22 Feb 2012

Hollowtech2 chainset


22nd 35-40F, 2-4C, heavy overcast, slightly misty, very windy. 25 miles.

Talk about confusion! I spent ages going through online bike sales website which listed local villages as outlets. Off I rode to the local bike shops and expected to be able to lay my hands on the stuff I had chosen. Except that they had nothing to do with the website! This despite them being the only bike shops in these villages. I think this is very unfair on the local bike shops. (LBS)

In the interests of keeping these helpful chaps in business I chose from their existing stock. What use is a cheap website if I can't get help, expert advice or back on the road in a hurry? Whatever savings I might make by buying from a box shifter are totally insignificant when viewed from that viewpoint. I'm unlikely to need the shop's bike mechanic skills but at least they are there if I get stuck. I seem to be endlessly exploring new technology with all the more sophisticated, modern kit which I am fitting to Mr Higgins. Nothing much changed for decades in cycle parts. Then it was suddenly all change without my having been directly involved. (or informed)

The upshot of all this philosophising is that I bought a modestly-priced, 9 speed, 22,32,42T, Shimano, MTB triple chainset (with Hollowtech2, hollow axle and external cups) and 175mm cranks. Also a new 9 speed, Spectra chain and a pedal spanner. The chap in the shop had a go at my stuck pedals and then suggested I saw a slot in the end of the scrap cranks. Very sensible. The old chainset is now worthless and owed me nothing back from the £10 I spent on it (secondhand) anyway. :-)

My reasoning (if it is of any interest) is that one doesn't buy a new chainset every day. Not even a modestly priced one. The secondhand chainset which I found in the shed is already well worn with some damaged teeth. So it is likely to wear out a new chain far more rapidly than running with a new set of rings. Given the cost of 9 speed chains, at four per year with my mileage, a new chainset is a long term saving.

The one remaining unknown quantity is the 9 speed Sram cassette which I fitted last autumn. Does it still have a few thousand miles left in it? Or at least enough to allow a decent mileage from the new chain before both have to be replaced? I shall find out if the chain starts skipping tomorrow.

The Shimano SPD pedals are no longer cosmetically attractive but should last quite a bit longer. They spin nicely and the shoe plate catches are still perfectly functional.  Replacing the pedals with the same model would be another £40-50 at shop prices. They are invisible when I have my feet on/in them. I just hope I can get them out of the old cranks without damage. It would be nice if Shimano made them out of thinner stainless steel. So they would not rust quite so obviously when subjected to road salt. Some might argue that I never clean my trike so I can't expect any better.

Now I'll have to read the 3 foolscap pages of close-packed, microscopic writing and drawings of the chainset instruction manual. Eek! Let's see now... FC-M542 uses 3 spacers with my 68mm bottom bracket width. Acknowledged, Houston. Lucky I remembered to buy the Hollowtech cup fitting tool. I'll have to dig out my old torque wrenches.

Work commenced after lunch with the removal of the old chainset. I followed advice of the bike shop owner and sawed slits in the ends of the cranks. The pedals then came out without much effort.

This was after cleaning up the threads with a steel wire brush.
No longer quite the bling of new, are they?

The square axle cups were removed and the bottom bracket threads brushed out with a small wire brush. This was wrapped in a cloth and repeatedly moved to new areas of the cloth to clean the threads as thoroughly as possible. The threads were then finally brushed with the naked steel bristles, wiped out again and then well greased.

The Hollowtech cups were screwed into place to 40nM. Using my small torque wrench and the specially shaped socket. The cup packing rings were arranged as per the instructions for a 68mm wide bottom bracket shell. I found that I could have reversed the spacers to bring the chainrings slightly inboard. To make the large chainring slightly more reachable by the front changer cage. In top gear the changer will not quite move out far enough to ensure clearance between the cage and the chain. 

The Higgins paintwork really needs attention as can be seen here. The marks on the tubes are from the plastic, frame-fitting pump.

The new chainset in place with the new chain fitted. I had to drop the front changer quite a long way to cope with the 6 tooth reduction in the large chainwheel. I just had time to take a snap as it started pouring down. The lower gears should suit me better than having a large chainwheel which I never used.

Note the state of the grass after weeks of permafrost and snow. This afternoon coincided with another growing storm. It is supposed to gust to 50mph tonight. My tools kept being blown off the workbench. I have only roughly sorted out the gears so far. Both cables were slightly too long after the changes. The ground clearance is further reduced. Not a problem on a trike, on the flat, but ramps and traffic calming humps can catch one out. I'll take some more pictures tomorrow in better light. I'm rather pleased with the improved appearance.

Click on any image for an enlargement.

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