Lowering gearing. Which mechs?

[jamesofyorkshire]

I have a 10-year old Giant FCR1, flat-barred, fast road bike. It was one of the early 'compact' road framed bikes......and I love it!

However, everything is tired-out and needs replacing. I've been toying with the idea of another, similar bike, but I don't know if I can find another, more modern equivalent one, geometry-wise.....so I'll replace the consumables on this one. Whilst I'm at it, I'd like to reduce the gearing.

Original gearing was 9-speed Tiagra (4403?) chainset, cassette (11-25), front and rear mechs.

Last year I replaced the chainset with one of Spa's 28-38-48. I got the original front mech to work, but not that great, the mech is a bit far off the big ring. But I love the reduced gearing. Much more usable here in the hills of the Yorkshire Dales.

Now I would like to change the chainrings to 24-34-44. That should be easy enough (famous last words!). I dont think the original front mech will handle the 44 ring as it wont drop low enough/close enough to it. (Original chainset had a 50 big ring)....and anyway the front mech is very worn and needs replacing. Front mech screws into the frame (is that called a 'braze-on'?).
So my first question is, what mech (specific model) would you recommend to handle the 24-34-44 up front and a 9-speed cassette at the rear?

As to the rear casstte, the original is a 9-speed, 11-25. I would like to change this for a 9-speed, 11/12 - 28/30....anyway a wider range than the original. The original rear mech is also worn and needs replacing.

I don't know if it's relative but the bar shifters are 3x9 Shimano trigger shifters, does that mean I need stick with Shimano stuff? I'm happy to stay with 9-speed. I don't need 10.

I'm trying to shed a bit of weight when upgrading the bike, and want decent gear....around 105 level...or at least Tiagra level (I hear the newer Tiagra stuff is good gear).....so bearing that in mind, what recommendations would you offer for a front mech, rear mech, casstte, and chain? Specific model numbers please so I can order them.

Any help/advice much appreciated.

[Malaconotus]

I wouldn't change the front again. It will definitely not shift any better, will probably be worse, and given that it sounds like it's currently not great that's got to be undesirable.

What you need is a Shimano Deore Shadow Rear Mech M592, the only 9-speed rear mech which will handle up to a 36T cassette... http://www.chainreactioncycles.com/shim ... -prod40542 12-36 nine-speed cassettes are also still available. This would, IMHO, have been a better and esier solution than changing the chainset which is more likely to produce a less smooth shift and doesn't actually lower your gearing as significantly.

[Brucey]

have you got a picture of the front mech setup? It might be that there is a better front mech out there but without knowing a bit more about the fitting it would be difficult to suggest something.

BTW before you go for a smaller big ring, do think about a 13 or 14-upwards cassette instead; you might have to build the exact one you want (R2 has some good recipes for this BTW, using two cheap 9s cassettes as a starting point, leaving you with leftovers that a roadie might buy, or some useful middling-sized spare cogs for the one you use) but the whole transmission will last a lot longer IME.

chers

[gaz]

.... Front mech screws into the frame (is that called a 'braze-on'?)....

It is indeed called a braze-on.

Ideally with smaller chainrings the front mech should be set lower than it is now. Take a close look at your current set up, does the braze-on slot allow the mech to be set lower than it is now? If it can be lowered how far can it go before it hits the chainstay?

Indexed front shifting is complex, if you can post the model numbers of your existing front mech and shifter it will help others more knowledgeable than I to give you good advice.

I run a 38T outer with a mech designed for a 53T dinner plate but friction shifting is much more forgiving.

[fatboy]

If you just make the inner smaller you probably won't need to change much else. On my tourer I run 24/38/48 and on my Audax I run 24/39/50. You do Need to shift the rear gears at the same time but for me this is a good solution and pretty cheap and simple. I did try 22/38/48 and that was a jump too far.

As for rear mechs pretty much any MTB one will do although the latest Sora incarnation can do 32 on the back.

[jamesofyorkshire]

Thanks for the replies.

The front mech is as far down as it will go.

I use the middle ring (38T) 90% of the time.......only dropping onto the small ring when I can't peddle out the saddle anymore and need sit down, but I'd like that chainring just a bit smaller to cover 95% of my peddling.......and the small ring only for when I'm absolutely knackered and can't make that last hill getting home (into the wind!). At the moment I NEVER use the big ring, if I lower it a bit, I probably will.
I don't want to go to a cassette that has a huge range, I like the gears quite close together.

I tend to peddle quite a high, and regular cadence, I just need lower gearing!
I ain't a racer, so the high gears are not important....if the wind is at my back and I'm flying along at 30...that's OK by me, I don't need do 40.

I figure if I just make all three rings at the front smaller, I'll get nearer to my ideal set up. Just that the Tiagra mech on the front wont go down the tube any further, I moved it as far down as it can go. Was wondering which mech to buy if I fit the smaller chainrings. Am I looking at MTB stuff?

[Valbrona]

If your chainset has 28/38/48 rings then it is quite possibly 130/74 BCD. What this means is that while you can fit a smaller inner chainring, the middle and outer chainrings are already as small as can possibly be fitted. To be able to use smaller middle and outer chainrings you will need a 110/74 BCD chainset. My point being ... it might be just as well to buy a complete new chainset if yours is indeed 130/74 BCD.

