Author Topic: rear tire and ideal wheel tire combo  (Read 6700 times)

rip_brotz420

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rear tire and ideal wheel tire combo
« on: September 12, 2003, 04:55:53 PM »
ok, not being up on the latest in tires for my 83, got a 120 80 18 bridgestone battleaxe, while there at the salvage yard went out and found a wheel off another model,  the tire mounting width was wider than the vision wheel. I took it home with 130 80 on it and still had more room.
the stock vision is 110 90
the new wheel takes 120 80 18  
      question is how wide on the wider wheel can i go  , and  and is this being a bolt on, worth the effort. the tire is all it will cost if i make the swap

Rick G

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Re: rear tire and ideal wheel tire combo
« Reply #1 on: September 12, 2003, 09:04:20 PM »
I'm curious as to what shaft drive Yamaha, the wheel came from . Any idea? Jason, can you comment?
Rick G
Go soothingly on the grease mud, as there in lurks the skid demon
'82.5 Yamaha XZ550 RJ  Vision,
'90 Suzuki VX800, 1990 Suzuki DR350.
'74  XL350   Honda , 77 XL350 Honda, 78 XL350 Honda, '82 XT 200 Yamaha, '67 Yamaha YG1TK, 80cc trail bike

Walt_M.

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Re: rear tire and ideal wheel tire combo
« Reply #2 on: September 13, 2003, 02:15:32 AM »
Me too, and isn't the Bridgetone Battlax a radial? I haven't tried radials yet but I'm pretty sure I'd want them on both ends when (if) I do.
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rip_brotz420

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Re: rear tire and ideal wheel tire combo
« Reply #3 on: September 13, 2003, 05:17:06 PM »
it came off a 650 turbo it looks identicle but has about 1/2 inch wider wheel where the tire mounts and uses drum and its shoes are wider than the vision

Lucky

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Re: rear tire and ideal wheel tire combo
« Reply #4 on: September 13, 2003, 05:28:22 PM »
Then it's a matter of swingarm & fender clearance...
1982/3 XZ550 Touring Vison, Gold on Black

rrip_brotz420

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Re: rear tire and ideal wheel tire combo
« Reply #5 on: September 13, 2003, 06:15:03 PM »
it had a 130  80 on it,was the same height inflated as the stock vision combo when i slipped it in and measured side of wheel to swing arm then noticed over 1/2 inch on the tire side clearance ? now is the extra brake and wheel combo worth buying the tire
metz compk 100 80 18 on the front it does not show whether it is radial anyone know

Rick G

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Re: rear tire and ideal wheel tire combo
« Reply #6 on: September 13, 2003, 09:39:25 PM »
Yes, the wheels on the Seca turbo are very similar to the Vision . I would at least price the brake backing plate and if its not to much  I'd get it . Give us the complete number from the tyre and I'll investigate  .
Rick G
Go soothingly on the grease mud, as there in lurks the skid demon
'82.5 Yamaha XZ550 RJ  Vision,
'90 Suzuki VX800, 1990 Suzuki DR350.
'74  XL350   Honda , 77 XL350 Honda, 78 XL350 Honda, '82 XT 200 Yamaha, '67 Yamaha YG1TK, 80cc trail bike

h2olawyer

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Re: rear tire and ideal wheel tire combo
« Reply #7 on: September 13, 2003, 11:36:40 PM »
The Bridgestone Battlax is available as either a bias ply or radial.  The BT-56 SS Ultra Hi-Performance is a Z speed rated radial.  The BT-45 Sport Tour is a bias ply available in either H or V speed ratings.  You can tell a radial from a bias ply by reading the letters in the size description of the tire.  A radial will always have an "R" designation after the speed rating.  Thus a 110/70 ZR 17 would be a radial with a speed rating of 149+ MPH.  A tire marked 110/70 H 17 would be a bias ply with a speed rating of up to 130 MPH.

Tire basics - Most tires today are measured in the metric formula.  Automotive tires follow the same formula.  Less common are alpha and inch - both are more common on dirt bike tires.

The first number is the height of the tire as measured from the rim to the highest point on the tread.

The second number is the aspect ratio or width compared to height.  (I've forgotten the equation to obtain the ratio - too many years & beers since my days as a tire tech.)  The smaller the number, the wider the tire (a 110/90 is narrower than a 110/80).

The final number - after the speed and carcass type (radial or bias) is the rim size.  

Speed ratings are as follows:
S - up to 112 MPH
H - up to 130 MPH
V - up to 149 MPH
Z - over 149 MPH  :o

I haven't looked too far as yet, but I haven't found a radial in the sizes that would fit a stock rimmed Vision.  Might be a fun search on the various manufacturer's websites.

One other measurement to consider when upsizing the rear tire is the clearance between the center of the tread and the exhaust collector in front of the rear tire.  My 120/90H-18 comes closer than I'd like.  A 130 may be too close - not likely a problem when moving but the heat when parked after a good ride might be very hard on the tire.

Hope this info helps clear up some tire sizing questions.
If you have an accident on a motorcycle, it's always your fault. Tough call, but it has to be that way. You're in the right, and dead -on a bike. The principle is not to have any accident. If you're involved in an an accident, it's because you did not anticipate. Then, by default, you failed.

