Tramlining. How to reduce it?

[944 man]

ORIGINAL: 944Turbo

ORIGINAL: GC8/944 man

In my opinion/experience; the only argument against 16"s centres on tyre choice. I moved back to 16"s on my hillclimber because it drove better, but in the early nineteen nineties 16" wheels were becomming popluar again, this time on more mundane vehicles, so tyre choice was increasing. This is no longer the case, of course.


Simon

16's dont fit over my brakes which is another fair reason for not using them [] though it could be argued big brakes are not required.
Tony

Im guessing that you have have Big Blacks then?

Simon

 

[sawood12]

ORIGINAL: edh

ORIGINAL: sawood12

I think tyre pressures, tyre sizes and wheel sizes are a red herring. Across everyone on this forum you have a massive variation as to what people run across those three variables with no evidence of tramlining being directly attributable. I guess all you can do is to methodically sure all your bushes are OK, your alignment and geometry is OK, nothing is bent or loose. If there is a camber on the road then any car will tend to follow it, so all cars will tramline to some extent.

Not true Scott - come round one day & drive my car on 17's - then swap to 16's. It will take you about 1 minute (the drive down my road) to see a huge difference.

Really? Is that on stock geometry? That's completely different to my experience. When I ditched my 16" rims for 17"'s I noticed no difference whatsoever relative to tramlining (i.e. nothing). Also recently i've sprung a slow puncture in one of my front tyres and when I did a routine check of tyre pressures it was down to 20psi when all others were at 30/32 psi - again, no tramlining whatsoever.

 

[Neil Haughey]

Haven't suffered from it in a very long time. Bushes and struts if worn and loose wheel bearings can amplify the problem greatly but as already said it is mostly down to geometry on the 44 IMHE. I prefer front toe set very close to 0 and this definitely helps tune it out, lots of toe and you will for sure have problems on some roads. I also run as much castor as possible and always at least 1 degree -ve camber on the front of any car but IMHO its the toe setting that really shows it up.

Our MX-5 weighs about 1100 Kg or so and runs on tiny rubber band tyres that would be the same as running a 944 on 19's. It has no tramlining whatsoever so its not a problem with low profile tyres its the car.

 

[944Turbo]

ORIGINAL: 944 man

Im guessing that you have have Big Blacks then?

Simon

Good guess []

 

[dlknight]

ORIGINAL: Hilux

I was getting paranoid about mine tramlining, had the geo checked twice and have now gone with slightly more aggresive camber settings which has helped alot. I'm running D90 16" wheels by the way.

I think it is just the sorry state of Britains roads that is to blame for tramlining, a recent episode of fifth gear highlighted how the councils now deal with road maintenance. Potholes are now only repaired if it is economical e.g. cost of damages to vehicles > cost of repairing. It stinks especially as fuel and road tax keep climbing, I imagine alot of "wear" that is done to our suspension is from the shoddy roads []

Nowt t`do with roads in my book................

I had 16`s on worn Mo30 - no tramlining on 33 f/r

I had 17`s (with 968 castor mounts) - no tramlining on 33 f/r

Its a geometry thing IMO and well set up there`s no reason why it should happen. I`m inclined to agree that slighty more aggressive camber settings may help dial it out but wrong toe/poor tracking is normally the cause especially under braking.

I`d suggest these cars are probably sensitive to geometry settings and knackered suspension as I never heard much discussion about it on other forums and with other cars I`ve owned/built over the years.

Hey Paul,

Well in the last year and a bit I have had new track rod ends, complete track rod on N/S. Replaced both front control arms with Hartech items, had both front shocks replaced with stock sachs (new). New Conti Sport Contact N1 tyres front and rear, 968 castor mounts. I cannot believe your cars never tramlined one bit? surely they must of on worn irregular surfaced roads? My car feels amazing on fresh tarmac (roads that have been tarmaced correctly in last 5 years or so) however some of the roads near me have probably never had a fresh lick of 'mac for 10 years or more.

Im going to get my wheels balanced soon but having had the geo checked and set twice (with printouts) I think as has already been said our Porsches are very sensitive, that is I guess what makes them a drivers car rather than some of the more modern or cheaper rubbish which deadens any feedback leaving the driver feeling isolated without any warning of the poor road surface or contact.

Dave K.

 

[pauljmcnulty]

I`d suggest these cars are probably sensitive to geometry settings and knackered suspension as I never heard much discussion about it on other forums and with other cars I`ve owned/built over the years.

I'd tend to agree. These are cars that were pretty well prefectly designed and built. Over 20+ years we've got to factor in the combined effect of all the worn parts, and they will affect a balanced car far more. Add in the way we tend to up the power, change wheel and tyre choices to more modern (but not within the original design) setups and it makes sense we get issues. Of course a car that's over-tyred and running on tired suspension will be less than perfect.

That's why it's always been banged on about here that you get the car sorted before you start to modify it. 968 castor mounts and a decent alignment before 18" wheels, head gasket before big turbo etc.

 

[Diver944]

Let's not forget the human factor.

There are plenty of people who swear blind that 944's handle horribly on 17" and 18" wheels. I have had 17"s on both of mine for the past 5 years at least and to me it feels perfectly normal with no problems whatsoever. I am sure that someone used to 16" or even 15" wheels would jump in and instantly profess that it is awful.

However if I don't drive the car for a few weeks and spend all my time in my big comfortable VW Transporter van, the 944's suddenly feel hard, harsh and crashy over any surface except a dead smooth dual carriageway

It's what you are used to.

 

[edh]

geo is slightly non-stock - -1.5 deg neg, 2.5 deg castor (from memory), ~ 0 toe

The only thing that could be loose on mine is the top mounts I think - will get them checked. Will also bump up the fronts, currently on 32.

