Wednesday, 26 December 2012

Triple Conversion Update

As regular readers of the Pixies blog will know, a few weeks ago I changed the Specialized over from a 4600 Tiagra compact 50/34 set up to a 5703 105 triple 30/39/50 set up (along with a few other upgrades to cables, bottom bracket etc) The earlier blog post on the subject can be found HERE  

I've done several hundred miles on the conversion now and thought it might be useful to provide a brief update on the conversion for those people considering a similar plan of action and also for those people that are interested in hearing how going from a compact set up to a triple has been in the real world?

I've ridden the Specialized over a variety of terrain, including some fairly tough hill training in Wales and three very different Sportives. One of the biggest benefits that I have found with the conversion is the fact that the middle "39" front chainring is providing me with a set of ratio's that suit my particular riding style and current level of fitness. I am finding that I spend a lot of time riding on the "39" and in conjunction with my preferred high (for a novice) cadence pedalling rate I am able to maintain speeds of 20-22mph over mildly undulating terrain with the full range of the rear cassette available to me. With the previous compact set up, I would find myself constantly swapping between the outer "50" and inner "34" over this type of terrain when trying to maintain a speed of 20-22mph, especially over ground that included long but not particularly steep climbs that were to much for the gears available on the "50" or required a the less than ideal "large to large" chainring/cassette combination. I'm sure this is a personal preference thing as the right gear selection is available with the compact set up, I just prefer to not be constantly swapping between chainrings and prefer a set up that allows me to easily maintain my preferred cadence rate.

Of course opting to use a triple rather than a compact brings with it a weight penalty and a little more complexity. With reference to the weight penalty, in the real world I reckon it's about 200 grams, which I can make up for by losing a little more body fat (I've still got plenty to spare LOL) If I was weight obsessive when it come to the bike, I guess saving a 200 grams in the weight of the crank and then going on to save weight in other components would be something to consider seriously, however at the moment I still have around 4-5 kilos that I can lose in body weight which is effectively cancelling out any theoretical small weight saving measures on cycle components. Therefore given the way that the triple set up suits my preferred cycling style, I think in the real world of being a relatively novice Sportive rider, I'm happy to live with the weight penalty to gain the spread of useable gears that the "39" provides whilst also having a lower set of gears for tough climbs and a higher set of gears for faster stretches of road.

On the subject of the weight of Shimano components, much is made in the world of cycling about the merits of buying a better group set to save weight when compared to a lesser group set. As some readers will no I am currently building a new bike around a LOOK 566 frame and I have been researching the differences between the current Shimano 5700 series 105 group set and the 6700 series Ultegra group set and one of the things that I have established is that the difference in weight between the two group sets is approximately 180 grams. The other difference between the two group sets is obviously cost with Ultegra being around £150-200 more expensive. So that's about a £1 extra spent per gram saved in weight. When the fact that the surrent 5700 series 105 probably performs as well as the previous incarnation of Ultegra and is not actually that far behind the performance of the current Ultegra, the "financially careful" amongst us might consider 105 to represent more "real world" value than Ultegra and we might choose to save those 180 grams by not eating as many pies for a couple of weeks!

What does 180 grams look like? this bag of sweets weighs 200 grams, not much is it?

Current Shimano group set weights (actual not claimed)

Dura Ace Di2    2375g
Dura Ace 7900 2111g
Ultegra 6700    2441g
105 5700         2624g

In terms of added complexity, the triple set up is a little more time consuming to initially set up as the front changer does seem to need to be in just the right place in relation to the chainrings and cable tension does seem to be more critical if consistently flawless shifting is required. It probably took me three or four attempts spread out over maybe two or three weeks to get this aspect of the conversion just right, however now that it is set up and the cables seemed to have stopped stretching, it shifting really well every time. I guess if I was having to take the bike to the local bike shop to have any required adjustments done, this initial setting up phase may have had the potential to test my patience, however as I do pretty much all of the work on the bike myself, it's just been a question of investing some time into getting the set up just right.

Photo from Park Tools

The Hope bottom bracket has been taken out a couple of times since it's initial installation in the pursuit of a good chainline, which has in turn probably helped to further improve the quality of gear shifts. Following the initial installation I noticed that I had a little bit of  sideways movement or "float" of the crank within the bottom bracket, not much, but it was there and left unattended I'm sure it would have led to premature wear of the bearings in the bracket. The float was removed and the chainline improved by installing a different selection of spacer washers from those originally supplied with the bracket (washers of varying thickness are available on e bay and from Hope) Getting this aspect of the installation was simply a case of trying different combinations of washers until the correct chainline was achieved and any float in the crank was removed, again a little time consuming but at least I wasn't paying somebody else to bugger around with it until it was spot on. There is a great article from Sheldon Brown on chainline and chainline adjustment HERE which is worth looking at if the subject of chainline is something that is new to you.

The Jagwire cables that I installed as part of the conversion have performed well. I can't say that they have improved the quality of shifting or braking in any significantly noticeable way, however they are quietly getting on with the jobs they are their for. I have had to take up some slack in the gear shift cables after about 300 miles which I am putting down to some initial stretching of the cables. It may be that this initial stretching may have only been noticeable on the triple because the front changer set up does seem to need to be "just right" and is definitely affected by cable tension. On a compact set up I suspect this initial stretching might go unoticed as they don't seem to be as fussy when it comes to front changer set up and cable tension. Would I change standard Shimano cables for Jagwire cables if all I was looking for was improved shifting quality? Probably not, because I suspect good quality Shimano cables are as good as Jagwire cables. If attention to cosmetic detail is one of the desired goals from a change of cables, Jagwire cable sets come in a variety of colours and can make a difference to the final look of a bike build. (I've got a white set sitting in the garage that are destined for the LOOK 566 that I am currently building up)

On reflection, this blog post is probably making the triple conversion sound like it has been difficult to get running right and us perhaps quite fussy to keep set up for flawless shifting? This hasn't been the case and now that it is set up and has a few miles under it's belt it is performing really well, with only the type of minor adjustment that would be required by the critical owner of any any set up. It's probably not a conversion that many people will consider as for many people a compact set up will do everything they want it to do in respect of providing a reasonably wide set of gear ratio's and being simple to live with. Where the triple provides added value for me is with the ability to provide a low set of gear ratio's for steep climbing via the inner "30" chainring whilst still be able to run a relatively closely spaced rear cassette to allow for a nice close set of gears whilst riding on the "39" It works for me and I guess that's what's important!

As always thanks for taking the time to take a look at the Pixie's blog and I hope you are able to pop back for another look sometime in the future.

Dha weles diwettha





No comments:

Post a Comment