Cycling UK Forum

Claireysmurf wrote:I'm just ordering some parts. Can anyone tell me if I need a clip on (and if so a 31.8 or 34.9mm) or braze on front derailleur?
I notice that a 105 front derailleur is £3 cheaper than a Tiagra one. I had intended to use an all Tiagra groupset. Is there anything to be gained from having some of the components from higher up the hierarchy?

It's a band on front mech. Its actually Neither of those two sizes. Take a look http://www.genesisbikes.co.uk/bikes/fra ... oix-de-fer

As for 105 vs Tiagra, always go up a spec if you can afford it, the longevity of bearings and quality of materials used is always an advantage. If for no other aesthetic reasoning that You will have less parts that rust.

Claireysmurf wrote:I'm just ordering some parts. Can anyone tell me if I need a clip on (and if so a 31.8 or 34.9mm) or braze on front derailleur?
I notice that a 105 front derailleur is £3 cheaper than a Tiagra one. I had intended to use an all Tiagra groupset. Is there anything to be gained from having some of the components from higher up the hierarchy?

What you need is a 28.6mm band-on front derailleur. They often come as 28.6mm/31.8mm - they have two spacers and you just use the one for 28.6mm to fit your frame.

Will

Claireysmurf wrote:I notice that a 105 front derailleur is £3 cheaper than a Tiagra one. I had intended to use an all Tiagra groupset. Is there anything to be gained from having some of the components from higher up the hierarchy?

The most important thing is to ensure inter-compatibility i.e. that the 105 front mech is designed for the number of teeth on the front chain rings and the difference of teeth between chain rings. For my build-up a 105 wasn't suitable for an outer ring of 48 teeth, but the Tiagra was. There is less to be gained from upgrading a front mech compared to a rear mech, which is used far more often when cycling.

Once you've decided which chain set you're going to use, check the compatibility on the Shimano Tech website.

I have been getting confused with the Shimano compatibility chart so would appreciate a pointer please

http://www.shimano.com/publish/content/ ... le.html/01)%20Drivetrain%20Compatability%20Chart.pdf

I was hoping to have an all 105 triple set up but prices for the 105 chainset are typically £60+ more than the Tiagra one. Can I use a Tiagra chainset with an otherwise 105 setup or Tiagra chainset and levers with otherwise all 105 components?

The components I am talking about are as follows:
105 5700 cassette 11-28T
105 5701 rear derailleur medium cage
105 5603 front derailleur (triple)
Tiagra 4603 triple chainset
Tiagra 4603 triple STI levers
105 5703 triple levers

If I can mix and match, will it make any difference to the chain to be used?

Thanks

it is all 10s stuff, so it will be just fine. Unfortunately the chart you linked to is out of date as it doesn't show the 4600 groupset.

However I would suggest that you consider another chainset with more gearing choices than this one. This one has IIRC a 92mm BCD on the inner chainring which means that a 30T inner is about it; no other sizes available, and certainly no smaller ones...(e.g. ~28T is the smallest you can fit to an 86mm BCD IIRC)

http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV-FC-4603-3145_v1_m56577569830753742.pdf

A Tiagra FC-4503 chainset is nominally a 9s chainset and has a more versatile 74mm BCD inner chainring mounting which allows down to 24T. It is otherwise very similar to the FC4603 model. Not a 'shimano recommended combination' I am sure to use a 9s chainset with a 10s system but perhaps someone else can comment on how well it works in practice; normally using a slightly skinnier chain (e.g. 10s on a 9s) is OK on a chainset.

cheers

The most important thing is to ensure inter-compatibility i.e. that the 105 front mech is designed for the number of teeth on the front chain rings and the difference of teeth between chain rings. For my build-up a 105 wasn't suitable for an outer ring of 48 teeth, but the Tiagra was. There is less to be gained from upgrading a front mech compared to a rear mech, which is used far more often when cycling.

I probably need to explain that a little bit further - and I hope I didn't put you off or confuse you with my previous post?

