Lightweight wheel options for Euro Look

[Dan Dryden]

Hi Guy's.

I have never posted in this part of the forum before, spending most of my time in the forced induction threads.
Here is a picture of my 1972 1302 Bug:



It currently sits on 18 inch TechArt rims. 8 inch wide up front and 9.5 inch wide out back.
As great as I think they look, I can't help but notice how heavy they are and wonder if there is a good lightweight alternative?

I'm liking the idea of switching back down to some 15 inch rims but would need them to be wide enough to fill my rear arches which are 6cm wider than standard.

When I google "lightweight wheels", a common match is Oz Ultraleggera's. Not available in Porsche 5x130 stud pattern, so I would have to change my hubs / adapters to a PCD which is available.



Do you think they will still work with the style of my car? Will I notice a big difference in handling? The Oz wheels weigh a mere 4.9Kg (10 1/2 lbs) each (plus the weight of the smaller tyres).
Do you have any other suggestions?
I have never weighed my current wheels, but would guess that the wider rears weigh at least 12kg (26 lbs) with the tyre.

I want to reduce the unsprung weight of my car as I feel the handling could be a lot more nimble when I take the car on track days.

[Marc]

I question whether the improvement in unsprung weight would be worth the effort and expense, especially when you consider the increased sidewall flex you'd have from a similar-diameter tire on the smaller rim...or did you intend to use a short tire to lower the effective gearing? That will also shorten the contact patch; the tire will build heat faster so a short tire can actually stick better in the early laps, but may suffer in an endurance event.
Unsprung weight's importance in in direct proportion to the undulations in the track surface. If it's mostly flat, I'd rate a short/stiff sidewall as a higher priority than a a couple pounds of unsprung weight.

[Dan Dryden]

That is interesting what you say about tyre heat. I have been told that my tyres are probably too big for the weight of my car to ever get up to a good operating temperature.

I disagreed at the time as my tyres certainly felt soft and sticky after my 20 minute track session, but the comment came from a semi pro hill climber, which left a bit of doubt in my mind.

I agree with what you say about a shorter tyre, so I would probably look to run short tyres on the smaller wheels, reducing rolling circumference & top speed, but gaining better acceleration.

[FJCamper]

Hi Dan,

Heed Marc. Trying to get a couple of pounds lighter is not worth the time and expense, unless you were in a Formula car.

Something inobvious you have going for you is your torsion bar suspension. You know that about half the weight of the suspension applies to your unsprung weight as well. A torsion bar suspension, exactly as it is on the VW, has the least unsprung weight of all street suspension designs.

FJC

[gearheadgreg]

I have been through lots and lots of VW and Porsche wheels over the years of buying and selling. There are good deals out there, and there are still lots of Porsche race car applications in 15" (because they are all going to much larger sizes unless vintage racing).

I would looke for BBS E50 or E52, or the 924 SCCA D-Production E78 - I've had all these, and they are light and strong and 2 or 3 pieces, so easy to change width and offset if needed.

I have also had some Compomotive mesh wheels that were surprisingly light - pretty uncommon in the USA, but more common in the EU.

My final recommendation might be to make some 3 piece wheels - I had a set of 15x 9/10 Fuchs 3 piece wheels, made from 16x6 Fuchs centers, with BBS shells. There are a few companies in the USA I know that do this if it isn't available in Europe and you want to go that way.

I'm surprised to hear FJCamper not endorse lighter wheels - as they benefits to lighter wheels are multi-fold, and he being a road racer, should know and appreciate it better than most. Lighter wheels means less unsprung weight, as mentioned, plus less gyroscopic forces for changing direction quickly, plus less mass to have to spin up or down when accelerating or braking. Experience on the racetrack is worth more than lots of conjecture, though.

[Steve Arndt]

I'm also playing with some heavy Boxster wheels at this time and shopping for tires. Something to note by browsing tirerack.com is that for the same exact tire sizing specs it is common to see a 5 to 6 pound range of weights from high to low. Just something to think of if you are nearing time to purchase rubber.

For example I've been looking at 215/55R17 and weights range from 21 to 26 pounds. It seems the higher the speed rating and performance category the lighter they get.

[FJCamper]

Hi Gearheadgreg,

Actually I do favor lighter wheels. We are very careful at my shop in weighing different wheel, tire, and brake combinations, right down to the weight of even the disc brake adapter!

My advice to not worry about a couple of pounds of unsprung weight is based on cost vs benefit as in what other changes might make him faster on the same wheel's and tires.

Dan is probably very savvy about his car and others. English and European drivers tend to be more serious and better informed than US drivers.

If I were there with him, we'd watch his driving and begin with improvments there first (free -- if you don't count the expense of the ego). Then we'd tune the handling with whatever was available to us (inside Dan's budget) to make him faster. That means yaw, pitch, and roll first. Then we'd go to tires and wheels.

