Pushing R8000 limits/capacity

Discuss light weight issues concerning road bikes & parts.
JScycle
Posts: 228
Joined: Wed Mar 08, 2017 11:41 pm

by JScycle

pdlpsher1 wrote:
Sun Oct 14, 2018 12:00 am
JScycle wrote:Thanks everyone. So just to clarify if I buy a mid-cage and run two chains it will work awesome with both 11-28 and 11-34?
To be clear, the cage length determines the chain wrap capacity. If you use a RD and pair it with a cassette that is not recommended by Shimano, you will not have sufficient chain tension for all of the gear combinations regardless whether you use a different chain or not. Using a longer chain will let you run a big-big gear combo but the derailleur won’t be able to take up the extra chain slack on a small-small combination if the RD lacks sufficient chain wrap capacity. There’s a very good reason why Shimano makes two different versions of the RD.


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So can you please clarify for me.
Would a short cage derailleur will suit 11-28. Can I get away with anything bigger
Mid cage will suit 11-32 and 11-34. Will it suit 11-28?

LiquidCooled
Posts: 78
Joined: Mon Oct 02, 2017 5:46 am

by LiquidCooled


JScycle wrote:So can you please clarify for me.
Would a short cage derailleur will suit 11-28. Can I get away with anything bigger
Mid cage will suit 11-32 and 11-34. Will it suit 11-28?
For the 8000 series, the short cage will be awesome for rear cassettes from 11-23 to 11-30. The medium cage will be awesome for cassettes from 11-28 to 11-34.

As always with Shimano, they are conservative and you might be able to get away with cassettes outside of their recommendations. You might, for example, be able to run an 11-32 with a short cage 8000 derailleur. It might work perfectly, it might have a slight degradation in shifting speed/smoothness, or it may flat out have bad shifting (ie, doesn't work). We can't say in advance because it really depends on your frame.
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2003 Cannondale R1000 (CAAD7)

by Weenie


pdlpsher1
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Location: CO

by pdlpsher1

+1 on what LiquidCooled said.

Also, I’m a big fan of wide range cassettes. Prior to my current setup I was using a Sram 11-28 cassette. I made the switch to 8050 GS because I ride steep hills and sometimes I have a strong headwind going up. I put on a 11-34 for special climbing days but I love it so much it became my everyday cassette. So my suggestion to the OP is get the GS and try the 11-34 or 11-32 cassette. You may like them enough to have them all the time.


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bm0p700f
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by bm0p700f

I have put a 11-36t on the clutch version and it worked just fine.

ND4SPD
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Joined: Sat May 19, 2018 4:10 am

by ND4SPD

JScycle wrote:
Sun Oct 14, 2018 12:33 pm
pdlpsher1 wrote:
Sun Oct 14, 2018 12:00 am
JScycle wrote:Thanks everyone. So just to clarify if I buy a mid-cage and run two chains it will work awesome with both 11-28 and 11-34?
To be clear, the cage length determines the chain wrap capacity. If you use a RD and pair it with a cassette that is not recommended by Shimano, you will not have sufficient chain tension for all of the gear combinations regardless whether you use a different chain or not. Using a longer chain will let you run a big-big gear combo but the derailleur won’t be able to take up the extra chain slack on a small-small combination if the RD lacks sufficient chain wrap capacity. There’s a very good reason why Shimano makes two different versions of the RD.
So can you please clarify for me.
Would a short cage derailleur will suit 11-28. Can I get away with anything bigger
Mid cage will suit 11-32 and 11-34. Will it suit 11-28?
Why don't you just look at Shimano pages?

Ultegra 6800:

https://bike.shimano.com/en-EU/product/ ... Derailleur

RD-6800-SS

https://bike.shimano.com/en-EU/product/ ... 00-SS.html

Average weight - 195 g

Low sprocket_Max. - 28T

Low sprocket_Min. - 23T

RD-6800-GS

https://bike.shimano.com/en-EU/product/ ... 00-GS.html

Average weight - 207 g

Low sprocket_Max. - 32T

Low sprocket_Min. - 28T


Ulregra 8000:

https://bike.shimano.com/en-EU/product/ ... r8000.html

RD-R8000-SS

https://bike.shimano.com/en-EU/product/ ... 00-SS.html

Average weight - 200 g

Low sprocket_Max. - 30T

Low sprocket_Min. - 25T

CS-HG800-11

https://bike.shimano.com/en-EU/product/ ... 00-GS.html

Average weight - 210 g

Low sprocket_Max. - 34T

Low sprocket_Min. - 28T


To answer you question, can you run SS with 32? Yes, but it is a very good chance you are going to break derailleur hanger... Happened to me on Ultegra 6800 SS with 50/34 11/32 combination...

