Silverbullet555

iTrader: (16)

Gear or ball diff.
If ball, grease slung on to case and the lubricant worked it's way through the case.
If gear, maybe the grease, or your diff is leaking and slinging the fluid on the inside of the case. It's 5 screws. Open it up and see.

RCW

iTrader: (29)

I posted this a while back. The case is very thin in this area! We have seen several of them leaking there. It will be leaking out the screw hole on the back side.

Alexv2024

iTrader: (2)

You cant do nothing. And just beacuse somene has similar gearing doesn't mean your track or driving style is similar enough. Drop your timing a little and a pinion size. But the transmission is different you wont be able to not change something else. Maybe a few people can here and there but thats rare.

MrLean

iTrader: (17)

Yep, and then Batta got first and Rivkin 2nd in the mains, both B7s.

More importantly though, Ethan Hoskins TQd and won with a B7 in 17.5, proving the platform is awesome in stock and the “5-gear isn’t good for stock” naysayers are totally wrong.

In fact, the TOP 6 in 17.5 were all B7s (maybe more, I’m not familiar with the 7-10th place drivers)

foosoomin

Silverbullet555 thank you for your advice on post #1050


Really appreciate it.


I no longer use the 17.5 motor.

I use Surpass V3 10.5T motor with 21T pinion gear, 78T spur gear to run my B7., no issue on this motor

Kraig

iTrader: (81)

Make sure everything spins freely. Sometimes a bearing going bad will cause excess bind and it makes things work harder.

foosoomin

Everything works fine though.


Maybe due to bumpy surfaces, up-slope, jumps stress the motor and 3 idler gears

RogerM

Weights make a huge difference. Static weight distribution is something you can't work around with geometry or shocks, if the balance of static tyre loading is sub-optimum then a set-up that is perfect for that weight distribution will also be sub-optimal. Dynamic weight transfer can only have an effect whilst the car is pitching / rolling, when in 'level' running it is the static weight forming the basis of the handling balance. Yes, admittedly you can make subtle shifts in static weight distribution by adding rake, normally the front lower than the rear, it can only make subtle differences though whilst remaining in sensible ride height ranges etc.

So far my prefered options for static weight distribution in various conditions are (my LiPos weigh 152g on average for reference);

Wet astro:- 11g aluminium ESC weight, 20g under LiPo in middle position 3 (need to update my setup sheet to reflect this now I've tested it)
Dry astro:- 33g steel ESC weight, 32g under LiPo in mid-forward position 2 (limited running and keep in mind that tracks aren't fully dry at this time of the year in the UK)
Carpet :- 15g TMG under servo weight + 2 x 5g weights, one either side of servo mount, 33g steel ESC weight 32g under Lipo in forward 1 position


Essentially yes. It could be potentially very useful on very high grip EOS / CRC carpet. As far as outdoor running is concerned it will limit how narrow you can run the hinge pin spacing but I am fairly confident that with the longer hinge pins (50.75mm) the kit C-block will be fine for all pill positions narrower than centre anyway. I have one coming to test, rubbish postal service in my area meant I didn't get it before the weekend :'(


I did think the same thing, if you drive in a way that maintains corner speed, which is after all what the B7 was designed to do better than any other 2wd buggy, the requirement to accelerate is less as you are entering the next straight faster anyway.
There is extra drag in the transmission, the kit bearings feel very heavily greased which won't be helping the stock guys.


1. See about the TMG C-blocks above, just remember to adjust your pills to suit when you fit one. I believe that David will be at MKGP with plenty of stock, he told me the production versions are due back from the anodisers today.

2. I'd use longer pins anyway, 3.5mm drill blanks cut down to 50.75mm will be perfect for use with 0deg toe, can probably run a touch longer (51mm ish) with the kit C-block in the 1deg toe position.



Both are 49.5mm so no advantage.


I can agree to this, I dumped in the 6 minute A-main on Sunday just after I crossed the finish line, I had been keeping the throttle below 95% with the ATL to stop it going into turbo for a few laps before as the ESC was hitting lipo cut off when it kicked in (more a ramp down on the HobbyWing XR10pro G2 thankfully). Meant I had no chance of chasing the win but held the 3rd spot.
When I got the car home and checked it over the transmission drag had increased noticeably, 2 bearings had started to go bad, 1 had been binding enough to polish the idler shaft. I will be changing all the transmission bearings out for ceramics when I rebuild it.

