Trackday tyre and wheel sizes

[brillomaster]

First things first - this is not related to a 350Z, but would be interested to hear everyones views especially those who do trackdays.

 

As most of you will know, me and Will have just bought an old BMW E36 328i for track use. Now, the car at the moment is running on the smallest wheels and tallest profile tyres ive ever seen on a 3 series - current sizes are 205/60/R15. it handles like a boat!

 

My question is, im seriously considering dropping down to 195/50/R15s, but am aware of the disadvantages this would have - namely, the rolling diameter is 8% lower, so speedo would be completely wrong, and ride would be a lot harsher.

 

However, as i see it, swapping from 205/60 to 195/15 means we get

Less sidewall flex - better turn in

effective shorter (or longer - cant remember which is which) final drive ratio - better acceleration at the expense of top speed

Lower ride height - an inch of drop without changing springs, with a further inch of drop available to maintain the same arch gap it was running on 60 profile tyres

lighter wheels - less unsprung mass, so better acceleration, braking and handling

 

Does this sound like a good idea? i'm a firm believer in small wheels for better handling, but is an 8% decrease in rolling radius and an 25mm drop just from tyres going too far? remember we're working to a budget, and 195/50/15 tyres are so ridiculously cheap its hard to ignore - full sets of part worn toyo R888s go for about £150 on fleabay.

 

Other options are 225/50/16s, or 225/45/17s, but both of these would require sourcing some new rims.

 

Any thoughts appreciated!

[Ekona]

I've stuck with stock tyre sizes on the '5, which are 185/60/14. I've left it on purpose like that as I like the handling like that, the extra sidewall flex gives you great feedback and allows the chassis to really shine.

 

I would stick with what you have, certainly until you've had a couple of trackdays in it to know how it feels. Skinnier tyres means more oversteer too, does an E36 really need that? How much are 888s in those sizes compared with if you were buying new in 195?

[brillomaster]

unfortunately cant get hold of R888s in 205/60/15 size, which makes direct comparison tricky! i take your point about narrower tyres being more prone to oversteer, but the tyres that are on there at the moment are smooth quiet running ones, so a more performance oriented compound would offset the narrower width. might need to play with the pressures as they are to improve feel - quite possible they're running too low.

[Dave-350]

I have owned E36's since I past my test and there isn't much I dont know about them... Running 15s though? I would get yourself on the bimmerforums or e36coupe.com as the guys there are seriously knowledgable and I have never known anyone to run 15's.

 

You want 17's imo.

 

My E36 328i Sport.

 

 

 

Edited March 18, 2013 by Dave-350

[Ekona]

Why would you want 17s? Aside from looks, there's no benefit that I can see from putting bigger, heavier wheels on a track slag.

[Dave-350]

Why would you want 17s? Aside from looks, there's no benefit that I can see from putting bigger, heavier wheels on a track slag.

 

Again, on the e36coupe forums there is masses of information as to what to run for track use and I would go by the experience of the experts.

 

A few bits I would advise:

 

Coilovers

XBrace

Strut braces

A correct geometry setup (A little rear toe helps with understeer, no toe in at the front though)

ARB helps alot too.

 

Plus, look at the kumho BMW championship cars... I think there is a small handful that run 15s but majority run 17s.

 

I could be wrong though! Or maybe it just doesnt make a hell a lot of difference!

Edited March 19, 2013 by Dave-350

[NeilMH]

If I was on a budget and just wanted to have fun I'd stick with what you've got initally. If I was going to change I would stay on 15s and lower the profile. However, this would be subject to what you feel needs doing to the brakes (they are usually the thing that causes the biggest problems). It's just that if you need bigger/different brakes you might need different wheels.

[brillomaster]

aye we'll see how we get on as it is - point taken about bigger rotors needing bigger wheels, but im hoping that better pads andhigh temp fluid will be enough - we'll only do a handful of laps at a time to try and not overwork the brakes.

 

will report back when we have taken her for a spin

[docwra]

Why would you want 17s? Aside from looks, there's no benefit that I can see from putting bigger, heavier wheels on a track slag.

 

Cheaper tyres, probably cheaper wheels and you know whatever brakes you go for are going to fit. Totally appreciate your logic but Id recommend a 17 as well, I had a 328i myself a while back

 

However ..........

 

the rolling diameter is 8% lower' date=' so speedo would be completely wrong, and ride would be a lot harsher.

