OSPW on high Tension for gravel?

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FlatlandClimber
Posts: 2378
Joined: Tue Mar 31, 2020 3:37 pm

by FlatlandClimber

Hi there,
Planning on a bike build. Gravel bike with Ultegra 8150. My biggest uncertainty is the RD not having a clutch/ damping, which might lead to strong chain slack.
I have heard the CS OSPW Normal setting for tension is "like a normal OEM RD cage". If that was the case, wouldn't setting the tension to "high" mitigate the missing clutch to some degree? I know it's not the same as a clutch, but would you expect an improvement over just leaving everything stock?
Many thanks in advance.
Specialized SW Æthos (2021) 6.1kg
Specialized SW Crux (2022) 7.2kg
Specialized SW Tarmac (2022) 7.1kg
Cervelo P5 Disc (2021) 9.1kg

*all weights are race ready bikes, large frame size.
Sold: Venge, S5 Disc, Roubaix Team, Open WI.DE, Émonda, Shiv TT Disc

by Weenie


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OnTheRivet
Posts: 651
Joined: Sat Jul 24, 2010 9:41 pm

by OnTheRivet

Or you could save a bunch of money and not put one of those (ugly and pointless) things on your bike? Someone said along the lines of "just tape a few $100.00 bills to your derailleur it will accomplish the same thing".

FlatlandClimber
Posts: 2378
Joined: Tue Mar 31, 2020 3:37 pm

by FlatlandClimber

Yeah, that was the type of comment I was looking for.
My question remains.
Specialized SW Æthos (2021) 6.1kg
Specialized SW Crux (2022) 7.2kg
Specialized SW Tarmac (2022) 7.1kg
Cervelo P5 Disc (2021) 9.1kg

*all weights are race ready bikes, large frame size.
Sold: Venge, S5 Disc, Roubaix Team, Open WI.DE, Émonda, Shiv TT Disc

apr46
Posts: 95
Joined: Thu Aug 26, 2021 1:46 pm

by apr46

FlatlandClimber wrote:
Wed Feb 01, 2023 1:12 pm
Hi there,
Planning on a bike build. Gravel bike with Ultegra 8150. My biggest uncertainty is the RD not having a clutch/ damping, which might lead to strong chain slack.
I have heard the CS OSPW Normal setting for tension is "like a normal OEM RD cage". If that was the case, wouldn't setting the tension to "high" mitigate the missing clutch to some degree? I know it's not the same as a clutch, but would you expect an improvement over just leaving everything stock?
Many thanks in advance.
Yes this will work, but a damper will be better. Way back i ran an 11spd etap RD this way and rarely had chain slap.

I think a lot of people miss the point of an OSPW gravel. Ignoring the watts claims, they allow for a bigger range while also reducing the sweep of the derailluer. This actually increases reliability and builds in more margin when you catch debris in there. Shift quality does suffer a little though.

With that in mind you might be better served with a more robust / less flexible option than CS.

Pyotrump
Posts: 85
Joined: Wed Jun 07, 2017 12:01 pm

by Pyotrump

apr46 wrote:
Wed Feb 01, 2023 9:09 pm
FlatlandClimber wrote:
Wed Feb 01, 2023 1:12 pm
Hi there,
Planning on a bike build. Gravel bike with Ultegra 8150. My biggest uncertainty is the RD not having a clutch/ damping, which might lead to strong chain slack.
I have heard the CS OSPW Normal setting for tension is "like a normal OEM RD cage". If that was the case, wouldn't setting the tension to "high" mitigate the missing clutch to some degree? I know it's not the same as a clutch, but would you expect an improvement over just leaving everything stock?
Many thanks in advance.
Yes this will work, but a damper will be better. Way back i ran an 11spd etap RD this way and rarely had chain slap.

I think a lot of people miss the point of an OSPW gravel. Ignoring the watts claims, they allow for a bigger range while also reducing the sweep of the derailluer. This actually increases reliability and builds in more margin when you catch debris in there. Shift quality does suffer a little though.

