DC5R - Torque steer, tram lining & tyre inflation pressure

[Norm]

Hi all. Thought I share some technical experiences i've been encountering the past day or so. Before I bring up the problem i'll put up my specifications.

Vehicle: DC5R
Suspension: Jap spec Tein Flex, mcpherson strut
The car is not ridiculously lowered. It measures 70mm from ground to front fender guard, and clears a low bodykit like mine at the front at 160mm. B-pipe 130mm. I know these measurements are pointless as each persons vehicle is different however to illustrate my point; car is not lowered to the extent some may think.

Wheel alignment:
Front - L & R , -3 camber both sides with 0 toe.
Rear - L & R, -2.5 camber both sides
Vehicle drives true and straight on an even surface road

Wheel specifications
Tyres Toyo R1R 265/35/18
Rims: 10.5 inch width

Tyre inflation pressure
40 psi as instructed by the wheel alignment/ tyre centre

Problems:

• On acceleration, the vehicle is evidently moving towards the right side.
• Road noise is enhanced from originally 32 psi to 40 psi.
• The vehicle trams along every groove on the road.

Question:

• Is this torque steer that is a result of wider width tyres/rim
• Can this be corrected? If so, how?
• Is inflation pressure for that tyre to vehicle weight combination correct? (40 psi)
• Is the tram lining effect a result of the wider width tyres
• Are those individuals who are running large front aggressive tyres for track use experiencing the same problem?

Thank you for taking the time to help with this technical difficulty.

[knobosaurus]

I'm keen to see what the solution to this is too since I'm getting some torque steer. Is your accelerating heavy?

[tinkerbell]

Rims: 10.5 inch width.

/end thread.

seriously.

sorry to be blunt, but seriously?

10.5in size rims belong on the rear of a Porsche. not the front of a Honda.

EDIT: to bring this back to a tech. reply.

since when did you notice the problems?

what happens if you put normal sized wheels on it?

does the problem go away?

does the car move to the right by itself or is it that you cant control the steering wheel?

[rhys.l]

I noticed a significant increase in torque steer going from a 15x6 wheel with 195 tyre to a 16x7 wheel with 205 tyre. I don't have a technical explanation for the reasons for why. This is just something I clearly noticed after the change.

[ZIPPIE Type-S]

Its probably the width of the front tyres Norm, its not just a dc5 issue. On my falcon i went from a 185/70R14 to a 235/45R17 and the steering was a big difference, bump steered and followed the camber and grooves of the road.. When i put the front runners on it which were 155/70R17 the car steered like a dream..
The higher tyre pressures would contribute to your road noise and would also result in a harder ride. i would try lowering tyre pressure down to 36psi..
As Tink suggested, try a standard size wheel on the front and see if there is a difference.... I'm sure there will be...

[tinkerbell]

i would try lowering tyre pressure down to 36psi..

is that hot or cold?

i'd be aiming for between 38 and 40 hot on 35 series tyres... (so starting around 36 cold)

[cordz]

Isn't obvious Norm? "The car drives straight on a flat road," so you're problem isn't a your wheel alignment.

A 265mm tyre and 3.0-degrees negative camber. Imagine how a tyre like this encounters an uneven road, as soon as a undulation favours one tyres angle, it will suddenly have more grip than the other tyres, this will then make the car "tram-line", pulling the car in a direction you didn't intend to.

As for your right-biased torque steer. I can only imagine the left tyre has more grip under acceleration, forcing the LSD to transfer torque to that side and forcing the car right.

Could be do to with how your tyres load up under acceleration, this could be down to weight balance, ride heights, asymmetrical alignment etc.

[ZIPPIE Type-S]

is that hot or cold?

i'd be aiming for between 38 and 40 hot on 35 series tyres... (so starting around 36 cold)

Yes cold temp setting of 36psi...

[Norm]

/end thread.

seriously.

sorry to be blunt, but seriously?

10.5in size rims belong on the rear of a Porsche. not the front of a Honda.

EDIT: to bring this back to a tech. reply.

since when did you notice the problems?

what happens if you put normal sized wheels on it?

does the problem go away?

does the car move to the right by itself or is it that you cant control the steering wheel?

I have't had a chance to put the normal wheels on. I've only noticed it from a change of 17 inch, 7.5 width to 18 inch 10.5 width and a year of not driving the car. The car moves aggressively right and I have to somewhat combat this effect. I've read the same reply you provided to the same technical question posted up some years back and there wasn't a conclusion from that thread other than the fact the person had not performed a wheel alignment.

