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Old 08-31-2010, 04:35 AM   #5521
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Originally Posted by sosidge View Post
Well, I've done a few calculations and measurements, and even with 0.06mm difference in the hex right at the point where the axle goes through, you would still get only 0.75mm difference at the wheel rim. I personally was unable to measure the depth of the pin groove in my cars hexes as my caliper will not fit in there or find a reliable flat to use as a reference plane.

But, regardless of that, I don't doubt that you are getting 1.5-2mm difference at the rim, and no I wouldn't be happy about it.

But there are a great number of factors beyond just the machining of the hex that can cause this - buckled wheels, bent axles, bent pins, all of which are possible on a car that has been run. Or is this car brand new out of the box and exhibiting these problems on the first build?

Either way, 0.06mm would likely be within the machining tolerance of the part, you could try exchanging parts until you get two more that are correct but it might be a long process.

As far as the hexes go, the clamp type puts a stress on the hex in the direction it is supposed to be driving the wheels... not good. And sometimes they tighten in such a way that the originally flat hex surface is slightly distorted. Captive pin types (made by Yokomo but anodised red) were use on the early Scythes - 3146R-SET2 should be the part number for a pair, if you can find them. Or get them from an old Yokomo. I've just test fitted one on my Photon and they go on fine, albeit with a slightly different offset, approaching 1mm wider than the standard 5.2mm Photon hex.
Excellent Info, Thanks for your help; The Captive pin looks like a much better design!

The kit was built and only run in the house for testing.. no crashing

FL - FR


RL - RR

for troubleshooting, say the problem shows only at RR, I will take the wheel from FL and swap with RR, (problem still shows and FL is still perfect) Then take wheel and hex+pin from RR and swap with FL.. (Problem shows at FL) and RR is now fine. I have also removed the shaft from the CV to remove any influence.

Here are some pics of the kit adapters, (this is during the build on a non-run kit)

1. flattened out with Dremel
2 & 3 - See brake from the fatigued metal..
4. Has same problem as 1. (before flattened out with Dremel)

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Old 08-31-2010, 04:48 AM   #5522
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Excellent Info, Thanks for your help; The Captive pin looks like a much better design!

The kit was built and only run in the house for testing.. no crashing

FL - FR


RL - RR

for troubleshooting, say the problem shows only at RR, I will take the wheel from FL and swap with RR, (problem still shows and FL is still perfect) Then take wheel and hex+pin from RR and swap with FL.. (Problem shows at FL) and RR is now fine. I have also removed the shaft from the CV to remove any influence.

Here are some pics of the kit adapters, (this is during the build on a non-run kit)

1. flattened out with Dremel
2 & 3 - See brake from the fatigued metal..
4. Has same problem as 1. (before flattened out with Dremel)

To be fair, I think you are greatly over-tightening them to break them on the build. The screw clamp only needs to be tight enough to stop the hex sliding off the axle, there is no benefit to clamping them down tight.

Even so, your picture does show the fundamental problems with the clamping hexes when taken to their limits.
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Old 08-31-2010, 07:34 AM   #5523
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Originally Posted by sosidge View Post
To be fair, I think you are greatly over-tightening them to break them on the build. The screw clamp only needs to be tight enough to stop the hex sliding off the axle, there is no benefit to clamping them down tight.

Even so, your picture does show the fundamental problems with the clamping hexes when taken to their limits.
anthony_ling, sosidge is right about the hexes being over-tightened. Mine are barely tight enough so it will stay on the axle when I take my wheels off.

If you are in North America, shoot us an email to topracingusa@yahoo.com we'll send you some replacements free of charge. We'll need proof of purchase from North America.

Thanks,

EJ
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Old 08-31-2010, 07:36 AM   #5524
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New Option parts

& Kit was back in stock !
Attached Thumbnails
T.O.P. Racing "Photon" 1/10 EP Touring Car-top-po-psh102.jpg   T.O.P. Racing "Photon" 1/10 EP Touring Car-top-po-psh103.jpg   T.O.P. Racing "Photon" 1/10 EP Touring Car-top-po-psh122.jpg   T.O.P. Racing "Photon" 1/10 EP Touring Car-top-po-psh123.jpg   T.O.P. Racing "Photon" 1/10 EP Touring Car-top-tc-pch20h.jpg  

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Old 08-31-2010, 08:35 AM   #5525
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Originally Posted by paraletic View Post
Ok so looking further into my diff failure

when I bought the diff it had no intstructions etc, as they all seem to
I hav also got my hands on a maintenance kit which does have instructions, so looking through them and my original diff, I noticed that it came from the factory one shim less than the instructions state???

Without the extra shim this would allow the gears to move an therefore not mesh correctly hence causing premature failure- surely

so did I just get a dud ?? Or does someone else have the same with there diff?
Perhaps this is why no instructions are included??
i think that you might have a dud, I had a front and rear on my car now over a month and its very smooth and no leaks
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Old 08-31-2010, 10:07 AM   #5526
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i think that you might have a dud, I had a front and rear on my car now over a month and its very smooth and no leaks
Ok cheers Marcos

so if I just build the new diff as per instructions I should be ok.
No need to do anything special etc?

