reducing unsprung weight: looking for light rims & tires

the Interceptor

Premium
Messages
4,191
Belgium
BEL / GER
Messages
theInterceptor77
I suppose I'm telling you nothing new when I say that cars have become too heavy nowadays. That doesn't only increase fuel consumption, but also diminish performance. That said, I'm currently giving my good old BMW (E36 323i) a diet. Several parts already had to go, and I have not only gained a higher MPG figure, the car also has become more agile. Currently, I'm looking into reducing unsprung weight, thus rims and tires. I was driving 225/40 r18 wheels on 8x18 rims last summer, but those didn't go well with comfort as well as fuel consumption. This time, I want to do better.

I am currently searching for lightweight rims and tires. The problem in Germany is that the TÜV (technical inspection agency) is pretty anal about legal parts, so I can't just slap anything on the car and go. Therefore, a lot of superlight racing rims are an absolute no no. At the moment, I'm thinking about the ...

OZ Ultraleggera 8x17
oz_ultraleggera_s_ci3_l.jpg


or the ATS DTC Superlight 7,5x17
ats_dtc_ksi.jpg


They are about equal in weight (16 lbs), so the decision is based on looks and price. However, I'm still looking for the appropriate tire to go with these rims. I'm currently looking into using 215/45 r17 tires of some known brand. It's not easy to find reliable sources for tire weights though, especially if you're looking for a specific tire size. I'm looking for summer tires. They may be sports tires, but shouldn't be too hardcore (= still have functionality in the wet). The price is no object at the moment.

So I'm turning to you guys. Does anyone of you know a website that has a database of tire weights? Do you know a specific tire that's very light? Have you faced the same problem and found the answer? Do you know a better rim / tire / size I should use?

Any help is appreciated! 👍

Regards
the Interceptor
 
I think so. The next smaller ATS DTC is 8x15, which is a bit small in my eyes (might as well use steel rims). And the TÜV says that I have to use 8x17 Ultraleggeras at least. I was looking into 7x17, but they aren't available for my car.
 
I would say the thinner ATS rim, because you can fit a thinner lighter tire on that. As for which tire, here in Ireland we have a really cheap brand called Kingstar, and IMO it is the lightest, however they may not last too long, but they should do you the summer and I think the are a lot lighter then say the same sized Hancook or Bridgestone. And obviously the smaller the side wall you can get the better also, I think 40 is the smallest. But all in all your only talking about saving at most a few kilograms. Let a passanger into the car and well it will be all for nothing!
 
According to Tire Rack, the Ultraleggera that's sold in the US in your size (17x8, +40 and your gargantuan 5-120 bolt pattern!!!!) weighs 17.6 pounds. SSR has a lighter wheel called the Type C RS and a few different fitments: 8.5 wide all around at 16.5 pounds, or 8 in front and 9 in rear, at 16 and 17 pounds respectively. Also they're hugely expensive, as SSRs typically are. I think you could probably get a set of Volks custom sized and colored, but in that size you'd be looking at well over $700 per wheel.

There's not that many other exceptionally light wheels on that site, but there is a wide selection from BBS. There would also be a wide selection of money out of your wallet for any of them.

It looks to me like all the super light racing wheels don't come in that ludicrous bolt pattern that only German people have heard of. Then again, there's not many race-car-light German mobiles I can think of except those that are actually race cars.

Good luck! And do not buy tires based on weight.
 
Dude.


Enkei RPF1.


The End.


EDIT: Wait, maybe they don't come in your bolt pattern, I'm not sure. If you are looking for lightweight though, there pretty much isn't anything lighter for the price.
 
Last edited:
I would say the thinner ATS rim, because you can fit a thinner lighter tire on that. As for which tire, here in Ireland we have a really cheap brand called Kingstar, and IMO it is the lightest, however they may not last too long, but they should do you the summer and I think the are a lot lighter then say the same sized Hancook or Bridgestone. And obviously the smaller the side wall you can get the better also, I think 40 is the smallest.
There are smaller sidewalls than 40, but that's another story. The idea is to find a tire from a well-known brand. Even the best car (not mine, but hey...) will only be as good as its tires, if you can't put it on the road, it's worth nothing. I'm looking into the Continental / Goodyear / Pirelli / Michelin corner, but I'm open for other suggestions. But most importantly: I don't want to save money here, I just need a good, light tire.

But all in all your only talking about saving at most a few kilograms. Let a passanger into the car and well it will be all for nothing!
True, but in 97% of driving, I travel alone. Experts say that reducing unsprung weight reduces the felt weight of the car by a factor of between 4 and 8. The 8x18s I talked about earlier are almost 46 lbs. Let's estimate I'll get the new tires down to 37 lbs. That'd be a difference of 9 lbs per tire, so 36 lbs for the whole car. Multiplied by said factor, that'll equal weight saving of between 144 and 288 lbs ... and that's a lot.

Interceptor -

This site will be incredibly useful to you

It's basically a list (4,274 long, at the moment) of different alloy wheel weights. It should actually enable you to compare the aftermarket alloys with the OE wheels too, they're bound to be in there.
Yes, thank you. I'm afraid I've already been there, and the majority of light rims I looked up is not available here. I'm pretty much stuck with OZs, BBSs and said exceptions as the ATS DTC. The latter are often used in amateur racing and they are quite cheap, so I might stick with them. I'm more on the look for the appropriate rubber.

