Nilks

That was the very first thing I checked, and the rims doesn't hit the arms. The problem is still there without the wheels (but a lot less, but enough to notice it is there).

I am going to the track in an hour, and will try some of the things mentioned in here.

Nilks

Update from the track:
Tried new A-arms, with no success. Tried changing the bearings (again), with no success. I am going to split it to pieces now, and put it back together.

Elliott Harper

Hi,
I have just been reading this thread and thought I may be able to give some help...

The wheel vibrations you explain are completely normal with the standard type driveshaft. You will also be able to notice this on the track. I think it is more noticeable on carpet tracks but can also be felt on tarmac tracks. This is the reason we use the double-joint type driveshafts in the front to eliminate the 'chatter'.

However, there are some things you can do with the standard driveshafts to ensure that the chatter is as little as possible, but can never be eliminated.

Firstly, ensure that the driveshaft can move in and out of the spool outdrive freely and that there is no excessive wear on the outdrive. If the driveshaft does not move freely in the outdrive and/or there is excessive wear forming notches in the outdrive, there will be more chatter.

Also, make sure that the driveshaft is well greased and is not to dirty/notchy when you turn it.

You may notice the aluminium driveshaft wears due to the pin. When there is a large notch, it is time to replace the aluminium part. This will also help to keep chatter to a minimum. The steel pin and axle part will last for a very long time so no need to replace these.

I recommend to rebuild the front driveshafts fairly often to ensure they are smooth with no excessive wear
I hope this helps
Elliott

Nilks

Thanks for your reply, Elliott.

I have uploaded two new videos, but I didn't manage to do one with the car on the track. The problem started between two heats, and last year's indoor season and this year's outdoor season I had no such problem. My 4th battery of this indoor season, it started with this.

+ YouTube Video

+ YouTube Video

Sorry for the ending of the first video, but the lamp providing light for the video fell down into the car because of the vibrations The car-stand actually dances around the table because of it
The problem might not be that visible in these videos, because I tried changing motor from 5.5T to 17.5T (but with same gearing at FDR 7.8 and minimal timing) to see if that was the problem, but it wasn't. So the motor can't pull that many RPM's

Normally with wheel chatter you can barely hear it on the track, but this I can very clearly hear. The grinding noices are still there on the track. I tried getting some of the other Tamiya's at the track (both 417's and 416X's) to do the same (steering plus throttle on the carstand) with very little to none vibrations at all, and almost no noices. So I have a feeling this isn't normal wheel chatter.

Minami

iTrader: (5)

if you've already checked every part of your front suspension, you might want to check the ribbing on your rims. i remember this happening on my TA05 before, and the cause was the inside ribbing on my rims is messing with the lower A-arm.

try running, or do a vid, without the wheels.

artwork

iTrader: (88)

Elliott-

Which double-joint drive shafts are you guys running? I saw some on Marc and Viktor's cars but forgot to ask at IIC.

Blueman Austria

Anyone?

Elliott Harper

@artwork - I am using the Arrowmax double joint driveshafts at the moment. But I am not sure what Marc and Viktor were using at the IIC....

@Blueman Austria - Normally we didn't use a hole in the shock cap this year. However, I think that a hole can help if the car is traction rolling sometimes.

Hope this helps
Elliott

Blueman Austria

THX for the reply!

VooDooPH

iTrader: (18)

make sure you're using the cross joint (51444) that's meant for the grubscrew-less application. i made the mistake of using a crossjoint that uses a grubscrew with the 417 axles and the pin colar and it made the axle vibrate excessively...

TryHard

iTrader: (4)

Honestly... I really do think it's a case of reaching the limit of the CVD's rather than anything else. Given everything else you've tried, and haven't got rid of the issue, thats the only thing it could still be.
Basically it looks like using too much lock in the steering, and that causes the binding to occur. It's noticeable the noise starts at the extreme ends of the travel, which is indicative of this.

That's also why it's not noticeable on other cars, as if they have a different steering setup (Servo, horn, EPA's etc) then will probably not be using as much lock, and hence no noise.

Do you have a setup station? Can you measure how much steering angle you have at maximum lock, as this will give a good indication if your running too much lock on the car.

