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SteveU30

Lunchbox FX10 Front Arm Conversion - Another Take

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Hi all, I know there's been umpteen threads on doing this over the years but I thought I'd add one more as I've never seen it done exactly like this.

As some will know, the lower shock absorber mounting point in the FX10 lower arm is far from ideal due to it being too far in towards the chassis which puts the shock at a very steep angle. I've seen some people put the shock on the top of the kingpin mount but this usually causes interference with the tyres if using standard lunchbox rims and tyres. I have seen another thread where a guy made his own mounts which put the lower shock mount a bit higher and a bit further out which seems ideal so I thought I'd have a go myself.

I decided against making my own lower shock mount brackets from modelling clay 1. because it was going to be a lot of faff with uncertain results and 2. there is a lot of unused plastic in the FX10 kit which just seems a waste.

I noticed that the thickness of the shock tower that comes in the FX10 kit is a perfect fit in the gap in the lower arm and the holes are exactly the same size as the metal pins that go in the arm so I set about cannibalising the shock tower as follows:

3FBEAB9F-A982-4589-9CB5-562C5B9DA3EE-765-0000006E32D6EE3D_zps627dc659.jpg

CB2B3EA2-31B9-44BA-912F-648173E74798-765-0000006E4EACE149_zpsd908bf78.jpg

47606ABC-DEE7-476E-AF42-01037783D5D5-765-0000006E76397F89_zps71c3658b.jpg

I then tried them in the arms to see how they fit:

00F78B19-65AE-4DB0-B36C-8244D2BF618D-765-0000006E925AC3AF_zpsf70f81a7.jpg

Not bad but I want them a bit lower and a bit further out so further hacksawing was required:

1C22A75F-FB64-41B2-8E58-4DFC6A5E1680-765-0000006EA37F7586_zpse5d3e97c.jpg

Perfect!:

24A9746D-A612-416C-B01E-AD103541D3E7-765-0000006EC94963E3_zps436c9801.jpg

79A396DE-D156-4026-B2B0-BE52AB523697-765-0000006EDADE85FD_zps2e36d4e0.jpg

Just need to attack it with a Dremel now to neaten it up but you get the idea. Will post more pics later once it's all mounted to my lunchie.

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Looking good. I love the innovation in this and turning spare parts into great working mods. Keep the pics coming please :)

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I have CRP oil shocks mounted on the top of the "king pin" on my LB and the stock wheels/tires do not interfere (I also have a .005" TRX shim behind them but that makes NO difference in the wheel/shock spacing)

LB4_zps6ffa0eea.jpg

LB5_zpsd8943020.jpg

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They barely clear though haha they use a 8mm spring which is nice but you're limited to CRP springs

I'd still like to see your setup though as I still have the left over CRP parts and you're onto something that I couldn't think of when doing my setup..

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Tyre flex (and they do flex) is enough for the tyre to rub the spring when you fit the damper to the old upper link mount.

I have a lower arm made up in RhinoCAD for this conversion that combines the CRP lower arm dimensions, but with the Lunchbox damper position. My problem is finding a plastics supplier in Australia that doesn't want 500% mark up on plastic stock prices, and one that will sell retail and not to businesses in bluk only so I can cut them out on my CNC mill.

Your idea has merit though, and it's been done before, but with a CNC part. I would have made a slot so that the piece you added cannot pivot up or down, instead of just notching out the bottom so it sits in place. With it how it is, when you wheelie the suspension will droop more than you want it to as the piece you made will also pivot.

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Tyre flex (and they do flex) is enough for the tyre to rub the spring when you fit the damper to the old upper link mount.

I have a lower arm made up in RhinoCAD for this conversion that combines the CRP lower arm dimensions, but with the Lunchbox damper position. My problem is finding a plastics supplier in Australia that doesn't want 500% mark up on plastic stock prices, and one that will sell retail and not to businesses in bluk only so I can cut them out on my CNC mill.

Your idea has merit though, and it's been done before, but with a CNC part. I would have made a slot so that the piece you added cannot pivot up or down, instead of just notching out the bottom so it sits in place. With it how it is, when you wheelie the suspension will droop more than you want it to as the piece you made will also pivot.

I've gotta admit I didn't think about wheelies when I made the cuts lol. I did realise afterwards my mistake though but I'll probably just cable tie my mounts to the arms for now while I figure it all out.

Have put a wanted ad on the main site for anyone with a spare FX10 shock tower so I can do it again with the proper cuts if it works.

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I'll send ya mine...

Wow, nice one!

Will send a PM with my address.

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10-4 I don't plan to change my LB so it's on me if you want/need it!

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Finally managed to get this all fitted although I've only temporarily fitted my lower shock mounts using cable ties to secure them until the replacements arrive which will be notched out to fit the lower arm properly.

