Luxurious turning circle

[SPQR]

The design engineers may have a minimum clearance they never go under as a matter of principle or policy (?).

If other geometries have been altered to address any tramlining issues, I do wonder just what they might be. The only thing that springs to mind might be decreasing scrub radius (associated with wheel offset relative to the steering axis, so could be changed more easily with offset than suspension component alteration), but I'd imagine scrub radius would probably be minimal in the first place (?).

Honda may then choose a wider tyre with a relatively soft sidewall to pre-empt complaints about excessive tramlining, even if this might mean the OEM wider tyre offers relatively little dynamic improvement over the narrower OEM tyre with the taller but stiffer sidewall (??).

I agree. I expect that the Honda design engineers probably do have minimum clearances. They probably designed the Euro to be fitted with 225/45R17 tyres on 7" wide rims at some stage. I think that they even come with 18" rims on some European models (if not optional).

They did alter the suspension of the Luxury compared to the Standard when they introduced the 17" wheel on the Luxury. Who knows to what extent they altered it.

I'm no suspension expert and certainly you sound like you know what you're on about. I've read some of your other posts. I could not begin to know what else they might have altered or what they could alter to counteract tramlining.

One thing is known; wider tyres and straight/hard/square sidewalls = tramlining.

As far as I know, the Bridgestone RE030 fitted to the Luxury is a high performance tyre with straight/hard/square sidewalls. But Luxury owners don't seem to report severe tramlining whereas my Standard fitted with the Honda 17" wheels and 225/45R17 tyres tramlines to a such an extent that I'm driven to distraction.

Honda should not just tell people that the 17" wheel is not to be fitted to the Euro Standard as suggested in another thread. They should say why.

[JohnL]

I agree. I expect that the Honda design engineers probably do have minimum clearances. They probably designed the Euro to be fitted with 225/45R17 tyres on 7" wide rims at some stage. I think that they even come with 18" rims on some European models (if not optional).

They did alter the suspension of the Luxury compared to the Standard when they introduced the 17" wheel on the Luxury. Who knows to what extent they altered it.

I'm no suspension expert and certainly you sound like you know what you're on about. I've read some of your other posts. I could not begin to know what else they might have altered or what they could alter to counteract tramlining.

One thing is known; wider tyres and straight/hard/square sidewalls = tramlining.

As far as I know, the Bridgestone RE030 fitted to the Luxury is a high performance tyre with straight/hard/square sidewalls. But Luxury owners don't seem to report severe tramlining whereas my Standard fitted with the Honda 17" wheels and 225/45R17 tyres tramlines to a such an extent that I'm driven to distraction.

Honda should not just tell people that the 17" wheel is not to be fitted to the Euro Standard as suggested in another thread. They should say why.

It might be educational if we could know the relative sidewall stiffnesses of these different tyres. Tread stiffness may also be involved. We might find the tyre fitted to the 'Luxury' is not a stiff as we are assuming...(?).

I couldn't think of what might be changed in the geometry other than scrub radius that might reduce tramlining. But, thinking about this, whatever else it might be could only be associated with the steering axis's relationship to the nominal centre of the contact patch (i.e. where within the confines of the contact patch the steering axis intersects the ground) and thus the manner in which forces generated at the contact patch are fed into the steering via the steering axis, which could only mean the degree of trail.

Decreasing caster angle would also decrease trail, and this may mean forces generated at the contact patch are not felt as strongly at the steering wheel, so the driver doesn't have to work so hard to keep the wheels straight (i.e. the driver would have more leverage on the wheel direction as tramlining affects are occuring). Do you know if there is any difference in caster angle between the standard car and the Luxury?

[SPQR]

Sorry JohnL, I don't have that information. I don't think that Honda dealers give that sort of information freely.

Manuals of for the USA Acura TSX can be had online apparently but that model only ever came with the 17" wheels; interestingly with a 215/50R17 tyre which has a slightly larger diameter more rounded sidewall than the 225/45R17.

[SPQR]

I thought I'd ask Honda why there is a difference in the turning circle between the Standard and the Luxury and why the 17" Honda wheel is not available as an accessory for the Standard. The following was the response from the technical department:

"Thank you for your recent contact regarding wheels and the turning circle for the Honda Accord Euro and Euro Luxury.

The two items that you mention regarding the fitment of accessory wheels and the turning circle are linked. You are unable to fit the 17inch alloy wheels on the standard Accord Euro as they will impinge on components it (sic) the front suspension. To remedy this on the Accord Euro Luxury different front suspension and steering components have been employed to reduce the amount of steering angle available."

I bet that the suspension differences also account for the tramlining suffered by the Standard when fitted with 17" Wheels!

