T-rex slider manufacturing error!!

[cardingtr]

This is very interesting. Mine was replaced after I layed down my bike. There is not even an impact when it happened. Zero damage to the bike whatsoever but the T-Rex slider has a crack just like the second picture in post #11.

I actually replaced it with a shorted slider because i thought it was too long.

I also bought it on March 2008.

 

[Fencer]

I also purchased a set in March of this year, and noticed a split in one of them this past weekend while washing the bike. I took the sliders off and e-mailed T-Rex about my findings. Have not heard back from them yet. I guess I'll be buying some new sliders from some other manufacturer.

I never heard from T-rex when I contacted them about my crack. one day a new slider just showed up.

 

[black cherry]

I'm with Kaitsdad, looks to be injection molded. There may be some better ones out there.

 

[mrksfjr]

I'm curious, did you apply the correct torque when installing them? Silly question, I'm sure. I purchased mine about 2 months ago and used 35 lbs. Did I use the correct torque?

 

[fjrshanta]

I'm curious, did you apply the correct torque when installing them? Silly question, I'm sure. I purchased mine about 2 months ago and used 35 lbs. Did I use the correct torque?

The instruction sheet I got with mine show to torque to 41 lb/ft. The "Bin O Facts" shows 35 lb/ft for those 12mm lower front engine mounts.

When I installed mine, they torqued to spec. the first time and after riding 60mi I checked them again and they still showed 35 lb/ft(my original value).

 

[Warchild]

Gentlemen -

We have heard from Tom of T-Rex-Racing.com on this issue.

He stated that the broken frame sliders apparently came from a bad batch. He claims the sliders that are currently for sale are totally free from this defect.

He also stated they would be refund you 2x the amount that you paid for the item, whether you got them from eBay or from their website: T-Rex-Racing.com.

So... youse guys with the broken sliders probably should contact Tom.

 

[just roy]

today i installed my sliders from t-rex. for the price i thought they were very nice. mine didn't look like the ones in your pictures. i did some machining on mine because as shipped they place a large compressive load on the delrin which will cause it to split even without bubbles. i only took pics of the right side although both sides required a little work.

the hole

the slider as delivered. the insert didn't even make it to the end of the plastic.

after machining.

you wouldn't need a lathe to do this. the same thing could be done with a dremmel or put a bolt thru it with a nut to clamp it and spin it with a drill while you filed it.

 

[fjrshanta]

Gentlemen -
We have heard from Tom of T-Rex-Racing.com on this issue.

He stated that the broken frame sliders apparently came from a bad batch. He claims the sliders that are currently for sale are totally free from this defect.

He also stated they would be refund you 2x the amount that you paid for the item, whether you got them from eBay or from their website: T-Rex-Racing.com.

So... youse guys with the broken sliders probably should contact Tom.

Thank you, Warchild!

I will give him a shout and see what else he has to say. :yahoo:

 

[fjrshanta]

today i installed my sliders from t-rex. for the price i thought they were very nice. mine didn't look like the ones in your pictures. i did some machining on mine because as shipped they place a large compressive load on the delrin which will cause it to split even without bubbles. i only took pics of the right side although both sides required a little work.

the hole

the slider as delivered. the insert didn't even make it to the end of the plastic.

after machining.

you wouldn't need a lathe to do this. the same thing could be done with a dremmel or put a bolt thru it with a nut to clamp it and spin it with a drill while you filed it.

I had noticed the same thing on mine when installing them. To compensate, I added a shoulder washer with the approximate Delrin to metal bushing offset. I was satisfied with my result even though it wasn't a perfect match and about .020" of the Delrin was compressed.

You did it the right way! Nice work! :biggrinsmiley:

 

[El Toro Joe]

Tom just e-mailed me back, they are sending me a new slider to replace the split one

 

[Joe2Lmaker]

...the broken frame sliders apparently came from a bad batch. ...

I'm not buying it.

kaitsdad is right. You can see the flow lines in the photos. (nice photos fjrshanta)

"bad batch" my ass. Someone doesn't know what they're doing.

 

[sin_loki]

...the broken frame sliders apparently came from a bad batch. ...

I'm not buying it.

kaitsdad is right. You can see the flow lines in the photos. (nice photos fjrshanta)

"bad batch" my ass. Someone doesn't know what they're doing.

It could be a bad batch. I work in a manufacturing facility and yes bad batches happen, most of the time it caused by a machine fuk up. yes the machinery could have been poorly maintained by a lazy operator, but the injection molding machine may not have shown any type of malfunction. unless they X-ray all of the work done, there is no way one can really tell if it is done right, until it gets used sadly.

