Why are they replacing back wheel?

[Scottmartin99]

Disc brakes or rim brakes? Broken spoke and loose/bent spokes shouldn't cause any binding with disc brakes.

Rim Brakes 👍

 

[Smudge]

Haven't you already put a thread up about this ?
If, as they claim, a spoke is broken...... why didn't you notice this ?

 

[Ajax Bay]

Halfords are replacing my Bike Back Wheel due to 1 spoke hanging off and various other S being slightly bent. I’m wondering if have any ideas on why that might solve the problem.

I gave you suggestions. Then I checked what else you'd posted and discovered this was a back wheel off an e-bike.
I think it would've been helpful if you'd shared that in your OP, as the rear wheel on a Carrera Crosscity is a bit different to a 'normal' bike wheel and there are obviously an additional set of possible reasons for the symptoms described.
Just saying.
[From other thread]

I purchased the electric Carrera Crosscity Halfords bike 6 weeks ago. . . . around 3 days ago, the peddling suddenly felt heavier. Almost like something was pulling it back as I peddled. I pumped up the wheels, put oil on the chain and the breaks where aligned. yet still the same problem. I noticed that when I’m NOT peddling and moving, the bike feels perfectly fine. When I peddle without the electric motor on, it was fairly heavy before, now it feels 3 times heavier than it did before.

 

[CXRAndy]

It’s a Carrera Crosscity Folding Electric Bike.

Apart from 1 person, everyone else at Halfords has been fine so far. This problem aside, I love the bike so hoping it gets resolved

Its a rear hub motor drive, so its most likely this sudden change in performance is due to the hub motor developing a problem or the drive electronics

 

[gbb]

A theory re the heavy feeling. I could imagine the loss of wheel rigidity (bent and broken spokes) could make it feel heavy, stodgy, the power just wouldn't be transmitted from motor to rims as well as it should.

 

[Scottmartin99]

Haven't you already put a thread up about this ?
If, as they claim, a spoke is broken...... why didn't you notice this ?

Yes and No. A problem was established and the back wheel is being replaced. So I put a thread it in the section for repairs to get some feedback.

I certainly hope to have not offended anyone.

 

[Scottmartin99]

I gave you suggestions. Then I checked what else you'd posted and discovered this was a back wheel off an e-bike.
I think it would've been helpful if you'd shared that in your OP, as the rear wheel on a Carrera Crosscity is a bit different to a 'normal' bike wheel and there are obviously an additional set of possible reasons for the symptoms described.
Just saying.
[From other thread]

You are correct, please accept my apologies.

 

[Scottmartin99]

Its a rear hub motor drive, so its most likely this sudden change in performance is due to the hub motor developing a problem or the drive electronics

Thanks. Question. If the motor is switched off, will be peddling performance of the bike, still be affected?

 

[Scottmartin99]

A theory re the heavy feeling. I could imagine the loss of wheel rigidity (bent and broken spokes) could make it feel heavy, stodgy, the power just wouldn't be transmitted from motor to rims as well as it should.

Interesting. If the motor is off, could the heavy pedalling still be there?

 

[gbb]

Interesting. If the motor is off, could the heavy pedalling still be there?

It's only my theory but yes.
How much effect it would have I dont know, its perhaps more likely to be the motor, life's full of unknowns sometimes eh ?

 

[CXRAndy]

Its quite hard to tell, whether a non functional motor would cause drag. I suppose a back emf could be created producing a magnetic force opposing forward motion of the wheel.


Its one of those that you might not be aware until you actually test the bike in that scenario.

Lets see if a new rear wheel cures your 'harder to pedal' feel

 

[MichaelW2]

Halford techs are of variable quality. Some know their trade, others tickbox the self assessment.
Ask the guy if he prestressed the spokes. If you get a blank look, the answer is no.

Pre stressing is grabbing a handfull of opposite spokes and squeezing. This can unwind spokes that have been rotated and bed in the elbow. Spokes often need tensioning and trueing after pre stressing.

You can ping the spokes and they should be the same (ish) note if components are good enough

 

[Ajax Bay]

Ask the guy if he prestressed the spokes.

No Halfords guy has touched the spokes of this wheel though, have they, except by accident when putting the wheel on before sale? Until he checked, found one spoke broken and others "bent". Then he decided to just replace the wheel (see above): no repair or "prestressing" (you mean stress relieving, (Jobst Brandt) I think) was involve or needed in this scenario as it unfolded.
More: from https://www.wheelfanatyk.com/blog/wheel-building-tip-no-4-how-to-pre-stress-your-wheel/ and says:
". . . refer to material science and the well established practice of stress relieving. What a new wheel can really use is not, technically speaking, pre-stressing. It’s stress relieving. Any assembled structure involves new forces within its component parts. These forces involve static loads but they also involve trapped stress. Sometimes this stress is beneficial but generally it will make the structure less stable and encourage fatigue failure. "
https://www.halfords.com/bikes/electric-bikes/carrera-crosscity-folding-electric-bike-750632.html
Remember this e-bike has a 20" wheel with a motor hub and thus deep flanges, so the spokes are really short and angled. High frequency ping!

 

[Ajax Bay]

Did you get any joy / resolve this, @Scottmartin99 ?

 

[Scottmartin99]

Did you get any joy / resolve this, @Scottmartin99 ?

Hi Ajax. They replaced the back wheel today which also has the motor inside. It seemed okay but the motor is very noisy. The back wheel doesn’t spin for long. I will do a Thread now with attached files