Another point of note is that the mesh is much tighter on the internal gears than the B6 series transmission, this means anything gets in causes big trouble as nowhere to go. Somehow, probably when rebuilding the diff before the meeting, a tiny spec of dirt had got in and was wedged in the final idler teeth. Transmission sounded like it was about to disintegrate, stripped down and found then cleaned the contaminated idler gear along with all others and it was back to being beautifully smooth again. No hint of the bearing issues I spotted after just 5 more runs.

RogerM

Found out that a single step on the front ARB is very effective on the B7, way more than shifting the whole range on the B6

mes

The joy of reduced slop in the sway bar assembly. 😊

MrLean

iTrader: (17)

What do you think about the rear sway bar?

On the bench it doesn't seem to have much of an effect, it actually reminded me of how the B6.4 front one looked on the bench.

BigBuckORamma

Lots of really good tuning and optimization learned at the Desert Classic.

I can do a deeper debrief if someone really wants it...but this is the quick over view of what i learned in tuning the car this weekend.

The chassis likes symmetrical shocks. White/White, Grey/Grey, Blue/Blue, or only one step up in the front if the track gets edgy. Like, Blue/Grey. I ended up on Grey/Grey. (Also played with 1up Red/Gold, which is a Grey/Grey equivalent, but they seemed a little more reactive at the limit, and i didnt like that)

Shock Oils make a huge difference in the cars handling. Controlling the Yaw and Pitching Moment, thanks to the centralized weight of the car, really matters. I went as high as 37.5, and as low as 27.5. I ended up with 32.5F/27.5R

In that same vein, shock pistons played a crucial role as well. Slightly bigger does seem better. I ended up the weekend with 1.6/[email protected] Front, and 1.8/1.9/[email protected] Rear.

If your diff isnt dialed...your car will handle like shit. Break it in carefully and properly.

Soft brake settings help the car rotate tremendously. I didnt play with it much because i was testing too many other things, but i am seriously going to look into incorporating some drag brake for this layout because of the 180's.

And the biggest "A'Ha!" Moment for the B7 of the weekend...Anti-Squat! The car is completely changed in how it accelerates and generates rear grip with just a .5 degree C Block change. If you have an issue with the car not wanted to accelerate cleanly...add in some anti squat. It actually settles the car more than toe in does. And i will even be experimenting with less toe when i play with the drag brake.

Mid corner speed was tremendous. Absolutely no hesitation in throwing the car hard into turn one. And going nearly full throttle into the little ski jump before turn two, landing almost at the apex of turn two. I was actually carrying so much speed that it was easy to over jump the triple. Took some restraint to not just send it.

Overall, the car is coming together nicely. There is still some tweaking to get it right, i think messing with front end weight will be the next little project to experiment with.


No if they could jsut fix the gearbox screw hole issue for the D Block, the hinge pin issue, and make the front bulkhead out of something other that forged aluminum pot metal...the car will be dialed.

b.j.a

iTrader: (2)

Appreciate the clay setup advise! I’m running a very similar setup so glad to see I’m not on an island. My shock package is nearly identical but I have liked the red/gold combo but honestly haven’t played a ton with springs.

The comment around anti-squat has been interesting since I’ve spoken to a few people who don’t seem to like the added anti-squat. I’ve been running middle down in c/d and it’s felt solid and planted but can get a little squirly when accelerating hard out of a corner, so I might give it a shot.

This car is an absolute monster on mid/high speed corners. It carries speed so well, and is so stable while hitting bumps/jumps when cornering at speed too.

NickMG

Morning, I am sure I’ve seen this issue mentioned else where but now can’t find it. I got the b7 out drives for the ball diff so I could make up a ball diff from parts. As it happened I forgot the diff balls so had to cannibalise an old diff. All was well although it did loosen a bit in use. Today I started a fresh rebuild and have the issue of the lugs on the lock nut folding up. I assume this is because the out drives are bigger than the old ones. I overcome the issue by reusing the old b6.1 lock nut which was fine, it must be stronger as it’s a different plastic, white as opposed to yellow. The problem is as it’s old the plastic no longer holds the thread tight so during breaking in the diff it comes loose. I am currently seeing if threadlock will help for now but any ideas how to overcome the issue until we get b7 specific diff parts. Otherwise I might end up not being able to run a ball diff which is very much needed in the uk at the moment. Thanks

4times

iTrader: (10)

Does the optional carbon transmission case resolve the gearbox hole spacing issue?