Lower Gearing on a Genesis CdF

[CharlesF]

I have a 2014 Genesis CdF with a Sora 50-34T Crankset and a 11-32 cassette which I changed from the original 11-30 one.

I have found that my lack of regular riding due to travelling for work and my age (64) has meant that many hills around Glasgow have become more than I can manage.

I need your help in lowering the gearing on my bike, do I fit a MTB rear derailleur and bigger range cassette or change the crank to the Sora triple? At the rate I ride, I not concerned about minor weight gains or not having a very high gearing.

Of course, the other option is a new bike with suitable gearing but I really like the CdF and want to keep it.

Over to you.....

 

[Osprey]

You already have low gearing there. There's quite a weight penalty with a CDF. My Croix weighs 12kg which I really notice on the hills. They're a quality bike so I wouldn't replace it, you'd miss it. I custom speced mine from new as a triple, but you would need to change the crankset, Brifter and froñt mech. Don't be afraid to get off and walk if the hills too challenging.

 

[CharlesF]

Thanks Osprey, I have bought second hand shifters for a triple crankset, I was just unsure what route to take, cassette or crankset. No, I don't worry about walking up hills, it's more about keeping an even pace. If you reckon I do have low gears, then I'm more unfit than I imagined!

 

[raleighnut]

If you fitted a triple then you could fit a 'tighter' ratio rear cassette, give you more chance of staying in your cadence 'sweetspot'.

 

[Ajax Bay]

you would need to change the crankset, Brifter and froñt mech

Maybe add to that a new bottom bracket (longer axle), but depends on the crankset you pick - Sora triple would just use the HII BB.
A 30 vice 34t chainwheel will get you 13% more. You've already got a 32 at the back - to get similar advantage you'd need to get a 36 large sprocket cassette. Would need MTB RD then.
I'd go down the triple chainset route, especially as you have sourced a second hand LH triple STI. Having said that worth checking if your current Sora STI might be able to shift a triple (3400 yes, 3500 no afaik).

 

[CharlesF]

Thanks Raleighnut and Ajax, it looks like the triple is the way to go. You have both given me really useful information; I do have the 3500 Sora version of SRI.

 

[Ajax Bay]

I'd only add that if you don't go for a new Sora FD, I'd avoid a Tiagra FD eg 4403, 4503 as I had the exactly the failure "the protuberance on the alloy casting which retains the tensioning spring had sheared off " as described by this poster:

"I bought the FD-4503 to replace an FD-4403 on which the protuberance on the alloy casting which retains the tensioning spring had sheared off - a frequent failure it seems. The FD-4403 is no longer available. However, the two mechs are not equivalent, as the 4503 is not designed to operate on the 52-42-30 tooth chainset as the maximum quoted operating difference is 20T (50-39-30). Whilst the chain shifted between all three chainrings, there was a lot of contact between the chain and cage on all chainwheels."

I fitted a 105 FD-5504 and have a spare FD-6503 ready as a spare - both about £15 second hand. They are both designed for 52-42-30 chainwheels.

 

[CharlesF]

I'd only add that if you don't go for a new Sora FD, I'd avoid a Tiagra FD eg 4403, 4503 as I had the exactly the failure "the protuberance on the alloy casting which retains the tensioning spring had sheared off " as described by this poster:

"I bought the FD-4503 to replace an FD-4403 on which the protuberance on the alloy casting which retains the tensioning spring had sheared off - a frequent failure it seems. The FD-4403 is no longer available. However, the two mechs are not equivalent, as the 4503 is not designed to operate on the 52-42-30 tooth chainset as the maximum quoted operating difference is 20T (50-39-30). Whilst the chain shifted between all three chainrings, there was a lot of contact between the chain and cage on all chainwheels."

I fitted a 105 FD-5504 and have a spare FD-6503 ready as a spare - both about £15 second hand. They are both designed for 52-42-30 chainwheels.

Thanks, I will definitely stick to Sora, basic but works well for me without any failures.

 

[raleighnut]

Thanks, I will definitely stick to Sora, basic but works well for me without any failures.

I was actually thinking of a Deore crank and front mech on your bike, pretty sure they can be got with a 48 top and down to a 24 inner. Be closer to the compact you have on but with a bunch of 'bailout' gears.
Ask yourself are you ever gonna push 52-11, highest gearing on one of mine is the 653 TT bike with 53-12 but that is a featherweight bike (lowest gear is 39-25 but it has a 10spd Campagnolo 12-25 cassette so it is almost 'corncob' gearing)
I've got a standard 52-42-30 on my Ridgeback but that only has a 7spd 14-28 on the back and is set up to be a Light Tourer/Audax bike and some hills defeat me so nowadays I'd go a bit lower geared (or pick another bike out of the shed)
@Rickshaw Phil would be a good guy to come in on this, he goes up some stupid hills on his bikes, be good to get his opinion.

