Need Advise On R Compound Tyres

[180 wanabe]

Hi guys this is my 1st post on this part of the site

I Have a V35 skyline which is balicaly stock apart from a nismo catback, DBA 4000 slotted front discs with Ferodo DS2500 pads and whiteline swaybars front and rear

The current wheels/tyres I have been using are KU19 245 40 R19 on the font and Federal 595 RPM 285 35 R19 on the back

Now the 1st time I went to the track I without the swaybars my biggest problem was inside wheel would light up when going around a corner "open diff + worn KU19s 275" anyhow the Federal 595 RPMs have fixed this problem to a degree

The problem I have now is that even though I have it set to the softest setting the whiteline swaybar on the front seems to be making the car understeer more which was sending my VDC into overdrive causing it to constantly grab the front left brake. Now the front tyres arent that far off the ware markers which was also something that would have contributed

I am happy with the way the rear or the car is behaving, yes I can still get it to step out if I want to but it seems to grip enough to keep me happy + I have a proper quaife LSD on the way

However I was thinking about buying a pair of 17 or 18" rims and throwing some R compound tyres on them and running them up front to try to reduce the understeer

The stock rubber/wheels for the front of the V35 is the same as the 350z

however I have 2 wheel/tyre stickers on the inside of my door one from japan and one which looks like a compliance sticker which have the same specs for the 17" rims but slightly different for the 18

iv attached pics of the stickers

if anyone could give me advice on what size tyre/rim to run on the front it would be great

I dont want to go less than the 245 im running now but I guess a slightly smaller size with a R compound would still be heaps gripper

[180 wanabe]

ok looks like the best choice is going to be a 245 40 R18 anyone know where the best place to pick some up on the Gold Coast/Brisbane is?

something R compound

[LSX-438]

i'm not sure mixing r's and streets is such a good idea. it may seriously upset the attitude of the car. i wouldnt do it, it could be dangerous.

have you tried with VDC off to see what happens?

[Marlin]

I did it without any drama on my old Magna wagon company car (shhhh) several years ago.

BUT, as an ongoing solution, it's far from ideal.

Turn the VDC off and put the original front swaybar on. Try that first.

[180 wanabe]

Yes Iv turned vdc off and the car was 2seconds quicker however the lack of front end grip was a pain in the ass and contributed to me coming off the track a couple of times. Not sure how u mean running r compound on the front is such a bad idea. The federal 595 Rpm are pretty dam sticky for a raod tyre treadware is 160 and I didn't have any Issues with the back kicking out unless I wanted it to which only happend on the hairpin

[SABBAi]

Have you had a decent wheel alignment done? Perhaps have a chat to the aligner and tell them the issues you are having. Poor turn in, poor mid corner grip, feathering and bluing of outer edge, inner edges overheating, etc

[LSX-438]

Yes Iv turned vdc off and the car was 2seconds quicker however the lack of front end grip was a pain in the ass and contributed to me coming off the track a couple of times. Not sure how u mean running r compound on the front is such a bad idea. The federal 595 Rpm are pretty dam sticky for a raod tyre treadware is 160 and I didn't have any Issues with the back kicking out unless I wanted it to which only happend on the hairpin

i would say running r's / non-r's around the car to correct a handling fault is a band-aid solution. might be a bad idea; like running cross plys and radials at the drag strip (ie. it's a big no no and disallowed). might work though, goodluck with it.

Edited October 8, 2010 by LSX-438

[180 wanabe]

At the same time though its not like the cars understeering when im driving it around town or anything, its only when im pushing it to the limit that im having issues. To give you an idea of how hard im pushing it im lapping 2 seconds slower than a 350z thats supercharged 220rwkw~ + r compound all round + brembos

if you read my 1st post ull see that my cars stock apart from DS2500 pads on the front a catback and the swaybars I dont even have a LSD yet LOL

[BezerkR32]

seems like you have already made up your mind then, but the fact the car is faster with the standard sway bar on tells me that your aftermarket one is not matched to the rest of your set-up.

At the same time though its not like the cars understeering when im driving it around town or anything, its only when im pushing it to the limit that im having issues. To give you an idea of how hard im pushing it im lapping 2 seconds slower than a 350z thats supercharged 220rwkw~ + r compound all round + brembos

if you read my 1st post ull see that my cars stock apart from DS2500 pads on the front a catback and the swaybars I dont even have a LSD yet LOL

[MrStabby]

At the same time though its not like the cars understeering when im driving it around town or anything, its only when im pushing it to the limit that im having issues.

This is how it works - you only notice which end has less grip when you push it to the limit.

+1 for stock front sway bar. Or if the rear is adjustable as well, make it stiffer. The outer holes are soft, inner holes are hard.

[180 wanabe]

Unfortunatly I ditched the stock swaybars so im stuck with the whiteline ones, im kicking myself for this now. The reason I did this was because I kept my swaybars for my old 180sx and ended up throwing them in the bin after I sold the car as the whiteline ones were way better. Unfortunatly this dosent seem to be the case on the V35 or more so the VDC system is based around the stock swaybar and goes into overdrive with the stiffer swaybar. VDC is good because it keeps the car on the black stuff no matter how stupid you try to drive the car. On the other hand turning it off = a faster time but if you push too hard you can come off the track

[ssxRicho]

Lift the rear of the car up a little, or lower the front (5-10mm). Either way.

