Author Topic: New frame: Longteng RD301-D  (Read 36731 times)

Ahodesu05

Re: New frame: Longteng RD301-D
« Reply #210 on: January 07, 2025, 03:16:54 AM »
Looks like the axle does not thread in enough, guessing the spacer would solve it.
But you can find out yourself easily, what happens if you insert another set of wheels?
Any bearing play in the wheelset (maybe test on another bike)?

I only have this bike and wheelset :( 

I do plan to try the washer. I’ve read elsewhere that others have the same problem, hope this solves it.

Alexander

Re: New frame: Longteng RD301-D
« Reply #211 on: January 07, 2025, 05:24:14 AM »
How are your builds guys? Any new observations? That picture od the inside of bb area got me concerned... Did anybody got hold of the TanTan (Seraph) variety? How is the storage compartment cover? This is one of the highlights of the frame, making it na alternative to Trek Domane, Argon 18 Krypton, BMC Roadmachine or even Enve Fray.

I have ordered from Tantan but have not received the frame yet.

maza

Re: New frame: Longteng RD301-D
« Reply #212 on: January 07, 2025, 11:08:10 AM »
I only have this bike and wheelset :( 

I do plan to try the washer. I’ve read elsewhere that others have the same problem, hope this solves it.
Can you try this?

1) Take photo from the drive side of the frame. Measure how far the through axle is from being flush to the nut / how far in the TA is.
2) Repeat without wheel but thread the axle all the way in. If there is no difference you can be sure the through axle is just wrong size.

In any case you could measure the through axle dimensions. Length from the base to the end. And length of threaded area.

kwantani

Re: New frame: Longteng RD301-D
« Reply #213 on: January 07, 2025, 11:25:10 AM »
regarding the rear wheel play on my case... as soon as I seat on the bike, the play is gone from the rear wheel.

violino21

Re: New frame: Longteng RD301-D
« Reply #214 on: January 07, 2025, 02:49:41 PM »
I have ordered from Tantan but have not received the frame yet.
Super. Let us know when it arrives if I may ask.

maza

Re: New frame: Longteng RD301-D
« Reply #215 on: January 07, 2025, 02:51:52 PM »
regarding the rear wheel play on my case... as soon as I seat on the bike, the play is gone from the rear wheel.
That is not possible. You're just not able to feel the play anymore as to move the wheel you would need to a create force greater than your body weight in the opposing direction. Uneven wear and potential to damage remains.

kwantani

Re: New frame: Longteng RD301-D
« Reply #216 on: January 07, 2025, 11:29:53 PM »
Ahodesu05,
     I think the #2 response is the correct diagnosis. Checkout my video here, that explained it right there. If it's the hub issue, you SHOULD not see the wobble play like this. Very obvious it's the TA and rear dropout mismatched length.
    Now where do I get the 2mm spacer?

I mentioned that my rear wheel has a bit of wobble and I couldn't figure out why. Attached is a video of the wobble. After pinging both Elitewheels and Longteng, each had different responses:

1. Elitewheels says it might be an issue in their rear hub assembly and sent me a set of new bearings.

2. Longteng says it might a case of the rear through axle being slightly too long. They suggested adding a spacer/washer to the rear drop out per the attached instructions.

I'm hoping to tap into this forum's expertise here: which is likelier to be the root cause? If it's the rear hub, then Longteng gets a pass (and I'll take the rear wheel to the LBS to get this sorted). If it's the rear through axle, then it's disappointing that a frame manufacturer got this wrong (and I'll either add the washer/spacer or maybe upgrade my through axles).

Thanks in advance.
« Last Edit: January 07, 2025, 11:31:38 PM by kwantani »

Ahodesu05

Re: New frame: Longteng RD301-D
« Reply #217 on: January 07, 2025, 11:40:33 PM »
Can you try this?

1) Take photo from the drive side of the frame. Measure how far the through axle is from being flush to the nut / how far in the TA is.
2) Repeat without wheel but thread the axle all the way in. If there is no difference you can be sure the through axle is just wrong size.

In any case you could measure the through axle dimensions. Length from the base to the end. And length of threaded area.

Thanks for this. I did some measurements:

1. When fully tightened to 10NM with the wheel on, the through axle is not flush to the end of the nut/cap on the drive side. It's about 6mm short of flush. When I removed the wheel and inserted the through axle, it's around the same 6mm short of flush.

2. I took measurements of the through axle and the rear drop out area.

Does this help to diagnose the problem?

maza

Re: New frame: Longteng RD301-D
« Reply #218 on: Today at 06:23:16 AM »
This thru axle gives 3mm more capacity. It fits if you trust 2mm is enough.

https://www.aliexpress.com/item/1005007535904782.html

Ahodesu05

Re: New frame: Longteng RD301-D
« Reply #219 on: Today at 07:16:46 AM »
This thru axle gives 3mm more capacity. It fits if you trust 2mm is enough.

https://www.aliexpress.com/item/1005007535904782.html

Is the problem that the thru axle is too long? Or is the problem that the threaded part is too short?  If I use the washer/spacer as LT advised, does this create any potential issues for rider safety or frame integrity?  Thanks for your patience on this :).

@kwantani I believe it's a standard "M2" washer with 20mm outer diameter and 12mm inner diameter. I called around and one LBS has it, I'm also going to check some hardware stores. I'll give this a try and see what happens, but if the thru axle is the root issue, the washer is a temporary solution until I replace the thru axle.

maza

Re: New frame: Longteng RD301-D
« Reply #220 on: Today at 09:43:34 AM »
Is the problem that the thru axle is too long? Or is the problem that the threaded part is too short?  If I use the washer/spacer as LT advised, does this create any potential issues for rider safety or frame integrity?  Thanks for your patience on this :).
Axle is too long or threads are too short. I would prefer this length axle with longer threading. Based on your measurements there is 6mm space before it protrudes on the drive side.

You should use as thin spacer as possible. With optimum thickness spacer you will be using all 15mm of the threads. 10mm too thick and it will engage only 5mm of the threads. At 15mm too thick the axle won't thread in at all. Someone more proficient with properties of materials is the one who to ask what is the minimum safe threading.
« Last Edit: Today at 09:50:52 AM by maza »

Bowen1911

Re: New frame: Longteng RD301-D
« Reply #221 on: Today at 12:14:00 PM »

You should use as thin spacer as possible. With optimum thickness spacer you will be using all 15mm of the threads. 10mm too thick and it will engage only 5mm of the threads. At 15mm too thick the axle won't thread in at all. Someone more proficient with properties of materials is the one who to ask what is the minimum safe threading.

General rule of thumb, is if you have the diameter of the fastener in thread engagement length, you will meet full material strength (for like materials).  It's certainly more nuanced than that, and I hate doing thread strength math, but it's a good starting point

kwantani

Re: New frame: Longteng RD301-D
« Reply #222 on: Today at 01:00:48 PM »
I've an extra TA from my java bike: 165MM M12*P1.5-L16
 I can try tonight when I get home... 165mm seems to be on the short side though.