 

[just roy]

i would say the bubbles were caused by the inserts not being up to temp with the mold. somebody was rushing.

 

[Joe2Lmaker]

1. Take a look at the size of that part.

2. Just off the top of your head, estimate the shot size.

3. How large a press would you need to fully pack a cavity with that shot size? (Guessing plus or minus 50 tons is close enough)

4. What kind of tooling would you need to run in that press?

And these parts are less expensive than machined parts? I doubt that the demand for sliders is high enough to offset the cost of the tooling.

I'm suspicious. Someone is cutting corners somewhere. A look at the part seems to support my suspicion that the molder does not have the process in control. I doubt this is the press operator’s fault.

We could settle this by sending the parts to The Polymer Lab in Hopkins, MN.

 

[fjrshanta]

1. Take a look at the size of that part.2. Just off the top of your head, estimate the shot size.W

3. How large a press would you need to fully pack a cavity with that shot size? (Guessing plus or minus 50 tons is close enough)

4. What kind of tooling would you need to run in that press?

And these parts are less expensive than machined parts? I doubt that the demand for sliders is high enough to offset the cost of the tooling.

I'm suspicious. Someone is cutting corners somewhere. A look at the part seems to support my suspicion that the molder does not have the process in control. I doubt this is the press operator’s fault.

We could settle this by sending the parts to The Polymer Lab in Hopkins, MN.

I think your suspicion is correct. Looking at the cost of any other frame sliders out there, these are about 60% cheaper than anything else. That was the main reason I purchased them. My thoughts at the time were; " What are the chances of something being wrong with a solid piece of Delrin". I guess I got my answer.

I am not saying that the company is manufacturing poor products, just that the chances for a manufacturing mistake are increased with a very low production cost.

 

[Joe2Lmaker]

I am not saying that the company is manufacturing poor products

I think they make good products.

I'd love to have one of their front stands!

I'm just questioning their molding process. “Buy factory direct and save. No middlemen." sounds like they might be molding their own sliders.

They might be well intentioned and simply out of their depth.

This next observation belongs with my earlier post:

Look at Fencer's photo. That's a different part than yours and shows voids developing in a different area along the core.

This definitely looks like a process issue and not a bad batch.

...the chances for a manufacturing mistake are increased with a very low production cost.

I don't think there is a direct correlation

 

[OES1]

I am not saying that the company is manufacturing poor products

I think they make good products.

I'd love to have one of their front stands!

I'm just questioning their molding process. “Buy factory direct and save. No middlemen." sounds like they might be molding their own sliders.

They might be well intentioned and simply out of their depth.

This next observation belongs with my earlier post:

Look at Fencer's photo. That's a different part than yours and shows voids developing in a different area along the core.

This definitely looks like a process issue and not a bad batch.

...the chances for a manufacturing mistake are increased with a very low production cost.

I don't think there is a direct correlation

I could be wrong, but I doubt they are molding these sliders. The sharp corners on the parts seem to suggest that they are bar-fed in a lathe and chopped off, which would be much faster and use a hell of a lot less energy. Since the biggest cost in slider manufacturing(manufacturers who use the good stuff anyway) is the plastic itself, some manufacturers will buy tons of cheap, recycled plastic to lower overhead. If the plastic is cracking, it most likely hasn't been through an annealing process like the more expensive plastic. Our plastic costs are pretty high, but we get good tech support from our suppliers, and we can feel confident that we are selling a quality product. Like any other company, we have looked for ways to reduce our overhead, but ultimately we get what we pay for. For those seeking further info, try looking up "Acetal" in Wikipedia, or "centerline porosity".

Noah Hendrix

OES

 

[fossilrider]

'we get what we pay for' I avoided the whole issue and purchased R&G Sliders out of England direct from R&G. We spend thousands on a bike we want, then hundreds + on farkles yet skimp on something as basic as bike protection??? I think $90 vs $29 speaks for itself.

 

[kolonial72]

I would not use sliders that don't have a metal sleeve inside the section that the bolt torques up against, between the bolt head and the end of the slider that goes against the FJRs frame. Without that sleeve you are compressing the delrin when you tighten the bolt and that may be contributing to the failures in the pictures.

+1.

 

[strike3]

I would not use sliders that don't have a metal sleeve inside the section that the bolt torques up against, between the bolt head and the end of the slider that goes against the FJRs frame. Without that sleeve you are compressing the delrin when you tighten the bolt and that may be contributing to the failures in the pictures.

+1.

My right side T-rex slider also did the split, I emailed T-rex and they asked for a picture of the problem. I emailed the picture and received a brand new one from them within a couple of days, I can not complain. And yes mine were torqued to 35 foot pounds. The left side has not had the problem as of yet.