This guy even made a video about it:

https://www.youtube.com/watch?v=qPLasomhTCw

If you want to keep SS, then you can use derailleur hanger extension, like Wolf Tooth RoadLink:

https://www.wolftoothcomponents.com/col ... s/roadlink

https://www.wolftoothcomponents.com/col ... oadlink-dm

alcatraz
Posts: 1295
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

JScycle wrote:
Sun Oct 14, 2018 12:33 pm
pdlpsher1 wrote:
Sun Oct 14, 2018 12:00 am
JScycle wrote:Thanks everyone. So just to clarify if I buy a mid-cage and run two chains it will work awesome with both 11-28 and 11-34?
To be clear, the cage length determines the chain wrap capacity. If you use a RD and pair it with a cassette that is not recommended by Shimano, you will not have sufficient chain tension for all of the gear combinations regardless whether you use a different chain or not. Using a longer chain will let you run a big-big gear combo but the derailleur won’t be able to take up the extra chain slack on a small-small combination if the RD lacks sufficient chain wrap capacity. There’s a very good reason why Shimano makes two different versions of the RD.


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So can you please clarify for me.
Would a short cage derailleur will suit 11-28. Can I get away with anything bigger
Mid cage will suit 11-32 and 11-34. Will it suit 11-28?
Yes you can "get away" with bigger than 11-28t.

Problem with asking will it work is it will work a little bit less well the more you stray away from the ideal size.

Don't be alarmed though. For most people it works perfect. For some it doesn't feel as good. Depends on how you perceive good shifting to be.

Working well or not assumes you have enough space between upper pulley wheel and the cassette switching from 2nd to 1st gear. If you don't have enough space or if your chain is sized poorly so that you stretch the derailleur in big-big then you risk damaging the derailleur hanger running such a setup.

Another reason why you can't get a clear answer, will it work or not, is because every bike has a bit different length derailleur hanger. It means on some bikes a derailleur can fit a bigger cassette, on some it can't.

Easiest check is to simply borrow a rear wheel from someone that has the size cassette you like and check if it fits (set B-screw and check pulley/big cog clearance). It doesn't even have to be an 11speed cassette. Any cassette with the same size big cog 28/30/32/etc is ok for checking fit.

Wolftooth road link or similar are pretty disappointing when it comes to shifting performance if you stray far from the ideal cassette size (which is the main reason to buy one = more or less always).

mattr
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by mattr

ND4SPD wrote:
Mon Oct 15, 2018 5:09 am
Why don't you just look at Shimano pages?
Shimano are massively pessimistic, i've not yet had a single shimano equipped bike that isn't capable of going outside of the specs shimano list. They are extremely worst case.
ND4SPD wrote:
Mon Oct 15, 2018 5:09 am
To answer you question, can you run SS with 32? Yes, but it is a very good chance you are going to break derailleur hanger... Happened to me on Ultegra 6800 SS with 50/34 11/32 combination...

This guy even made a video about it:

https://www.youtube.com/watch?v=qPLasomhTCw
Good chance? Nah, slight chance. Unless you set it up badly and then shift into a stupid gear, like the guy in the video.

Only real way to test with shimano is to actually build it.

pdlpsher1
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Location: CO

by pdlpsher1

mattr wrote:
Mon Oct 15, 2018 11:01 am
Good chance? Nah, slight chance. Unless you set it up badly and then shift into a stupid gear, like the guy in the video.

Only real way to test with shimano is to actually build it.
Can someone tell me what's the advantage of 'pushing' Shimano parts beyond what's recommened? To save a few bucks? To save someone's self-esteem of a not being able to push a 11-23?

spdntrxi
Posts: 1956
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by spdntrxi

pdlpsher1 wrote:
Mon Oct 15, 2018 6:15 pm
mattr wrote:
Mon Oct 15, 2018 11:01 am
Good chance? Nah, slight chance. Unless you set it up badly and then shift into a stupid gear, like the guy in the video.

Only real way to test with shimano is to actually build it.
Can someone tell me what's the advantage of 'pushing' Shimano parts beyond what's recommened? To save a few bucks? To save someone's self-esteem of a not being able to push a 11-23?
I think it's nice to know the RD is capable of handling more then the stated 34t. I have been using it with the a 34t and it's been perfect. Now if someone wants to come here are say a 40t still works but has this or that issue... I'm fine with that too as long as not on the complaining side of things (because well they are not using it in the stated range)

ND4SPD
Posts: 9
Joined: Sat May 19, 2018 4:10 am

by ND4SPD

mattr wrote:
Mon Oct 15, 2018 11:01 am
Good chance? Nah, slight chance. Unless you set it up badly and then shift into a stupid gear, like the guy in the video.