In all honesty, it was out of a lack of research and impulsive buy that we went to those wheel specs. I understand that its not ideal for a Honda, however it is what I have right now and i'd like to investigate it deeper without considering new rims at this stage. If it indeed can not be correct and is somewhat something I have to "live with" then so be it and wait until I can purchase new rims.

Isn't obvious Norm? "The car drives straight on a flat road," so you're problem isn't a your wheel alignment.

A 265mm tyre and 3.0-degrees negative camber. Imagine how a tyre like this encounters an uneven road, as soon as a undulation favours one tyres angle, it will suddenly have more grip than the other tyres, this will then make the car "tram-line", pulling the car in a direction you didn't intend to.

As for your right-biased torque steer. I can only imagine the left tyre has more grip under acceleration, forcing the LSD to transfer torque to that side and forcing the car right.

Could be do to with how your tyres load up under acceleration, this could be down to weight balance, ride heights, asymmetrical alignment etc.

Do you mean lesser grip on the left side? thats why its transferring torque to the left and forcing the car to the right? I've never considered the possibility of LSD kicking in to on road extent. Having said that though, theoretically on a perfectly flat road with identical tyre presentations, the mentioned symptoms should technically be non-existant right?

Its probably the width of the front tyres Norm, its not just a dc5 issue. On my falcon i went from a 185/70R14 to a 235/45R17 and the steering was a big difference, bump steered and followed the camber and grooves of the road.. When i put the front runners on it which were 155/70R17 the car steered like a dream..
The higher tyre pressures would contribute to your road noise and would also result in a harder ride. i would try lowering tyre pressure down to 36psi..
As Tink suggested, try a standard size wheel on the front and see if there is a difference.... I'm sure there will be...

Yeh. I might trial a lower tyre pressure at this stage. I mean there isn't a textbook to define exact tyre pressure as each application is different.

[tinkerbell]

its still not clear in what circumstances/conditions/situations your car is pulling right, you need to explain more descriptively what the phenomena you are experiencing is like for anyone to really answer your questions about what is happening.

this won't absolve the culptrits though, it will only help you understand why 265 wide tyres with 3 degrees camber on a FWD are likely to make your car handle poorly...

[Norm]

Well what I'm experiencing is somewhat a pull of the vehicle towards the right side when travelling in a straight line on what I see as a "flat" surface at approximately 4000-5000 rpm when I'm accelerating. It causes great instability as the steering wheel is turning towards the right and I'm somewhat left with fight to keep the steering wheel centred. I mean, excuse my lack if experience in this area. I just wanted to understand abit more so I can make the right choices to correct this symptom. I was under the impression that a larger tyre would provide greater stability in travel and not display the mentioned symptoms.

[tinkerbell]

only at 4000-5000 rpm?

that specific? is that where VTEC is set to engage?

[Norm]

Well, it occurs when I accelerate hard. Regardless of the 4000-5000 rpm range, but within that range, its more significant. My vtec engagement is set at 3800 rpm and the increase torque could well exacerbate this effect. The symptoms continue above 5000rpm and worsen as I continue accelerating. I have to fight the steering hard to maintain a straight line of drive.

[tinkerbell]

I was under the impression that a larger tyre would provide greater stability in travel and not display the mentioned symptoms.

i can recall of no literatre that has ever given me that impression.

most things i have read indicate that going to larger tyres (& altered contact patch) leads to a series of tradeoffs - better traction at the expense of handling.

and vice-versa

most things i have read indicate that going to smaller tyres (& altered contact patch) leads to a series of tradeoffs - better handling at the expense of traction.

however - because you have so drastically changed much more that just contact patch, like scrub radius, camber, shock height, wheel offset, car track, etc etc

and combined this with the DC5's 'less than ideal' MacPherson strut suspension design - you are going to face issues that only radically changing the existing suspension design, or changing the wheel and tyre combination and camber settings can solve...


however - as i am blessed with a beautiful DC2 with a delightful double wishbone suspension set up - i have never had to delve into the black arts of making a DC5 handle...

so hoping Tom can chime in with his advice....

or you could have a look here perhaps :

http://honda-tech.com/showthread.php?t=2639666

[tinkerbell]

well - here's something useful:

http://www.tuneruniversity.com/blog/...-size-matters/

and dont play too much with lowering tyre pressures - as you want to sell those rims without buckles