BST wheels?

[Teddy]

Not to mention they managed to get well under the minimum weight very easily, which isn't much help if you have to strap some lard on somewhere else.

If you want to see a return of carbon and similar exotics on larger components in racing, then ask the racing bodies to reduce the minimum weights.

Kinda picking your post apart here, not intentionally, but with regards to this statement above....

You are much better off reducing the unsprung, rotating mass on a bike and adding weight to the lower part of the chassis to meet min weight requirements than you are keeping the weight in the wheels/rotors/calipers/lower fork legs etc... 360lbs on one bike is not necessarily 360lbs on another bike if the weight is distributed differently. When it comes to handling, braking and suspension reaction, reducing your unsprung weight is one of the best moves you can make

All of that being said, I do not have any facts why MGP teams are not using the CF products, most likely a modified compilation of the reason that have been speculated here. I do think that CF wheels have a bad rep mostly based on the assumptions that people make without ever having any first hand experience with them. I think this thread proves that. All a person has to do is hold a CF fairing in their hand and associate what that feels like with having a set of wheels made from the "same" material and people start assuming that a CF wheel will desitigrate if something hits it......it is just not true

 

[KaTooM616]

I have had BST wheels on my 04 ZX10R for some time now. Lots of trackdays, some street, some strip. They really make a difference on high speed handling.

The rear was damaged by a tire machine bead breaker incident. There was a nice little 1" crack on the edge. The shop would NOT take responsibility. I e-mailed BST and disclosed what had happend. They told me to send it in for evaluation. I got an e-mail back saying it was fixed no charge. When I got it back it looked brand new and I could not even find the repaired area. They even sent it back with a shipment of new wheels to save on shipping.

Great customer service!

 

[2nsane]

For Petes Sake would you either buy the 08 or get the damn wheels and stop Flip Flopping? Your like a Woman that has Bi-Polar

 

[jrace]

The fastest motorcyclists in the world, whose class rules allow for carbon wheels, still don't use them. Not in MotoGP, WSBK, BSB, AMA SBK, you name it.

This sounded like puffery, so I took 20 minutes to look it up.

MotoGP = CF OK (actually, zero mention of wheel material in the rules)
WSBK - Alloy Only (unless OEM fitted sec. 2.4.6.5)
AMA SBK = Alloy Only (sec. 2.14)
BSB = Alloy Only (Unless OEM fitted sec. 5.3.2.6.5)

I didn't provide links intentionally, so if someone intends to refute it they get to look it up too and prove me wrong. But at least I provided the section numbers...

::speculative bullshit ends::

-jim

 

[RobP]

AMA, WSBK and presumably BSB do not allow CF wheels for the same reason they do not allow Carbon brakes; to manage costs and allow the non-factory teams to compete. It is a cost containment measure and nothing more.

Carbon Fiber has both a higher ultimate strength and higher stiffness than magnesium alloys and aluminum alloys. This means wheels of equivalent dimensions will be stronger and stiffer if they are made from CF. The arguement that metal wheels bend and CF wheels don't is naive at best. A bent wheel is failure which can result in a catastrophic crash. A Mg and Al wheel will fail while the CF rim will still be usable.

CF truck wheel:

 

[jrace]

The arguement that metal wheels bend and CF wheels don't is naive at best. A bent wheel is failure which can result in a catastrophic crash. A Mg and Al wheel will fail while the CF rim will still be usable.

Metal wheels will bend under some circumstances yet still retain air. Under those same conditions, a CF wheel will flex (as in BEND) but will return to it's designed shape very quickly and close to spec and still retain air.

Most major incidents that will destroy (as in break) an alloy wheel will also destroy a CF wheel. They aren't invincible.

Saying the exclusion of CF wheels in WSBK is a cost-cutting measure is "naive at best" given the other allowances in the rules. Try reading them lately?

Maybe in AMA SBK or BSB, but blanket statements don't cut mustard. Cite?

