Derailleur Capacity query - Shimano 105 RD-5600 in 9sp

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Derailleur Capacity query - Shimano 105 RD-5600 in 9sp

Postby MichaelB » Wed Mar 26, 2008 2:25 pm

Hi all,

Just trying to confirm whether a plan I have for an up & coming ride will work.

Currently, on my bike, I have a 105 9sp Groupset with 38/50 Front chainrings, and a 12-26 SRAM cassette on the rear.

For the Grand Slam series, one of the next rides will be up Willunga Hill, and due to the gradient, my weight and the length of the climb, I have had dark thoughts on sourcing an 11-28 cassette to assist with the climb.

I have done a bit of research into the capacity of the RD, and from the Shimano website, it states :

Model Number : RD-5600-SS
Series : 105
Cassette Compatibility : 10-speed (mine id 9sp, but shouldn't matter ?)
Maximum Sprocket : 27T (oh dear ?)
Minimum Sprocket : 11T (no probs :D )
Maximum Front Difference : 16T (no probs :D )
Total Capacity : 29T (no probs :D )

Now the confusing thing is that a number of other 3rd party sites list the Max rear sprocket at 28 Teeth.

CDF says that the Shimano site should be MORE correct, but for a short term usage, will it be OK ?

No, I can't get up the hill with the 26T, as I cannot grunt that low for that long. :roll:
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by BNA » Wed Mar 26, 2008 3:20 pm

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Postby mikesbytes » Wed Mar 26, 2008 3:20 pm

I would say that your safe going to 28t, it shouldn't be that picky that 27t fits and not 28t. BTW, you will need to adjust the screw at the back that most don't even know its there.

If your chain is short then it may not fit, however you always change the chain when you change the cassette.
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Postby MichaelB » Wed Mar 26, 2008 3:48 pm

mikesbytes wrote:I would say that your safe going to 28t, it shouldn't be that picky that 27t fits and not 28t. BTW, you will need to adjust the screw at the back that most don't even know its there.

If your chain is short then it may not fit, however you always change the chain when you change the cassette.


I thought so, but wanted to check. It may also be that the 27T is listed as a max, as Shimano don't do a cassette with a 28T bigger cog (for road bikes anyway).

Can you elaborate on the highlighted part ?

The cassette won't stay on for long, so chain may not be an issue.
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Postby rustychisel » Wed Mar 26, 2008 6:00 pm

Michael - it's more an issue of having a chain which mates successfully with the cassette. ie, doesn't jump or do bad things... so another chain, adjusted to the correct length is more the issue.

Mike was talking of the 'B' screw which adjusts the angle of the derailleur body relative to the chainstay, and thus the amount and angle of body movement... he'll be back to explain further, I'm sure.

WRT permissable number of teeth, you can usually easily exceed the recommended difference, but as a caveat I'd warn against [EVER] cross chaining such that you're in the big x big combination. There may not quite be enough chain to stretch to that.
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Postby mikesbytes » Wed Mar 26, 2008 6:49 pm

rustychisel wrote:Mike was talking of the 'B' screw which adjusts the angle of the derailleur body relative to the chainstay, and thus the amount and angle of body movement... he'll be back to explain further, I'm sure.


Thanks rusty, you know more about than I do, I just know that you turn it and the derailleur moves downwards.

Thinking this a bit further, you could try adjusting the screw to max and seeing how much clearance it gives you.

BTW, I have a shimano tigra 9 speed deralier on my 7 speed commuter that has a 28t and it works fine.
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Postby mikeg » Wed Mar 26, 2008 8:17 pm

According to a very knowledgable person that was on Cycling Forums (Bordeaux) and Bike Forums, the spec for max sprocket by Shimano is conservative, and that road derailers would often work with as large as a 30 tooth cassette.
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Postby Hawkeye » Wed Mar 26, 2008 9:39 pm

rustychisel wrote:WRT permissable number of teeth, you can usually easily exceed the recommended difference, but as a caveat I'd warn against [EVER] cross chaining such that you're in the big x big combination. There may not quite be enough chain to stretch to that.

Hmmm... My thought in response to that is the idea there is to set your chain length so that it covers you for the big x big combination, plus half to one chain link pair (ie an inner + outer), and no more.

