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Anothet victim to the RMD steering wheel

Davey D - 25/6/15 at 06:02 PM

I was on a trackday at Cadwell Park yesterday. Weather was amazing, did my 3 sighting laps, and then got out on track straight away with the first lot of cars. 6 laps in coming around Mansfield and my steering wheel suddenly felt all wobbly. Looked down and the arm on the right hand side of the wheel had completely snapped!

Thankfully I didn't have far to go to get back to the paddock. That was my day over by 10am. Needless to say I was gutted, but it could have been much worse if I had lost control of the car.

Managed to blag a few passenger rides with other drivers helped ease the pain a little

I have heard stories of these wheels breaking, and was only just talking to Relph on here on Saturday last week about these wheels breaking.

This time I'm going to splash out on a Momo mod 27 wheel.

If anyone else has one I would recommend binning it and get something better

40inches - 25/6/15 at 06:10 PM

That's worrying I have a RMD flat bottomed 300mm wheel fitted, do you have any photos of the fracture? How old is it?

ian locostzx9rc2 - 25/6/15 at 06:17 PM

I looked at these wheels and they appeared very flimsy so I bought a momo wheel .

Davey D - 25/6/15 at 06:19 PM

quote:
Originally posted by 40inches
That's worrying I have a RMD flat bottomed 300mm wheel fitted, do you have any photos of the fracture? How old is it?

I don't have any photos but it is a straight clean break just where the suede covering starts

Its been on the car around a 1.5 years, which is around 200 road miles, and this would have been the 6th trackday I used it

[Edited on 25/6/15 by Davey D]

ian locostzx9rc2 - 25/6/15 at 06:25 PM

I think you need to contact the seller of these wheels a sap

Davey D - 25/6/15 at 06:45 PM

quote:
Originally posted by ian locostzx9rc2
I think you need to contact the seller of these wheels a sap

There are a few companies that sell these wheels, but I got mine from furore sports cars on here

BangedupTiger - 25/6/15 at 06:49 PM

I've got a brand new momo 27 for sale.

Davey D - 25/6/15 at 06:57 PM

quote:
Originally posted by BangedupTiger
I've got a brand new momo 27 for sale.

Ooh what size? Have you already drilled it? Why are you selling and how much do you want for it?

BangedupTiger - 25/6/15 at 07:11 PM

270mm, undrilled, brand new. I'll dig it out the garage tomorrow and send some pics over.

Same as this http://www.demon-tweeks.co.uk/motorsport/steering-wheels/momo-model-27-steering-wheel

Doctor Derek Doctors - 25/6/15 at 07:29 PM

I had one of these RMD race steering wheels break in exactly the same way but it was on little garden go kart so I never reported it on here but its worrying that it seems to be a trend.

40inches - 25/6/15 at 07:54 PM

Do you think it breaks at the point that the "suede" is trimmed, possibly a score line left by a knife?

Slater - 25/6/15 at 08:19 PM

See similar thread from 2013

linker to thread

Relph - 25/6/15 at 08:45 PM

quote:
Originally posted by 40inches
Do you think it breaks at the point that the "suede" is trimmed, possibly a score line left by a knife?

Yes mate that's where it breaks.

Sorry to hear it ruined your trackday Dave.

I've been looking at steering wheels, the momo 27 does look nice.
Don't suppose you've got another one for sale have you Bangeduptiger. Lol

BangedupTiger - 25/6/15 at 08:50 PM

Just the one mate. I'm too scared to drill the holes in it lol.

So going for a ready drilled one. Precision isn't really my thing, if you can't fix something with a hammer, I don't bother trying lol.

Relph - 25/6/15 at 08:55 PM

Yeah that's one of my worries, I know if I didn't get it spot on it would annoy the hell out of me.

I take it Dave has had the one you offered him ?

Davey D - 25/6/15 at 08:55 PM

I plan on using the broken RMD wheel as a drill through template for the Momo wheel. That's all is good for lol !

Relph - 25/6/15 at 09:01 PM

Hi Dave, I can't believe it happened to you and we were only talking about it Saturday night.

Davey D - 25/6/15 at 09:09 PM

quote:
Originally posted by Relph
Hi Dave, I can't believe it happened to you and we were only talking about it Saturday night.