-jim

(who has CF experience as a fabricator, so there. )

 

[RobP]

Metal wheels will bend under some circumstances yet still retain air. Under those same conditions, a CF wheel will flex (as in BEND) but will return to it's designed shape very quickly and close to spec and still retain air.

Most major incidents that will destroy (as in break) an alloy wheel will also destroy a CF wheel. They aren't invincible.

Saying the exclusion of CF wheels in WSBK is a cost-cutting measure is "naive at best" given the other allowances in the rules. Try reading them lately?

Maybe in AMA SBK or BSB, but blanket statements don't cut mustard. Cite?

-jim

(who has CF experience as a fabricator, so there. )

Jim lets take things one by one. First you are talking about two seperate material properties. Bending (more appropriately called yielding) is when the materials has a permanent change in its dimensions, plastic deformation. "Bending" as you have described in regards to the CF wheel is actually not bending but a function of its stiffness (think of a spring). These are two very different material properties. Parts fail because the stresses in the part exceed the material stresses. The ultimate strength (maximum stress) of carbon fiber is higher than Mg and Al alloys so they can handle higher stresses than the Al and Mg counterparts. CF will fail but at higher loads than Al or Mg. To put it a different way CFRP has a higher specific strength (you can look it up).
I stand by what I said about the rules.

~Rob

(who has a degree in Materials Science as well as Mechanical Engineering, so there. )



Anyway, that's all I'll say on the matter. I won't get into a pissing contest about who knows what since the internet is full of experts.

 

[BIG186]

 

[jrace]

JAnyway, that's all I'll say on the matter. I won't get into a pissing contest about who knows what since the internet is full of experts.

Well my uncles brother on my Dads side is an engineer too and he says....

You're right. Next!

-jim

 

[RobP]

I think you are premature with the popcorn

 

[SM610]

2 seasons ago a BST carbon wheel came apart on a racers duc and caused a pretty big crash. i personally would get a metal wheel. PVM makes a couple models that weigh a little more than the carbon, but have a lower MoI and thats what really counts. not to mention you can't straighten the carbon wheels. having bent several DOT legal stock wheels i can't imagine having to replace a carbon wheel instead of having it straightened.

My guess is that the wheel was mistreated. Tire warmers(that are too warm) and certain chemicals(brake cleaners etc) can cause the wheels to delaminate(thats why I would never buy a used one).

Both of those issues are adressed in the documents that come with the wheel(which is serial #'d).


acct hijack by 07chuck...

 

[aciurczak]

This sounded like puffery, so I took 20 minutes to look it up.

MotoGP = CF OK (actually, zero mention of wheel material in the rules)
WSBK - Alloy Only (unless OEM fitted sec. 2.4.6.5)
AMA SBK = Alloy Only (sec. 2.14)
BSB = Alloy Only (Unless OEM fitted sec. 5.3.2.6.5)

I've been accused of many things, but it's been awhile since puffery was one of them. I kinda like that label. Sorry to send you on a wild goose chase; I could have sworn I read about Proton using CF wheels for awhile in WSBK, so either the rules have changed over time or my memory isn't what it used to be.

But nevertheless, MotoGP has the most expensive, fastest, most inventive, and most heavily tested 2-wheel machines on the planet, and machines in that class set the track records at every location they visit. CF wheels are legal in that class. If CF wheels would reliably provide even a 0.1 second advantage in qualifying, they'd be on the bikes. Since they aren't, it stands to reason that racing minds a heck of alot smarter than all of us blabbering away on the internet have determined that as of right now, CF rims simply do not provide superior performance to the alloys that they currently use. Can there really be any other explanation?

 

[jrace]

I've been accused of many things, but it's been awhile since puffery was one of them. I kinda like that label. Sorry to send you on a wild goose chase...

Wild goose chase implies you find no fowl. I found foul.