[/quote']

 

Its a trackcar dude, ride quality and speedo accuracy arent really all that important

 

A few bits I would advise:

 

All good advice but trust me, get an M50 manifold fitted before you do anthing, the engine frees up so much at high revs it feels like a different lump and also get a decat (i.e. with an angle grinder) will make it sound nice too and doesnt cost anything.

[Dave-350]

All good advice but trust me, get an M50 manifold fitted before you do anthing, the engine frees up so much at high revs it feels like a different lump and also get a decat (i.e. with an angle grinder) will make it sound nice too and doesnt cost anything.

 

Did you not see my Dyno results? I had M50 Inlet, BBTB and BBTCB (Yes it had TC rather than LSD) with DaveF induction. It made 20BHP and better torque curve buts its not noticeable...

 

Any release of pressure on the exhaust will result in loss of torque on those engines, been there done that and the standard system is actually the best system to use without a remap. The supersprint system was the only one to give gains, of about 2BHP!

[docwra]

All good advice but trust me, get an M50 manifold fitted before you do anthing, the engine frees up so much at high revs it feels like a different lump and also get a decat (i.e. with an angle grinder) will make it sound nice too and doesnt cost anything.

 

Did you not see my Dyno results? I had M50 Inlet, BBTB and BBTCB (Yes it had TC rather than LSD) with DaveF induction. It made 20BHP and better torque curve buts its not noticeable...

 

Ummm, I had one and it was extremely noticable, like an extra 1500 useful revs, I also know at least 10 people who would agree - the engine is artificially stangled at high revs, how can freeing it up not be an improvement?

 

I wouldnt even drive one without it having been done first. Seriously.

Edited March 19, 2013 by docwra

[Dave-350]

All good advice but trust me, get an M50 manifold fitted before you do anthing, the engine frees up so much at high revs it feels like a different lump and also get a decat (i.e. with an angle grinder) will make it sound nice too and doesnt cost anything.

 

Did you not see my Dyno results? I had M50 Inlet, BBTB and BBTCB (Yes it had TC rather than LSD) with DaveF induction. It made 20BHP and better torque curve buts its not noticeable...

 

Ummm, I had one and it was extremely noticable, like an extra 1500 useful revs, I also know at least 10 people who would agree - the engine is artificially stangled at high revs, how can freeing it up not be an improvement?

 

I wouldnt even drive one without it having been done first. Seriously.

 

Yea it's good results according to the dyno run, but I didnt notice it driving the car. And if Alpina527 still manufactures the kits to bolt straight on it is worth doing!

 

And just to throw a spanner in the works, you could just save up a few extra pennys and buy a cheap M3, problem solved

[docwra]

And just to throw a spanner in the works, you could just save up a few extra pennys and buy a cheap M3, problem solved

 

I paid £200 for it mate. The M50 and fitting cost more than the car did

[NeilMH]

Completely different but I bought an ex Group N Peugeot 309Gti for a track car because it had all the safety stuff already on it....full roll cage, plumbed in extinguishers, rally spec seats and harnesses, double throttle springs, brake pipe protection, etc, etc. It had standard profile wheels and tyres but I bought good tyres for it (might have been Yoko 021R...it was a long time ago). I actually found that the "feel/give" from the standard profile tyres added to the fun (albeit not to the overall speed ). They were very light cars even with the roll cage - I stripped everything else out that I could (and got polycarbonate windows, etc. The brakes were always the issue however, even with Mintex race pads and posh fluid - I really needed to spend a bit more...but I would just put in a few laps then have a break. I was just trying to do it all as cheaply as possible. Naturally if I had a bigger budget who knows but it was still great fun and the guy who bought it from me just carried on as I did. Good luck chaps

[Ekona]

'Tis a good point.

 

Do you want to win at track days, or do you want to have immense amounts of fun? Genuine question, no right or wrong answer. I used to be all about the speed, but now I'd rather just play and try and work with what I have than worry about overtaking everyone.

[NeilMH]

'Tis a good point.

 

Given your last posting may I crave your indulgence by granting me the new and recently introduced "Ekona Seal of Approval" ?

 

I also wish to know if it is like a Royal Warrant - would I then have it "permanently" until removed or is it only awarded on a post-by-post basis. Or perhaps there are certain qualifications I might need - like matching tyres all round (which I hasten to say I have ....but only Avons)? I look forward with some anticipation to your reply

Edited March 20, 2013 by NeilMH

[Will370z]

Haha they are hard to come by Neil