ORIGINAL: sawood12

ORIGINAL: edh

ORIGINAL: sawood12

I think tyre pressures, tyre sizes and wheel sizes are a red herring. Across everyone on this forum you have a massive variation as to what people run across those three variables with no evidence of tramlining being directly attributable. I guess all you can do is to methodically sure all your bushes are OK, your alignment and geometry is OK, nothing is bent or loose. If there is a camber on the road then any car will tend to follow it, so all cars will tramline to some extent.

Not true Scott - come round one day & drive my car on 17's - then swap to 16's. It will take you about 1 minute (the drive down my road) to see a huge difference.

Really? Is that on stock geometry? That's completely different to my experience. When I ditched my 16" rims for 17"'s I noticed no difference whatsoever relative to tramlining (i.e. nothing). Also recently i've sprung a slow puncture in one of my front tyres and when I did a routine check of tyre pressures it was down to 20psi when all others were at 30/32 psi - again, no tramlining whatsoever.

 

[jet951]

the major reason for tramlining comes down to wheel offset. both the 944 and particuarlly the 928 act quite badly to even small changes in wheel offset. 86 model 944's and earlier have a 23mm offset, later 944's including the 968 use a 65mm offset on the front. it is very important to keep this offset for correct car balance and feel. The majority of late model Porsche wheels are only 50-55mm offset. hense the feeling of tramlining when they are fitted. we have found that using brand new tyres will mask the tramlining on incorrect offset wheels for a while but it will return as they wear. more camber will also induce tramlining.
Sean Buchanan

 

[dlknight]

ORIGINAL: Diver944

Let's not forget the human factor.

However if I don't drive the car for a few weeks and spend all my time in my big comfortable VW Transporter van, the 944's suddenly feel hard, harsh and crashy over any surface except a dead smooth dual carriageway

It's what you are used to.

Spot on, I haven't driven mine for sometime over last few months due to a knee injury and afterwards its spent some time in garage and bodyshop being fettled []

I drove down the M50/A449 to Cardiff yesterday and it felt amazing on the newer sections of tarmac, had some fun keeping up with a nice silver 993 that was "making progress" and car felt very stable and solid. Guess I just need to get used to that Porsche feedback feeling again.

BTW I'm running between 32-34PSI on front tyres and 34 on rear.

Dave K.

 

[Hilux]

Hey Paul,

Well in the last year and a bit I have had new track rod ends, complete track rod on N/S. Replaced both front control arms with Hartech items, had both front shocks replaced with stock sachs (new). New Conti Sport Contact N1 tyres front and rear, 968 castor mounts. I cannot believe your cars never tramlined one bit? surely they must of on worn irregular surfaced roads? My car feels amazing on fresh tarmac (roads that have been tarmaced correctly in last 5 years or so) however some of the roads near me have probably never had a fresh lick of 'mac for 10 years or more.

Im going to get my wheels balanced soon but having had the geo checked and set twice (with printouts) I think as has already been said our Porsches are very sensitive, that is I guess what makes them a drivers car rather than some of the more modern or cheaper rubbish which deadens any feedback leaving the driver feeling isolated without any warning of the poor road surface or contact.

Dave K.

The other aspect is that lowered 944 cars with slightly more agressive camber settings tend to self centre less and the steering assistance around the centre is a lot less than newer cars so it could be that you`re experiencing this aspect whereas modern cars are fully assisted and light to the touch.

To repat (honestly) I never had tramlining issues apart from the usual issues related to wheel width spacings relative to lorry wheels when they have furrowed up a road due to the single wheel philosophy they use nowadays.

On irregular roads the KW was fine compared to the baggy original Mo30, bumped and crashed (less) but never really felt tramlining.

I still think its a geometry thang and especially if the original type castor mounts are `spongey` as there`s a lot of movement potential thats done away with in fitting 968 castor mounts.

Good luck with it anyway.

 

[Neil Haughey]

ORIGINAL: jet951

the major reason for tramlining comes down to wheel offset. both the 944 and particuarlly the 928 act quite badly to even small changes in wheel offset. 86 model 944's and earlier have a 23mm offset, later 944's including the 968 use a 65mm offset on the front. it is very important to keep this offset for correct car balance and feel. The majority of late model Porsche wheels are only 50-55mm offset. hense the feeling of tramlining when they are fitted. we have found that using brand new tyres will mask the tramlining on incorrect offset wheels for a while but it will return as they wear. more camber will also induce tramlining.
Sean Buchanan

Good point, however I have been running 6mm spacers on my S2 up front for a long time without tramlining. The 968 has a tiny amount of tramlining as the castor mounts are worn. Race cars here often run as much spacer as you can get away with, typically 15 to 20 mm with 8" wheels all round. Will be interesting to see what my S2 is like on the road with 245 wide tyres up front and 20 mm spacers. BTW the 65 mm offset was only on 17" rims or the forged D90's AFAIK, my 16" cup 1 wheels are 55 mm offset on the front 7" size ISTR, the same as standard size 7" cast D90's.

 

[ChasR]

I got my new arm from Hartech today and proceeded to fit it. I hate to say it but I actually vaguely enjoyed working on the '44. The old arm came off easily, and the new one went on easily too. Not much rubber mallet action was needed!

Took it for a quick drive and it no longer pulls to the right, and the tramlining is definately less, but not gone. But it does need new castor mounts (old ones are just starting to crack) which I'll be getting with my surcharge off the old arm. 968 mounts they will definately be, in addition to new ARB bushes

The strange thing is that the old arm's balljoint play was only apparent when it was on the car fairly clearly. Not massively gone but enough to see and feel it. With the arm off, the BJ was looser than a new one but still relatively stiff. Quite odd that.