Your existing FD will most likely work very well with smaller chainrings than your existing 28/38/48 combination. But you have the problem of getting it even further down the seat tube. In the case of some Giant frames, the bracket for the FD is simply screwed-on, which means you can remove it and fit a clamp-on FD. If you have to use the bracket, it might be wise to stick with a 48 outer chainring for the sake of 'doing things proper'.

Note also that front mechs mostly come in two flavours. There are the 'road' ones that typically only work with STI levers, and there are the MTB ones that mostly work with trigger shifters. In the case of your hybrid it is advisable to determine which type of FD you have despite the fact that trigger shifters are fitted. It is after all a road bike and not an MTB.

[Malaconotus]

Was wondering which mech to buy if I fit the smaller chainrings. Am I looking at MTB stuff?

Not unless you want to change the shifters as well.

The reason you want close ratios is you're only using one ring. If you used the cassette to make the big ring usable you'd gain the in between ratios from front shifting. Or just fit this 12-27 mech which leaves your ratios just as close and lowers you gearing almost as much as changing the chainset... http://www.chainreactioncycles.com/shim ... tAodbRcAyg

As general advice I would never change the chainset when the same result can be achieved by changing the cassette and, if needed, the rear mech. It's quicker, cheaper, easier and gives better results.

You should have a play with this before parting with more cash. Note how my own set-up, with a 12-36 cassette, has more even gear spacing, with fewer big gaps, than your current 11-25 setup... http://www.gear-calculator.com/#KB=28,4 ... 205&SL=2.5

[Brucey]

if you fit a different cassette you will be able to use the 48T ring more of the time. Tell us which gears you use with the 38T ring and lets see if it can work out.

Why might you want to do this? Well two reasons;

1) you won't have to put up with rubbish front shifting or some dreadful bodge because of your braze-on front mech mount and

2) your whole transmission will last longer.

cheers

[jamesofyorkshire]

So if I leave the chainset be (28-38-48) and change the cassette instead......the rear derailleur is currently a Tiagra 4403 I think. According to Shimano tech docs, this will handle up to a 27 cog......which doesn't drop the gearing much from my 25. If I wanted to fit say a 11-30 cassette....what RD would I need? I don't mind buying a new RD as the original one has had a lot of use. I just don't know which one.

[bryce]

What was the original chainset? The current road triples are 50-39-30, ideally the gap between the top and the middle should remain the same. The little ring can be dropped significantly so long as the chain doesn't hit the bottom of the cage. The easiest and cheapest way to gain range is to reduce the size of the little ring up front.

I'm running a 11-28 with a 9 speed Tiagra rear mech, it works fine and could probably handle a slightly bigger cassette. It's my ideal 9 speed cassette.

The flat bar front mechs have a cable pull that's a lot closer to mountain standards than regular road standards. That's why they're preferred for shimergo set-ups with modern shifters and big chain-rings. You may be able to use a mountain front mech if it could be positioned correctly. They'll often run 48-36-26 as their standard large option.

Given, it's a flat barred bike, it would be possible to upgrade the entire transmission to a mountain one with trekking cranks and front mech which should provide plenty of ability to go lower.

As the limit seems to be getting the front mech lower, the two easy options are changing the cassette and accepting bigger jumps or changing the front chain-ring.

[CREPELLO]

Can you get an 11-30 9 speed cassette? That might prove tricky.

If it's any help I run one bike with a 48/38/28 chainset and an 11-32 8 speed cassette at the back. An RX100 medium cage rear mech completes the set up*. This is an old Shimano road mech, which should be similar to the Tiagra one. Not many people report using this combination, but I can say that it works very well. The only compromise is that I can't run the 28T at front with the smaller cogs at the back, which isn't usually a problem.

*The complete set up actually uses RSX STI's and a Campag front mech, which again, nobody seems to report using. Perhaps I'm just lucky but all this disparate components mesh very well together for me.

[jamesofyorkshire]

Yes.....HG50 11-30 9-speed cassette.

[freeflow]

Have a look at shimano Deore LX Trekking stuff. They do a front deraiilier that will take of 44 tooth chainring. I have one on my Galaxy but that dates from the mid 90's. For a rear deraiilier any 9 speed normal style rear deraiilier will be fine. The Deore XT is certainly rated well.

[Brucey]

I wouldn't find a reason to use 48/11 very often hence I'd sooner carry a lower gear instead. So my choice would be

- 48 T big ring, others to suit
- custom cassette (say) 13-36
- shimano shadow 9s rear mech (Deore LX or XT)
- front mech to match shifters (IIRC shimano do a 'road' mech with MTB cable pull; you need that if your front shifter has an MTB cable pull). If you post your current front mech model number it can be identified.

I think this whole idea of going to a smaller big ring is daft; you simply won't get a braze-on mech that fits or works properly.

BTW on a ten year-old alu frame with lots of miles on it, I'd inspect it very carefully for cracks before refurbing the drive train. These frames don't last for ever.

cheers