In the meantime, back the EPA's down on the transmitter, and give the car a little more steering via setup (Springs etc). If your using that much lock around the track, then it will be slow as well, as it will cause the fronts to scrub across the track, reducing corner speed. Should only ever really need enough lock to do a full circle within the track width.

HiH
Ed

Bony85

Elliott

Do you know what length shafts the arrowmax are equivalent too when built, I'm guessing 44mm?

Also do you know any shops in the uk who are selling these?


Mark

TryHard

iTrader: (4)

On other topics, went to the track yesterday and had another good productive day.
Played a lot with wheelbase and ackerman settings, trying to get my head round what each setting did, as well as see if I can't make the car more comfortable. Also tried quite a few different bodyshells, and one other interesting trick... more in a bit!

Track was pretty low-medium traction, as it had rained the previous night, and only a few of us there.

Started out the day with as I have been running. 0.5mm behind the front arm, and 3.5mm in front of rear. Good front end, and quick rotation. Too quick in fact, difficult to stay on top of the car, and couldn't push. First change was to move the rear shock up to hole 2, which helped, but still too quick to rotate round.

Tried going back to 1mm/3mm wheelbase (and remembering to adjust the ackerman shims as well), made the car much more stable to drive, but now didn't rotate fast enough, and lost some front end (as to be expected!).

Next run I switched back to 0.5mm on the front only, and this gave back some of the entry, but with the stable rear, so felt very good at that point.

However, next run I had to switch to new tyres having worn the previous set to the canvas! The new set gave more traction due to being new, and using a different insert, so was back to being too safe with too little mid corner rotation. So back to 3.5mm in front of the rear, and was back to good rotation.

In terms of ackerman, flirted between 1.5 and 2mm shims (with the 0.5mm front wheelbase). 2mm felt smoother through the whole corner, whilst 1.5mm was more direct in the middle... still not so sure on which I prefer, think it's a "on the day try both" kind of change

Did play with the camber links again, but traction levels dictated staying with the middle hole/5F/4F combo, especially on the newer boots. 4F/3R felt like it had good reaction, but overall less grip.

With bodyshells, did a couple of runs changing the shells every two minutes (and mixing up the order to keep it fair!)... Speed6 was as expected nice and stable, seemed to flow nicely through the turns, with a natural push. LTC-R was, for me, the best, good steering all the way through the corner, but with a predicatble transition from entry to exit. Now the oddity was the P37. That seems to have the entry steering similar to the Speed6, but with rotation and exit of the LTC-R. Makes, for me, for an odd experience driving, where the rear seems to break away too quick, so the nose would miss the apex, then the rear snap round. IMO, it requires a slightly different style to drive, or if you have a car with a darty front end would help to calm it down... but for me, I'll take the LTC.

I did also try a different wing with the P37 (Ride HD Lip) to see if it would help calm the rear, but if anything made it worse! The wing uses a 90° return at the top, like a gurney... but personally I think it works more like a flow blocker rather than a staller, in effect reducing the downforce. Suffice to say, the wing will be staying in the box!

Last run of the day, I thought I'd give something a try I'd been discussing with some friends back in the UK. And that was 2 gears in the gear diff, but with thicker oil. On the bench, this gives a nice smooth action, if anything better than the 4 gear. However on track... well lets just say the griding noise I heard when first pulling away wasn't good! Managed a couple of laps, but the gears had stripped. So forget that then

Overall... good day at the track

Nilks

I have tried backing down the D/R on the transmitter, to the point where it stopped, and I had to go down to 45% percent steering, and I can't get the car round the track with that setting.

But lets say that it is "natural", but then I don't know why it started after 1 complete season. I never had this beforehand, and none of the other Tamiya's in the area does this.

I will try to measure the steering angles at maximum lock, when I get the chance.

TryHard

iTrader: (4)

Some chatter will be there at full lock for sure... but given from the list of what you've changed so far (i.e. everything!) to solve it, can only reason that that is the problem.

When you say you turned the steering down, was it on the bench? or on the track?

The rims themself are round yes? Have you tried a newer set of tyres since it occured, can't remember if you mentioned it or not. I mean, if you are running on carpet, tyres tend to last a while... so could simply be them out of balance. Otherwise running out of ideas!

HiH
Ed