Ruf wheels "denloc" problem

[Falk930]

Hello,
I have bought a nice set of Ruf Speedline wheels
front 9x17, rear 12x17 for my 930.
The rear ones was a special build by DP,
here in Germany you need TÜV load test
to drive them legal which I recieved from DP.
fine so far...

calling Ruf I was told that these wheels are old
denloc wheels and I NEED to drive denloc tyres
on them.
bad! where to get payable 315/35x17 denloc tyres?

I searched the forum and few here seem to have
normal tyres on these Ruf denloc wheels.

Is it no problem to put normal tyres on them
or is there any risk?

thanks for help
Falk

[Rory Mckenna]

I have head of people running normal tires on them.. where did you get 12x17s!? nice.. Do you happen to have a picture of that rear wheel?

[Falk930]

Only have this, the angle dont show how wide they are,
tyres are 315/35 17. Will post a better pic tomorrow.

The seller told me that he dont know anything about
"denloc" and used only normal tyres on them.
But, with my wheels I try to be on the safe side.



Falk

[Craig 930 RS]

I have the same wheels -

"DENLOC only" is painted onthe inside of the rim - so far so good...... I ignored it on advice of others more knowledgeable than I -

[930gt-40r]

what the hell is denloc? I have never even heard of that

[Falk930]

Originally Posted by 930gt-40r

what the hell is denloc? I have never even heard of that

Exact that I was thinking this morning when Ruf told me
its not possible to run normal tyres on my nice new rims.

For language reasons, I am sure others here can explain "denloc" better.

Falk

[les_garten]

I had a dog and Google was his name...

http://www.tirerack.com/tire-12/Bridgestone/RE71%2BDenloc.shtml

Les

[930gt-40r]

Why dont you call one of the tire companies and see if they could shed some light on the subject- If they dont know then there is a real problem.
Another problem, where in the hell do you get 315/35/17s? I would be very angry if I could not drive on those beautiful rims.
Now the TuV- do they issue a certificate that you keep in the car at all times? If not, then how would anybody know that you didnt have them approved?
I thought our DMVs were bad...

[Craig 930 RS]

?

315/35/17 are EASY to find:
http://www.tirerack.com/tires/Sizes.jsp?make=BFGoodrich&model=g-Force+T%2FA+KD

Again, I run Goodyears on my Denloc rims with zero problems........but then again we don't have the TUV crap to deal with ;-)

[930gt-40r]

I didnt know anyone made 17s like that any more. I got to get diffrent rims

[Falk930]

AS far I could find out, denlocs was not produced
in a 315/35 x17 size. But my rear 12" was definitly used.
I am quite sure they was used with normal tyres all
the time.
Today I will take of one tyre to check the bead geometry.
Hope that will bring some light in here.

regarding TÜV: It is neccessary here in Germany to visit
TÜV engeneers to let them check for example different
then stock wheels. For this 12" DP ones, they need a load
test to proove they are strong enough. This test was performed
from DP in 91 and I have a copy. They really cutted another
set of Ruf Speedlines and welded them to 12".
The TÜV is not the problem, I only dont like to run a unsafe
tyre/rim combo at 280 km/h

Falk

[Falk930]

@Rory
here a pic from the rear 12x17 with 315/35 tyre



Falk

[les_garten]

Nice wheels!!

TÜV Crap!!

What I would say about the TÜV is that they do real inspections, not just the money making scheme we have in this country that calls itself an Inspection. Sure, total pain in the Ass, but anybody who has driven on the Autobahn would like to know the car next to them had brakes, tires, wheels, lights, etc that were in good order. My experience was that TÜV inspections are REAL inspections.

[Jim2]

Craig, what does the Denloc rim look like compared to a rim with a conventional bead lock? I can't find a picture anywhere.

[Falk930]

I took on tyre off to compare with a "standard" rim.
On this picture both are 17" rims, left side is the Ruf.
Visible is for sure the denloc groove (red arrow).
I measured the hump, comparing these 2 rims,
the Ruf hump is about 0,1 inch lower.
My racing shop buddy told me its no problem.



Falk

[Craig 930 RS]

It is no problem. Aside from tough TUV regulations in Germany - hell, just run them.

[Racerbvd]

Originally Posted by Falk930

I took on tyre off to compare with a "standard" rim.
On this picture both are 17" rims, left side is the Ruf.
Visible is for sure the denloc groove (red arrow).
I measured the hump, comparing these 2 rims,
the Ruf hump is about 0,1 inch lower.
My racing shop buddy told me its no problem.



