Lower Gearing on a Genesis CdF

[CharlesF]

The info keeps coming, I'm going to have to sit down and sort it all out; Ajax thanks for the highlighting some pitfalls, and I'm adherent to the KISS principle. The Snail has some interesting stuff and confirms the Alivio crankset works with the Sora FD. I was going to do this myself, but I can see I will need to speak to George at the LBS and I don't like getting his knowledge and then walking out without spending money so he might end up completing this for me.

 

[Nigelnaturist]

I have triple compact chainset 74/110mm bcd, with the FD 5700 I can do a 24 tooth change on the front currently 26/38/50 with a 12-13-14-15-16-17-19-21-24-27
Cassette left chainrings top, gear inches table

I did have it setup with a 28/38/50 and 12-23 until recently, both setups ran on the same chain length, on a RD5703 (A) I think GS (medium, cage)

 

[CharlesF]

I have triple compact chainset 74/110mm bcd, with the FD 5700 I can do a 24 tooth change on the front currently 26/38/50 with a 12-13-14-15-16-17-19-21-24-27
Cassette left chainrings top, gear inches table
View attachment 129643

I did have it setup with a 28/38/50 and 12-23 until recently, both setups ran on the same chain length, on a RD5703 (A) I think GS (medium, cage)

What model is your chainset?

 

[Nigelnaturist]

What model is your chainset?

Its a chainset from Spa a standard square taper jobby, http://www.spacycles.co.uk/products.php?plid=m2b0s109p3052, Rings are reasonable £10/15/20 for inner to outer well they were http://www.spacycles.co.uk/products.php?plid=m2b0s210p0 black or silver, I have a UN55 BB, most of my riding is done on the middle ring the 12th gives me upto 24-25mph, the 38x27 is almost as low as the 28x23 was it was something like 33" I thought I would miss the 18th cog but i haven't as much as I thought, it ran 12-13-14-15-16-17-18-19-21-23
This is how it was geared.

if I wanted I cold just slip the 12-23 back on, but I am carrying more weight on the bike at the mo so the extra gearing helps. the big problem with the 26-38 is you have to go down the cassette a tad further to be in the same range

 

[Ajax Bay]

Have a play around with this gear calculator. You can change all the parameters.

 

[CharlesF]

Its a chainset from Spa a standard square taper jobby, http://www.spacycles.co.uk/products.php?plid=m2b0s109p3052, Rings are reasonable £10/15/20 for inner to outer well they were http://www.spacycles.co.uk/products.php?plid=m2b0s210p0 black or silver, I have a UN55 BB, most of my riding is done on the middle ring the 12th gives me upto 24-25mph, the 38x27 is almost as low as the 28x23 was it was something like 33" I thought I would miss the 18th cog but i haven't as much as I thought, it ran 12-13-14-15-16-17-18-19-21-23
This is how it was geared.
View attachment 129669

if I wanted I cold just slip the 12-23 back on, but I am carrying more weight on the bike at the mo so the extra gearing helps. the big problem with the 26-38 is you have to go down the cassette a tad further to be in the same range

Thanks, this very helpful!

 

[Nigelnaturist]

Have a play around with this gear calculator. You can change all the parameters.

I have a spreadsheet, with gear ratios, cad speed ect, I did it ages ago.

 

[CharlesF]

Have a play around with this gear calculator. You can change all the parameters.

This the best one I have seen, I like the graphical presentation, thanks

 

[Nigelnaturist]

This the best one I have seen, I like the graphical presentation, thanks

The charts I have shown here are only a quick one, the other on the other comp, is better i.e. colour and a graph, but not visually as good as that.

 

[richbrown]

Sorry to resurrect this thread, I cam across it on google and am thinking about doing something similar on my 2015 CdF

Just wondered what OP did in the end and how it worked?

Also, are there any real problems running a deore chainset with a road (tiagra in my case) cassette? Don't they require different chains?

Thanks

 

[richbrown]

In addition to the above, will a MTB chainset on an otherwise road setup not cause chainline issues?

 

[Nigelnaturist]

In addition to the above, will a MTB chainset on an otherwise road setup not cause chainline issues?

Depends on what BB you have square tapers come in various lengths so can be got for the right chain set, for example I have one that takes 113mm one that takes 116mm and one that takes 110mm, you can for example fit a 115mm to the 116mm and bring the chain line in a little ect......
This example is a really low geared touring chainset SPA CYCLES 104 Touring Triple Chainset takes a 107mm BB, the bigger problem and I can't answer this is what FD would be more suitable a MTB one or a Road one.

 

[CharlesF]

Sorry to resurrect this thread, I cam across it on google and am thinking about doing something similar on my 2015 CdF

Just wondered what OP did in the end and how it worked?

Also, are there any real problems running a deore chainset with a road (tiagra in my case) cassette? Don't they require different chains?

Thanks

What a coincidence; I was going to update this thread at the weekend after I had fitted the components.

As I was in the area, I visited Spa Cycles and spoke to them. I ended up buying this http://www.spacycles.co.uk/m2b0s109p3383/SPA-CYCLES-TD-2-Super-Compact-Chainset-with-Zicral-Rings, the 46T/30T combination. When I was there, they only had silver, now I'm tempted ask if they will exchange that for the black version. The bottom bracket is Stronglight JP400-113.5.

Thanks to Nigelnaturist for pointing me to Spa Cycles

 

[Nigelnaturist]

@CharlesF word of warning with black it rubs off, silver will look better longer. They also do compact triples which is what I have.

Thats a 50/38/26, the 26 is basic cheap ring, its a bit scuffed these days being two years old and 6,000 miles in, but the middle and outer ring are fairing well.

 

[CharlesF]

@CharlesF word of warning with black it rubs off, silver will look better longer. They also do compact triples which is what I have.
View attachment 139761
Thats a 50/38/26, the 26 is basic cheap ring, its a bit scuffed these days being two years old and 6,000 miles in, but the middle and outer ring are fairing well.

Yes, I'm sticking with the silver mainly to avoid the hassles of returning it, even though it doesn't match. I decided against a triple as it would have meant a new derailleur plus fitting the brifters which I have and will now sell on. The super compact looks good quality.