What pads in the rear?

LSD and bit of trail braking will help it turn.

The characteristics sound similar to my car. In that I have chewed up a set of front 595rsr (onto second set) while the rears are still going strong (still on first set).

Bit or trail braking and steering using the right foot seems to work well at winton.

I would try for a 595rsr. Wide as you can get on front, 245. I will be trying that next tire set, if I can.

[180 wanabe]

Lift the rear of the car up a little, or lower the front (5-10mm). Either way.

What pads in the rear?

LSD and bit of trail braking will help it turn.

The characteristics sound similar to my car. In that I have chewed up a set of front 595rsr (onto second set) while the rears are still going strong (still on first set).

Bit or trail braking and steering using the right foot seems to work well at winton.

I would try for a 595rsr. Wide as you can get on front, 245. I will be trying that next tire set, if I can.

The LSD im getting is Quafie so its Helical and acts as a 1 way LSD, the V35 is my daily and I didint want a clunky 1.5/2 way mech diff

still using stock struts/springs so cant change the ride height

Dont have any plans on turning the car into a serious track/time attack car but I do want to be able to get around quickly enough given what the car is, wednesday arvo sprints for me is just a fun day out. Hence the band aid solution

[Strik3r]

If you are *2 SECONDS* faster with VDC off, then drive with VDC off..... 2 seconds is a MASSIVE difference around QR. Does the car still understeer lots without the VDC getting in the way ?

[180 wanabe]

If you are *2 SECONDS* faster with VDC off, then drive with VDC off..... 2 seconds is a MASSIVE difference around QR. Does the car still understeer lots without the VDC getting in the way ?

Now that I think about it I dont think the cars understeering that much, the VDC is however going hyper and constantly grabbing the front left brake which is making the car feel like its understeering more than it is. I like VDC because no matter how stupid you go through a corner its pretty hard to come off. However it slows the car down so thats the other reason why I want R compound on the front so I can have VDC off and have a better chance of keeping the car on the track.

[Marlin]

It's understeering, so, if you feel like you're going to head off the track, just ease out of it a bit. I felt that worth mentioning, sounds like you go off quite a bit!?

[180 wanabe]

It's understeering, so, if you feel like you're going to head off the track, just ease out of it a bit. I felt that worth mentioning, sounds like you go off quite a bit!?

haha only a couple of times

[badhairdave]

Get the diff installed, it'll fix the inside wheel spinning issue.

Then you can set your sway bars correctly so you don't have to put up with the understeer resulting from your current compromised settings

Then get semis all round if you still feel the need.

The problem with going an r compound on the front only is that for a few laps it'll be great and then the rears will start to over heat and lose traction and before you know it you will be backing it off the track when the rear suddenly lets go at turn in.You will be faster for a couple of laps though. You're also going to destroy the semis as you won't have the right wheel alignment, plus the inherent understeer issue, so it'll chew up the outside of the tyre in no time. 1000 bucks worth of semis might last you 3-4 days.

[180 wanabe]

Get the diff installed, it'll fix the inside wheel spinning issue.

Then you can set your sway bars correctly so you don't have to put up with the understeer resulting from your current compromised settings

Then get semis all round if you still feel the need.

The problem with going an r compound on the front only is that for a few laps it'll be great and then the rears will start to over heat and lose traction and before you know it you will be backing it off the track when the rear suddenly lets go at turn in.You will be faster for a couple of laps though. You're also going to destroy the semis as you won't have the right wheel alignment, plus the inherent understeer issue, so it'll chew up the outside of the tyre in no time. 1000 bucks worth of semis might last you 3-4 days.

Could you please elaborate more on the wheel alignment? V35/350z are heavier cars than the R series skylines

The car drives straight so I havent taken it in for an alignment yet but was going to get it checked anyway when I fitted new tyres to the front of the car which isint that far away

[warps]

The car drives straight so I havent taken it in for an alignment yet

Tracking straight has nothing to do with a suitable wheel alignment for track. If there is any adjustment, then a track setup would have a bit more camber, possibly slight toe out at the front, and more castor (if that's adjustable). These will all make the car track worse than you good "street" aligmnent, and probably wear tyres a bit uneven. Quite a few people will do this for track days (again, assuming the car has adjustment)

I'm going out on a limb here but how experienced are you at driving? Have you spent many hours belting cars around a race track, or is all of your experience from playstation? Not meaning to be offensive, it's common these days for track day newbies to go balls out, because that's what PLaystations teach us about driving. In the real world, this translates to cars sliding off tracks regularly. Of course there's nothing wrong with spitting the car off the road once you're going as fast as the car is capable. However, just because you went off doesn't mean you reached the car's limits.

If it were a standard car with healthy suspension, I'd suggest to learn to drive it properly. If it's happened since changing suspension settings, I'd suggest you might have upset the balance of the car. In either case, running different spec tyres front to back is only going to mask the real issue, and should be considered as the last option.

Initially, maybe try to keep the red mist at bay, and learn to drive the car fast. This won't happen on one or two track days though, and you might even need to take some driving lessons. I'd be surprised if the V series of skylines had inherently bad handling traits on a race track. They may not be the best behaved car out of the box, but if it's spitting you off the track regularly, then look at your own driving first.

Just something to ponder