Rear mech question

[Harleyboy]

Morning,

Am running a semi compact (52/36) with an 11-30 cassette and have a hilly Welsh sportive coming up soon so am thinking of changing the rear cassette for this ride only to either 32 or 34.

The internet suggests that I need a long cage rear mech to accommodate this. I think mine is the short cage version. My question is whether I could swap the cassette and not change the chain or mech without causing a failure? As long as I don’t cross chain big to big (my Di2 is programmed to stop this happening as is) will this be ok?

Also not sure if the di2 would need a programme change for different cassette?

You may be thinking why am I bothering for an extra gear or two....I might need it after 5000’ with a couple to go!

Many thanks

[Maximus_Meridius101]

You won’t need to do anything with the Di2. You could easily get away with 11-32 and your semi up front, ( although I’ve never personally tried it with a short cage mech , only a GS medium cage) it’s not ideal, but it should work, without going to a long cage. You could either get a long cage mech for the 11-34, or a wolfs tooth ( or similar ) hanger extender. Make sure you have a long enough chain as well.

Edited by Maximus_Meridius101 on Tuesday 1st June 12:19

[Dnlm]

Harleyboy said:

Morning,

Am running a semi compact (52/36) with an 11-30 cassette and have a hilly Welsh sportive coming up soon so am thinking of changing the rear cassette for this ride only to either 32 or 34.

The internet suggests that I need a long cage rear mech to accommodate this. I think mine is the short cage version.

Many thanks

Just to check, why only think? It should show up as GS (long) or SS (short) on the etube app.

i upgraded recently and forgot to specify to the bike shop. when checking it was long they said that's become the norm by far (and they only fit short cage di2 on request). Makes sense when di2 shifts are perfect every time, and how few want close shifts vs easier gears.

[ribbit]

Wild Wales Challenge?

I run 32T with standard compact 50/34 and a medium cage, so not exactly an answer to your question. However, I'm no athlete and those ratios have seen me complete every climb during the past few years.

Edited by ribbit on Tuesday 1st June 12:27

[Harleyboy]

Thanks, good to know about di2. Even a 32 might just help me out a bit!

I will need to check the chain but am hoping that as long as I keep out of the big/big scenario it should be ok.

Just to be sure, pic of my mech attached. Pretty sure this is a short cage?

[Harleyboy]

ribbit said:

Wild Wales Challenge?

I run 32T with standard compact 50/34 and a medium cage, so not exactly an answer to your question. However, I'm not athlete and those ratios have seen me complete every climb during the past few years.

It’s the Beyond Wales sportive. Medium route 6600’. Your set up is about the same as mine and I’m ok with it for my usual riding but haven’t done anything more than 5000’ in one ride

[Harleyboy]

Dnlm said:

Just to check, why only think? It should show up as GS (long) or SS (short) on the etube app.

i upgraded recently and forgot to specify to the bike shop. when checking it was long they said that's become the norm by far (and they only fit short cage di2 on request). Makes sense when di2 shifts are perfect every time, and how few want close shifts vs easier gears.

I didn’t even think to check the app. It’s the 8050SS so short cage

[ribbit]

Harleyboy said:

It’s the Beyond Wales sportive. Medium route 6600’. Your set up is about the same as mine and I’m ok with it for my usual riding but haven’t done anything more than 5000’ in one ride

Looks like a good event. Obviously, I don't know you, but if you've ridden similar distances and 80% of the climbing, I would have thought you'd be OK with your present setup.

[Harleyboy]

Yes, am looking forward to it. Riding with a mate who is training for an ironman so he’s a bit fitter than me but I’m riding about 125 miles a week so ‘should’ be ok. Got a few weeks to get some more hills repeats in.

Just realised what I said earlier was incorrect. My semi and 11-30 is a couple of ratios down on a compact with a 32. That’s the same set up as my winter bike which is easier on the hills but I won’t ride that as not as nice a place to be for a few hours

Edited by Harleyboy on Tuesday 1st June 12:59

[waynecyclist]

You would be better to run a mech extender

[Gilhooligan]

I went from a 30T to a 34T with a compact Tiagra groupset which had a short cage derailleur. It ran fine as long you didn’t cross your chain.
The bigger jumps between gears were the only downside.

[SpartacusF]

Are you sure you need it? It's the steepness of extended climbs that you have to accommodate - short stuff you can honk (stand), and extended shallow stuff you won't be in the lowest ratio. Find the route on Strava, find the longest steepest climb, and compare to a hill you know and have ridden on your current 36/30 lowest.

[Harleyboy]

Hi, that’s a really good point. I’m not sure I actually do. Went out yesterday and did three steep hills (13-15%) and managed each of them without using the lowest gear. So the overall elevation was only about 60% of what I would have even doing (event has been cancelled for no real reason - so annoyed!) so I’d have more tired legs to contend with but I think I’ll still with what I have

Thanks for the input - genuinely appreciated

[TCX]

Cheap as chips,always find it handy to have a 'bail out' gear,
https://www.googleadservices.com/pagead/aclk?sa=L&...

[wattsm666]

Would it be easier to put a compact chain set on instead

[Harleyboy]

Mmm, not sure it would be easier to change the chain set, or cheaper.

I’m going to stick with the current set up but the hanger extender is a good shout. The event has now been cancelled by the total shower that Beyond Events. Second time they’ve cancelled an event for no definitive reason