Drivetrain tension question

[DieselnDust]

Just an honest question, my son always moans I do mine too tight, is it possible to be too tight?

Yes , extra clamping force adds additional preload on the bearings in some hub designs

[BaGearA]

is the QR done up too tight?

No

[BaGearA]

Logic tells me it has to be something between the "cassette lockring" and driveside QR end cap

 

 

I'll take off the cog tonight and have a look

 

 

But if you think it can be whatever else suggest it

[DieselnDust]

If the skewer tension is OK then try this.

If you fit the tensioner so that it runs under the chain as opposed to over it does it do the same?

 

You say the wheel spins freely when out of the frame but does the freehub turn freely by hand? The spinning wheel has more inertia than the spinning Crank and chain.

[BaGearA]

If the skewer tension is OK then try this.

If you fit the tensioner so that it runs under the chain as opposed to over it does it do the same?

 

You say the wheel spins freely when out of the frame but does the freehub turn freely by hand? The spinning wheel has more inertia than the spinning Crank and chain.

Yes when the wheel is out of the bike and I turn the cog by hand it spins very lightly, no friction or binding present

[DieselnDust]

and that's a new SRAM 12speed road chain isn't it...?

 

 

 

Besides bearings what else has changed?

Edited July 29, 2020 by DieselnDust

[BaGearA]

and that's a new SRAM 12speed road chain isn't it...?

 

 

 

Besides bearings what else has changed?

Single speed chain

 

Nothing has changed this is a new build, the bearings were changed because the old ones were toast

[DieselnDust]

Single speed chain

 

Nothing has changed this is a new build, the bearings were changed because the old ones were toast

 

 

Ok then I reckon whats going on is that when you turning the cranks and the wheel the inertia of the wheel is overcoming the seal drag in the bearings.

When you back pedals the seal drag makes it feel like there's a slight bind in the system.

The chain tension will drop anyway on a single speed with tensioner. Once the seals are worn in the drag will disappear

[Mojoman]

I would have thought freehub body?....pawls not releasing....I've had similiar issues before....and wound up walking home when the freehub completely fails....(last time was cranking up a steep bit of track...hub failed...i took a fall)

[droo]

Bearings pressed in with a bearing press or a socket? If bearing press, pop one of the freehub bearings out and check the condition of the spacers between the bearings. If one of them is worn the freehub will drag. If you used a socket, you may have pushed the outer race in too far which will have the same effect.

[DieselnDust]

Bearings pressed in with a bearing press or a socket? If bearing press, pop one of the freehub bearings out and check the condition of the spacers between the bearings. If one of them is worn the freehub will drag. If you used a socket, you may have pushed the outer race in too far which will have the same effect.

 

 

Bearings would then misbehave in both travel directions surely

[BaGearA]

Bearings pressed by a shop, cause I sold my press a few years back (like an idiot)

 

The drag is from when the wheel is clamped in, I put the wheel in loose spun the freehub by hand and it's light and as expected as soon as it's clamped there's binding somewhere

 

Spacer between hub and freehub is in

Wheels spins forward freely

 

 

Alll of this has been said above

[droo]

Bearings would then misbehave in both travel directions surely

 

Indeed, but harder to tell from spinning the wheel because of added momentum - and obviously you can't turn the freehub backwards to check because of the nature of a freehub.

[Meezo]

Mine has been like that since i moved away from the older single speed chainrings to the newer narrow wides that are 10/11/12 speed compatible.

It hasn't bothered me apart from taking pictures i have to make sure the gearing is in "tension" mode.

I do have a sliding dropouts so i can be precise on my tension.

...my drivetrain is about 8000km in i normally get 12000-15000km

Edited July 30, 2020 by Meezo