-jim

 

[gixxerboy55]

Aciurczak don't assume anything, there is probaly a lot of reasons motogp does not use cf rims, like people have stated safety, or cleaning up the track after a crash. Sometimes change takes time as for performance ask anybody who has a set of bst wheels and they will tell you they perform very well.

 

[aciurczak]

ask anybody who has a set of bst wheels and they will tell you they perform very well.

Laptimes are a heck of lot more reliable than an individual's butt dyno. Otherwise we could determine a race winner by rounding the riders up afterwards and asking them who felt they went the fastest.

The only assumption I'm making is that those whose very livelihood depends on getting those track record laptimes week after week, and who also happen to have virtually unlimited budgets when it comes to choosing parts and materials for their bike, have chosen not to. I wouldn't even hazard a guess as to why they've chosen this, but it's still pretty telling information, wouldn't you say?

Sometimes change takes time

It sure does, but it doesn't happen faster anywhere on the planet than MotoGP. If they are off by a few tenths, they have new engines and new frame designs every month, sometimes even weekly. If that statement was meant to imply that trackday riders and club racers are ahead of the curve by choosing CF and MotoGP will catch up in time, I'm reasonably skeptical.

Wild goose chase implies you find no fowl. I found foul.

There was some tasty fowl around the edges with some of the supporting data, but the main premise remains foul-free, as far as I can tell.

 

[2nsane]

Random monkey
Random Thread

 

[Joebar4000]

Kinda picking your post apart here, not intentionally, but with regards to this statement above....

You are much better off reducing the unsprung, rotating mass on a bike and adding weight to the lower part of the chassis to meet min weight requirements than you are keeping the weight in the wheels/rotors/calipers/lower fork legs etc... 360lbs on one bike is not necessarily 360lbs on another bike if the weight is distributed differently. When it comes to handling, braking and suspension reaction, reducing your unsprung weight is one of the best moves you can make

All of that being said, I do not have any facts why MGP teams are not using the CF products, most likely a modified compilation of the reason that have been speculated here. I do think that CF wheels have a bad rep mostly based on the assumptions that people make without ever having any first hand experience with them. I think this thread proves that. All a person has to do is hold a CF fairing in their hand and associate what that feels like with having a set of wheels made from the "same" material and people start assuming that a CF wheel will desitigrate if something hits it......it is just not true

Well, this is my rusty memory we're dealing with, but I seem to recall this was back in the day when they were having major issues with stability, running stupid rake numbers and then slapping a hooge steering damper on to accomodate.

So, why they're not using them now, I have no idea? Cost can't possibly be the reason, nor can lack of strength. If they are so light that they lose too much gyroscopic effect, it's pretty damn easy to add weight. Can't believe strength isn't the reason either - weight for weight, CF wheels are far stronger.

Dunlops famous wheel failure at the IOM was a mag wheel, I seem to recall. Mag wheels are hardly durable either...

For the street, you might consider them overkill. But after riding Terry's bike, I wouldn't care if they really dropped my lap times, they just made the bike AMAZINGLY easy to change lines. Felt like a mountain bike with an engine in it.

 

[elskipador]

a CF wheel will flex (as in BEND) but will return to it's designed shape very quickly and close to spec and still retain air.

the bent ones i've seen did not return to shape. both were fronts that had taken a crash, one was r. kennedy's, IIRC, anyway after the crash he brounght the rim in to have the tire stripped off and inspect the rim. when we spun it on the trueing stand you could see a noticable "hop" in the wheel. and i highly doubt BST would ship out a wheel with that much run out. he took it over to gerry of gp frame and wheel...who said he couldn't straighten it. so we put a tire back on it and he continued to ride it. not sure if gerry meant he couldn't straighten it @ the track or that it couldn't be straightened @ all. i'll have to call him and see.

 

[insider]

My guess is that the wheel was mistreated. Tire warmers(that are too warm) and certain chemicals(brake cleaners etc) can cause the wheels to delaminate(thats why I would never buy a used one).

