M/C Safety reqs

Moderator: DLRA

User avatar
AuotonomousRX
Posts: 621
Joined: Wed Jan 06, 2010 10:05 pm
Location: Eyre Peninsula SA

Re: M/C Safety reqs

Post by AuotonomousRX » Sat Nov 24, 2012 8:45 pm

The SCTA Rules currently have that section you must be referring to Greg

200MPH +
In excess of 200mph special tires for racing
as designated by the manufacturer must be used.

So do we need to make sure this is not put into the Rules in the future?

I think the Fashion Accessory Hump reference is about off the shelf Road Leathers,
If you look at the size of the Moto GP humps they are a fair bit bigger than retail Leathers.
I found that Safety article because I have heard that they were there as a Safety Enhancement,
and from that article they are not.

Pete
#866
Metric Target 250 on a 250 on a Red Bike

Pete :shock:
DLRA #866
SATA #49

rgn

Re: M/C Safety reqs

Post by rgn » Sat Nov 24, 2012 9:07 pm

AuotonomousRX wrote: 200MPH +
In excess of 200mph special tires for racing
as designated by the manufacturer must be used.
#866
I was looking at this and wondered if 'manufacturer' refers to the manufacturer tyre or bike? Cheers.

User avatar
Greg Watters
Posts: 749
Joined: Mon Sep 27, 2004 8:57 pm

Re: M/C Safety reqs

Post by Greg Watters » Sun Nov 25, 2012 12:51 am

Thats it Pete



i think most of the accepted tires have race written somewhere on the sidewall

David Leikvold
Posts: 955
Joined: Mon Apr 16, 2007 11:57 pm
Location: Brisbane

Re: M/C Safety reqs

Post by David Leikvold » Sat Dec 01, 2012 1:23 pm

This might be some useful progress from Goodyear and Sam. Be sure to watch both videos.

http://m.motorcycle-usa.com/499/14057/M ... 20mph.aspx

Cheers
Dave
Good, Fast, Cheap, pick any two!

rgn

Re: M/C Safety reqs

Post by rgn » Mon Dec 24, 2012 1:13 am

Greg Watters wrote:and another
Image
I did this to a tire every run and from what i can figure out its cold tearing
I can't get this out of my head. Do you think it is possible that the places that the tread is missing corresponds to the ignition-combustion cycle of the engine? 12500 rpm (or whatever) @ 256 mph ... with how much boost banging into the equation? How far apart would each combustion pulse present at the tyre? perhaps if your gearing didn't spread the pulses (and you ended up with a hot-pulse spot) you will shred? Cheers.

PS: I know that you have shown a photo of a disintegrating front tyre, but I think that is a simple case of tread de-laminating from the carcass.

Stayt`ie
Posts: 889
Joined: Fri May 13, 2005 11:47 pm
Location: Mackay

Re: M/C Safety reqs

Post by Stayt`ie » Mon Dec 24, 2012 10:08 am

interesting observation rgn,, i agree with the frount tyre delaminating,, however i question the rear tyre scenario,, have a look at my tyre (earlier post) compared with Gregs, my gearing at that time was at a "much" lower ratio than what Greg was running,, you notice that my blisters a closser together, with the lower ratio gearing thay should be further apart than Gregs blisters,, :) ,, the blisters seem to always appear at the leading edge of a groove, and in most cases are circumentrical(spelling :lol: ) around the tyre,,, :)
First Australian to ride a motorcycle over 200mph at Bonneville,,,

User avatar
gennyshovel
Posts: 819
Joined: Tue Mar 29, 2005 10:10 am
Location: Broken Hill

Re: M/C Safety reqs

Post by gennyshovel » Mon Dec 24, 2012 10:31 am

Screen shot of Greg's tyre chunks

Image

The key tag has a hissyfit during the chunking as the wheel balance goes haywire too, which would have instigated an automatic Freckle response.
Tiny
Tiny DLRA# 484
Postiebike Racing , created & funded by TwoBob Engineering

User avatar
AuotonomousRX
Posts: 621
Joined: Wed Jan 06, 2010 10:05 pm
Location: Eyre Peninsula SA

Re: M/C Safety reqs

Post by AuotonomousRX » Mon Dec 24, 2012 11:13 am

Just thinking out loud, but there is clearly two things going on here, Chunking (rear tyres on Greg and Ron's Bikes) meaning the tread's being torn off and De-laminating the thing that happened to Greg's front tyre.

The confusing thing is that some Bike/tyre combinations get Chunking or some De-lamination and some don't. :?

Like rgn said there might be some suspension/tyre to ground contact thing happening with the rear tyres.

Also, all Hi Performance/Race Tyres, as far as I know, have an optimum operating Temp and just don't do what they are meant to do if they are not at that Temp.

