Best rim size and lowering kit/coilovers

[Stevie G]

Hi Guys

I am new to these forums. i recently got myself a 2011 1.4 VVW Polo Comfortline. I am from South Africa. i am stuck between a 15'', 16'' and 17'' rim and cannot decide which one will be the best in terms of fuel consumption, loss of power and wear and tear on the car. the car originally have the 15" Riverside alloy wheels with 185/60 R 15 tyres.
specs Polo Range. < Polo < Models < Volkswagen South Africa
i was thinking of putting on the Budapest 7½J x 17" alloy 215/40 R 17 Cross Polo Rims. how will these rims affect the above mentioned concerns.

which lowering kit/coilovers will be best for my car. we have a distributor for eibach lowering kits. what is the difference between the lowering kit and the coilovers and which is better and cheaper. which of the 2 will not compromise the ride quality.

i would appreciate your guys input.

[bigfoot]

g'day Steve, welcome aboard

If anything fuel consumption, power (to weight) and handling will improve, albeit by a small fraction. The alloys should be ligher and therefore better for fuel economy. Ride quality may not be as good with the smaller profile tyres. The Budapests are a standard Polo size so you won't have any fitment issues (i', assuming the offset is the same as the Boavista wheels.

both lowering coils/kit and coil-overs will make the ride harsher (but handling better). Coil overs are goind to be about 4 times the price of coils alone. H&R seem to be popular, can't comment on eibach though.

[gavs]

If your car came with 15" wheels, the first thing you will notice going to the larger alloy is the decrease in ride comfort. You have suddenly lost 2" of nice, squishy, compliant rubber between the road and the wheel rim. You will also see a loss in perceived power due to the rolling diameter increasing, hence the handle point of the wheel acting upon the drive shaft is further away so more energy is required to turn the wheel, but this will also be compunded by the increase in weight, especially evident on your 1.4 Naturally Aspirated Polo. The 17" polo wheels, with tyres are all ~20kgs. I am not sure what the 15" wheels you pulled off weigh but I doubt they will be this much.

My suggestion would be go far as light an alloy as you can afford if you are after handling and drivability, if you are purely after looks, then it doesn't really matter and the difference while evident on the drag strip or on a track, probably won't show up that much in daily driving.

Regarding springs, Eibach have been around for years and the only reason more people haven't used them is because H&R were first to market, so the first people bought them, and then they reccomend them so it becomes the "norm". To give you an idea of the pedigree of the Eibach product, Eibach make all the springs for Bilstein cup kits and also their lower-end coilovers. They are bloody good spring manufacturers.

In regards to the difference between the coilover kit vs just the lowering kit, the lowering springs will give you an approximate drop in ride height with just replacing the springs. These springs are somewhat matched to factory dampers to try and retain a stock-ish ride but they do become stiffer towards the end of their travel to stop bottoming out, this is why they're called "proggresive rate" springs. The coilovers however are full replacement dampers and springs that are matched together so that the spring forces match to the rates that the damper can dispell the energy. On these vehicles, the rear is separated and the front is a full replacement strut. The "advantage" in regards to lowering with coilovers is that you can go as low as you want based on the design of the setup and the springs should still match the damping rates, depending on the brand. This however will come at the detriment of ride control and handling prowess.

So, in conclusion, if you just want to go as low as you can, look at coilovers. If you just want to lower the car a littel bit, go the springs. If you want to go a bit lower as well as better handling prowess, a matched spring and damper setup or good quality coilovers are the choice.

[Stevie G]

Thanks guys for your input. i really do appreciate it. i think i will put on the cross polo rim withe a 215x40x17 tyre on and then decide if i want to lower the car or not. that is the best rim that i can find at the moment. will post some pics soon

[DunlopRS]

you will see a significant decrease in ride quality going down to that tyre size. Think carefully about the types of roads you drive on. I took the 18s off my octavia RS as they did not work at all for me off the freeway.

[Stevie G]

you will see a significant decrease in ride quality going down to that tyre size. Think carefully about the types of roads you drive on. I took the 18s off my octavia RS as they did not work at all for me off the freeway.

what tyre do you suggest then or what would suit the car the best

[DunlopRS]

I guess I should re phrase - "going down" to that profile.

I personally would not go below a 50 profile. Its all to do with the sorts of roads you drive on and personal choice - for me my car is primarily to get me from A to B as fast as is allowed in comfort and safety. Looking good in relation to rim size is a bonus. On the 40s that were on the 18s I did not get any of those 3 (especially as fast as is allowed) - and I felt that I was going to break something (I have bent the tops of shocker towers on previous cars - on roads called national highways in Australia - and did not want to go there again).

If it was me, I would see what options I had around a 50 or 55 series tyre re width/rim size combinations to give the correct diameter/rolling circumference. There won't be many.

FWIW here is my (recent) story - reference to some size calculators in there etc

http://www.vwwatercooled.org.au/forums/f149/reducing-rim-size-vrs-73054.html

If it were also for me - I would make sure the tyre was at least a little wider than the rim so when the inevitable happens and someone brushes a kerb the tyre protects the rim....

Good luck.

[kaanage]

The alloys should be ligher and therefore better for fuel economy.

From the OP

the car originally have the 15" Riverside alloy wheels with 185/60 R 15 tyres.

As for Stevie G's questions, see gavs response - it's all there.

[gavs]

40 series rubber isn't the issue, it's the width factory that generates the profile height. If you have a 205 width tyre then 40 series rubber will give you a sidewall height of 80mm. On a Porsche type tyre, 40 series rubber will give you a sidewall height of 130mm. It's all relative and down to the person. My GTI has 40 series boots on 215mm tyres and it's not the tyres that give it a stuff ride, but will I get the same tyres when I replace them? Nope, I'm going wider so this will also increase the sidewall height.

[DunlopRS]

40 series rubber isn't the issue, it's the width factory that generates the profile height....
.

granted -they go hand-in-hand

[kaanage]

40 series rubber isn't the issue, it's the width factory that generates the profile height. If you have a 205 width tyre then 40 series rubber will give you a sidewall height of 80mm. On a Porsche type tyre, 40 series rubber will give you a sidewall height of 130mm. It's all relative and down to the person. My GTI has 40 series boots on 215mm tyres and it's not the tyres that give it a stuff ride, but will I get the same tyres when I replace them? Nope, I'm going wider so this will also increase the sidewall height.

But due to the nature of tyre construction, width and enclosed air volume, ride/compliance will correlate most closely to profile series rather than the absolute height of the sidewalls.

[Stevie G]

Ok, now i have come across this website, where i calculate the difference in tyre size and so on

http://www.1010tires.com/tiresizecalculator

with my tire size of 185x60x15 being replaced by a 205x45x17 it will be Speedometer Difference: 2.192% too slow and Diameter Difference: 2.15%

I am going to fit my polo with cross polo wheels with this tyre. not going to drop the car at this stage.
what do you guys think?

[kaanage]

You forgot the .asp at the end of your link - that is my favorite tyre calculator since it lets you compare multiple options.

I think not dropping the car is a good move since the Cross is raised 15mm vs your Polo so it presumably runs longer, softer springs to do this which keeps the compliance in the overall suspension.

That said, you can get the Comfortline models here with a Sports Pack which drops the car by 15mm with shorter, firmer spring and gets you 17" Boavista rims (I think also with 215/40R17 tyres) so it all depends on what you can live with - there's another thread here where someone complained about the harshness of their Polo with the Sports Pack and then someone else posted that they thought that their Polo with Sports Pack rode just fine.

As you stated earlier, you can always drop it later.