New fangled.

30 06 2013

After the XT hub imploded on the Krampus, I decided to change the drive chain on the bike at the same time as re-building the rear wheel. I had one of the new-fangled thick/thin chainrings from Works Components, which I had pre-ordered out of curiosity rather than need. The ring is nice though, with reassuring thickness, well profiled teeth and neat relief. It is made from 7075T6 aluminium, which has seemed durable in the conditions I encounter. I was also curious about how an 11-36 cluster would feel. For the last couple of years, I have been happy with the range a 34 tooth ring with an 11-34 cassette gives me. On Maul, I even have a 35 tooth ring as that bike is aimed at going quickly. The engine sometimes lacks horsepower though, so it may be reduced to a 34 soon!

If you look closely, the tooth counts on a 11-34 cassette are 11, 13, 15, 17, 19, 21, 23, 26, 30, 34. An 11-36 is a little different in the lowest four gears. The gears I probably use the most, those in the middle, are the same, so I felt that I may well gain from the increased range when things get really steep. Having spent so many years on singlespeeds, I am undaunted by grunting up climbs or walking if needs be, but particularly when loaded with bikepacking kit, The Krampus takes a wee bit more effort as you ascend than my other bikes.

So, the tooth counts of the 11-36 are 11, 13, 15, 17, 19, 21, 24, 28, 32, 36. In going to 10 speeds, I needed to replace the rear derailleur and shifter as well. I have also been curious about the thick/thin ring’s ability to retain the chain, along with a clutch style mech. So I decided to fit a Zee rear derailleur. This is not only a lot less expensive than a Saint rear derailleur, it is designed to cover the 11-36 cassette – a whopping 25 tooth range. Most short cage derailleurs will only work with a reduced range, as the length of the jockey wheel cage is too short to take up the slack in the chain required for wide range cassettes. I am unclear if the B tension range is different, or if the geometry of the upper jockey wheel placement is different as well. The Saint, depending on where you look, seems to work with 11-36, but Shimano officially rate it to a maximum of 34 teeth. I don’t want to find out that it causes undue stress or damage on the derailleur in the middle of no-where so the Zee seemed to be a good option, though I fear I will miss the Saint’s added robustness and bash ‘rail’ that runs next to the parallelogram to protect it. In parts, the Zee uses stamped, formed metal sheet rather than (presumably) forged aluminium pieces as well. It will be interesting to see how the function is affected by this over time, or whether it is purely for weight and aesthetic appearance.

The rear wheel build was, well, awkward. Maybe because the rim is singlewalled and it had already been built? there was also a small flat spot on the rim, not noticeable to the naked eye, but the Centrimaster showed about a 0.3mm sharp, dip that could not be trued out – a clear sign of a dent in the rim. I don’t really know why, but the tension range in the wheel is broader than I would normally like – around 15% difference – but otherwise the near symmetrical spoke angle and tension led to a wheel build I am relatively confident will be durable. Of note, the ERD at 617mm and use of 298mm disc side, 300mm drive side led to perfectly full nipples and only some very minor Dremeling in order to remove protruding spoke. Again, I used freespoke for the calculations.

The drive chain parts went on very easily indeed and removing the Paul chain keeper felt speculative to say the least. However, on a quick ride around the block, bumping into curbs, jumping and hopping, the system was quiet and there was no indication I might lose the chain.

I will be interested to see how this system copes with Scottish conditions and probably more pertinently, wear of the ring. The chain line is pretty good on the Krampus, so I don’t think there will be undue wear on the wide teeth on the ring, but over time, the chain will no doubt become more rattly on the ring and I am curious to know whether it will have a reasonable service life or not. Obviously, as SRAM may take legal action, at least in the USA, the after market thick/thin ring market may well change soon as well…

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5 responses

30 06 2013
davechopoptions

Legal action? Interesting behaviour from a company who directly unashamedly ripped off Shimano’s HG cassette sprocket profiles.

1 07 2013
billy

Hi,
Been enjoying your posts in recents times and reading your past offerings.

Aren’t the numbers you quote here the number of teeth on each sprocket rather than ratios? Also, the chainline must vary quite a bit between the large and small sprockets. Do you set it straight for the gear you use most frequently?
Have you ever considered an internal geared hub?

1 07 2013
Singular Cycles (@singularcycles)

Was the rim flat spot at the join Jon? I had the same on recent builds of Rolling Darryl rims. Also got a Works ring on the way, hoping it works as advertised!

1 07 2013
velopest

@Billy: many thanks! and yes, thanks for pointing that mistake out, i will edit for clarity: internal geared, yes, i have, a friend has a rohloff that i have tried. you never know, though with the current crop of tough derailleurs and quick, slick 1×10, i’m not sure i’ll ever invest!…who knows!. i do try to get the chain line from the ring to the middle of the cassette, or as near as i can. it is easier on maul and B.A as they have 150mm rear hubs…which i think really ought to be the norm for most mtb these days.

@Sam: let me know your thoughts. i think they are pretty neato rings!

2 07 2013
velopest

Oh, and the flat spot wasn’t at the weld area. I have never punctured the tyre, so wondering if it was just a significant bump on a root or rock? No biggy, overall I have been very impressed with the RH/Knard combo.

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