Alternative tyre profile height

[Fullers1845]

I need a new front tyre on my Zx6r J1, the trouble is that the specific tyre for that year is 120/65 R17, and the 65 profile means there’s very little choice about, in particular there are no sports touring tyres, and all I’m finding are a couple of ‘super sports’ tyres, I’m not at all a fast rider so moving to a 70 profile would bring a good choice of sports touring models.
Is it sensible to run a 70 instead?

[Nobby the Bastard]

The tyre is described as W/H R

W =width of the tyre in mm
H = the percentageof the height of the tyre (not the wheel!) Compared to the width W
R = The radius of the wheel.


It's up to you to decide if a 5% change in the profile will make a difference.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Fullers1845]

[Nobby the Bastard]

6mm either way. Forgot to say R is inches.

Tyre sizes are the best example of how to make things complicated.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Easy-X]

[jeffyjeff]

Clearance between the tyre and front fender will be reduced if you mount the 120/70 R17. Also, if your speedometer is driven off the front wheel, it will read slower with the higher profile tyre and your odometer reading will be affected as well (probably insignificant).
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History shows again and again how nature points out the folly of men - BOC

[Pete.]

2.4% difference in speedo reading so only 1.45mph at 60mph.

It will probably improve the accuracy of he speedo somewhat.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[blurredman]

I wonder if the difference of a brand new tyre vs one worn to the bars has more of a effect on speed displayed and any physical difference felt than such a slight difference of a 65 vs 70 tyre?
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CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S, 1979 MZ TS150.
Current: 1973 MZ ES250/2 - 18k, 1979 Suzuki TS185ER - 10k, 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (295cc) - 40k, 1989 MZ ETZ251 - 51k.

[stinkwheel]

I'd put a 70 section michelin road 5 or 6 on it.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Fullers1845]

OK, looks like I'll go for a change, I've got about 15mm mudguard clearance and the speedo is off a sensor on the final drive.

[MarJay]

The only bike of that era that had a 65 profile was the Yamaha R6 as I recall. I reckon the J1 ZX6 *should* be on a 70 section anyway.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[MCN]

[that_impulse_guy]

same shit happen on pre-haldex mechanical quattros, e.g. b5 series s4/rs4 etc. mismatch in tyre sizes per axle/front+back makes the diffs work overtime, all the time. I had a front tyre blister in the sidewall after a speedbump and opted for 4 new ones.

to mr tyre profile above, dont worry, just fit a 70. its in the splitting hairs category, i.e. doesnt matter in real life.
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Gone: Yamaha DT50lc, Suzuki DR500, Suzuki A100, Kawasaki z250ltd, RD350YPVS, Suzuki DR Big, Kawasaki AR125, Kawasaki KMX200, Suzuki GS1000S, Katana 1100, GS550M, Suzuki RGV250
Now: Suzuki GSX400X, Suzuki RF900R, NS400R

[Kentol750]

Does it affect your insurance if you fit a tyre different in spec to what manufacturer uses? Do kawasaki say its safe to run a 70?
If its Ok and it won't invalidate your insurance then go for it.
If not, Michelin pilot power 2ct.
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Some bikes.