[aaronng]

You are unable to fit the 17inch alloy wheels on the standard Accord Euro as they will impinge on components it (sic) the front suspension. To remedy this on the Accord Euro Luxury different front suspension and steering components have been employed to reduce the amount of steering angle available."

Does anyone with a base model euro have 17/18/19" rims with 7-8.5" width rims and 225-235 tyres experience rubbing when turning full lock?

[hooyn]

I have a lux, 18" 8.5" wide 225 tyres no rubbing.

but you want to know base model.

anywho.

[JohnL]

I bet that the suspension differences also account for the tramlining suffered by the Standard when fitted with 17" Wheels!

The changes are to limit rubbing of the larger tyres by by limiting steering lock. Since we're betting, I bet these changes to the 'Luxury' (whatever they actually are) don't affect tramlining behaviour. I bet they do limit the degree of lateral rack motion (either by changes to internal rack 'stops' or external steering arm 'stops'?), but would be very surprised if the changes are of the sort that would have any affect on any geometry that affects steering or handling characteristics.

Without being able to ascribe guilt beyond reasonable doubt, I would still be tending to point the finger at the tyre.

PS Why 'SPQR'? Roman connection?

[tony1234]

When we picked up our 2008 Euro Lux (with stock 17" wheels) the car would follow cambers aggressively and was already starting to tramline. I changed the one-week old RE040s for Michelin Pilot Preceda 2's and the difference was night and day. Straight away the car tracked straight regardless of the road surface. No tramlining at all, and camber-following was much reduced.

The only diference was the tyres - the wheels alignment wasn't touched. To me that say's it's the Bridgestones are at fault. At least on my car.

Same thing with my car as well.ChangedRE040s for Conti Sport contact 2s and the car tracked better.i have mine lowered as well.

[Merlin086]

My 06 lux had minor tramlining until lowering and replacing with 17x7's with a 45 offset.
No tramlining and is the most directional car I have ever driven!...and this has been running the RE040's until 29k's.

Have had the Pirelli Dragons on for 6k now, still no tramlining but the grip ability of the Pirelli Dragons is very disappointing in the dry compared to the RE040's, as the limit of adhesion is only about 75% of the bridgestone.

[SPQR]

The only diference was the tyres - the wheels alignment wasn't touched. To me that say's it's the Bridgestones are at fault. At least on my car.

I did have secondhand 225/45R17 Bridgestone RE040's on my Euro Standard (with 17 inch wheels on loan but with 45mm offset) and there was tramlining present in large doses. I then got a set of the 10 spoke Luxury wheels from Merlin086's car (55mm offset) and fitted the same secondhand 225/45R17 Bridgestone RE040's. The offset did not make any difference. The tramlining was just as bad. Then I got new Dunlop SportMaxx tyres and the tramilining was much diminished but still present. The tyres are over a year old now and the tramlining is now just as bad as the Bridgestone tyres.

I wonder if the Michelins will also misbehave once they're run-in or older?

One should be able to fit any quality tyre without getting any tramlining.

Before my Euro I had the 2001 Civic 5 door. I fitted 225/45R17 Dunlop tyres to it (OK, they were slightly oversize) but there was never any hint of tramlining.

It seems to me that once tyres get any sort of distance on them, they will all "cause" tramilining on the Euro. Therefore, there must be a suspension geometry design fault that causes all brands of tyres to eventually tramline.

Merlin086 had tramlining with the Euro Luxury 17" wheels with the Bridgestone tyres.

I assume most people in the southern states drive on smooth roads and so tramilining is not evident. Darwin has had and is having a massive building and development boom and so many of our roads are furrowed from the weight of trucks. The Government here doesn't acknowledge the problem lest someone might link the accident rate to the state of our roads. Instead, they constantly tell us we are very naughty speeders and that our wallets/purses need to be taught a lesson.

[SPQR]

PS Why 'SPQR'? Roman connection?

Italian citizen? Alluding to the authority of the Senate and the People of Rome (Senatus Popules-Que Romanus)? I don't know. Maybe I just like the Roman standard at the head all the Roman armies and buildings and everything else the Romans touched. Or maybe a reminder of people power: Vox Populi Vox Dei (The voice of the people is the voice of God) which is a reminder to politicians and people in power to behave or they'll answer to the people.

[Merlin086]

[QUOTE=splashalot2000;1633593][QUOTE=SPQR;1633566]

I wonder if the Michelins will also misbehave once they're run-in or older?.........It seems to me that once tyres get any sort of distance on them, they will all "cause" tramilining on the Euro. Therefore, there must be a suspension geometry design fault that causes all brands of tyres to eventually tramline.
QUOTE]

Sorry,got to disagree.....

After my initial minor tramlining when my lux was new, once my suspension was modded any tramlining had virtually disappeared, and this did not change as the Bridgestone RE040 tyres approached the end of their life, if anything I would say they became more directional and responsive...