Luxurious turning circle

[Merlin086]

Does anyone know why the Luxury with 17" wheels has a larger turning circle than the Standard?

I found a previous post about fitting the Honda Luxury/Sport 17" wheels to the Standard that mentions the turning circle but nothing really illuminating on the subject.

http://www.ozhonda.com/forum/showthr...turning+circle

My car is a 2004 Standard to which I have fitted Luxury 17" wheels. It tramlines badly. The 17" wheels have the same offset as the 16" wheel. I wonder if the front suspension geometry is different? It might explaining the different turning circle and the tramlining.

Does anyone know?

I would have thought maybe a larger rolling diameter for the increase in turning circle.......

Damn, are those wheels still tramlining SPQR!.......

Only ever noticed a slight tramlining in the first month when new before you bought them, and the Avanti 17" that replaced them have a offset of 45mm.

Still a very slight tramlining effect, but then after lowering 45mm on Tein coilovers a month later I have found in almost a year now that the car goes wherever I point it with no tramlining except a couple of times on extremely grooved roads, but only then minor.

I have only just replaced the Bridgstone RE040 with Pirelli Dragons, and it seems even more direct.

Is it possible the steering geometry was altered between the 03-05 and the 06 on?
I had heard their was some suspension mods between models

[SPQR]

I would have thought maybe a larger rolling diameter for the increase in turning circle.......


Is it possible the steering geometry was altered between the 03-05 and the 06 on?
I had heard their was some suspension mods between models

Hello Merlin086!

The 225/45R17 tyres of the Luxury and the 205/55R16 tyres of the Standard have virtually the same rolling diameter and the the 17" wheels and the 16" wheel have the same 55mm offset.

The Honda Australia website specification lists a turning circle of 10.8m for the Standard and 11.2m for the Luxury. Check the "Dimensions" tab at the following page:

http://www.honda.com.au/wps/wcm/conn...pecifications/

This to me suggests a difference in suspension geometry between the Standard and Luxury.

I remember that when the Luxury came out standard with 17" wheels, Honda said that the Luxury suspension was changed to suit the 17" wheels. I thought this was only to make the suspension softer to compensate for the reduced sidewall height but it might also have included a geometry change; perhaps to reduce tramlining.

I did try 17" wheels with the stock Bridgestone RE030 tyres. These were aftermarket with 45mm offset. The tramlining was quite evident. I did not think that Honda 17" wheels would have the problem.

The thread that I quoted in the first post (above) talked about a Honda Dealer telling a member that the 17" wheels would not fit the Euro with 16" wheels. Maybe there was a good reason for this.

I don't think the tramlining is such a problem on the Luxury as it is with the Standard fitted with 17" wheels.

[JohnL]

Hello Merlin086!

The 225/45R17 tyres of the Luxury and the 205/55R16 tyres of the Standard have virtually the same rolling diameter and the the 17" wheels and the 16" wheel have the same 55mm offset.

The Honda Australia website specification lists a turning circle of 10.8m for the Standard and 11.2m for the Luxury. Check the "Dimensions" tab at the following page:

This to me suggests a difference in suspension geometry between the Standard and Luxury.

I remember that when the Luxury came out standard with 17" wheels, Honda said that the Luxury suspension was changed to suit the 17" wheels. I thought this was only to make the suspension softer to compensate for the reduced sidewall height but it might also have included a geometry change; perhaps to reduce tramlining.

I did try 17" wheels with the stock Bridgestone RE030 tyres. These were aftermarket with 45mm offset. The tramlining was quite evident. I did not think that Honda 17" wheels would have the problem.

The thread that I quoted in the first post (above) talked about a Honda Dealer telling a member that the 17" wheels would not fit the Euro with 16" wheels. Maybe there was a good reason for this.

It suggests at least a steering change to me. Assuming that the 17" wheels (fitted with wider tyres) are also wider in the rim than the 16" wheels fitted with the narrower tyre, or even only because the only tyres are wider, if the larger wheels have the same offset as the smaller wheels then the larger wheel and wider tyre will extend farther inward into the wheel well. This could mean interference problems with either bodywork or suspension components at full lock.

To address this Honda may have simply decreased the limits of lateral rack motion (?), thus a bigger turning circle.

[SPQR]

It suggests at least a steering change to me. Assuming that the 17" wheels (fitted with wider tyres) are also wider in the rim than the 16" wheels fitted with the narrower tyre, or even only because the only tyres are wider, if the larger wheels have the same offset as the smaller wheels then the larger wheel and wider tyre will extend farther inward into the wheel well. This could mean interference problems with either bodywork or suspension components at full lock.

To address this Honda may have simply decreased the limits of lateral rack motion (?), thus a bigger turning circle.

I don't know if Honda reduced the limits of lateral rack motion/full lock position of the Luxury: The 17" wheels fit the Standard Euro without interfering/touching with the suspension or other internal wheel-well objects. I have never encountered this even in hard cornering with the suspension fully loaded.

I still think the geometry change and larger turning circle might be so to address the tramlining that would otherwise happen.

[Exar Kun]

I don't know if Honda reduced the limits of lateral rack motion/full lock position of the Luxury: The 17" wheels fit the Standard Euro without interfering/touching with the suspension or other internal wheel-well objects. I have never encountered this even in hard cornering with the suspension fully loaded.

I still think the geometry change and larger turning circle might be so to address the tramlining that would otherwise happen.

Almost every review I've ever read has had the particular models in a range with a larger wheel/tyre package having a larger turning circle too. I'd always assumed this to be because of the reason above - i.e. the wheel extending further in towards the car.

[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?

[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.

[JohnL]

I don't know if Honda reduced the limits of lateral rack motion/full lock position of the Luxury: The 17" wheels fit the Standard Euro without interfering/touching with the suspension or other internal wheel-well objects. I have never encountered this even in hard cornering with the suspension fully loaded.

I still think the geometry change and larger turning circle might be so to address the tramlining that would otherwise happen.

You may be correct, but keep in mind that hard cornering doesn't necessarily mean hard cornering at full lock. Just because the tyre may never actually touch anything on full lock in practice (or when you've been cornering hard) doesn't necessarily mean that Honda may not have increased the clearance just to be absolutely certain it never happens. 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 (?).

If you fit wider tyres then an increase in tramlining would be to be expected, the most practical way to address this to whatever degree would be to use tyres with a softer sidewall, even if in handling dynamic terms this might mean you take one step forward and one step back (or maybe two steps forward and one back as the wider rubber will give slightly improved grip levels).

Keep in mind the probable main reason for Honda to fit wider rubber (or offer it as a more expensive option) will likely be percieved customer demand for wider rubber, i.e. most people assume wider will be better (true or not, depending on the application, less so for front drivers not driven on baby bottom smooth race tracks), and also tend to just like the way it looks.

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 (??).

[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?