Both of those issues are adressed in the documents that come with the wheel(which is serial #'d).


acct hijack by 07chuck...

Not sure if this has been posted already. Here's the letter from BST post analysis in regards to that incident at Thunderhill. (and some other incident not specifically mentioned.)



Well it has been some time in the making, but the tests on the broken Ducati wheel from Thunderhill are finally out.



The most important thing to come out of all of this is that “The breakage surface of the rim also appeared to have broken as a result of force and not of structural fatigue failure” and “The wheel had been built to specification in terms of the construction” and “It is our considered opinion that the cause of failure cannot be ascribed to materials and construction of the wheel”.



I attach here a copy of the final report from the Centre for Polymer Technology (www.cpttech.co.za ) which specializes in failure analysis, product development and testing of polymers and is part of the Tshwane University of Technology located in Pretoria. They conducted all tests and produced the report.



The purpose of the tests was to discover if the wheel was correctly made (built to specification) and if the materials and construction were correct.



The analysis included: discussions with authorities in carbon composite manufacture, differential scanning calorimetry, thermogravimetric analysis, infra red spectroscopy, burn-off tests, dynamic mechanical thermal analysis and electron microscopy.



We were always confident that the wheel broke on impact, and this report proves that the materials and construction were 100% according to specification. How the impact occurred was beyond the scope of the exercise, obviously, since the testing centre only had access to the wheel.



I trust this will put an end to the speculation. We are finished with the issue, having met our commitments.



Thanks for your support. If you have any queries, please let me know.



Cheers for now,

terry

Terry Annecke

BlackStone Tek (Pty) Ltd

Tel: +27 11 704-0026

Fax: +27 11 704-0031


Incident 2: Wheel deformed by faulty tire warmer (apologies – tire is USA spelling for tyre!)

I have been in contact with everyone involved and am getting a very positive reaction, and BST will be working with Pantera in the USA to provide wheels for their track days at a couple of demo and promotion days (a jolly good idea, I think).

The wheel has been assessed by the Polymer Testing Centre and the findings indicate that the damaged areas of the wheel have seen a 10-15% deterioration of heat resistance after being exposed to too high temperature for too long. It’s difficult to say what temperatures were achieved in order to create this damage, so we did a lot of tests to try and recreate the situation, and found the following:

1. Very often the tire warmers generate much higher temperatures than they state – several sets rated 90 degrees C actually achieved in excess of 130 deg C.

2. BST wheels heat up slowly until they reach saturation temp after 3-5 hours, and that temp was never higher than 60 degrees C. On forged magnesium the sat temp is a couple of degrees lower (52-55 deg C) and is reach quicker (3 hours) because magnesium is a better conductor of heat.

3. Full enclosed tire warmers lead to a higher sat temp - approx 75 deg C for normal tire warmers and 85 deg C for defective warmers. The combination of fully enclosed warmers and defective warmers can lead to damage on a carbon rim.

4. We simulated a defective warmer – the temp exceeded 150 deg C and the wheel got to 105 deg C, saturation time was approx 3 hours, and damage became evident. This was exacerbated by the use of a fully enclosed tire warmer.

5. Without a doubt the tire warmer used by our rider in the US was faulty, and it appears that the wheel saw temperatures in excess of 140 deg C.



If you have existing wheels in stock, as a precaution, please add the following label to the box:

Instructions on the use of tire warmers on BST wheels:

Ensure that the warmers and regulators are operating correctly
Do not use enclosed tire warmers (side covers that blanket the entire wheel)
BST wheels are designed to operate at up to 80 degrees Celsius (180 degrees F)


There is a margin of safety already built in at 80 degrees C.



Thanks a lot and please call if you have any queries,

terry







Terry Annecke

BlackStone Tek (Pty) Ltd

Tel: +27 11 704-0026

Fax: +27 11 704-0031

www.blackstonetek.com

 

[Hooli]

You can't use side-curtain warmers on BST's?

That's weaksauce.