Sram transmission issues

Discuss light weight issues concerning mountain bikes & parts.

Moderator: Moderator Team

Post Reply
NiFTY
Posts: 1497
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

Having issues w shifting on my t type setup.
Very slow shifting particularly making one ipshift from 7th to 8th gear (5th smallest sprocket). It completes more 1 revolution prior to shifting most times so it is not a gating issue. Whether suspension is locked out or at sag makes nil difference. Its better in the syand than on the road.

Having done everything according to the videos, in correct setup key correct chain length etc. Have removed and repeated everything invluding cassette installation. Having used the app as well as the chainlength manually to determine the correct setup.

Frame orbea oiz 2023 size m. Xx nonsl group. 32t oval absolute black ring.

Ideas?
Evo 4.9kg SL3 6.64kg Slice RS 8.89kg viewtopic.php?f=10&t=110579" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

by Weenie


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

www.starbike.com



Hexsense
Posts: 3320
Joined: Wed Dec 30, 2015 12:41 am
Location: USA

by Hexsense

7th cog to 8th or 6th from big can be the slowest shift of the entire cassette in Transmission System. It's certainly the weakest point of Transmission cassette.

What happen is: 11 out of 12 cogs in Transmission are narrow-wide where wide teeth can only accept outer chainlink.
But 7th cog is not narrow-wide as it is the only odd number cog in the cassette. So the chain can ride on the cog in 2 ways.
10-12-14-16-18-21-24-28-32-38-44-52

It's then 50-50 luck if chain is riding the right way to shift to the neighbour cog or not. If it's not the correct orientation, you need one more rotation to re-align chain outer and inner links to match what their neighbour cog expect.

NiFTY
Posts: 1497
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

That makes so much sense. But is so stupid from a design point of view
Evo 4.9kg SL3 6.64kg Slice RS 8.89kg viewtopic.php?f=10&t=110579" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

scant
Posts: 272
Joined: Fri Apr 30, 2004 2:05 pm
Location: S.Wales UK

by scant

I had a friend of mine complain about this same issue earlier this week.

User avatar
JayDee81
Posts: 422
Joined: Mon Jan 07, 2019 10:45 pm
Location: Czech Republic

by JayDee81

Of course. It behaves as if there was something misaligned because it doesn't shift properly. Typical "It's not a bug, it's a feature." thing.

NiFTY
Posts: 1497
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

So have it shifting well now. The clocking of the oval makes a big difference when in the setup key and taking out the chainslack.

If you adjust when the oval is "biggest" it will mean the mech sits closer to the cassette and thus shifts better. This does not result in a slack chain when riding.
Evo 4.9kg SL3 6.64kg Slice RS 8.89kg viewtopic.php?f=10&t=110579" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

by Weenie


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

www.starbike.com



Post Reply