 

[CharlesF]

I was actually thinking of a Deore crank and front mech on your bike, pretty sure they can be got with a 48 top and down to a 24 inner. Be closer to the compact you have on but with a bunch of 'bailout' gears.
Ask yourself are you ever gonna push 52-11, highest gearing on one of mine is the 653 TT bike with 53-12 but that is a featherweight bike (lowest gear is 39-25 but it has a 10spd Campagnolo 12-25 cassette so it is almost 'corncob' gearing)
I've got a standard 52-42-30 on my Ridgeback but that only has a 7spd 14-28 on the back and is set up to be a Light Tourer/Audax bike and some hills defeat me so nowadays I'd go a bit lower geared (or pick another bike out of the shed)
@Rickshaw Phil would be a good guy to come in on this, he goes up some stupid hills on his bikes, be good to get his opinion.

This makes perfect sense for my type of riding, and I hadn't thought of it but it raises more questions. Do I have to use a Deore front, derailleur and a different bottom bracket?

 

[raleighnut]

The Deore is Hollowtech 2 (or should that be Hollowtech 11) so same BB, your front mech may cope (depends on how long it is but it is a compact) but if all else fails a Deore front mech ain't mega money.
I'd be nipping off to a bike shop and asking "would one fit", see what they say (there may be frame clearance issues)

 

[Rickshaw Phil]

Someone called.

Yes, I do occasionally ride hills that are a wee bit steep: http://shrophills.blogspot.co.uk/p/asterton-bank-long-mynd.html ** and my bikes are a little on the heavy side (17kg and 18kg) so I'm a big fan of low gears.

Your current set up gives a lowish bottom gear at approx 28 gear inches but not seriously low. From the options mentioned upthread, this is how they'd compare:
Road triple, 52-42-30 with 11-32 cassette: approx 25 gear inches bottom gear.
Deore triple, 48-36-26 with 11-32 cassette: approx 22 gear inches.
Deore triple, 48-36-26 with 11-34 cassette: approx 20 gear inches.
Deore triple, 48-36-24 with 11-32 cassette: approx 20 gear inches.

My personal opinion is that you wouldn't regret gearing as low as you can. If you opted for the road triple it would be noticeably easier than your current setup but you'd find the Deore triple would be even better.

The only issue is that I have a feeling there is a difference in pull ratio between STI shifters and MTB front derailleurs so they may not be compatible with a Deore front mech if you went along those lines. It's not something that I've tried so can't confirm whether they will work together. I'm sure someone with a bit more experience can advise on that.

** Edit: not my blog by the way - I just thought it a good description of the climb.

 

[CharlesF]

Thanks Raleighnut for giving me more to think about, in a good way!

Phil, this very interesting, as Raleighnut says, I need expert help about the shifters; luckily George at my LBS is very helpful and I need to pay him a visit.

 

[the snail]

Another option is the cranksets from Spa cycles, with lots of options for different chainrings. On the older cheaper shimano cranksets you can get replacement chainrings to lower the gearing. I'm running 105 5703 with a 26T granny ring which gives a pretty low gear with 11-28 cassette. If you want to mix road shifters and MTB crankset, then you need to choose the FD carefully, you can have problems with chainline, getting the derailleur close to the big ring without fouling the chainstay or the chain rubbing on the derailleur on the granny ring. My tourer has a sora FD and alivio MTB crankset.

 

[Ajax Bay]

Your current set up gives a lowish bottom gear at approx 28 gear inches but not seriously low. From the options mentioned upthread, this is how they'd compare:
Road triple, 52-42-30 with 11-32 cassette: approx 25 gear inches bottom gear.
Deore triple, 48-36-26 with 11-32 cassette: approx 22 gear inches.
Deore triple, 48-36-26 with 11-34 cassette: approx 20 gear inches.
Deore triple, 48-36-24 with 11-32 cassette: approx 20 gear inches.

Phil has given some options. I'd observe that the last two would probably require a new RD as well, the third because of largest sprocket capacity limit (max 32), the last because of total RD capacity (ie wrap, you'd be needing 24 + 21 = 45), beyond OP's current RD limits.

I think the KISS principle is worth taking into account. Keep it simple, stupid.