Could the cold tyres + the extreme centrifugal forces be having unexpected consequences.

Is it worth experimenting with Suspension settings as well as Tyre warmers? :wink:

Or is it that the Tyres available have reached the edge of "Safe Operating" range? :(

Pete
Metric Target 250 on a 250 on a Red Bike

Pete :shock:
DLRA #866
SATA #49

rgn

Re: M/C Safety reqs

Post by rgn » Mon Dec 24, 2012 2:57 pm

Stayt`ie wrote:.my gearing at that time was at a "much" lower ratio than what Greg was running,, you notice that my blisters a closser together, .
I saw your tyre as well! Not something you would want to see at all (from a safety and cost point of view)

I would have thought that lower gearing would have the combustion pulses occurring closer together as shown with your tyre. Greg's longer legs put them further apart (strides are larger)... (if this is what is causing the blistering)

Just say the tyres that are blistering are geared on a on a even pulse cycle, meaning the combustion pulse occurs at the same point of the tyre on every revolution... and the tyres that are not coming apart, are inadvertently geared odd, meaning the pulse occurs at a different point on the tyre each time the wheel goes around, and thus sharing the hot spots around the tyre, and as a result not experiencing the extreme localised stress?

It's only a thought, and I also agree it may be chatter or wheel spin occurring also, or a combination (or not related at all...lol). I clearly don't have a clue, but the occurrence of this type of tyre damage is quite interesting.... and concerning.

Are you allowed to run 'for race use only' slicks on your bikes for over 200mph runs, or do they have to be a treaded tyre? I'm having a bit of trouble interpreting the tyre section of the the rules. Have a safe Christmas break. Cheers

Stayt`ie
Posts: 889
Joined: Fri May 13, 2005 11:47 pm
Location: Mackay

Re: M/C Safety reqs

Post by Stayt`ie » Mon Dec 24, 2012 3:10 pm

rgn, to try and avoid the lower gear/higher gear confusion (people do inturept different), i said "lower ratio", ie 2.0 : 1, say over a higher at 2.98 : 1,,, with the lower ratios the bang at motor per rear wheel revolution is lessened, or, also described as less power strokes between telegraph poles,, or longer strides,, :)
First Australian to ride a motorcycle over 200mph at Bonneville,,,

Mossy
Posts: 187
Joined: Thu Jun 24, 2010 4:57 pm
Location: Pt Augusta

Re: M/C Safety reqs

Post by Mossy » Wed Dec 26, 2012 2:58 pm

Stayt'ie
2.0:1 is a `high' gear ratio compared to 3.0:1 which is a `lower' ratio. The reasoning being that at 3,000rpm your back wheel is turning 1,500 times at 2.0:1, where'as a 3.0:1 ratio would require the motor to spin at 4,500 rpm to achieve the same 1,500 rpm wheel rotation. So lets say you bike run at 50 mph at 3,000 rpm with a 2.0:1 ratio. At 3.0:1 your bike would require 4,500 rpm to do the same 50mph. This makes 3.0:1 a lower gear than 2.0:1
Cheers Mossy
PS, I've had a few wines so I hope this makes sense :-)
DLRA # 959

momec3
Posts: 714
Joined: Tue Mar 01, 2011 10:36 pm
Location: Cedar Grove Qld

Re: M/C Safety reqs

Post by momec3 » Wed Dec 26, 2012 9:43 pm

Sorry Mossy,

I agree with own Northern Brother.
2.00:1 is a lower numerical ratio than 3.00:1
Lower means smaller number final drive ratio.

Chris
Chris

User avatar
Greg Watters
Posts: 749
Joined: Mon Sep 27, 2004 8:57 pm

Re: M/C Safety reqs

Post by Greg Watters » Thu Dec 27, 2012 7:44 am

guess i'm ass about too
to me low has always been slow and hi fast

Mossy
Posts: 187
Joined: Thu Jun 24, 2010 4:57 pm
Location: Pt Augusta

Re: M/C Safety reqs

Post by Mossy » Thu Dec 27, 2012 1:52 pm

Sorry Momec but your wrong as well :) My 4wd goes a lot faster in high range top (transfer box ratio of 1.22:1) than it does in low range top (3.32:1 transfer box ratio). :)

Cheers Mossy
DLRA # 959

momec3
Posts: 714
Joined: Tue Mar 01, 2011 10:36 pm
Location: Cedar Grove Qld

Re: M/C Safety reqs

Post by momec3 » Fri Dec 28, 2012 10:09 am

Well Mossy, looks like I'm outvoted, very hard to reprogram my old brain so I'll just agree to disagee. :)

Chris
Chris

Post Reply