Bearing Up

It was only a matter of time before the Univega’s UN52 finally succumbed to slop. Mercifully its swansong commenced at the close of a fifty mile saunter, some sixty metres from Stenningrad.

Largely superseded by external cup designs, 8,000 miles plus isn’t outlandish from these venerable square tapers so long as jet-washing and similarly destructive habits are avoided. 

However, as component designs evolve, or indeed fall from vogue; supplies of older mid-range stuff often dwindle, leaving the market polarised between bargain basement and top drawer.     

Within two minutes of powering up the laptop and entering “68x113 square taper” into Google’s search bar, we’d scored a brand new, unboxed UN55 for the princely sum of £12.50 including postage! I’d been fishing for an XT grade UN72 but these have become rarer than hens’ teeth and I didn’t fancy playing the ebay lottery.

Without taking a grinder to their shells, aluminium alloy cups and hollow axles separate the 50s, saving a few grams without sacrificing strength; though avoid lithium based greases when speeding them inside ferrous frames, or risk the joy of seizures many miles hence.

Less than 48 hours after adding to cart, transplant surgery proved very straightforward given the existing unit was introduced with lashings of stout ceramic prep, complimented by copious quantities of home brewed corrosion inhibitor. Curiously enough, the UN55 has also reduced the Q-factor slightly but this is pretty academic on a tubby tourer. Now for some self-extracting M8 crank bolts methinks…   

   

Transformation Complete

Having left Kushi KA for servicing/MOT testing, Meg the magic (Nissan) Micra spirited us to Maldon Shot blasting & Powder coating for the grand finale’. Upon arrival, Chris had already tended the affected areas with Metafil-an aluminium based filler that seems much sleeker than thermal putties, although care is needed to avoid generating air bubbles since these can bleed through during the final curing phase.

Perhaps unsurprisingly given its age, there’s trace, corrosion induced pitting along the inner, drive-side chainstay, thankfully long dormant and before my adoption. This superficial scarring won’t present in the final colour coat, nonetheless, Chris leaves nothing to chance and gives said section a final, precautionary tickling in the glass bead cabinet.

Three minutes later, we’re ready for masking and that all-important zinc phosphate primer. Pedants might advocate chromates but the former is much kinder to personnel and planet while performance differentials are negligible. Indeed this brand cures with phenomenal, seemingly elastic tenacity given ten minutes at 200 degrees whereupon Chris graciously offers to create an exotic two-tone effect with no cost implication. However, accepting such would be tantamount to bladder milking, so we commence with RAL5024-pastel (sometimes called “French”) blue.

Being an electrostatic process, there’s no wastage and he achieves comprehensive, even coverage in five minutes, lovingly hanging it in their walk in oven for a further ten. At this juncture decals can be applied and sealed under a two-pack lacquer but I prefer a quiet, mysterious air. Speaking of which, there’s no need to clear coat-a finish of this calibre will look resplendent for many years. However, an acrylic was applied since opportunity presented itself.

Unlike polyesters, there’s no risk of crazing but acrylics cannot be sprayed to warm surfaces; hence said chassis sits patiently for twenty minutes beforehand. Lacquers appear white for sprayer convenience but form a glossy invisible barrier within the oven. Job done, we are reunited and homeward bound. Once again, I’d like to thank Lee Cooper (www.leecoopercycles.webs.com) and MSBC (http://ctc-powder-coating.co.uk/) for their remarkable generosity of spirit and obviously, taking such good care of my beloved frame.  

In the days since, I’ve reinstated the sealed square taper bottom bracket and am reflecting on headsets while doing some post (successful pass) MOT sill surgery- Kushi’s are sound, though demanded sanding and marine primer TLC to halt the silent killer’s relentless advances during the grottier months. Now, off to play with some 700x29 tyres!