mtb – T3mppu.kapsi.fi

New frame!

Today I got a new frame, Cube Stereo 160 C:68 27.5 action team 20″.

Here is some porn.

Converted to hardtail via 20mm electricity tube. (to prevent the swing from hitting the frame)

The scales were tipped at 2259g for the frame with internal routing guides and some screws.

Wheel clearance is quite good, chainstay measures from 75 to 80mm in the tire area.

Unfortunately the Pike is not quite the same color ;P

The downtube seemed like black in the retail pictures, but it is not 🙂

Geometry

From Cube web page:

Frame features:

Material: Carbon C:68 Monocoque Advanced Twin Mold Technology, ATG, ETC 4-Link, Boost148
Seat post: 31.6mm
Seat clamp: 34.9mm
Front deraileur: Direct Mount Side-Swing (Only compatible with Direct Mount Side-Swing front deraileur!)
Headtube diameter: Tapered 1 1/8″ – 1 1/2″ integrated IS41 – IS52
Bottom bracket housing: Pressfit 92mm
Disc brake mount rear: Postmount
Wheel size: 27.5″
Rear Shock installation length: 200x57mm
Bushings: 22x8mm / 30x8mm
Recommended Fork Travel: 160mm
Dropout: Thru Axle X12 (12x148mm) Boost

Myllykallio Enduro Training Center 3rd person + new line

Routed a new line on Myllykallio. This is so far the most technical and might still change a little as the flow was broken few times.

Here are also few of the spots in 3rd person view for a little bit better measurement.

Myllykallio Enduro Training Center Pt2

Another training session at Myllykallio with one new track (EK7) and some improvements to old ones.

EK7, a new track with a nice little huck in the middle.

EK2 got just a little reroute to include two new hucks.

Continue reading “Myllykallio Enduro Training Center Pt2”

Myllykallio Enduro Training Center

I had a thought, that my local (500m from home) rock could act as a training place when I would not have time to go further.

Now I finally got to go route it and got a friend with me. We spent few hours routing and cleaned some rock and wood, and in the end, we had 5 new routes.

As per usual, the camera makes everything so smooth and nice 🙂

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.

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.

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Talviklassikko 2016-02-13 (Winter MTB w/ fails)

Here’s some material from winter group ride in Espoo. We didn’t anticipate that there would be so much snow, resulting in a very eventful ride as we mostly had skinny tires.

Playlist for all the videos: Talviklassikko (Winter MTB w/ fails) (separate videos below)

NOTE: Finnish people should have audio on, it will be worth it 🙂

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

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?”

First time on a dirt track

We went to a dirt track after the last mtb group ride in local forest. This was my first time in actually built jumps, but luckily I had watched some videos in the internet. Most importantly I knew to lighten the front on the edge of the jump and then steer the front back down to landing while in air.

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 )
“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”