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View Full Version : Disappointed in jomurema and reflex


BrandonGR
2011.12.16, 04:42 PM
I just got the Reflex diff kit. I've had it for half an hour and took my time putting it together. I used the Jomurema ceramic pressure plates along with the reflex diff housing and a PN ultralight weight shaft. I was VERY careful to make sure that nothing was binding or too tight. Within one minute of putting batteries in the car, the inner pressure plate snapped directly along the 3 lines of the 3 prong reflex housing. I just honestly do not know what to say, after investing nearly 80 dollars in a diff, this is just disappointing.

LED
2011.12.16, 04:47 PM
The normal way of businiss is that you contact the vendor of your part and try to work it out with them. I'm sure they will simply get you a new. If this si the first case they are probably also interested to know why it broke. So instead of complaining on a public forum, call them or sent hem an emai. If they do not respond the way you want to, then come here and complain.

Good luck!

VAzRACER
2011.12.16, 04:51 PM
Have you contacted Cristian/Reflex about the issue? I'm sure he would be more than willing to help out.

I've been using the ceramic plates since they came out. Origionally with the Qteq diff housing and later with the Reflex housing. Personally I've yet to have any issues. One thing you may want to do in the future is glue the plates to the housing, I do that with all of mine. A few small drops of ca will do the trick. Mainly you do this to make sure the plates dont spin on the housing. It will cause a slipping effect instead of the diff working properly.

EMU
2011.12.16, 07:33 PM
What wheels were used with this differential? I broke a ceramic plate in a PN diff a while back because I installed a set of ATM wheels which had a different spacing from the Kyosho wheel that was on previously. The ATM wheel provided more pressure to the diff half once I installed the wheelnut and cracked the plate. If using certain ATM wheels, try a 2mm bearing in the rear right wheel instead of a 2.5mm.

I have not had another plate crack on me since, I use it in two cars, one on a Reflex diff, the other Atomic. I also have built up a few diffs for fellow racers and have not had this problem. Were there any big collisions or was the differential too tight?

It is very important to have the diff rings glued to the pressure plates, as stated above.

BrandonGR
2011.12.16, 08:14 PM
Both plates were glued. I was using a set of PN 2mm offset wheels. MR2071R2. The car didn't hit anything at all, the pressure plate broke when I turned around in the floor a few times at a low rate of speed. They both looked structurally fine before I installed them.

I won't be able to get a replacement since I had to outsource the plates on ebay. It looks like I'm stuck with buying another pair. Another issue that I had was getting the PN diff shaft pin into the reflex housing.

Rune
2011.12.16, 08:32 PM
Could be that the plates have had a defect when you installed it. The ceramics is quite brittle, but I have had plates glued to both PN and RR diff halves that I have removed with force and they still held up. Just make sure you dont bend them.
Contact jomurema about it. Mr johannes is a good guy, and I am sure he will replace it for you.

blt456
2011.12.16, 08:43 PM
If worse comes to worse, just get the R241 pressure plates. They are extremely smooth out of the package and require no extra work before putting them in the differential! I have used Atomic, PN, kyosho (the 7 dollar pair), Reflex and r241 diff plates. The best ones are r241. They are about double the price of most of the other plates available, but they are cheaper than the Jomurena and won't crack.

If you are concerned about weight, you can reduce the weight of the differential by using a carbon fiber/aluminum differential shaft. You might not be able to tell much of a difference between the r241 and ceramic plates when driving anyway.

BrandonGR
2011.12.17, 10:06 AM
Is it normal to have part fitting issues with the PN aluminum drive shaft locking pin and the Reflex Diff housing?

Rune
2011.12.17, 10:35 AM
I am sitting here with a couple of PN shafts, a Jomurema shaft, Kyosho shaft and a Atomic shaft.
All of them fits in the RR diff halves, but I notice a couple of them are quite snug.
As long as you are able to cram them in it is all good.

Also check for burrs on the drive pin. These are pressed in the shaft, so they can be slightly deformed at one end.

BrandonGR
2011.12.17, 09:49 PM
After a streak of bad luck with differential parts, it looks like I'm in the market for a drive shaft too. Is there a difference between how well the Jomurema and the Atomic carbon and alloy shafts fit into the reflex housing? A mini guide showing where to glue the pressure plates onto the housing, how much glue to use, and tips to center it would be really helpful.

unearthed name
2011.12.17, 11:47 PM
My reflex diff parts with atomic shaft can withstand 2 days of race without anything happen to them

CristianTabush
2011.12.18, 12:35 AM
Brandon, I have encountered some shaft pins that do not work with the Reflex housing, but this is not due to the housing, but rather the pin length and diameter that is inconsistent on the different diff shafts.

