YT may be lying on the Jeffsy's frame design, about Yoke and Rear triangle design

A

airsodam

Squid
Hi Guys,

I have purchased a new 2020 Jeffsy 29er (carbon frame), and found a strange thing on the frame.

I would like to know if this gap is normal in the red oval drawing (Middle picture).
There is a gap of 3mm between the Yoke to the right side (drive side) upper arm bolt hole surface while there is no gap on the left side.
Due to this gap, the drive side arm needs to be pushed with a great amount of force against the rocker in order to put together, this also causes a bit of distortion in the rear triangle. However the rear wheel looks parallel to the seat post tube.

Below pictures with the blue backing tape are just to show the unequal amount of space using the seat tube as a center (datum).
All the way to the right, you can see blue through the seatpost tube, and the upper arm, but the middle picture does not show any blue backing tape in between.

I have contacted YT, they stated that the gap on the drive side is normal, it is in fact preset in all jeffsy. I just have a hard time believing this statement.
That's why I am here asking you guys if you have noticed something like this...

What do you think?


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mike14

mike14

Likes Bikes and Dirt
That looks weird, although it seems a strange thing for YT to lie about.

There's a pretty active Jeffsy thread over at Pinkbike, so might be worth asking the same question over there
 
C

creaky

XMAS Plumper
Ideally the rear triangle would be square obviously but not sure if that 3mm (if that's correct) is going to affect performance.

Why did you pull it apart, or did it come unassembled?

What is the prior correspondence with YT on this issue?
 
A

airsodam

Squid
moorey said:
Are you sure you aren't missing something like a 2mm spacer for each side?
Click to expand...
The upper arm was fully raised to get a better view of the uneven spacing, but no there was a spacer on each side.
If I add a 3mm spacer on the right side, it would be perfect, but that means the shock mounting location will be out of alignment by 3 mm.
 
moorey

moorey

call me Mia
airsodam said:
The upper arm was fully raised to get a better view of the uneven spacing, but no there was a spacer on each side.
If I add a 3mm spacer on the right side, it would be perfect, but that means the shock mounting location will be out of alignment by 3 mm.
Click to expand...
Cool. Flying blind here, I just know that all my bikes have a spacer on any pivots between the bearings. Good luck with it. Try the other forums as suggested.
 
A

airsodam

Squid
creaky said:
Ideally the rear triangle would be square obviously but not sure if that 3mm (if that's correct) is going to affect performance.

Why did you pull it apart, or did it come unassembled?

What is the prior correspondence with YT on this issue?
Click to expand...

I pulled it apart because there was a gap in front of the yoke that was not matching each other between the yoke and the main frame. Asked YT about this finding, but all they said was it is normal. I could not believe it, so i investigated further to see if anything was out of center. Here it was that the arm and yoke was having the uneven spacing.
 
Flow-Rider

Flow-Rider

Burner
You don't want your shock compressing at an angle otherwise it will cause all types of issues. The hole for the front shock might be out or the yoke is offset to one way but it looks like they've done it because of the offset on the rear triangle bracket on the BB.
 
Mattyp

Mattyp

Cows go boing
Probably "within tolerance"
My Giant doesn't have that sort of misalignment and that's saying something.
I would be asking someone with same frame to check theirs. Nothing should need to be forced into position to fit.
 
A

airsodam

Squid
Flow-Rider said:
You don't want your shock compressing at an angle otherwise it will cause all types of issues. The hole for the front shock might be out or the yoke is offset to one way but it looks like they've done it because of the offset on the rear triangle bracket on the BB.
Click to expand...

Your comment led me to another important point, the shock doing the job at an angle. This photo was taken at the main frame side while the stanchion side was still attached to the yoke.

The shock spacer is not aligning with the frame, off about 1mm.
As I mentioned earlier, there is about 3 mm misalignment from the upper arm to the yoke, then the yoke counteracts the most, but a little tiny misalignment still present which is leading up to the shock mounting location at the frame.

This evidence has made me to conclude that YT was not transparent about this issue, tried to foul me.

P.S. No wonder my rear shock made a bit of noise while i was pushing up and down stationary ( I sent a video clip to Fox tech, they told me to send it in...)
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C

creaky

XMAS Plumper
This is a carbon frame yeah?

Are frame alignment issues commonly a problem in carbon given they come out of pressed moulds? I assume that, unless it’s a widespread mould issue, the only way either the front or rear triangle could be warped would be by misalignment if the metal inserts like BB shell, pivot points etc.?
 
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