ArrrGeee

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Re: rear tire and ideal wheel tire combo
« Reply #8 on: September 14, 2003, 05:25:05 AM »
curious,
the specs for the 650 turbo on this page list the wheels as the same in the rear and a 19" wheel on the front.

http://www.xjowners.com/info/secaturb.html


you might want to check out the description of this ebay ad.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=35601&item=2432557572

and possibly this one:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=35601&item=2432557936


-Ron

« Last Edit: September 14, 2003, 05:29:43 AM by Ron_Ghetti »

QBS

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Re: rear tire and ideal wheel tire combo
« Reply #9 on: September 14, 2003, 01:28:39 PM »
h20:  Your observation about 130 clearance between tire center and collector is astute and slightly flawed.  The clearance problem there DOES occure at speed.  Years ago had a brand new 130 something on the back of my '83 when I came up on a gaggle of Ducatis'.  They took off and I decided to see how hard they wanted to play.  Went for top speed and much to my surprise and dismay was only able to see 85mph.  At my next stop I was amazed to see lots of powdered rubber in the swing arm area and small chunks of rubber missing from the highly polished center of my new rear tire.  Diametric expansion due to centrifugel force was the cause.  Due to $ issues, I rode that tire for another year, but never at more than 85mph.  There was also a tolerable contact issue with with driveshaft swing arm.

Bottom line 130s' are over the line.  Cheers.

h2olawyer

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Re: rear tire and ideal wheel tire combo
« Reply #10 on: September 14, 2003, 05:22:58 PM »
I stand corrected.  I forgot about the tendency of centrifugal force to expand tire size.  I still don't like cooking one spot on the tire like that, though.
If you have an accident on a motorcycle, it's always your fault. Tough call, but it has to be that way. You're in the right, and dead -on a bike. The principle is not to have any accident. If you're involved in an an accident, it's because you did not anticipate. Then, by default, you failed.

rrip_brotz420

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Re: rear tire and ideal wheel tire combo
« Reply #11 on: September 14, 2003, 06:40:35 PM »
the 120 80 18 is 3/4 inch from ex, the 130 80  turbo wheel looks to be the same in the 83 frame i am working with,  i have not dismounted the  tires and measured there tire mounting width so if the brake is the only advantage to the swap and not a better tire selection its cons outweigh the advantages so i may take the 120 80 18r battleaxe back and exchange it for something to go with the  nos compk metz  100 80 18 for the front .
    by the wayQBSwhen you changed the tires back what top speed would you run, my 83 will bury the needle to the peg

QBS

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Re: rear tire and ideal wheel tire combo
« Reply #12 on: September 15, 2003, 02:13:30 PM »
rrp: My '83 will hit red line in fifth gear, an indicated 113 mph.  No way you're actually hitting beyond  140 mph.  cheers.

rip_brotz420

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Re: rear tire and ideal wheel tire combo
« Reply #13 on: September 15, 2003, 02:36:05 PM »
my speedo will move past the 140  mark  but usually to busy to notice  but on the flat freeway around here with 90 90 18 cheng shin tire  on the front and dunlop  491 belted mp85hb18 on the back  went on road trip and hit those speeds no sure now how stock the bike is had it for 5 years, and would always turn that speed. I got that top end apart now and will look it over really close.
      Buy the way any one ever figure out the camshaft's # for the years 83

Walt_M.

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Re: rear tire and ideal wheel tire combo
« Reply #14 on: September 15, 2003, 05:10:32 PM »
My '83 would do probably 110+ when it was new. If yours is going 140+, you would be turning around 12,500 rpm in 5th. It would also be making over 90 hp, stock is 67.
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rip_brotz420

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iRe: rear tire and ideal wheel tire combo
« Reply #15 on: September 15, 2003, 06:27:55 PM »
ok, i do not believe my bike was stock because i can hit those #, now I have the machine apart and would like to know if anyone has messed with there cams (stock stuff) And begin to measure this stuff while assembly, maybe find out more of the differances i can show this live but my vision broadcast got me in trouble last time and at those speeds how accurate are these instruments

Brian Moffet

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Re: rear tire and ideal wheel tire combo
« Reply #16 on: September 16, 2003, 08:21:58 AM »
Just as a note (and a bit of physics).  If the bike in question does 140, and the top end of a normal bike is 113, then the needed horsepower is 102+, not 90.  

140/113 = 1.24 (rounded)

since you need the square velocity ratio times the horsepower (takes 4 times the hrosepower to do twice the speed), this means you need 1.54 (rounded) times the horsepower.

Multiplying this by 67 ponies, gets you to better than 102 ponies to get a vision to do 140.

Just a minor tangent on motorcyle top ends.

Brian

Walt_M.

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Re: rear tire and ideal wheel tire combo
« Reply #17 on: September 16, 2003, 12:52:25 PM »
That would be assuming the top speed were horsepower limited instead of rpm limited. I had an '85 FZ750 which had a top end of over 140 and it had about 87 hp. It would hit the rev limiter in top gear pretty hard. I can honestly say that I was not looking at the speedo of tach all that much but I could certainly feel it when it hit the rev limit.
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Brian Moffet

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Re: rear tire and ideal wheel tire combo
« Reply #18 on: September 16, 2003, 02:09:59 PM »
Yes, assuming the bike could rev high enough.  Also, this calculation is for a single Vision, if you were suddenly able to pump in 102+ HP, you might have a chance to do 140, it would probably take more.  This example could logically be expanded to most Visions of the same build (fairing, dual disks, all the draggy bits...)

An FZ750 at 87 HP is a much different beast than a Vision with 87 HP, like comparing apples and oranges actually...  Or maybe Apples and Cumquats, I don't know.

An FZ750 is probably a less draggy bike than the Vision is :-)

Brian

rick_nowak

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Re: rear tire and ideal wheel tire combo
« Reply #19 on: September 16, 2003, 04:20:35 PM »
V Max ??
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