To make it fit, just sand down the pin a bit on each side, eventually, they should fit smoothly and freely. It does not take much to do it,

As for the ceramic plates, please look at the part that failed. It was not a reflex, but rather a Jomurema item, so even though I understand your frustration, I hope you reconsider your position on the statement made.

arch2b
2011.12.18, 10:12 AM
as originally suggested, first course of action should always been to contact the retailer/manufacturer. if still unsatisfied, there is a marketplace feedback area for comment on service/experience and you can post requesting assistance/suggestions/tutorial on specific parts or assemblies. as a matter of decorum, contacting the responsible parties before publicly criticizing them is the preferred method. they after all, will want to respond and it helps if there is not animosity already present which simply adds resistance to your end goal.

i certainly do hope you get it sorted out. there are plenty of very experienced diff builders here that have and can assist you as well. :p if or when you get time, i'd like to see pictures of the diff you are building.;)

bermbuster
2011.12.18, 05:01 PM
Brandon, I have encountered some shaft pins that do not work with the Reflex housing, but this is not due to the housing, but rather the pin length and diameter that is inconsistent on the different diff shafts.

To make it fit, just sand down the pin a bit on each side, eventually, they should fit smoothly and freely. It does not take much to do it,

As for the ceramic plates, please look at the part that failed. It was not a reflex, but rather a Jomurema item, so even though I understand your frustration, I hope you reconsider your position on the statement made.

Christian do you include a shaft pin with the Reflex housing?

I can definitely feel Brandon's pain. In his post he was not pointing fingers but venting frustration. When building a diff of this precision everything has to be perfect. Flat, smooth, and tensioned correctly. Ceramic has awesome properties but must be handled properly. Our reality is we like the technology
but does it really make us faster??? Look at what the world champions use in there diffs....those guys are fast and you very rarely see there cars break during a race.....

arch2b
2011.12.18, 05:03 PM
i would still like to see pictures:p

CristianTabush
2011.12.19, 12:55 AM
Christian do you include a shaft pin with the Reflex housing?

I can definitely feel Brandon's pain. In his post he was not pointing fingers but venting frustration. When building a diff of this precision everything has to be perfect. Flat, smooth, and tensioned correctly. Ceramic has awesome properties but must be handled properly. Our reality is we like the technology
but does it really make us faster??? Look at what the world champions use in there diffs....those guys are fast and you very rarely see there cars break during a race.....

No pin. Most shafts have a pin that is pressed in and practically impossible to press out. We have tried. The easiest solution is some sand paper. Typically the Jomurema and 3 Racing shafts have the most consistent pin size. If we oversize the recess size on the diff half, then you would have slop issues with some shafts.

George, I still don't see how this is a Reflex issue. I have always felt your animosity towards Reflex, so please, I ask you, don't stir the pot. If you don't like me or Reflex, or our products, just stay away, we don't need you to be the thread police. Your comments are so far off on a tangent that I just rather move past the discussion.

Brandon, if you need help, just contact me directly @ contact@reflexracing.net

bermbuster
2011.12.19, 06:14 AM
No pin. Most shafts have a pin that is pressed in and practically impossible to press out. We have tried. The easiest solution is some sand paper. Typically the Jomurema and 3 Racing shafts have the most consistent pin size. If we oversize the recess size on the diff half, then you would have slop issues with some shafts.

George, I still don't see how this is a Reflex issue. I have always felt your animosity towards Reflex, so please, I ask you, don't stir the pot. If you don't like me or Reflex, or our products, just stay away, we don't need you to be the thread police. Your comments are so far off on a tangent that I just rather move past the discussion.

Brandon, if you need help, just contact me directly @ contact@reflexracing.net

Where did i say it was a Reflex issue??? Brandon used pieces from various manufacturers and the assembly broke. We as racers spend our $$$ buying products we hope will work out. In this case something went wrong. I know when I spend money and it doesnt turn out well I am frustrated as well.
You talked about custom fitting the pin as a solution. To me when I buy a part I would like to see the disclaimer.....drop in fit....or may require modifications to make work.
If I hated Reflex like you are stating then why do I use your parts???:confused:
Mini Z is a small community and vendors should work in a positive way. Now you reached out to Brandon and offered him help. That goes a long way.....

BrandonGR
2011.12.19, 10:47 AM
I want to thank Mr. Tabush for offering me assistance.

To get straight to the point of the thread; I brought up ReflexRacing because the part directly connected to the pressure plate was the Reflex housing. At the time it broke, it seemed like it happened because of an oversight in how the points of contact would direct stress and force across a non-ferrous pressure plate. My thread was created in the spur of the moment, rather than addressing the issues as they should have been.

After speaking with Mr. Muehlbacher, he assured me that the fracture was the result of a small flaw in the edge of the plate from rough shipping. He has graciously offered me a replacement.