Just wondering if anyone has had long term experience with Koing Dekagrams (or other Koing Rims) in 15x8 or 15x9, and has an idea how long until they'll start to show any fatigue issues (cracks). My last sets of wheels lasted about 60-70 race hours over 4 years (one set was second hand, so no idea if it had done much track use before I got it) and trying to decide whether spending more money = greater rim life, or stick with the more cost effective options and know they might only last a few years.

I've been using A050 tyres and no aero, so not the most lat g's. I assume those on slicks with aero would be seeing issues sooner than I am.


Interested in any feedback on wheel life really. It would be interesting to know when/if forged rims like the TE37's start to have issues with fatigue, and to know what race teams (GT3, Porsche Cup etc) do with regards to wheel life.

 

I’ve run konig flat outs in 15x8 +25 since start of 2015, so easily 150+ track hours.
Car does 99% track work, so trailered to/from events. Normally 5-7 x 20min sessions per event.

I run 215/50 ao50s, with 4” splitter, large rear wing. Rotrexed with ~110rwkw, Does 1:49s at Phillip island, and it chews through front hubs regularly so it’s getting a workout.

Rims are still perfectly fine, no buckles or cracks, balance up fine each year when I fit new tyres.

I was pleasantly surprised, as they were quite light (5.6kg each) yet very cheap (US$99 ea) when purchased , and I thought at the time that if I get a couple of years before needing new ones them thats not too bad, but 8 years later getting bounced regularly over curbs and ripple strips with reckless abandon, they are still going strong.

I would have no hesitation buying konigs again,( probably Konig countergrams in 15x9 if I was to get another set.)

 

I'd be amazed if the high level (pro) teams did not either life their wheels or crack test them regularly, maybe both.

Can't help with your survey, not used Konigs. My 6ULs (15x7/8) have been in use since around 2007 with varying aero from nil to lots, probably less that Rascal's 150 hours total, with zero failures.

 

It depends heavily on how you use them. High grip cars with Hoosiers and aero are going to load them a lot more heavily than a Lucky Dog car on RS4s. How much you ride the curbs also matters.

--Ian

 

Most race teams have several sets of wheels and log the hrs. There are several variables that come into play, most importantly the track and wheel geometry. A forged wheel will be more ductal and less prone to cracking. A cold formed wheel is not a forged wheel. A cast wheel will usually be stiffer for a given weight because of the lower density and same modulus. For wheel to wheel racing on a rough track/big curbs etc, I would go with a stronger forged wheel (TE37 etc) and not worry as much about weight. Although from my experience the TE37 is light, strong, hard to get and expensive. My recommendation for track days or time trials would be a cast wheel like the RPF1.

 

No real way to know other than inspecting them carefully on a regular basis. Too many variables to suggest a specific time frame.

Generally spending more money won't necessarily get you more durability. They may get you similar durability at a lighter weight, or, in some cases, even lighter weight but LOWER durability than the cheap wheels. Jongbloeds are heavy, but they're probably pretty damn burly.

We've gone pretty far down the rabbit hole in preparation to re-release wheels next year. They are engineered for optimal strength-to-weight ratio, and will likely no longer be the lightest wheel in their category. A slightly heavier wheel optimized for strength will be burly.

 

Thanks for the responses!

Cheers! Exactly the kind of info I was after. I got about 1000km out of my last front left hub.

Yeah, I figure regardless what I get, they'll still be cleaned and checked after every event.
Was hoping for a few more responses as I assumed there would be others who knew how long they had the wheels and how many miles/hours were on them before cracks showed. Understand, the devils in the detail, but it would have given me a good idea.

The extra fatigue testing rays does on there wheels is pretty interesting. Should explain some of the cost of them - but again, pretty hard to know if 3500AUD rims vs 1200AUD rims are going to last 3 times. You would hope so...
I can't find the below image on the rays webiste, though I swear I've seen it there.

All You Ever Wanted to Know About Wheel Performance Standards - BimmerPost

Next time i'm at the track, i'll ask one of the cup car or GT3 teams about their wheels and what they do with them - just out of interest. Might get an answer ¯\_(ツ)_/¯

 

If there's ever any question, they just order more, cost no object. The wear is also spread out over a half a dozen or more sets of wheels, by the time they've all cycled through, there's less time on them than you may think. As far as design, usually their last concern is weight, strength is a bigger concern due to the amount of wheel to wheel contact in...wheel to wheel racing.

I have a feeling that if you hypnotized a GT3 chassis engineer and told him he should build a miata, he'd buy the heaviest/strongest wheel that's readily available and have no issue making the car work. The more likely scenario is the sanctioning body would pick the wheel for him. There's definitely a lot of concerns and questions in the track day world that aren't even considered in the racing world. I've hung around enough race teams to know I know nothing, $10,000 is a very small amount of money, and private jets are a huge time saver.