as rebuilt wheels with SixPack Racing spokes (double butted, 2-1.8-2mm) and Stans Flow Mk3 rims.

I thought that the bearings could be smoother and decided to take apart the hubs and check what kind of bearings they have.

1st step was naturally to take off the brake disc to prevent any contamination. Continue reading “Checking the bearings on Specialized Hi-Lo hubs”

Reducing sag on Reverb Stealth

Has your Reverb Stealth developed sag?
You don’t dare to use your Reverb in the winter in fear of the sag and expensive rebuild?

About 20mm of sag after riding an hour in -17C

Fear not, the sag does necessarily mean full rebuild, as it can easily be reduced with fork oil level tool (and few open end wrenches).

Continue reading “Reducing sag on Reverb Stealth”

Recon Silver bushing replacement part 1: removal

My trusty RockShox Recon Silver had one broken bushing as shown in my previous post. I believed that the bushings could not be changed as 2011 Recon (Silver) manual says so, but then I heard that they could be replaced and looked into 2013 manual which did not contain the info, that lower legs should be replaced after bushing wear.

I then tried to reason between running it with the broken bushing until it breaks, taking it to local shop for bushing replacement or buying new bushing and trying to fix it by myself.

The little engineer/mechanic in me took over and soon I was googling how the bushing could be replaced. I finally found a post on mtbr.com forums that had some good stuff written by username bad mechanic . So I ordered new 32mm bushings and started gathering materials for the tools.

M12 washer seemed to be properly oversized to make the extractor tool.

32mm_bushing_and_washer_for_removal_tool
32mm bushing and M12 washer. NOTE: the old and compressed bushings were only 34.5mm, so proper tool diameter would probably be 34mm.

Continue reading “Recon Silver bushing replacement part 1: removal”

GoPro mount adapter for bicycle lamp

It is best to have as much light as possible when mountain biking in the dark. Mostly this means to have at least two reasonably powerful lamps, one in the handlebar and another in your helmet. The one in the handlebar should point pretty close to give you peripheral visibility in front of you while spotting the route ahead.

I wanted to have some easy mounting solution for my helmets and GoPro mount was an easy choice as I already had some mounts on my helmets. I started working with an J-buckle as it already has holes in it for easy screw attachments.

J-buckle in parts
J-buckle in parts

I then took a small piece of 20mm electrical tubing and attached it to the mount. First try revealed that there was a small clearance issue between the rubber band on the lamp and GoPro mount.

Tube, clearance issue and fix
Tube, clearance issue and fix

Continue reading “GoPro mount adapter for bicycle lamp”

Fixing reverb remote with bent piston & broken bushing

Last summer I managed to ride into a pretty severe OTB (over the bar), which resulted in a few weeks break from driving, buying knee and elbow protectors and the most severe of them all, a broken Reverb remote.

From outside I could tell that the remote had a bent piston and broken bushing. After the breakage, I could still use it a little on the rest of the ride, until it leaked too much and stopped working. The leakage resulted probably because the piston head was not perpendicular to the cylinder. Normally the bushing keeps the button level and guides the (straight) piston rod and centers it in the cylinder.

Bent piston and broken bushing
Bent piston and broken bushing

When I took the remote apart I also found that there were some scratches inside the cylinder, probably due to still using the remote after the initial breakage.

reverb_remote_parts

scratches inside the cylinder
scratches inside the cylinder

Continue reading “Fixing reverb remote with bent piston & broken bushing”

How much temperature effects the pressure?

I heard/read multiple instances of people pondering if they should or shouldn’t change their tire and/or shock¬† pressure for winter. This got me thinking how much of a change there is and should I take it into account?

Science to the rescue!

Ideal gas law
Ideal gas law

In this scenario the amount of gas ( nR ) does not change and also the change in volume is not significant. We can then derive the following equation to calculate the necessary fill pressure to achieve a desired riding pressure, based on the temperatures of filling and riding.

ideal_to_fill_pressure
equation to calculate the filling pressure

Continue reading “How much temperature effects the pressure?”

RockShox Reverb rebuild (without Reverb bleed tools)

I have a 125mm RockShox Reverb (A1) in my Enduro bike. The bike was bought second hand and the Reverb had some sag and extended easily if bike was lifted from the saddle. So it was clearly in need for full rebuild but I was lazy and kept riding as it still mostly worked.

Then came winter weather with -10 degrees C, which was enough for the Reverb in its current condition and it didn’t stay up anymore. At home I took it from the bike and it had leaked oil (or something similar but more gooey) under it, no use trying to fix it by pumping more air.

Oil / slime on the bottom of the post
Oil / slime on the bottom of the post
the foam washer had also given up
the foam washer had also given up
Leaked internal seal head and slimy IFP
Leaked internal seal head and slimy IFP

Continue reading “RockShox Reverb rebuild (without Reverb bleed tools)”

Doval 30T MTB3032 14% oval

After monitoring my current 2×10 (32-24 : 11-34) gear usage and comparing different oval chainrings I came to a conclusion, that Doval 30T 3032OCP would be good for my usage, but also ordered 32T 104bcd version.

  • only oval that is available for 104bcd in 30T size with the 3032 mounting system and 99.5bcd

    Doval 99.5mm bcd (image from DOVAL )
    Doval 99.5mm bcd (image from DOVAL )
  • “double oval” i.e. rapid transition to minor axis after power stroke on major axis (see mtbr forum for more pictures and details)
  • cheap and easily available from ebay

Continue reading “Doval 30T MTB3032 14% oval”

Toothpaste to restore headlights? ***MYTH CONFIRMED***

The headlights in my car were in pretty bad and blurry condition and I even thought about buying new ones. I had previously tried to clean them with soap, alcohol, etc. but with zero to none results.

Then I decided to try to find if the current ones could be restored and after a short google, I found several different kits to clean and polish the lights and then some instances about toothpaste.

could toothpaste really cure the lights?

Continue reading “Toothpaste to restore headlights? ***MYTH CONFIRMED***”