What counts is lap times, not how comfortable or uncomfortable Dan might be with the adjustments. Slow drivers are usually "comfortable" with their cars.

Last, we'd alter power and gearing.

FJC

[gearheadgreg]

Understood.

[Dan Dryden]

Thanks for the replies guy's.

You have successfully talked me into sticking with the wheels I have.

For the record, I'm probably not as savvy as I should be on this subject but understand the basic principles.
I will be the first to admit that my driving skills could certainly be improved upon!
I just like the idea of a classic car, with an inherently poor design for handling (rear engine) being able to show some of the more modern machinery on track a thing or two!

I'm running a type1 1776cc EFI turbo which has been dyno'd at 194bhp / 222lb/ft torque. I just want to ensure I am making the best use of that power.

I hope to spend a bit more time on track this year and get to know my car's limitations a little better.

[vwo60]

I run a set of Image wheels that i had made for the car in the UK, they are a three piece billet wheel, i had Fuchs wheels running Falkin semi slick, i fitted the image wheels with Continental tyres and there was a 3 KG per wheel reduction in weight, the difference in the ride and handling is dramatic, billet 91 are the wheels that i run.
http://www.imagewheels.co.uk/pages/wheels_billet.html

[Jadewombat]

Just thumbing through a copy of the SCCA magazine, in 15" diameters you could check out:

Sparco Assetto Gara 13.8-14.6lbs.
TR C1 12.8-14.6lbs.
Kosei K4R 10.7-13.1lbs
Kosei K1 13.5-14.5lbs.
Kosei K1-TS 12.6lbs.
Enkei Ultraleggera HLT 12.0-12.4lbs.
Enkei RPF1 9.5lbs.
Enkei PF01 12.1-13.0lbs.

[Dan Dryden]

Thanks again for the responses guy's. I think I'm gonna run with what I have for this summer and maybe look back into this next winter when I take the car off the road to hibernate.

The way I see it is that you wouldn't be able to run as fast wearing heavy boots as you would with some lightweight snickers. It's a simple analogy but makes sense in my head! Haha!

[buildabiggerboxer]

Hi Dan, Johnny here, my you stirred up a hornets nest, really, for track days you need another set of rubber, my view is everyone has gone the wrong way anyway, victims of fashion following production car trends of ever taller rolling radius instead of thinking it through and dropping down on wheel and tyre sizes. 13" wheels have it all going for them for Beetle use, Lowers the car with no geometry problems, cures wheel arch fowling, sorts the over geared problem for racing, weight is lost in the wheel with the smaller sizes, and there are all the light weight Kevlar hot rod slicks available for serious racing, I've gone as far as checking 13s will go over my Tarox calipers, and they do, so my plan is to use 13s on the front to start with, no time scale yet, as ever, the budget is spent before the car gets an upgrade, imagine, your car will clip over a second a lap off its times at Lydden Hill with no other changes, that sort of time loss takes 40 plus extra horses and all the extra work on cooling and brakes, win win for the 13s in my book.
O2s and O3s have a problem getting low enough for racing, so they are bang on for these cars, b/j cars are easier to run extremely low, but still gain better geometry and travel, as above really, I can't wait to go back to where I started, or will you beat me to it lol... Regards J.

[buildabiggerboxer]

Dan, your above analogy is a good one, you may know of my recent change to inverted a arms to reduce rear camber, at the same time I moved the shocks to the top side and the end of the a arm with new top mounts into the roll cage " just in case " I ever go back to coil overs, anyway, the point being the shock setting, I used the 'old' full hard setting, needless to say the car was hopeless, big oversteer, the extra control the shock had over the suspension leverage, being now at the end of the arm, was eye opening, it now runs only 5 clicks, not the full hard the stock arm required, so yes, un sprung weight and the control of it has a huge bearing on how your car performs, reduced wheel and tyre weight is key as you correctly stated, lighter is always faster..... Take stuff off and keep them simple to go quick, complexity is the mother of un reliability,, and so on..

[Dan Dryden]

Hi Jonny, thanks for your input. What you have said is confirming my trail of thought about this subject, but I just wanted to confirm I wasn't missing something - hence the reason for this thread.

Lighter wheels and bringing my axles closer to the ground can only be the recipe for better handling right?
As much as I love the look of my 18" wheels, they are doing exactly the opposite - adding unsprung weight & raising my axles further from the ground.

What 13" wheels would fit a bug?

I saw the 15" wheels above as a good compromise (on size & style) as my car is mainly used on the street with maybe 2-3 track sessions per year. Running a second set of wheels would be an added expense I could do without at the moment. - My wife already moans about the time & money I put into my car! Lol!

Will I see you at Apex Festival this year?