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Old 19-01-2013
djmcnz djmcnz is offline
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Default [REPORT] 84315 TRF511 Chassis Upgrade Set

Okay guys, so I took my 511 with the subject upgrade kit for a proper run today and here is my experience over 4 packs. I've previously broken it in with two packs and readjusted/tightened everything.

Let me first say I'm very proud of my diff builds. I took the one way out of the font when I put the upgrade on and also rebuilt the rear diff out of necessity for the 39T pulley. I'm ecstatic that after 6 packs they haven't needed a single bit of maintenance and still twist perfectly smooth - the slipper pads are fine too. I still believe Fredrick's (pending) diff covers will be an essential upgrade though.

First of all, I'm sorry but this was not a direct back-to-back. I have made two changes since running without the upgrade kit:
  1. Front ball diff instead of a one-way
  2. Solid damper caps with bladders (no aeration)
Both of which dramatically affect the "feel" of the car so I simply tried to compensate with my eyes and brain.

The first and most noticeable effect of the upgrade, no doubt related to the motor position, is that there's way less yaw and much better yaw control if you hit the top of a jump wrong - steering and throttle mid-air provide a much more 'direct' control of the yaw. It's not going to help if you're clipped in the air but for those times when you're not perfect but only 10% off it's going to allow you to line up the landing much easier. It was predictable and even quite fun.

My rear traction has suffered and this is a little bit of a mystery unless it's to do with the characteristics of the front diff... tbh I'm a bit lost on this as it's most noticeable on corner exit once the chassis is settled and I'm going back on full throttle. It's almost like too much power. [Edit: manifests as mild oversteer on exit and then rear end twitching upon acceleration] I'm not sure that this is all front diff action... it might be a weight distribution consideration with the new chassis? I'll look at damping as well I think or perhaps a stiffer stabiliser because I think it may be lateral judder (chassis pitch)... not sure.

Overall I must say that all up it's a very, very subtle driving change - less than the transition from a 501 to a 511 and that wasn't huge (in driving terms). I never suffered belt or pulley failures with the original 511 and don't imagine the extra teeth will make any difference in that regard or any other for that matter - maybe more stress on the centre pulleys actually, I'll keep an eye on these.

On my last pack I noticed the vehicle "hopping" around left handers and for the life of me couldn't work it out with a quick visual inspection. As it turns out when I got it home I found that I'd badly bent the inside ball stud for the right hand rear upper link... indicating the weakest part in the hard cup + Lunsford Ti turnbuckles + kit steel balls is the ball itself... the stud bent before the cup released... amazing... time for some hard studs or a return to the soft cups I think!

1 breakage and nearly 3 hours of fun in the snow (read: ice), on (wet-ish) astro and hard dirt... (at the local field hockey and construction park) absolutely no complaints. I've spent ~€130 on this and already, through the rebuild and testing have had >6 hours of value. Happy.

Now for a front gear diff and double slipper...

Additional info:
Thread - TRF511 Chassis Upgrade Set
Thread - Tamiya 511 Upgrade Kit - Fitted pics
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TRF511 w/upgrade kit | LRP Flow Works | LRP X20 6.5

Last edited by djmcnz; 19-01-2013 at 11:47 PM. Reason: Added extra links
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Old 20-01-2013
fastinfastout fastinfastout is offline
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although I have no reason to doubt the upgrade pack is better, the handling characterisitics you are describing has more to do with the change from 'one way' to 'front ball diff'. There is a HUGE difference, believe me........
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Old 20-01-2013
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Rich D Rich D is offline
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Quote:
Originally Posted by djmcnz View Post
On my last pack I noticed the vehicle "hopping" around left handers and for the life of me couldn't work it out with a quick visual inspection. As it turns out when I got it home I found that I'd badly bent the inside ball stud for the right hand rear upper link... indicating the weakest part in the hard cup + Lunsford Ti turnbuckles + kit steel balls is the ball itself... the stud bent before the cup released... amazing... time for some hard studs or a return to the soft cups I think!

hey

thanks for the feedback. Just so you know, the kit ballstuds are only fit for the bin anyway, you need Tamiya part number 53969 to replace them. They do a shorter version too 53968

Only ran mine the once on a medium to low grip surface. It was hard to tell any differences aside from the fact that i was now undergeared.

The diffs are certainly a lot better i agree.
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Old 20-01-2013
djmcnz djmcnz is offline
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Quote:
Originally Posted by fastinfastout View Post
although I have no reason to doubt the upgrade pack is better, the handling characterisitics you are describing has more to do with the change from 'one way' to 'front ball diff'. There is a HUGE difference, believe me........
I couldn't agree more. I've quite some experience with both types of diffs and for the most part understand how they act differently. Indeed most of the feedback from my session I left out because of this. I just noted some of the things I think could be related to the kit more so than the diff.

I'll be trying a gear diff too soon so it will be good to compare that as well.

Quote:
Originally Posted by Rich D View Post
hey

thanks for the feedback. Just so you know, the kit ballstuds are only fit for the bin anyway, you need Tamiya part number 53969 to replace them. They do a shorter version too 53968

Only ran mine the once on a medium to low grip surface. It was hard to tell any differences aside from the fact that i was now undergeared.

The diffs are certainly a lot better i agree.
No problem Richard, and thanks for the part number. I've never had one bend on me before so hadn't given them much consideration. I'm using the fluorine coated ones at the front, I wonder if they're also of the stronger variety.

I also need to review my gearing but I was running pretty short courses yesterday so didn't notice it as much... and it was below freezing so temps were not an issue!
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