Specialized Secteur upgrade query

skippy_77
skippy_77 Posts: 35
edited January 2019 in Workshop
I'd recently put a post about upgrading the rear derailleur on my Sectuer.
The suggestions were that i could and to put a medium cage. However I've got 8 gears on the back but the derailleurs suggested were 9 or 10 gear derailleurs.
I've been told by my local trusted bike shop I've used for years that i can't put a 9 or 10 speed derailleur on and that I'd have to put a 9 or 10 gear cassette on.
I want to know what other Sectuer owners have done to put more gears on.
I'm new to all this gearing malarkey. I would love more gears but i don't want to fork out on new shifters etc.

The Shimano 2300 derailleurs aren't good and just want a long term upgrade.

Is it possible to put 9 or 10 gears on the back of a secteur with out replacing the shifters.

What cheap options could i go with?

Comments

  • thepainandsuffering
    thepainandsuffering Posts: 44
    Your shifters control how many gears your bike has. 8 speed shifters will only change through 8 gears on the cassette. If you want to run 9 or 10 speed cassettes you will have to change the shifters to match. No way around this.

    Rear derailleurs are dumb and just follow the amount of cable movement from the shifter as long as they share the same shift ratio. Shimano 8, 9 and 10 speed rear mechs all have the same shift ratio of 1.7 and so will all work on your bike. If you fit a 10 speed rear derailleur you will still only have 8 gears as you have 8 speed shiters. The new Tiagra 10 speed 4700 is the exception to this and will not work so don't get one of them as the mech shift ratio changed.

    Lots of help here with compatibility, it does get very confusing:-

    https://www.artscyclery.com/science-beh ... atibility/

    Hope this helps.

    TP&S
  • slowbike
    slowbike Posts: 8,498
    I had 2300 on my Allez - fine whilst it lasted - but I hated the button that rubbed against my thumb.

    I upgraded it to 10 speed - 5600 - replacing the shifters, rear mech (didn't bother with front), cassette, chain & chainset - cassette & chain were new, chainset was s/h as were the shifters & rear mech - so didn't cost an arm & leg.

    You can't change the number of gears without changing the shifter, cassette, chain & rear mech
  • keef66
    keef66 Posts: 13,123
    Slowbike wrote:
    You can't change the number of gears without changing the shifter, cassette, chain & rear mech

    Technically, moving from 8 speed Shimano to 9 or 10* speed you could get away with changing just the shifter, cassette and chain. The original 8 speed rear mech would still work.

    But if you're going to the expense of new shifters you might as well do the lot, and it's academic since I think the OP has already replaced the rear mech

    * but not Tiagra 4700
  • pilot_pete
    pilot_pete Posts: 2,120
    Is it possible to put 9 or 10 gears on the back of a secteur with out replacing the shifters.

    Simple answer - no. The cable that operates the rear derailleur pulls a set amount with each click of your shifter. The derailleur moves a set amount to change from one sprocket to the next. The shifter ratchet system (the clicks) determine how many ‘shifts’ can be made. It also determines how much cable is pulled with each click. If the ratchet only has 8 clicks then there is no way of having more than 8 sprockets and getting that shifter to work.

    Now, if you fit a 9 or 10sp shifter, the ratchets are different. They will pull a fraction less cable through with each click, which is translated by the rear derailleur into a smaller inward or outward movement to correspond with the smaller gaps between sprockets on the rear. They will also be designed with the corresponding number of ‘clicks’ (shifts) to allow for 9 or 10 from one extent to the other.

    As has been pointed out, many rear derailleurs have exactly the same dimensions (measurements for the pivot points on the parallelogram) and the cable attachment point geometry to in effect just have their operation slaved to the shifter. In other words the cable pull is dictated by the shifter - the derailleur just moves in response to that and is not fixed in terms of “1 click equals a fixed amount”.

    So, cheapest way to get 9 or 10speed would be to buy a second hand pair of shifters - if you scour for sale classifieds/ eBay etc, you may find singles being sold off, or a pair with one smashed up. I have however seen Sora shifters for less than £70/ pair new.

    You will need a matching cassette and chain. Again, lower end stuff is certainly cheap enough new in 9 and 10 speed so just google the usual places and apply discount codes!

    You should be able to get away with the same crank and front mech. Worth trying before you shell out on either of those.

    Good luck

    PP

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