It's not the cost etc, it's just I wanted to know if I had possibly done something wrong which I could avoid doing again
or of it was possibly jus a faulty unit
hopefully the next one will be more reliable
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Old 08-31-2010, 12:04 PM   #5527
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hi i run my photon on carpet ( mixed and fast flowing aswell ) , its excelent and consistent , im just after some more off power steering and to be better on direction changes/chicanes ..

its pretty much stock set up except ...

for the foam top deck
hpi pinks on the front and silvers on the rears
tamiya 3 pistons , 416 bladders and 1mm hole in the top cap for 0% rebound etc
anti roll bars 1.4front and 1.2 rear .. and a few little suttle changes ..

like i said its really nice to drive.. i just want a slight change thats not going to make it twitchy / inconsistent ..


going throu the pages , i keep reading about modifiying the foam to deck and cutting the front -rear brace off it .. also fitting the medium wings ...
will any of this help ..

ive also been advised by an excelent uk team driver to adjust my front roll centres , but i didnt get time to try this at my last meeting ..

and i try not to adjust something that i dont understand fully , as we dont get any practice time before our next heat etc ....
im also waiting for a gear diff , but that wont be here by the time i race it next , but for when im ready to fit it ...

what sort of wt oil would you recomened .. as above its on carpet and rubber tires ..

also has anyone got anymore suggestions for my above post ...
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Old 08-31-2010, 03:10 PM   #5528
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Originally Posted by E.J. Evans View Post
anthony_ling, sosidge is right about the hexes being over-tightened. Mine are barely tight enough so it will stay on the axle when I take my wheels off.

If you are in North America, shoot us an email to topracingusa@yahoo.com we'll send you some replacements free of charge. We'll need proof of purchase from North America.

Thanks,

EJ
EJ Thanks for your support, i'm from Brisbane Australia, and purchased from Overseas. I accept that i will not get any assistance from that vendor...

I do recognize that I had over tightened the hexes during the build and decided to purchased the optional 6.2mm (from Australian retailer http://www.TopRacing.net.au) as a replacement at my cost.

at the time it didn't seem that I was putting too much force on them, as i've been using Alum clamp based hex on a nitro car for over 3 years.. (Kfactory K1418) -

I'm was frustrated that I've still got the same problem, even though my 6.2mm hex are not deformed from over tightening..

sosidge, again thanks for your help. its guys like you that make this forum/thread one of the best.
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Old 09-01-2010, 04:10 AM   #5529
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Hi guys
I have v1 shocks and can I use tamiya pistons and shock shafts in them also do you recommend stock Bladders or should I use tamiya bladders for the best result?
Thanx in advance
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Old 09-01-2010, 07:26 AM   #5530
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Hi guys
I have v1 shocks and can I use tamiya pistons and shock shafts in them also do you recommend stock Bladders or should I use tamiya bladders for the best result?
Thanx in advance
I have v1 shocks with all those Tamiya parts in them. In my opinion it builds a better shock than the original parts.
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Old 09-01-2010, 07:37 AM   #5531
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IMO the only problem with the original shocks is the bottom plastic piece in the seal. If you dont want to buy new shocks and can replace that with the delrin one ou should be alright.
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Old 09-01-2010, 07:48 AM   #5532
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Let me try tamiya bottom derlin bits if they will fit or not
Thanx for your help guyz
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Old 09-01-2010, 07:52 AM   #5533
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They wont.
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Old 09-01-2010, 08:11 AM   #5534
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They would only if you are using tamiya bottom cup...
Anyway piston seems a little smaller diameter so I m not gonna use them
Little bit shock slime to green o rings may help and tamiya bladders maybe on top
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Old 09-01-2010, 08:47 AM   #5535
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Default high speed steering

@L. Fairtrace

Trying to find that elusive 0.4s the very quick guys have, its clear that I needed a fresh approach both to set up and driving style

Was pondering the comments you made about thinking in terms of roll.

Thinking about roll, perhaps the car was rolling too much, too early in the corner, and pushing. So I fitted a thick bar to the front aiming to keep the car at optimum roll..and the high speed steering appeared, like magic. But it took away a lot of low speed steering. Maybe not enough roll due to slow/medium speed. I was able to compensate with ackermann, using the near hole in the steering block, insert 9 and 100% throw. With these changes the steering actually felt miles better than previously, really crisp but not twitchy. Most important it had similar response at high and low speed.

Much more actual steering than normally use but the bar seems to couteract it nicely it at low speed and assists at high speed

Stood up the rear shocks for stability into the sweeper and I can just chuck this thing in now without hardly lifting, carrying the speed, it holds its line and doesn't load up and snap into the tight infield. Wow

Tried a thick bar in the back to stabilise the exits, it was terrible, the car pushed for a couple of feet then oversteered. Guess the bar was holding the car flat then it was breaking away as soon as any real power was applied. I was amazed I could really feel the difference between a 1.2 and 1.4

So I just took the thing off altogether..and it steered totally consistent all the way out of the corner, just could not believe it, pure confidence

Think I'm on the right track now

Cheers Dude
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