This is the setup instruction that came with both SRAM and Wippermann chains that I've bought in the last 12 months.

It is far more common for chains on bikes to be set up ex-factory too long than to be too short. On all the bikes I've bought in he last two years the chains they came with were at least a chain link pair too long (giving rise to the chain intermittently missing the granny gear and jamming/chewing up the frame around the BB :evil: ).

So I'd not be terribly worried about that particular possibility. If you're worried, a simple check by trying to engage big x big with the back wheel off the ground would quickly confirm if a problem existed or not.
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Postby toolonglegs » Thu Mar 27, 2008 7:24 am

Easiest way to get bigger cluster on rear...27 is normal.28 should be ok but may get mesh of jockey wheel.Is to get older style or after market jockey wheels.Can't remeber if it is 10 or 11 tooth.But it will be oine less than what you have.Apparently 30tooth is happy with that easy mod.
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Postby MichaelB » Thu Mar 27, 2008 8:15 am

Cheers for the info guys.

So it looks like a goer. :D

The Big x Big combo as mentioned will be unlikely, but I'll be very careful. The chain length will be setup accordingly and I'll let you know the outcome.

The ride date is 20th April, so will be doing some hill work in the leadup !!!

Cheers

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Postby rustychisel » Thu Mar 27, 2008 10:40 am

okay, the suggestion of avoiding the big x big combination was not based entirely on a (hypothetical) calculation of chain length, more a suggestion of not over-extending the capacity of the gear train, particularly derailleur. Clearly, this is most critical in the longest travel combination: the big x big. Equally, in the small x small combination the issue is unacceptable chain slop, ie lack of tension.

The B screw on a derailleur is used to position and limit the amount of movement... you've seen it move as you turn the screw, the idea is to position the derailleur body parallel to the chainstay. This in turn affects the position of the uppermost jockey wheel (pulley) relative to biggest cog on your cassette which sits above it. Obviously, you do not want the jockey wheel clipping the cog...
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Postby munga » Thu Apr 03, 2008 7:34 am

thanks for the tip on that 'B' screw. I bought a used bike for my wife a while back and assumed the sora rd was knackered as one of the jockey wheels rubeed on the cassette when pedalling backwards. Glad I didn't throw it out. Her bike currently has a long cage ex300 on it as an interim fix.. you guys rock!
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Postby LuckyPierre » Thu Apr 03, 2008 8:54 am

Can I offer a different view?
Too late, here it comes.
Why not just change your small chain ring to a 36 tooth one? That's what most compact cranks seem to run anyway ie. 50/36 rather than 50/38. You'd still need to check your chain length.
I did the Palmer hill on the TdU challenge stage without getting lower than 39x24. I haven't ridden up Willunga Hill so I haven't got direct experience of how they compare, but parts of the Willunga climb look steeper on the bikely profiles I've seen.
ps. I find it very hard to stand up and pedal in a 39x27 gear, there's just not enough to pedal against even on Apollo Road or the climb to the end of the bitumen on Brindabella Road and they're both pretty solid climbs.
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Postby MichaelB » Thu Apr 03, 2008 11:57 am

LuckyPierre wrote:Can I offer a different view?
Too late, here it comes.
Why not just change your small chain ring to a 36 tooth one? That's what most compact cranks seem to run anyway ie. 50/36 rather than 50/38. You'd still need to check your chain length.
I did the Palmer hill on the TdU challenge stage without getting lower than 39x24. I haven't ridden up Willunga Hill so I haven't got direct experience of how they compare, but parts of the Willunga climb look steeper on the bikely profiles I've seen.
ps. I find it very hard to stand up and pedal in a 39x27 gear, there's just not enough to pedal against even on Apollo Road or the climb to the end of the bitumen on Brindabella Road and they're both pretty solid climbs.


My crank is not a compact one - it is still 130BCD, so the 38T is the smallest you can get.

The Willunga hill climb is a lot longer and is an average gradient of 7%, vs Palmer Hill at closer to 4 - 5%

At a price of A$38 for a NEW cassette delivered, it is a worthwhile exercise :lol:
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Postby LuckyPierre » Thu Apr 03, 2008 12:38 pm

MichaelB wrote:My crank is not a compact one - it is still 130BCD, so the 38T is the smallest you can get.