I know, it seems crazy! Maybe I jinxed myself by not touching wood when I said my steering wheel was ok hehe

russbost - 25/6/15 at 09:37 PM

quote:
Originally posted by Davey D

quote:
Originally posted by ian locostzx9rc2
I think you need to contact the seller of these wheels a sap

There are a few companies that sell these wheels, but I got mine from furore sports cars on here

Hi Davey

If we've sold this wheel then I would be very greatful if you could return it to us so we can return it to the supplier for analysis, if they don't have the wheel back there is no way they can determine the cause of fracture

I have heard previously of some RMD wheels having this issue, but we've only ever sold the "D" shaped wheel & I've never been made aware of any breakages on this type as opposed to the many other styles RMD sell.

The thing I find strange is that the wheel should not normally be stressed in the plane that would cause a fracture to a spoke. If you think about the normal direction of forces on a steering wheel it is a torque around the circumference of the wheel - why would there be any significant force pushing or pulling the wheel in a forward/aft motion? I can see that possibly on a race car the wheel might be "manhandled" somewhat roughly fore/aft, but then on a race car I would personally be carrying out a frequent & thorough inspection of all steering components.

I have a detailed university analysis of the "normal" forces applied to the steering which we had done to assess the steering column on the Furore for IVA, it only ever speaks of torque qround the column, never about fore/aft forces

It would seem to me that if one were using the wheel as a "grab handle" to pull yourself out of the seat to get in & out of the car for instance, that would not be within the normal remit of a steering wheel - do you use the steering wheel of a tintop to do this? I certainly don't, surely to fracture a spoke (I'm assuming this is a stress fracture) there has to be a significant force pushing the wheel back & forth, which on any alloy based wheel would sooner or later lead to a fracture.

If anyone thinks I'm being daft here please point me in the right direction? I would say it would be impossible to fracture a spoke with a torque applied around the centre even if you're a body builder & you jam the steering against the lock stops, however work it back & forth in a forward/backward motion for long enough & a fracture is almost inevitable, irrelevant of the manufacturer of the wheel ................

Relph - 25/6/15 at 10:49 PM

Hi russbost, I understand what your saying but they seem to fracture down a score line that is made when the suede is cut. If the manufacturer was a little more carefull when trimming the wheel I don't think we would be having this problem.

alex1991 - 25/6/15 at 10:50 PM

I've always used my steeribg wheel to help me out of tin top cars when I had bucket seats.
I bought an RMD about 2 months ago, it's going to have to do for a bit although it feels pretty strong. I was just hoping it was an early batch of wheels that snapped.

Ben_Copeland - 26/6/15 at 04:05 AM

Rally design (RMD) are fairly well known around here for having everything made cheap in China with (some say) inferior steel/alloy.

I have a RMD D steering wheel and the yellow centre line isn't even in the centre!!

The fuel caps they sell, the mounted holes aren't drilled inline with the cap latch so they look odd.

The RMD alloys I've heard they fracture as well.

The RMD hydraulic clutch master cylinder I had refitted while still building the car blew it's seals because the steel centre rusted against the alloy outer. Costing me an engine tuning day.

Unfortunately Rally D's official answer is they sell thousands of these things to racers and never heard of any issues. Which is bollox !

russbost - 26/6/15 at 06:44 AM

quote:
Originally posted by Relph
Hi russbost, I understand what your saying but they seem to fracture down a score line that is made when the suede is cut. If the manufacturer was a little more carefull when trimming the wheel I don't think we would be having this problem.

Yes, I've seen the other thread talking about this & fully understand the issue re a score line - in fore/aft flexing a scoreline would certainly be likely to increase likelihood of a fracture along that line, however it would make virtually no difference in the sideways/torque direction.

I can honestly say we've been selling the RMD "D" shaped wheel for probably at least 5 years now - the above failure is the first I've been told of that we have sold - until a broken wheel has been examined by a metallurgist (which I most certainly am not) you can only speculate with regard to the actual CAUSE of the failure

We don't sell anything else by RMD in our range so can't comment on their quality generally, but I think it is only fair to compare apples with apples rather than low price with high, we use the RMD wheels on our own cars, I've put probably 6 or 7 thro' IVA & they are happy with the quality & we've certainly never had one fail, difficult to say anything else without seeing a failure

Digimon - 26/6/15 at 07:37 AM

I did question this with Rally Design before I brought my 300mm flat bottomed wheel.

They told me that they did have failures in the past because of the metal being to thin ( around 2.5mm - 3mm ) and they had the wheels remade with thicker metal ( around 4.5mm - 5mm ) and they haven't had any reports of failures yet.

