Wednesday, 16 June 2010

A Disk brake Mundo

It took a lot longer than I thought, but then I got the wheel back in and the disks are on. 160mm front, 190mm rear.

This morning was lots of assembling  and disassembling it all, checking with small spacers the amount of metal to add in. I had forgotten about the axle adapter I had on yesterday  - that was an extra 2mm. All up the wheel dropped down 7mm from the original dropout spot. I ended up getting a 14mm bolt, filing the grove for the 10mm axle, and brazing that in the dropout. Then a 4mm plate on the long part of the dropout slot at the rear to get the whole thing to 10mm.  Lots of filing today.

It works, but its still going to be a bit fiddly to change the wheel. The wheel will not just drop in or out. The axle plate on the Rohloff hits the chain stay tube when at the front of the dropout. With the 14mm dropouts, I didn't notice this as there is more room on both sides for it to all move about. With the dropouts being 10mm, its noticeable. If I put the 4mm on the opposite side (the front of the dropout slot) it would have been better. Putting the wheel in or out, there is some jiggling, and rotating the external gear mech and the OEM axle adaptor, before it all drops in (or out). I'm not about to change it now. I don't need to get the wheel on/off that often, and its not that hard to do.

I did have a moment of wondering if the 203mm disk would be a just bolt on. There is enough room for it. Decided not to try it - as I didn't want to wait more days for a rotor and adapter.  Also had a wonder if there was another size caliper adapter that I could have used instead. Anyway if at some time in the future I want to change it, the bits added in can all be ground out.

The chain - I wanted to have the chain tensioner pushing up, but it didn't work out. The chain hits on the wide loader. Down still works. Don't know how many links on the chain, and I'm not counting them. I'm running 39/16 cogs, with 165mm cranks. Ended up using a half link to get the length just right.

Just as I finished, it started raining - and hasn't stopped. So there was a very short ride in the liquid sunshine.. The brakes feel a bit spongy. Need to ride a bit more to see if that is a real problem, or just my perception of them. Both hoses are too long. The front has way too much hose. Not sure if this affects the brake feeling. Will check this out more when its not raining.

The weather encourages getting mudguards on next. They will not go on easily. Brake calipers are in the way. Can make up short adapters to fix this, but am also thinking about making up some wider guards. I running 1.35 tires on at the moment, at some point I might want to got bigger. I'd like to not have hassles with mud guards then. Going to go hunt about tomorrow and see whats available. Corflute would be handy right now.

I also will put a piece of tube over the chain runs - as I want to try and keep muck off the chain as much as possible. It will also help keep the  bottom run from slapping against the frame. Ideal would be fully enclosed chain running in oil, but that's to hard to do. But any covering has to help with keeping the chain clean. Certainly will help with keeping me clean. I have a piece of 13mm poly tube, but want to try with a larger size. Another thing for tomorrow.

Out of interest, I wondered what the load limit on the Rohloff is. Ended up sending Rohloff an email last night asking. The answer is; there isn't any - but you do have to honor the gearing limits they set. So I can pick up as much stuff as I want - long as I can pedal it. That works for me.


  1. My experience with brand new disc brakes is that it takes time for all of the little imperfections on the pads to wear off, and all the little imperfections in the rotor to be impressed upon the pads. Once this has happened the effective surface area of the rotor is increased and the braking power improves a lot. The same is true for drum brakes (although the break-in is shorter).

  2. Good stuff. Keep us posted. I echo keller74's comments that your disc tab is different than my V3- with my holes essentially parallel to the chainstay. Also I noticed threaded bosses on the downtube near the head on Jim's orange V3 that are not my V3. For the bread rack I guess? John


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