B*gger, that wrecks my idea!
MichaelB wrote:The Willunga hill climb is a lot longer and is an average gradient of 7%, vs Palmer Hill at closer to 4 - 5%

See, I told you that I didn't have real experience - but, Apollo Road climbs over 500 metres in 7 kms and I've ridden that.
MichaelB wrote:At a price of A$38 for a NEW cassette delivered, it is a worthwhile exercise :lol:

It surely is!
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Postby lukas » Thu Apr 03, 2008 1:13 pm

I have a 105 rear derailleur and a 11-28t SRAM cassette, and it gets on just fine, though I'm soon to change to a 12-27t and a compact up front.
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Postby rustychisel » Thu Apr 03, 2008 3:38 pm

see you on the Willunga Hill michaelB. It's a good route, that one - watch for the sting in the tail on lap 1.
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Postby MichaelB » Fri Apr 04, 2008 8:30 am

rustychisel wrote:see you on the Willunga Hill michaelB. It's a good route, that one - watch for the sting in the tail on lap 1.


What sting ?

Hopefully the rain stays away.

Bloody speed sensor has had an attack of the "scared of rain" again, so trying to see what I can do to solve it.
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Postby MichaelB » Fri Apr 04, 2008 8:34 am

LuckyPierre wrote:
MichaelB wrote:My crank is not a compact one - it is still 130BCD, so the 38T is the smallest you can get.

B*gger, that wrecks my idea!


Otherwise I would have already done it 8)
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Postby MichaelB » Thu Apr 10, 2008 10:41 am

Well, bugger me, it doesn't quite work :(

Fitted the cluster, and whilst it works, the upper jockey wheel contacts the 28T gear, and the B screw doesn't have sufficient travel.

This means that I'll be forced into pushing through the mental barrier and pedalling hard.

Bugger that I haven't ridden this week and am off work with the flu :roll:
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Postby MichaelB » Wed Apr 16, 2008 9:11 am

After some perseverance, and full adjustment of the "B screw", it worked just.

Have had a ride and it all worked well, and 99% of the chnages were fine - some feedback was that due to the adjustment of the screw, some of the chmnages wouldn't be good, and this is true.

But it worked well enough.

After a week off the bike with Flu, I am building back up, and checked the climb details out again.

Average gradient of 9% for 4km. :shock: Ride is this Sunday, and weather is forecast to be good :P
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Postby rustychisel » Wed Apr 16, 2008 10:52 am

good news Michael. See you there, or not... the 'sting' is the climb above Willunga township at the end of lap 1, just enough to sap some energy. It's a good route though.
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Postby MichaelB » Thu Apr 17, 2008 9:01 am

rustychisel wrote: See you there, or not... the 'sting' is the climb above Willunga township at the end of lap 1, just enough to sap some energy. It's a good route though.


I'll be the big guy on the Blue LeMond huffing and puffing up the hill.

Weather looks brilliant.

Got the route and profile out yesterday and understood the "sting" comment. Hopefully won't be too bad. I'll be conserving the energy for the Willunga climb !!
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Postby rustychisel » Mon Apr 21, 2008 10:13 am

Hi Michael,

nice to catch up briefly yesterday, the weather was brilliant, the ride good. My legs? non-existent... the engine room was giving me 'no power, captain'. Ah well. Hope you had a great ride.
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Postby MichaelB » Mon Apr 21, 2008 11:43 am

rustychisel wrote:Hi Michael,

nice to catch up briefly yesterday, the weather was brilliant, the ride good. My legs? non-existent... the engine room was giving me 'no power, captain'. Ah well. Hope you had a great ride.


Yes it was. Great ride, great weather, bastard hills.

Made it and did better than expected.

Thank god for the 28T going up Willunga Hill. Kept it steady and did well. Averaged 11.5km/hr at a cadence of 67 going up the hill :shock:

Legs are a bit sore, but pretty good considering.

Just "bikely'd" the Grand Slam #3 route :shock: :shock: :shock: Almost double the amount of climbing and an extra 30km to boot :shock: :shock: :shock: :shock:
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