With that in mind you might be better served with a more robust / less flexible option than CS.
I also use OSPW on red 22 mechanical derailleur to capacitate 34t. but high tension on pulley cage negates that minute wattage save gone so zero sum in the end.

FlatlandClimber
Posts: 2378
Joined: Tue Mar 31, 2020 3:37 pm

by FlatlandClimber

Yeah, I don't expect any efficiency gain in this case, but a little better chain retention would be the goal.
Specialized SW Æthos (2021) 6.1kg
Specialized SW Crux (2022) 7.2kg
Specialized SW Tarmac (2022) 7.1kg
Cervelo P5 Disc (2021) 9.1kg

*all weights are race ready bikes, large frame size.
Sold: Venge, S5 Disc, Roubaix Team, Open WI.DE, Émonda, Shiv TT Disc

Steve Curtis
Posts: 1021
Joined: Thu Jul 31, 2008 12:20 pm
Location: Hampshire UK, Dublin Ireland and Geneva Switzerland.

by Steve Curtis

FlatlandClimber wrote:
Thu Feb 02, 2023 7:43 am
Yeah, I don't expect any efficiency gain in this case, but a little better chain retention would be the goal.
I've played this game a few times and always go back to a rear mech with a damper.
When you hit a bump, it isn't usually the 1st wave of chain that causes the drop, but the 2nd or 3rd wave.
I saw some really nice slo mo video of this but can't remember where.

High tension doesn't prevent the waves or the drop, and I don't think it make the occurrence of a drop any less. However, dampers on whatever rear mech, do make a significant difference to all chain oscillations.

While not 100% fool proof, they are the best solution available right now.

CampagYOLO
Posts: 394
Joined: Thu May 06, 2021 3:58 pm

by CampagYOLO

Quick question, does it have to be Ultegra 12 speed?

GRX or SRAM would avoid this matter. Maybe that new GRX might even come out this year!

FlatlandClimber
Posts: 2378
Joined: Tue Mar 31, 2020 3:37 pm

by FlatlandClimber

It kinda has to be, yes. I need the bike by March, and I'm not building up a bike with a groupset that's going to be replaced this year.
I can just swap out the Ultegra rear mech with the new GRX...
Specialized SW Æthos (2021) 6.1kg
Specialized SW Crux (2022) 7.2kg
Specialized SW Tarmac (2022) 7.1kg
Cervelo P5 Disc (2021) 9.1kg

*all weights are race ready bikes, large frame size.
Sold: Venge, S5 Disc, Roubaix Team, Open WI.DE, Émonda, Shiv TT Disc

stevesbike
Posts: 309
Joined: Thu Oct 24, 2019 5:33 pm

by stevesbike

I'd ask CS customer support about this - how much their high tension setting differs from a standard shimano rear derailleur before making a pretty significant investment for what's likely to be a small gain especially since you're going 2x where a clutch is less necessary - a lot of people (eg Jom on gravelcyclist) don't even use the clutch setting for 2x except in really bad conditions. I use a fairly inexpensive ospw (J&L) on my red 11 speed mechanical gravel bike (mostly because I already have a lot of 11 speed equipment and am holding off on 12 speed for now). I did it to use a 36 cog cassette - it required swapping the top pulley with a stock SRAM one, but it works well and haven't had any chain drops so far. I also use a protective layer of high density rubber around the bottom bracket because chain drops are inevitable (even with clutches).

markdjr
Posts: 224
Joined: Sun Sep 17, 2017 10:21 pm

by markdjr

FlatlandClimber wrote:
Thu Feb 02, 2023 10:47 pm
It kinda has to be, yes. I need the bike by March, and I'm not building up a bike with a groupset that's going to be replaced this year.
I can just swap out the Ultegra rear mech with the new GRX...
I've built bikes with CS OSPW in the 2nd or 3rd tension slot on the Shimano 12s. Although it doesn't have a clutch, it is noticeably stiffer than 11s non clutched derailleurs. So far we haven't have any issues with Shimano 12s on gravel. If you are doing a lot of underbiking on single track, that may be a different story.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

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