I've been on holiday in Norfolk this week, not cycling but walking on this occasion. Norfolk is a great location for for doing both, its expansive never ending horizons provide for long days even in winter. This is because it is generally flat, devoid of the hills and hillocks I've become so familiar with on my cycling tours of Devon. In Norfolk, I could probably pedal forever. Here in Devon, my treasured Specialized Tarmac has been beaten on some hills, its semi pro 52/36 crank just simply runs out of steam on some of the more severe climbs. You may remember that in the summer, I chose to take my older Roubaix with its 50/34 compact chainring to climb Mont Ventoux. So, while I've not done any cycling this week, I have taken the opportunity to
Devonise the Tarmac. Yes, I've upgraded the chainrings to the hill climbing 50/34 compact configuration.
This is a change I've been pondering for some months. I originally added the Tarmac to my stable to give me greater speed on the straights. My feeling being that the Roubaix was soaking up power through its gel suspension system and that the Tarmac's rigidity and better gear ratio would give me the increased speed I was seeking. In the stats below, the Tarmac (semi-pro) is shown above the Roubaix (compact). The left figure shows the gear ratio for the big ring / small socket - flat riding and right the small ring / big socket - climbing configuration ..
In moving to the compact chainring, I assessed - using a handy iPhone app - that over 10 miles, I'd be just 43 seconds slower and have to spin my legs an additional 65 rotations .. this assumed the impossible that I'd find a 10 mile level piece of road and was physically able to maintain 90 rotations a minute and a speed of 33 miles per hour! This settled it, until I move to Norfolk, being able to actually make it to the top of hills was going to be more important than any 'marginal gains' over the non existent flats!
The next job, was tracking down the parts and fitting them. I had some really good advice from Chain Reaction, Wiggle and a new find, Tweeks Cycles. Both Wiggle and Tweeks recommended a French manufacturer's chainrings, TA Zephyr. Chain Reaction and Tweeks provided the most useful advice, so I sourced the rings from Tweeks and the tools from Chain Reaction, it seemed only fair .. particularly as Wiggle get most of my other business.
Fitting them was surprisingly easy. The 5 screws came free after initially breaking them free and then it was just a simple case of swapping one for the other. I think the new black TA Zephyrs look much smarter than the standard FSA fittings, and perhaps even a little lighter - may be I will find 'marginal gains' after all!
I was not sure if I would need to shorten the chain. The forums did not seem to agree on this. My plan was to compare chain lengths with my Roubaix, now of the same configuration, but could not believe it when they were an identical 54 links! I found, however, that the chain clunked a little when leaving it unchanged, so removed a link and found it to run much smoother. This was most odd, considering the bikes are the same size. The other change was to the height of the front derailer. This was, however, another inexact science. I think the final position chosen is OK as in the test ride gear changing was smooth enough, naturally time will tell!
I'm now hoping for a dry weekend sometime soon to take it on a hillclimb test .. may be even another trip to Mont Ventoux in the summer?!