GTD Wheel hop/tramping testing

[fredgroves]

Ok, so I went out yesterday to try and map out a pattern of wheel hop and things that might make a difference.

After finding a safe piece of private road (*ahem*) I had a few goes to nail down exactly how I could create the problem. Basically accelerate from about 15mph in second with a swift boot of the pedal.

The road was dry and the car reported a temp of about 8 degrees.

My GTD is a manual with no tuning. I have DCC.

After trying it all in "normal" mode I tried changing DCC to comfort and sport by changing the settings in Individual mode (so only the suspension changed). Sport seemed to create less hop - which maybe is to be expected as the drive train becomes stiffer?

I also tried turning off stability control.... now this really does seem to kill it.

Whether or not you'd feel happy driving around with all of the electronic safety net turned off is up to you, but it does seem to to fix it.

[ffrank]

Interesting stuff Fred! Which tyres are you running again?

I've only had tramping/hops in first gear, and don't recall ever having it until the tyres were more worn (6000 or so).

Interesting thing for me is most of the time when I am giving it some I am in sport mode, so his may explain why I've had even less issues than some.

Conti sport 2's and DCC.

I have yet to try ESC off!

Vreds are going on this week so I will report back on those.

[fredgroves]

Sorry, I should have said, the OEM Tombstones had gone in the bin and I've got Goodyears on the front now.... and still hopping like a mf'er.

BTW when I turned off the ESC, I did it in the menus to knock it back to maximum off (you can't kill it all on a Mk7)

This was last little muck about to try and nail it, before I consider some new hard suspension bits

[richbeech]

I'm not an expert in this field, I've had my GTD for about a month now; DSG with Pirelli's which are supposed to be pretty sticky tyres but even I've been getting some tramping and wheel spin when I give it some wellie, especially off the line and especially if it's wet.

Now as I said I'm not an expert but IMO if you're going give it some off the line / doing 15mph or less in 1st / 2nd gear you're going to get wheel spin no matter what tyres you've got on. The car has 180 brake and nearly 300 lb/ft of torque! That's a lot of power going through the front wheels and any tyre is going to struggle to cope.

Now of course some cope better than others and I'm looking forward to trying some Michelins when these P Zeros run out. But the reason I say all this is because I've been chucking my car round a few corners and roundabouts in the last couple of weeks and even in the wet I couldn't get anywhere near the limits of the grip. It's like the car wasn't even trying. There was clearly huge amounts of grip even in the wet when going round corners but if I floor it or even give it 70% throttle in the wet in 1st / 2nd gear I get wheel spin.

That's just my opinion though I'm sure others will have different experiences.

[fredgroves]

There is a difference though between wheel spin and wheel hop - the former is just the tyre spinning up because of lack of grip... but wheel hop is something altogether different - its the banging noise like someone taking a hammer to the car.

Spin might decrease your acceleration, hopping creates a violent reaction that can damage your drivetrain!

It seems the hopping is caused by a harmonic in the drivetrain and possibly its initiated by loss of grip but I'm starting to think its then amplified by the ESC... the intervention the car makes for traction control is to back off the throttle for a short moment, but then the throttle comes back in and then out... making a pendulum effect...

Obviously you can avoid the situation by having front tyres that have better grip to start with (and the road being dry... or warm) but we live in the UK and our roads are sh*t and the OEM tyres hate the cold...or wet.

I'm strictly an amateur with this stuff, I'd be interested in some of the more petrol headed sorts chucking in their 2 pence...

[richbeech]

When ever I get wheel spin it is (sometimes) accompanied with a fairly large judder that feels like it comes through the dashboard. Would you class that as wheel hop / tramping?

I always thought it did that because even though the wheels are spinning they (intermittently) grip the surface and cause the wheels to judder which then resonates through the dashboard and into the car. Therefore I just thought wheel spin / hop were one and the same thing.   

[mcmaddy]

I've got the conti 2's and dcc on my gtd and have never had wheel hop. Only recently had spin but that's due to the tyres wearing. Has something not come lose in the engine bay Fred that might cause this hop?

[fredgroves]

I don't think anything has come loose... although it might sound like it!

With the Tombstones gone, its definitely better... but still reproducable with a firm application of right foot.

The thing I've noticed is that the road surface temperature can be much colder now before I see it with the Goodyears.

I still reckon the PS3's would be better still.... (*%%^$%^ lease company buggers!)

[corgi]

I still reckon the PS3's would be better still.... (*%%^$%^ lease company buggers!)

PS3's... that's what my lease company put on... I've not had the tramping with either the PS3s or the Conti SportContact 2s the car cam with...

[NBirkitt]

Not totally familiar with the wheel hop issues on Golf 7 GTD, but on all previous Golf chassis types it is closely related to gearbox and engine mounts – because they allow some movement to absorb vibrations etc, the standard mounts reverberate under duress, eg excessive drivetrain torque reaction. The trick to ameliorate wheel hop / tramp on the Mk 4 Golf was always to fit the uprated "dogbone" mount, also on the Mk 5/6 chassis to fit the poly inserts into the voids of the standard bottom mount. I presume that there are, by now, uprated gearbox and engine mounts available for the Mk 7 too... eg Volkswagen Racing