Just finished a 21 speed conversion - shame to loose the gold cranks, but the original 42/24 gearing wasn't sufficient for road riding at my age (and fitness)! I'd already squeezed a 7 speed 13-28 on the rear - which helped, but I wanted more.
So I picked up few things off ebay Suntour Supurbe triple (52,39,26!) + bottom bracket £23, Tiagra long cage rear mech £7.00, Sora front mech £7.60, crank puller and bottom bracket tool £8 and set about the job.
Old cranks took a bit of shifting after 32 years - threads on the non-drive side weren't 100% and getting the tool to engage the threads was tricky - lots of thread cleaning and stop-start to get them to engage - OK once engaged. Then lots of nervous tightening until they eventually popped off. The original bottom bracket had been "ticking" and with weight of the cranks off they felt very rough. Fixed cup was also a pain to get off - good soak in plusgas and a big spanner did the job in the end. All balls were intact but several bits of swarf floating around in the bearings.
Now for assembly - problem straight away a) the UN26 BB that came with the cranks won't fit - the threads on the non-drive side are too deep for the threaded section on the frame b) my £4 bottom bracket tool doesn't fit - splines are too thick. So a trip to the LBS thinking they would have some knowledge on bottom brackets that didn't need as much thread as the UN26 (there is about 1 inch of threads on the non-drive side). The guy there doesn't seem to understand the problem and said all BBs will be the same (and different models/makes will all have this thread depth). Had the UN26 with me to show him - but no joy. After asking about the BB tool - he does get a UN55 BB off the shelf to see if my tool fits and that only has about 1/2 inch of threads - exactly what I need. End up paying over about £15 over internet prices for a UN55 and pukka BB tool. But I want to get the job done and I am supporting our LBS I tell myself.
Back in the garage I find the UN55 is chunkier than the 26 and was fouling the rivet that holds the gear cable guide on the bottom bracket housing, so out with a little grinding tool to grind the back of the rivet down until the BB fits.
Straight forward from there on. I see that Sunrace index downtube shifters are only £9.99 on ebay so go for some of those as well. All the old parts are nearly stored away so I can return the bike to original one day should the fancy take me (thinking about building a 531 based bike with 2*9 STI - perhaps a rat build for passing people on their carbon bikes on the local cycle track).
So here we are (waiting for some 99p gold ferrules to finish off the cable ends):
Test ridden a couple of times now - all works well - going up our local hills (ones I'd avoided before) I managed to stay seated with a couple of gears to spare. So happy that I can take on any route I fancy now without having to run through the hills in my head first.
So I picked up few things off ebay Suntour Supurbe triple (52,39,26!) + bottom bracket £23, Tiagra long cage rear mech £7.00, Sora front mech £7.60, crank puller and bottom bracket tool £8 and set about the job.
Old cranks took a bit of shifting after 32 years - threads on the non-drive side weren't 100% and getting the tool to engage the threads was tricky - lots of thread cleaning and stop-start to get them to engage - OK once engaged. Then lots of nervous tightening until they eventually popped off. The original bottom bracket had been "ticking" and with weight of the cranks off they felt very rough. Fixed cup was also a pain to get off - good soak in plusgas and a big spanner did the job in the end. All balls were intact but several bits of swarf floating around in the bearings.
Now for assembly - problem straight away a) the UN26 BB that came with the cranks won't fit - the threads on the non-drive side are too deep for the threaded section on the frame b) my £4 bottom bracket tool doesn't fit - splines are too thick. So a trip to the LBS thinking they would have some knowledge on bottom brackets that didn't need as much thread as the UN26 (there is about 1 inch of threads on the non-drive side). The guy there doesn't seem to understand the problem and said all BBs will be the same (and different models/makes will all have this thread depth). Had the UN26 with me to show him - but no joy. After asking about the BB tool - he does get a UN55 BB off the shelf to see if my tool fits and that only has about 1/2 inch of threads - exactly what I need. End up paying over about £15 over internet prices for a UN55 and pukka BB tool. But I want to get the job done and I am supporting our LBS I tell myself.
Back in the garage I find the UN55 is chunkier than the 26 and was fouling the rivet that holds the gear cable guide on the bottom bracket housing, so out with a little grinding tool to grind the back of the rivet down until the BB fits.
Straight forward from there on. I see that Sunrace index downtube shifters are only £9.99 on ebay so go for some of those as well. All the old parts are nearly stored away so I can return the bike to original one day should the fancy take me (thinking about building a 531 based bike with 2*9 STI - perhaps a rat build for passing people on their carbon bikes on the local cycle track).
So here we are (waiting for some 99p gold ferrules to finish off the cable ends):
Test ridden a couple of times now - all works well - going up our local hills (ones I'd avoided before) I managed to stay seated with a couple of gears to spare. So happy that I can take on any route I fancy now without having to run through the hills in my head first.