It would be interesting if you could measure the thickness of your steering wheel because I might change mine if one of the re designed wheels has failed

coyoteboy - 26/6/15 at 08:02 AM

If you have a score or even if not, thin alloys will tend to fatigue and the occasional mishandling can have big impacts on the fatigue life of a part, as can stress concentrators. To assume a steering wheel sees only torsion about the centre axis is a vast over simplification and sounds like the sort of mistakes a formula student team would make in a first year entry - was it an fsae paper/report?

Lots of people use the wheel as a grab handle. As a designer I'd say you would have to be somewhat naive to ignore that use. But plenty of products are on the light side because consumers demand it -.doesn't mean they're bad.

You have to remember people hold on to a wheel when accelerating and under hard breaking they will use it to resist forward lunge too. This sort of cyclic loading is precisely what would cause failure like this. There are also questions in the past about whether the metal is heat treated properly.

[Edited on 26/6/15 by coyoteboy]

907 - 26/6/15 at 08:22 AM

^^^^^
+1

I push my car out of the garage rather than fill it with fumes.
I have one hand Pulling on the roll bar while the other hand is pushing on the steering wheel. (Momo Race)

I often run over my foot though.

Paul G

jeffw - 26/6/15 at 08:28 AM

quote:
Originally posted by 907

I often run over my foot though.

Paul G

made me smile....been there done that

907 - 26/6/15 at 10:20 AM

quote:
Originally posted by jeffw

quote:
Originally posted by 907

I often run over my foot though.

Paul G

made me smile....been there done that

When I did the corner weights I made sure that wheel was the lightest.

RickRick - 26/6/15 at 10:25 AM

If you have paddle shifts fitted like me each gear shift is pulling the paddle and the wheel together not a huge load but repeated many times

Grimsdale - 26/6/15 at 11:14 AM

quote:
Originally posted by russbost
I can honestly say we've been selling the RMD "D" shaped wheel for probably at least 5 years now - the above failure is the first I've been told of that we have sold - until a broken wheel has been examined by a metallurgist (which I most certainly am not) you can only speculate with regard to the actual CAUSE of the failure

I'm a metallurgist specialising in failure analysis, so if I can be of any help, let me know. I've had a very brief look at an intact rmd steering wheel, and it was very soft (~40HV). I'd be amazed if the failure was anything other than fatigue due to insufficient strength.

Andy

MikeRJ - 26/6/15 at 11:39 AM

quote:
Originally posted by russbost
If anyone thinks I'm being daft here please point me in the right direction? I would say it would be impossible to fracture a spoke with a torque applied around the centre even if you're a body builder & you jam the steering against the lock stops, however work it back & forth in a forward/backward motion for long enough & a fracture is almost inevitable, irrelevant of the manufacturer of the wheel ................

How many other manufactures wheels ( e.g. Momo, Mountney etc) have been reported as having failed on here or on the RH forums? If a score has been made in the metal where the suede covering is trimmed, a fatigue failure has pretty much been manufactured into the wheel.

Davey D - 26/6/15 at 01:56 PM

Here are some pics of the steering wheel showing where it has gone

BangedupTiger - 26/6/15 at 02:10 PM

Sam_68 - 26/6/15 at 02:12 PM

I'm NOT a metallurgist, so Grimsdale may tell me I'm talking absolute nonsense, but since it's fractured at a score-line for the suede covering, is it possible that it's suffered a fatigue failure, starting from the stress raiser of the score line, because the mass of the rim was vibrating at high frequency (possibly hitting a critical frequency)?

Digimon - 26/6/15 at 02:47 PM

Do you have any vernier calipers to measure thickness of the material?

I'd really like to know because I will be binning mine for a Momo replacement if the new wheels are also faulty

[Edited on 26/6/15 by Digimon]

40inches - 26/6/15 at 03:14 PM

Just checked mine. Purchased from Rally Design at Stoneleigh 2014 (Show Offer).
All three spokes are scored on both sides, but they are 5mm thick
Still not sure what to do .

Davey D - 26/6/15 at 03:28 PM

Just checked and mine is 4mm thick

Digimon - 26/6/15 at 03:33 PM

That maybe one of the old batch only being 4mm

leon51274 - 26/6/15 at 03:38 PM

Just checked mine and its 4mm

alex1991 - 26/6/15 at 04:00 PM

Just measured mine with vernier calipers and it's 5mm thick.

BangedupTiger - 26/6/15 at 04:37 PM

If it's going to snap at 4mm, it'll snap at 5mm. Thickness isn't the important factor. Just chuck the pieces of poo in the bin.