Trek Rail 9 - play in drivetrain?

[kiwidude]

Hi all

I’m looking at buying a new Rail. During test ride I noticed a slight (5 or 10 degree?) slackness in uptake when beginning to pedal. Is this normal?

of it were an old acoustic bike I’d say it felt like slop on the free hub... but it was more like intentional uptake in a drivetrain than wear-related looseness.

I’ve only ridden Levos which don’t have the same feeling

Any thoughts?

 

[Stihldog]

Hi all

I’m looking at buying a new Rail. During test ride I noticed a slight (5 or 10 degree?) slackness in uptake when beginning to pedal. Is this normal?

of it were an old acoustic bike I’d say it felt like slop on the free hub... but it was more like intentional uptake in a drivetrain than wear-related looseness.

I’ve only ridden Levos which don’t have the same feeling

Any thoughts?

The free hub on the rail generally has 3 pawls. If there is too much grease or improperly installed the free hub may not operate properly.
On the typical free hub you can add pawls (6 total) which may give a faster engagement(?). 3 pawls is enough though. I’ve only taken mine apart twice for cleaning and greasing.

 

[kiwidude]

Thanks. It didn’t feel like it was in the hub though - more like in the motor.

ill try to get a ride on another rail to see if it’s a characteristic or whether the first had something wrong

cheers

 

[Stihldog]

Thanks. It didn’t feel like it was in the hub though - more like in the motor.

ill try to get a ride on another rail to see if it’s a characteristic or whether the first had something wrong

cheers

Ah, I may have misunderstood. I’ll check or video the amount of play in my drivetrain.

 

[kiwidude]

Thx. It was when torque was applied to the pedals, it felt like something was slotting into place within the drivetrain.

 

[Doug Stampfer]

yeah mine is like that. You have to load it up a lil bit to start on a steep hill other than that it isn't a problem

 

[sgh77]

Brought Rail 9 the other day and noticed this play in drive chain, I must say it feels wrong, I will take it into the bike shop on the way past and inquire. Does anyone know if this is considered normal on the Bosch CX Gen 4 motors?

 

[Hamina]

Brought Rail 9 the other day and noticed this play in drive chain, I must say it feels wrong, I will take it into the bike shop on the way past and inquire. Does anyone know if this is considered normal on the Bosch CX Gen 4 motors?

Can you specify more precisely where the play is:
- Cranks
- Front chainring
- Chain
- Cassette
- Freewheel
- Rear hub

or a mix of these?

 

[sgh77]

Can you specify more precisely where the play is:
- Cranks
- Front chainring
- Chain
- Cassette
- Freewheel
- Rear hub

or a mix of these?

I think its just a slight turn of the pedal before the motor engages (an inch or two), where it feels like nothing then contact. I know in an old bike it would mean the crank spindle is worn.

 

[Me90]

My rail has something similar where there is a bit of play and rattle through the pedals before motor engages.
Have resisted taking to bike shop so far under the assumption it’s fine - be interested to hear what yours say.

 

[qwertycube]

Also interested as I’ve only just started to notice this on mine which is now coming up on 700miles. It was fine before this.

 

[Dhmorelia]

Hi everyone, I’m new to the forum so please be kind.
I’ve recently purchased a Rail 9 2021 and have a similar issue. I had a test ride on a 2020 9.8XT before ordering and didn’t notice the issue.
I’ve been back to the LBS and they said it was normal, although I don’t have a lot of confidence in them. They said they re-applied the software (it was already updated) and the motor delay was reduced quite a bit.
Has anyone discovered a possible solution?

thanks

 

[JMD]

There's a freewheel mechanism in motor also one in the rear hub, pickup isn't super fast. Sounds normal. Ride bike & stop worrying.
The levo has a different type of freewheel mechanism in motor (sprag) better pickup, but has had reliability issues

 

[Dhmorelia]

Great. Thanks for the feedback.

 

[aimage]

My new Rail 9 had this play out of the box, didn't seem right and after 200km run in under instruction Bosch replaced the motor. Its definitely better now, still.some play but ok. Now just have to solved the battery falling out issue.