Rear mech for hills on old racebike

[blaaat]

I have an old (2004) race bike with a Sora 3x8 groupset. I am looking into converting the gearing system, to accommodate better for climbs (in the Czech Republic now and am struggling on 15% slopes), but also to enable towing a child trailer. Because the bike is old and was cheap to begin with, it doesn't make too much sense to spend too much, but then I don't want to end up with a useless configuration either .
Current setup:
Front: Sora triple 52/42/30
Rear: Derailleur Shimano RD-2200 (specs) with an 11-24 8-speed Sunrace cassette.

I have looked into this a bit and I believe one option could be a derailleur extender with an 11-34 (CS-HG50) cassette, which would probably be the cheapest but I am unsure if a derailleur extender is compatible with a triple front and if all accommodate for 11-34 cassettes with my derailleur.

Another (better?) possibility might be a Claris medium cage derailleur such as RD-R2000-GS with the 11-34 cassette.

Any advice, pro's and cons on the above, or other ideas are welcome.

[slowster]

Welcome to the forum. The link you have provided is to a russian site, and for the benefit of others I note that it is a pdf of a Shimano rear derailleur specification sheet (I had not heard of birota.ru, but they appear to be a retailer based in St Petersburg and they have some mentions on other cycling sites. I presume they are hosting copies of manufacturers manuals on their website in a similar manner to Paul Lange in Germany).

[blaaat]

Ah, I'm sorry for the link to the Russian website. For the reader here is a screenshot of the most important information in the datasheet of the RD-2200 derailleur.

[gregoryoftours]

You could also use any 8 or 9 speed Shimano mountain bike rear derailleur, as the pull ratios for Shimano road/mtb rear mechs don't part ways until 10 speed and above. So that will expand your choice of medium/long cage mechs. Using a suitable rear mech in conjunction with a 34t sprocket on your cassette will give you plenty low enough gears, although being 8 speed the jumps between gear ratios at the low end will likely be pretty big.

[MartinC]

What Gregory says, plus the old Sora chainset will be 130/74mm Bolt Circle Diameter so changing the chainrings is easy *Spa Cycles have plenty). Fitting a 28 tooth inner is cheap. Fitting 48, 38 and 26 rings will preserve the original spacings so is almost bound to work. I'd also be tempted to try a 24 tooth inner if I did this. As long as the front mech clears the chainstay.

Fitting an extender on the rear will make the change less precise. 11 to 30 or 32 (12 to 32 are available too) are an option if you drop the chainring size. The current rear mech may well handle a 30 tooth sprocket anyway. You've plenty of choices.

[LuckyLuke]

Hi, just to echo the excellent advice above, a 24T inner ring + 48 & 38T rings works. I used to run a Stronglight Triple with130/74 BCD 15-20yrs ago with 48-38-24. It worked well, thought it was with bar end shifters, not brifters.

Your rear mech will probably handle a 13-26 8 speed cassette (maybe a 11-28? But I’m speculating).

If you wanted a cassette with sprockets with more teeth, I can confirm the longer cage Claris rear mech works well with 11-32T & 46,36,24T up front, on my touring bike (I haven’t tried it with 11-34T, so can’t confirm.)
A 8/9 speed Shimano MTB rear mech should also work, and allow 11-34T.

Re the jumps between 8 speed 11-32 / 11-34. This used to be a big issue for me, though as I’ve got older less so.
I used to make a custom 13-30 8 spd cassette (a tip picked up from the likes of R2 on this forum. Thanks!)

I would take a 13-26 8spd cassette (13,14,15,17,19,21,23,26).
Drill then punch out the 3 thin pins holding the cassette together.
Remove the 14T sprocket, and add a 30T on the end.
Later on I would take apart a 9 speed 11-34T cassette, remove the 11 & 13T sprockets, remove the 9 speed spacers and replace with 8 speed ones, and fit an 13T knurled bottom sprocket from a 13-26T 8 speed cassette. Would give you 13,15,17,20,23,26,30,34. Which worked ok for me on a tourer.

Best wishes,

Luke

[853]

I would take a 13-26 8spd cassette (13,14,15,17,19,21,23,26).
Drill then punch out the 3 thin pins holding the cassette together.
Remove the 14T sprocket, and add a 30T on the end.

I'm not disagreeing with any of your good advice, it's just I have found it easier to remove the 3 pins that hold the cassette together by using an angle grinder on the heads of the pins at the large sprocket end. With some care the heads of the pins (only) will be worn away and the cassette can be separated with light prising of a screwdriver between the sprockets. After doing 3 or 4 cassettes it now takes me less than 5 minutes to do this

[LuckyLuke]

Hi 853, good idea, more than one way to skin a cat!
Best wishes,
Luke

[djnotts]

".....have looked into this a bit and I believe one option could be a derailleur extender with an 11-34 (CS-HG50) cassette, which would probably be the cheapest but I am unsure if a derailleur extender is compatible with a triple front and if all accommodate for 11-34 cassettes with my derailleur."

Yes and almost certainly to the 2 questions.

[GuyBoden]

Shimano Deore RD-M591 SGS Rear Derailleur.


microSHIFT Acolyte H083 8 Speed Cassette 12-42.


Works great with my 8 speed indexed barend shifters.


Don't use Big-Big or Small-Small chainring-Sprocket. Or change your Sora triple 52/42/30 triple to something more usable.

[blaaat]

Hi all, thanks for the advice.
I have made some minor modifications a few weeks ago.

First of all I need to correct myself in my original post: the original race cassette was a Sunrace 12-24 8 speed cassette, with 12/13/14/15/16/18/21/24 sprockets. I can't find such cassette anymore, maybe it is not manufactured anymore?

Next, I found a second hand Deore derailleur for a tenner, RD-M591, 9 speed. I have installed it. It is running OK and I can take all gears. Still I am wondering if it could benefit a bit more from further fine tuning... Since I am running an 8 speed cassette, do I need to adjust the + and - screws as if there was an imaginary 9th sprocket, and if so, at which end?

Finally I found out the misses was running an 11-32 8-speed cassette on her hybrid trekking/mountainbike . So I swapped our cassettes and will try this one for a while to find out if the jumps between gears are bothersome, and next time I am in the Czech Republic will try if I can manage the steep climbs better.