Being the owner of a few bikes and having experimented many times with gearing, in particular with a light touring bike and a heavy-duty expedition touring bike, I had a very good idea of what gearing and which ratios I would require for my Croix de Fer when building it into a medium weight cycle-camping touring bike. I would be using it for 2 or 4-pannier touring and in Devon and Cornwall or Scotland I may require gearing as low as 22". For cycling along on the flats I don't need anything more than 100", but anything more than that would be useful for going down hill.

So, I decided my gearing before I even thought about what chainset I would buy and decided I would go for a 48-38-26 (I also have a 46-36-24 as a standby for heavier duty touring or hillier terrain) and I also wanted an 11 - 32 cassette. Therefore I decided I would be better off with a 9-speed set-up. the Tiagra FD was better suited for the chainset I wanted to use even if I went down a couple of teeth. I went for a Mtb Shimano XT medium cage rear mech so that I could go up to 11 - 34 if required.

In Summary, I decided what gearing I wanted to achieve before checking what was compatible rather than looking at any groupset or individual components.

Good Luck!

I haven't replied earlier because I thought I would think about what gearing I would really like.

The answer is still unclear to me but if I don't get the answer right it always give me justification for a bit more of n+1

I may just have sold my Dawes Clubman which makes me think my original choice of a drop bar audax/light touring bike is appropriate as there will obviously be no overlap between the two bikes.

However, I am chomping at the bit to get the bike built and do think you have made some good points about gearing. Therefore I wonder what you guys think of this deal? Obviously would go with some straight bars, not drops.
http://www.merlincycles.com/bike-shop/m ... upset.html

I thought some more and ordered Ultegra 6700 stuff as there are some good deals around at the moment with 105 levers. I haven't completely ignored your advice as have goone a teeny bit lower for the rear cassette. 50-39-30 triple with a 12 (11?)-30T cassette.

Now to buy brakes and wheels

have you left any wriggle room with your gearing choices?

When I was a lot fitter I could get away with gearing like that even with a modest load on, but not these days. If you have a chainset with a 30T inner ring (smallest that can be fitted) and a rear mech/cassette with 30T (largest that can be fitted) then your gearing is only a small amount lower than the dawes clubman, and again perhaps with little or no scope for further lowering if (when) required.

cheers

My rides to date have been a couple of panniers of clothes/tools/spares/locks for a couple of nights away with friends or in a B&B rather than proper touring and I guess if I do want to go touring I can always get an MTB rear on it. Most of the time the bike will be fairly lightly laden and my priority was a nice, slick groupset for day rides, commuting etc.

At the end of the day, it will be a Croix de Fer with slightly lower gearing than standard for a built up bike (their front is 50-34 IIRC) and so I think I will be happy with it.
If I have replicated the Clubman, I will be happy as it will be a similar bike but able to run mudguards on 32mm tyres and so quite similar but with better brakes and a little bit more rugged for gravel and dust paths.

And....when I did pop a link to the wildcard (for me) MTB groupset suggestion, nobody responded

Hi
I'm also thinking of building up a Croix de Fer after wrecking my last bike.
I'm in Cardiff area too...could you message me where you got your frame from. Interested to see if they have one in a 54?
thanks
Andy

Hi Andy I bought it from The Bike Shed on Cathedral Road.

Claireysmurf wrote: ...And....when I did pop a link to the wildcard (for me) MTB groupset suggestion, nobody responded

maybe not, but you can't use most MTB 10s stuff with road STIs, not unless you go with SRAM.

IIRC several folk have suggested that the best rear mech with a shimano-based 10s road touring setup is a 9s MTB mech (which will take a 34T rear sprocket or larger and work with 10s road STIs) , and that a chainset with (or with the possibility of) MTB-sized chainrings (but a road chainline) might be a better choice.

Slightly different choices might have left you with the possibility of an easy gearing change giving you (say) a chainring of 24T and/or a rear sprocket of 34T or larger should you have needed it. Maybe you won't need such gears (and you won't if you are strong and ride unladen, I am sure), but keeping your options open is never a bad idea.

cheers

cheers, thought you might have.
Tried them and they've only got a 52 in stock anyway....
ah well will keep looking.
Will be interested to see how your build goes...maybe tapping your brains later!

andygo wrote:Will be interested to see how your build goes...maybe tapping your brains later!

From my questions on here you may have gathered I am a bit clueless