Only real way to test with shimano is to actually build it.
I had Ultegra 6800 SS with 50/34 11/32 combination, and my derailleur hanger snapped... Did it work? Yes, untill it snapped, rear derailleur went into spokes, I had luck that I didn't destroyed carbon wheels, or injured myself (it happend when I was going about 15 km/h, imagine that at, let's say 70 km/h)... That guy in the video had it, derailleur hanger snapped... In the comments, one guy said he had that combination, derailleur hanger snapped...

I'm not doing that mistake again, I will respect what Shimano recommends...

Everyone have a Google, so they can search on they own...

mattr
Posts: 3822
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

pdlpsher1 wrote:
Mon Oct 15, 2018 6:15 pm
Can someone tell me what's the advantage of 'pushing' Shimano parts beyond what's recommened? To save a few bucks? To save someone's self-esteem of a not being able to push a 11-23?
Means you can get away with running none standard set ups without having to buy a complete new set up for a specific purpose. i.e. running a larger than stock front (52/34 maybe) difference for a training camp. Or sticking a 12/30 cassette on.

Just needs a longer chain. And maybe you can't use 34/12-14.
ND4SPD wrote:
Mon Oct 15, 2018 7:09 pm
I'm not doing that mistake again, I will respect what Shimano recommends...
The only thing you forgot to respect was shimanos recommendations on chain length.

ND4SPD
Posts: 9
Joined: Sat May 19, 2018 4:10 am

by ND4SPD

mattr wrote:
Mon Oct 15, 2018 7:51 pm
The only thing you forgot to respect was shimanos recommendations on chain length.
You didn't mention adjusting the b screw...

It's funny how you know what I did and didn't forget...

LiquidCooled
Posts: 78
Joined: Mon Oct 02, 2017 5:46 am

by LiquidCooled

So the guy in the video fits a 11-32 on a bike with a short cage derailleur and then proceeds to size the chain to make sure small-small works. :noidea: Of course the chain will be too tight for big-big, and I'm not surprised that the hanger snapped. If one wants to go outside of Shimano's recommendations, be prepared for compromises. If you're putting a bigger sprocket than recommended, size the chain for big-big and be prepared to deal with the loss of 34-11 or 34-12. At least you won't have a catastrophic failure like the guy in the video.
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2003 Cannondale R1000 (CAAD7)

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Calnago
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by Calnago

^This. And unlike Campy, where small/small is in fact the correct way to size a chain (12sp excepted) and have it correct for any cassette that it is compatible with, Shimano’s method of big/big is really only applicable for the size of the cassette you’re working with. And if you throw the newest derailleurs into the mix, then everything becomes even more dependent on each other, chain length, hanger placement, cage length etc, depending on what gearing you are using. Especially if you’re striving for optimal performance.
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by Weenie


pdlpsher1
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by pdlpsher1

I have in the past done outside of Shimano’s recommendation. But my situation was such that it was only temporary. Before the 8050 GS was released to retail I had couple special rides with very steep climbs. I installed a RoadLink to a 9070 and sized the chain for the big-big. I did this because I know there’s a chance for an unintended shift to the big-big. So I was playing it safe. I did lose the small-small combos (the smallest three cogs). I used it on two rides only. On my tandem this is how it went. From the factory the bike had a 6800 GS on a RoadLink, along with a 11-40 cassette. With this combination there’s enough of chain wrap capacity for both big-big and small-small. So safety isn’t a concern. I don’t know why it works, but it does. The tandem does have super long chainstays. When the 8000 GS came out the factory started to put them on the new bikes, but less the RoadLink. I bought a 8000 GS and sure enough it cleared the 40 with some B screw adjustment. The new ‘shadow’ RD has a very wide range B screw adjustment. Even without the RoadLink it handled all gear combinations including 50-40 and 34-11. This is probably a unique situation as I said this is on a tandem, not a normal bike with 410mm chainstays. Earlier this year I built up a custom bike. I knew I wanted a 11-34 cassette and without hesitation I got a 8050 GS. Never did I consider a 9150 or a 8050 SS. I truly wanted the right component for the job. The extra weight penalty is well worth it. As for the tandem I’m sticking to the 8000 GS until someone tells me that another RD will handle the 11-40 by design. I don’t think the MTB RD will work with the Ultegra shifters. In summary it’s best to stick to the recommended component.


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