I used as much of the FX10 kit as possible including the King Pins, ends of the steering arms (chopped off and fitted on top of the steering knuckles where they are supposed to go). I even chopped off the narrow part of the shock tower mount and glued it to the inside of the front bumper mounting block to give extra strength where I drilled through to mount the inner camber arm ends.

I also ended up swapping my Ansmann shock around so the 75mm are on the back and the 85mm are on the front. This has made the Lunchie dead level as well as having the benefit of the rear shocks no longer foul the motor.

Pics:

93AA0924-8FC1-48FE-A9EB-B13C2EB0BAD8-11702-000004372BB3AC9F_zpsd77d34a8.jpg

5C55B294-FA96-4B92-AD51-E9E05799D2A5-11702-000004373268518D_zpsa9154586.jpg

7C24FC16-A033-4E18-9E9F-BB6CDFEFCAB1-11702-000004373BF953A9_zps8a5ce40b.jpg

D0717E76-91B0-4404-BECD-F48E714F43B2-11702-00000434F95D7E9C_zps2e2143a0.jpg

07944FE9-386B-4B2D-B84F-92263D134F5E-11702-00000434F346CE9D_zps5c760a67.jpg

BD70AC63-0A16-40F8-B5F5-746561C3636D-11702-00000434E7E72367_zpsc2f3b2bf.jpg

8CE754BD-B81D-46A1-966F-0F12F1FB67B9-11702-00000434E167DAD2_zpsc630db8c.jpg

3B8EFDF9-974B-4F98-9C25-C0063B70DA61-11702-00000434CFF0B034_zpsad6c2bc5.jpg

ACC80A77-835C-4E03-802A-30EECEFD8868-11702-00000434FF970DD4_zpsa1a299e9.jpg

975F148C-7A88-4DF8-BF1D-53AFE4A13D19-11702-0000043505F82EF2_zps10bd0666.jpg

C66B3CA6-F7A5-495F-B230-9E2613C8355B-11702-000004350C161397_zps12a9ad55.jpg

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That looks pretty good to me. One minor thing I'd change it the cable ties. If your sticking with them I'd swap them for black ones so they blend in better. It certainly fixes the bump steer!

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That looks pretty good to me. One minor thing I'd change it the cable ties. If your sticking with them I'd swap them for black ones so they blend in better. It certainly fixes the bump steer!

They are just temporary as Zac is kindly sending me the rest of his FX10 kit for me to do the lower mounts again 'properly'.

I just drove it today for the first time and it handles like it's on rails!! Seriously, I can turn at full speed (standard silver can on a 4700 NiMh) and it just turns! I especially like the fact that it corners so hard that it lifts one rear wheel as it leans over!

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They are just temporary as Zac is kindly sending me the rest of his FX10 kit for me to do the lower mounts again 'properly'.

I just drove it today for the first time and it handles like it's on rails!! Seriously, I can turn at full speed (standard silver can on a 4700 NiMh) and it just turns! I especially like the fact that it corners so hard that it lifts one rear wheel as it leans over!

Time for more power now! Hehehe.

Have a 5700Kv MambaMax on 2S Li-Po in mine. Standing backflips amounts of power. :lol:

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Time for more power now! Hehehe.

Have a 5700Kv MambaMax on 2S Li-Po in mine. Standing backflips amounts of power. :lol:

Am definitely going the brushless route now although I'm thinking more along the 4000Kv region as I like my Lunchbox to be the right way up more often than not! :lol:

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Wow, that sounds like a huge improvement in handling SteveU30. Those big Nimh batts help keep the COG low too.

How robust is the front end now? I'm building a midnight pumpkin for my 5yo daughter and was wondering if its worth doing this conversion to help tame the chassis.

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Well I've not driven it over any 'sweet jumps' yet but it's definitely a lot more solid now.

I would definitely recommend centring the servo and fitting a high torque servo saver, that alone makes a huge difference to the steering.

Oh and I also fitted Pro-line tyre inserts which also massively improve the handling!

Here's a quick video I made on my lunch break today, sorry about the out of focusedness.

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Wow looks like it handles lovely. I like the idea of turning at speed without toppling over!

Definitely on the list to do!

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It certainly does that! Not sure what will happen when it's brushless mind :lol:

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It certainly does that! Not sure what will happen when it's brushless mind :lol:

It's hard to steer when your wheels rarely touch the ground. :lol: Wear out the wheelie bar before the front tyres.

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Just tidied up my Lunchbox last night as it had a few outstanding issues and it had me idly Googling LB mods this morning where I came across this...

http://www.msuk-forum.co.uk/topic/150160-am-i-expecting-too-much-from-my-tamiya-lunchbox/

Specifically the "triangles DVD case mod" - to move the shocks further out towards the wheels. As its completely reversible (as the one above) I might give it a go... I cant help wondering about the strength of it but I guess its worth a go to see :)

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