According to Tire Rack, the Ultraleggera that's sold in the US in your size (17x8, +40 and your gargantuan 5-120 bolt pattern!!!!) weighs 17.6 pounds. SSR has a lighter wheel called the Type C RS and a few different fitments: 8.5 wide all around at 16.5 pounds, or 8 in front and 9 in rear, at 16 and 17 pounds respectively. Also they're hugely expensive, as SSRs typically are. I think you could probably get a set of Volks custom sized and colored, but in that size you'd be looking at well over $700 per wheel.
An interesting website nonetheless, with lots of information. 👍

I like those SSR rims a lot, and due to the good exchange rates, I could even have a go. But I'm afraid they're not offered here, and I need to have a TÜV certificate for them. If they don't have one, I'd have the TÜV to make one. They do that, but they need another rim to destroy in the process and charge you a nice 1,000 Euros (US$1,500) extra just for the work. :sick:

Good luck! And do not buy tires based on weight.
No worries, I won't! (see above)

Dude.

Enkei RPF1.

The End.

EDIT: Wait, maybe they don't come in your bolt pattern, I'm not sure. If you are looking for lightweight though, there pretty much isn't anything lighter for the price.
Agreed, but there's no certificate for these either. See above.

Basically, I'm mostly looking for the right rubber rather than rims. As you probably noticed, finding a brand that is available here, has a wheel that fits my car (gargantuan 5-120 bolt pattern!!!!) and is approved by the TÜV is no easy task, so the above options (or maybe a BBS) are what I'm gonna have to stick with.

Thankfully, TireRack.com also has tire weights, so I can have a look through the appropriate sizes to find a good and light tire. Thanks for your help guys! 👍

Obviously, every contribution to this subject still is welcome. :)
 
Last edited:
The new BBS designs are good... but obviously expensive. I particularly like the idea behind their air-filled flow-formed ones... but those apparently come in 18" and up...

While it's a good idea to lessen weight on the wheels, tires aren't going to be that big of a difference in weight... usually just 3-5 pounds within the same size... and I'd rather get a tire that's about 3 pounds heavier than average if it's a good tire than worry about the weight... just concentrate on finding the right lightweight rim and pick a tire based on what gives you the best combination of performance and fuel economy... probably a 205/50R17... but if the TUV will let you get away with smaller, 205/45R17s will make it feel much more agile... though your odometer will read differently (as per http://miata.net/garage/tirecalc ).

You can't go below stock size as per TUV? From what I remember of the E36... it should have been available with 16's, depending on the trim level...
 
I like the Michelins

Generally, they also have lower rolling resistance (better fuel economy) if they have "green X" technology or some nonsense in them. I'm pretty sure they make them in 225/45-17 sizes which is about what you should be looking at.

Primacy mxv4 (all season luxury touring) if you arent trying to be a race car driver on weekends
Pilot sport AS (all season high performance)
 
Last edited:
The new BBS designs are good... but obviously expensive. I particularly like the idea behind their air-filled flow-formed ones... but those apparently come in 18" and up...
I'm afraid so.

While it's a good idea to lessen weight on the wheels, tires aren't going to be that big of a difference in weight... usually just 3-5 pounds within the same size... and I'd rather get a tire that's about 3 pounds heavier than average if it's a good tire than worry about the weight...
Yeah I know, but there actually are some differences in it. The Continental range seems to be fairly light, I found the Sport Contact 3, which is a good and popular tire here, to be one of the lightest among the bunch at 19 lbs. A Goodyear Eagle of the same size easily sports 23 lbs. That's only 4 lbs difference, but don't forget: 4 tires, and difference times 4 to 8 makes 64 to 128 lbs overall.

just concentrate on finding the right lightweight rim and pick a tire based on what gives you the best combination of performance and fuel economy... probably a 205/50R17... but if the TUV will let you get away with smaller, 205/45R17s will make it feel much more agile... though your odometer will read differently (as per http://miata.net/garage/tirecalc ).

You can't go below stock size as per TUV? From what I remember of the E36... it should have been available with 16's, depending on the trim level...
The papers say mine even had 15s as standard. Still, there seems to be a lower limit for specific rims. I can probably get away with the smaller rims as well, but that entirely depends on the guy at the TÜV.

I made myself an Excel chart to calculate the dimensions of different rim and tire combinations. 205/45 r17 would be fine, that'd be just a tad smaller than the original 205/60 r15 from the papers, which is a good thing.

I like the Michelins

Generally, they also have lower rolling resistance (better fuel economy) if they have "green X" technology or some nonsense in them. I'm pretty sure they make them in 225/45-17 sizes which is about what you should be looking at.

Primacy mxv4 (all season luxury touring) if you arent trying to be a race car driver on weekends
Pilot sport AS (all season high performance)
Yes, I found them in that size, and they do look good. I'll definitely put them on my shortlist. 225/45 is a bit too much though, that'd be bigger than the stock tires. 225/40 would fit better.
 
Cheaper idea: I know the E36 M3 alloys are fairly light, and since they're an OEM wheel I don't think you'll have much trouble with the TÜV. 17" too, probably easier and cheaper to get by if you look around the web a bit, considering how many M3s you see everywhere with BBS and the likes.
 
Good point, but the E36 M3 is very rare here, and so are its rims. I found two sets on eBay, but they are neither cheap, nor are they in good condition. :indiff:

EDIT:

Okay, so far it looks like it's going to be the ATS DTC superlight at 7,5x17 together with the Continental Conti Sport Contact 3 in 215/45 R17. Those two would add up to a total weight of presumably 36 lbs per wheel. Quite a difference compared to the 48 lbs of my old wheels, and not to steep at about 300 Euros ($US 465) per wheel.

Thanks to everyone who participated in this thread! I'm going to leave it open for others to ask similar questions or bring in their own experiences and recommendations.
 
Last edited:
Back