Short or Medium Cage Shimano 105 5700 Rear Mech for 30T Cassette?

Updated 12 April2015

Do you need a medium or long cage rear mech to run a 30T Cassette? This was the question I asked myself recently. We're going to the French Alps for our Summer Holiday this year. Whilst I hope to be properly bike fit I am really keen to make sure that I can ride all the climbs - including the difficult ones like Mont Ventoux - without running out of energy and failing.

I normally run a 11-28T cassette with a compact chain set (as I am old!). Until last year I had never failed to get up anything using this gearing - although I failed on Hardknott Pass. I saw that as an aberration but  recently (March 2015) I failed again on Rosedale Chimney and Boltby Bank. Whilst these three climbs are special cases with very steep sections it just shows that if I'm over geared I know I am lining myself up for a failure. The climbs in the French Alps are quite different in that the gradients don't reach over 25% but the challenge is in the length - which can be 20km in some cases.

I was not as worried about the gradient but more about the duration - for example I am estimating 2 hours for Mont Ventoux. The backup plan was therefore to lower the gearing and the option was a 30T cassette. However 28T is the biggest for 105 (5700), and so the option is Ultegra where a 12-30 is available. Until last year the word "Ultegra" would mean a non-starter on cost grounds. What has changed is the introduction of Ultegra 6800 and 105 5800 ranges - i.e. 11spd. This has meant that Ultegra 6700 (10spd) is now more affordable (although not cheap). So I ordered a 12-30T Ultegra 10spd cassette.

The next challenge was whether or not my 105 5700 rear dérailleur (short cage) was up to the job of managing an 18 tooth difference across the cassette (although only 1 more than needed for an 11-28). I do have a spare medium cage 105 5700 rear dérailleur so if the short cage would not work I had a fall back plan.

The voice of the internet on the question of short or medium cage is fairly evenly split between short cage so the only way to really see was to try it.

First I photographed the 11-28 cassette on 28T in both the 34 and 50 chain rings:

34-28

50-28

This set up has worked very will for me for many 1000's miles so I am fully satisfied with it.

I then removed the 11-28 cassette and fitted the 12-30. The biggest issue is probably the big-big combination here:

50-34T

In big-big the dérailleur is on the limit and I would not use it. I occasionally use the big-big with the 28T cassette but only for a few meters at a time as the chainline is poor. It shows that with the 30T cassette I need to make sure I never go lower than the 2nd gear.

In small-big (the one I want for the Alps) it actually looks OK. In this picture I have adjusted the B Screw by about 3 full turns tighter to pull the jockey wheels away from the cassette and after this all was fine. The photo does not show it but these few turns made all the difference

34-30T (B Screw tightened)

Having fitted the 12-30 cassette all gears can be selected smoothly and without snatching or slipping, when using the work stand. This includes front ring shifting both up and down in all the most likely combinations of gears on the cassette.

This gives me a lot of confidence that all will be fine. I might be at the limit but as long as I am careful I see no issues.

 
The next steps is to actually ride it on the road - so all this review can say at the moment is that all is fine on a work stand. I'll report back when I have ridden it.

Updated 12 April 2015 - I have ridden the bike a few miles and can report all is well. More miles needed but I think all OK - just don't select big-big.

The good thing about this is I can fit the 12-30 before I go to France and then if its not as hard as I thought I can refit the 11-28 while I am there. I only need take the cassette lock ring tool and a chain whip

Bargainacious Ultegra 10 Speed Cassette

Every now and then some great offers appear and they are too good to pass. An example of this was my Scott (here and here). This week it was an offer from Halfords that I found out from a post on BikeRadar in the Commuting Chat section in the long running thread "Tell People About the Bargains you've spotted". This was for an Ultegra Cassette for £20 - but only  a 12-25 and not any of the other ranges.

After a little bit of deliberation (well not a lot) I decided I'd get one as a spare. I knew that for the Scott I'd not be able to put it on and just leave it - I need the 11-28 I have on for any big hills or long rides - but for a lot of riding it would be fine and when I needed lower gears I'd refit the 11-28.

The Giant has a 105 12-25 cassette fitted for most of the year and I manage fine on that and have used in the winter for some rides. I am on the 34-25 for some (slow) climbs but I can live with it.

I wrote about cassette sizes here and here

Unfortunately our local Halfords did not have any in stock  - there were some in Castle Bromwich and also in Stratford upon Avon. We decided that I'd cycle down to Stratford whilst my wife would drive down. We'd meet at Halfords, I'd put the bike in the car and we'd go into Stratford proper for a walk round and some lunch. About 30 minutes before I left I had a polite call from the store confirming that it had been put aside. 

I set off on my bike and did a meandering route criss-crossing the A3400 on this route:

It was pretty cold and some of the smaller roads were still icy so care was needed but I still arrived within 10 minutes of my wife and within 5 minutes of the planned arrival time.

We went to the Costa where I also got changed, had a coffee, and then strolled over to Halfords.

Compared to the Solihull store the experience was really great. I handed over the emailed ring and reserve confirmation. The assistant recognised the order and observed that she'd spoken to me earlier. She went to get it and found it within 30 seconds. I asked for the 10% British Cycling discount which was accepted without any issue which brought the price down further to £18. I was asked for my membership card which I had and there was a short conversation about needing to check as people had been asking for it without any proof. I also offered up an Electron gift card as payment that I had for Christmas and that all went through OK as well. So all in all a good deal and a good experience.

Here's the proof:

When I service the Scott for this year's riding I'll weigh the cassettes I have and compare the weights (105 12-25, 105 11-28 and Ultegra 12-25).

Then we went into Stratford and had a very pleasant (late) lunch in one of the many eating places in Sheep Street and a walk around. Despite it only being 40 minutes drive I don't think that I have been to Stratford for a number of years - we'll have to go again when the weather is better - although a cold winters day certainly kept the crowds down and made it a pleasure to walk round and park!