In pursuit of low gears

[hondated]

This afternoon in the pursuit of lower gearing I decided to replace the Shimano triple chain set FC 4520/4503/4550 ( these are the markings on the cranks) with a FC M590 crank set and FD M591 mech on a Dawes Audux frame set I recently built up but unfortunately I couldn't get it to work.
Its got a 68mm bottom bracket so I initially used 2 Hollowtech spacers on the drive side and a single spacer on the other side. This is what is recommended on the installation guide. Because that never worked I tried just using one spacer on the drive side but still no luck.

Now I am wondering whether I should have no spacer on the drive side and use all the spacers on the non drive side. And if the front mech is incompatible.

I wonder whether anyone else as faced this or a similar problem and could offer me some advice on how to resolve this issue.

[willcee]

perhaps a pic or two would assist any of us who would try to suggest a solution, not knowing from shimano part nos which chainset or meck you have now fitted i'd guess in your quest for low gearing its MTB kit?? will

[hondated]

Thanks Will fair point I will take some and post tomorrow Ted

[willcee]

might help..
]FD M590 - Bike Components
https://static.bike-components.de/.../d ... 08d49680...
SL-M590. SIS-SP41. FD-M590 / FD-M591. FC-M590 / FC-M591. SM-BB51 ... This release lever is equipped with a 2-way release mechanism which allows release operations to be ... levers, always be sure to turn the crank arm at the same time. ... FD-M591. FD-M590. Low adjustment screw. Chain. Pro-Set alignment block.

[cycleruk]

In what way won't it work?
If you are still using road STI then you will need a road front mech' to match. (or change the cable attachment point on the new mech') (Clamp cable on inside of bolt)
Road STI (left unit) only pull 12mm cable per click whereas MTB mech's need 19mm cable pull each ring.
I still kept the old road mech' when I fitted an MTB chainset to my bike. (I think it is a Deore M610 10 speed.)
http://www.chainreactioncycles.com/shim ... prod106873
I still had to move the spacers though to the non-drive side to get the chain-line as near as correct as I could.

[hondated]

Thanks again will and cycleruk. Theres some handy info there cycleruk, especially about the mech as I think now the one I used was off a mountain bike.
I am using an old road front mech with the chain set fitted and tomorrow I will move all of the spacers over to the non drive side and see if I can get a better chain line.
Only fear I have now is getting a good night sleeps as when I get things like this on my mind and I wake in the early hours sleep can wait and I set too to doing it.

[Valbrona]

If a Shimano FD part number is suffixed with the letter 'M', then it is MTB style and will not work with road STI levers on account of different cable pull ratio. Lots get around this by pairing an MTB FD with bar end levers.

[RickH]

If a Shimano FD part number is suffixed with the letter 'M', then it is MTB style and will not work with road STI levers on account of different cable pull ratio. Lots get around this by pairing an MTB FD with bar end levers.

Or, if you already have the road shifters & the MTB FD then this Shiftmate (I think I've got the right one) ought to match up the cable pulls.

Rick.

[hondated]

Thanks Volbrona ,RickH some great information there again. I am particularly interested in the significance of the M.
I have been messing about with it again today and because it seems to be such a kerfuffle to change it I think I will stick with the 50-39-30 chain set I have on there. For goodness sake I even have a 34 rear sprocket so climbing hills shouldn't be too hard should it.
What set me off on trying this is that my Roberts is fitted with an XT 44 chain set, 10 speed Veloce Levers, a XT rear mech and a Campag front mech so I thought changing the Dawes over to much the same would be easy to do.
Truth be known probably spend too much time with fettling my bikes than I do riding them.

[Erudin]

I swapped the inner rings on my Tiagra 4503 9 Speed Road Chainsets from 30 to 26 (Stronglight 5 Arm 74mm P.C.D Chainring) to get lower gearing. The advantage of this approach is you don't need to alter the front mech/shifters, it is just a straight swap of the chainrings and you are done.

I also fitted Deda dog fang chain catchers as a precaution.

[Brucey]

worth noting also that the front mech is also often chainline-specific, ie an MTB FD will work OK on an MTB chainline but not on a 'road' chainline. Obviously that shouldn't have been a problem with a 'matched' chainset and FD as here, but it is worth bearing in mind.

BTW if you don't fancy splashing out on a shiftmate you can sometimes make an MTB front mech work with road shifters by altering the cable mount on the mech.

I'd do what Erudin suggests in the first instance; it requires a little more front mech capacity, but it usually works OK.

cheers

[fatboy]

I swapped the inner rings on my Tiagra 4503 9 Speed Road Chainsets from 30 to 26 (Stronglight 5 Arm 74mm P.C.D Chainring) to get lower gearing. The advantage of this approach is you don't need to alter the front mech/shifters, it is just a straight swap of the chainrings and you are done.

I also fitted Deda dog fang chain catchers as a precaution.

I went down to 24 teeth without issue (Sora 9 speed groupset). It's a bit of a jump but it seems to be otherwise ok.

[hondated]

Thanks Erudin,fatboy,and Brucey. More great ideas. I think I may have either a 24 or 26 chain ring in my box of bits.
For the record I was out on it at 6am this morning when it was raining and blowing a gale just so you know I do actually ride as well as fettle.
Just thought of another question and it is what determines the capacity of a FD ?. Is it the length or depth of it ?.

[recordacefromnew]

Just thought of another question and it is what determines the capacity of a FD ?. Is it the length or depth of it ?.

Assuming you are talking about the existing FD (which has been setup properly), RD (which has adequate capacity) and chainset, and assuming you don't want the chain to drag on the tail of the FD cage when you are on, say, small front small back (a gear one wouldn't normally use but nonetheless...), if you measure the clearance between the top run of the chain and the tail of the front mech when in such gear, roughly every 2mm of clearance will allow you to reduce the small front ring size by 1T.

[hondated]

Just thought of another question and it is what determines the capacity of a FD ?. Is it the length or depth of it ?.

Assuming you are talking about the existing FD (which has been setup properly), RD (which has adequate capacity) and chainset, and assuming you don't want the chain to drag on the tail of the FD cage when you are on, say, small front small back (a gear one wouldn't normally use but nonetheless...), if you measure the clearance between the top run of the chain and the tail of the front mech when in such gear, roughly every 2mm of clearance will allow you to reduce the small front ring size by 1T.

Thank you that gives me a better idea of what I should be looking at.