Falk

Are these Denlocs?

[Jim2]

From an old thread Byron:

Originally Posted by JBL930

Stole this pic off the other thread, the red arrow shows the Denlock bead, can't honestly see how this could cause an issue anyway!

[alwaysflat6s]

I just ran across this.... If anyone cares, a long time ago Alois Ruf told me that running regular tires on my Ruf Denloc wheels was not a problem. I have run a variety of Ruf wheels on my cars since the 80s, including some of the very first generation Ruf Denloc wheels. I just Googled "Dunlop Denloc bead" and found a variety of responses... including some special made Bridgestone RE 71s that Tire Rack apparently still sells exclusively for 959 owners - NO price indicated.

I know when they were first introduced supposedly the tires and wheels were exclusive to each other. Way back when I wore out my first Bridgestone Dunloc spec tires I discovered that at that time there were no available Dunloc bead tires on the market! That led me to more information and discovering that... apparently the TIRES were only suitable for Denloc wheels but the wheels were suitable to normal bead tires also. The point of of all this was to provide run flat safety. I still have 2-3 sets of early Rufs and suspect some are Denloc. Whatever. At a certain point I stopped paying attention to this.

If you are really interested in this subject I suggest trying my Google suggestion. Meanwhile, here is some history and information from TR regarding their RE 71s [hope I am not violating any rules including this but the history is interesting, even if I do NOT agree with their statement that you must run Denloc tires on Denloc wheels. I studied the insides of Ruf Dunloc vs non-Denlocs and could see no reason this could be a problem. I can see where back in the day they would insist that you run Dunloc spec tires on these wheels to eliminate any confusion as to whether the car had a that extra high speed safety margin.

--------------
From TR site:

Porsche 959...The First Supercar and its Tires

During the early 1980s, the FIA (Federation Internationale de l'Automobile) established the rules for international racing and the Porsche 956 prototype remained pretty much unbeaten in the Group C class. With the aim of encouraging more manufacturers to participate in motorsports, the FIA made the Group B class rules more liberal and only required manufacturers to build a minimum of 200 identical vehicles.

The new Group B rules offered interesting possibilities. For Porsche, the 911, the oldest series in the Porsche stable still, had a tremendous unexplored potential representing an ideal test bed for assessing the future models. Since there was no question of 200 customers accepting a racing car in disguise, Porsche chose to develop the car for racing in Group B class.

NOTE: FIA Group A class rules stipulating sedan-type cars and production of at least 5,000 units in twelve consecutive months, not possible for Porsche.

The project was officially launched in January, 1983 when Porsche developed the ultimate "911" specification based solely on technical considerations, regardless of the cost or the work involved.

A production run of the 200 Porsche 959 vehicles needed to meet the FIA rules were built and sold in 1986.

Initially, Dunlop developed tires with the intention of producing road tires derived from their competition tire used on the Porsche 956. Dunlop's Denloc tires had a unique rubber rib attached to the bead that "locked" into a recess in the wheel that would prevent the tire from coming off the rim and suddenly deflating in the event of a puncture.

In addition to the recess to accommodate the Denloc bead profile, the 959 alloy rims featured a hollow-spoke design with a central locking nut. The wheels' hollow spokes form a single air chamber with the tire. When fitted with the Porsche air pressure monitoring, the system can detect pressure loss due to cracked wheels and/or punctured tires. A hub sensor reads the pressure in the chamber and transmits it to the on-board computer, which activates an alarm below a certain pressure.

The Dunlop Denloc tires were replaced by Bridgestone RE71 tires on the road version of the Porsche 959. The RE71 tires were one of the world's first self-supporting run-flat tires. They featured the Denloc bead profile, reinforced sidewalls and were capable of meeting the road-going Porsche 959's top speed of 202 mph.

Bridgestone has built new RE71 N0 tires featuring the Denloc bead profile in the Porsche 959 sizes. These are the only tires available for real Porsche 959 vehicles and also fit RUF (a Porsche tuner) wheels produced in the 1980s that feature the Denloc bead profile.

These tires cannot be installed on standard 17-inch diameter wheels and tires with standard 17-inch bead profiles cannot be installed on Denloc wheels.

Only a few of these tires are manufactured in Japan each year. The tires we have received are intended solely to support customers in North America. They cannot be exported!

[16Volt]

Nearly all first gen Ruf speedlines will be Denloc. I am running normal tires on mine without issue.