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Author Topic: why H rated tires on bikes over 70mph?  (Read 9263 times)
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jaguarsurfer
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« on: July 30, 2010, 01:38:51 PM »

im looking to build a small 125cc bike to run in a few 4 stroke classes.
im having a very hard time finding H rated tires that will work on the smaller rims IE 1.40 or 1.85.
i dont really want to run a 90/90 front and 100/90 rear on a bike so small.

what i really would like to do is run BT39ss tires like on the honda dream 50R.
but they are s or p rated.

i plan to run in the 80-90mph range.

i understand that ratings on tires are important and i would not want to ever try to run a H rated tire at 175mph but im talking about running 115mph rated tires at 90....

is there someone to appeal to and plead my case or is it just the way it is and i need to work around it?
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nrhs sales
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« Reply #1 on: July 30, 2010, 03:36:23 PM »

H rated tires are only good for up to 130 mph so they are definately what you should be using if you expect to go 115 mph. Not sure where you got your 175 mph figure from but that is not an H rated tire.  175 mph requires either a Z or W rated tire.
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tomsmith
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« Reply #2 on: July 30, 2010, 04:01:26 PM »

I have looked a lot of places for small displacement tires (and rims) for my 1950 Harley Hummer 125cc.  I hope that this information will help you.  I like the 2.25x18 Heidenau M3 (H-rated racing) along with 1.60"x18 non-valenced rims.  I thought that the BT39ss tires were legal off road racing tires (therefore legal).  You might want to contact them yourself for more info.  Here is my e-mail reply from Bridgestone:
-------------------------------------

Hi Tom,
You can get this tire from any Honda shop, the Honda part number is 42711-NX1-003. 
You can also order it from our race tire distributor - Performance Tire Service Company - phone 800-828-9143, ask for the motorcycle department.

Regards,
Kevin Hunley

Customer Service/PDIC Manager
Motorcycle/Kart Products
US & Canada Consumer Tire Sales Division
Bridgestone Americas Tire Operations
535 Marriott Drive
Nashville, TN  37214
Phone (615) 937-3334
Fax (615) 937-3431
-------------------------------------
Also, you CAN get H-rated race tires in the US.  Here is my e-mail:

Hello,   I have the 2.25-18 here, No K55 and the street version of the K56. will that work?  John B
Come check m out at http://www.moto-amore.com/
and www.heidenauusa.com

Date: Sat, 1 May 2010 11:17:08 -0700
From: tomsmith18@verizon.net
To: motoamore@hotmail.com
Subject: Heidenau tires (racing)

------------------------------------------
Matching rims are available from:
http://www.discovolantemoto.co.uk/wheels/morad-non-valanced-rims/prod_143.html
------------------------------------------
Another source for other Heidenau tires and rims are here:
http://www.emot.nl/webwinkel/index.php?act=viewCat&catId=47
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tomsmith
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« Reply #3 on: July 30, 2010, 05:40:21 PM »

Addendum:  I forgot to mention that the Heidenau 2.25x18 M3 tire comes in non-racing (NOT H-rated) and a racing version (H-rated).  Be sure to get the right one.  The tread pattern is 70-ish but don't fear - it works, although I'd trim the tread down some to reduce centrifugal forces a bit.  Note that they recommend a 1.60 or maybe a 1.85 rim.  I originally thought that was too wide, but they spec 1.60 minimum.
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jaguarsurfer
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« Reply #4 on: July 31, 2010, 12:06:05 PM »

H rated tires are only good for up to 130 mph so they are definately what you should be using if you expect to go 115 mph. Not sure where you got your 175 mph figure from but that is not an H rated tire.  175 mph requires either a Z or W rated tire.
Yes I understand about the ratings.  That's what I mention.
I just don't think I need 130mph tires to run under 100mph

I will look into those tires.  Thanks so much for the help

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jaguarsurfer
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« Reply #5 on: August 02, 2010, 11:15:19 AM »

they make a 17 inch race tire too?
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Peter Jack
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« Reply #6 on: August 02, 2010, 11:47:09 AM »

The tire requirement isn't based on what you think you can run. The requirement is based on the record in each class. If you bump the class record above the rating for the required tire you'll also bump the tire rating requirement for every vehicle in that class.

Pete
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LSR Mike
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« Reply #7 on: August 02, 2010, 12:23:48 PM »

Guys,

something to ponder, Cars get 150MPH on H rated Tires in the SCTA and 175 in the ECTA. why only 130 in Bike Classes? different construction?
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Mike M.
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ECTA Record Holder/Former Bonneville Record Holder
jaguarsurfer
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« Reply #8 on: August 02, 2010, 02:52:33 PM »

The tire requirement isn't based on what you think you can run. The requirement is based on the record in each class. If you bump the class record above the rating for the required tire you'll also bump the tire rating requirement for every vehicle in that class.

Pete

im sorry im new but i dont really understand what you mean.
the record in any of the classes that im looking to run in is under 70mph.  maybe one or two are in the under 80mph range.
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fredvance
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« Reply #9 on: August 02, 2010, 03:40:15 PM »

There is only one 125cc record under 70mph p-pp
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Peter Jack
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« Reply #10 on: August 02, 2010, 04:20:17 PM »

Fred, it looks like you and I both got caught out by not checking the top of the page. This is an ECTA post. huh huh huh

Pete
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fredvance
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« Reply #11 on: August 02, 2010, 04:30:25 PM »

OOPs, I hate it when that happens!! rolleyes
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WORLDS FASTEST PRODUCTION MOTORCYCLE 213.470
Vance&Forstall Racing
WOS 2011 235+MPH
Engine by Knecum, Tuned by Johnny Cheese.
Sponsers Catalyst Composites, Johnny Cheese Perf, Knecum Racing Engines, Murray Headers, Carpenter Racing
jaguarsurfer
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« Reply #12 on: August 02, 2010, 04:44:27 PM »

Yeah I was just going to check my rule book for the 2009 records in the small cc classes.
Also I'm looking to run in the four stroke class too.

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relaxedphit
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« Reply #13 on: August 02, 2010, 07:48:49 PM »

Is your bike a 2 stroke or 4? While we can run up in displacement, fuel w/ a gas bike, blown if NA, modified or MPS with a production bike (yeah I know, right coast only), I don't think one can cross enter 2/4 (only ECTA recognizes that distinction). Good luck with your project. I can't find anything over V rated tires for a 19" 90/100; but I probably couldn't afford them anyway.
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jaguarsurfer
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« Reply #14 on: August 02, 2010, 11:25:25 PM »

I am a four stroke and only plan to run in four stroke classes

I'm having a hell of a time finding H rated tires that will fit either a 1.60/1.85 x 18
Or
1.40x 17
Wheels
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