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-   -   Wider rear tyre? (http://forums.sv650.org/showthread.php?t=150971)

bald git 02-05-10 09:11 PM
Wider rear tyre?
 
the standard rear tyre on my sv is 160. there is ample room to take a 170, but would it be ok on the standard rim and be of any benifit at all.

TSM 02-05-10 09:21 PM
Re: is bigger better
 
dont bother

bald git 02-05-10 09:23 PM
Re: is bigger better
 
yeh, that answers the question pretty comprehensively

k31tha 02-05-10 09:25 PM
Re: is bigger better
 
when i bought my bike i came with a 170 on it so i know no diffrence

TSM 02-05-10 09:30 PM
Re: is bigger better
 
non standard size tyre on rim could cause insurance issue, bike is not designed for a 170, it will turn slower
why bother, even bikes of yesteryear that had 190 are nowerdays 180

bald git 02-05-10 09:34 PM
Re: is bigger better
 
Quote:
Originally Posted by TSM (Post 2258772)
non standard size tyre on rim could cause insurance issue, bike is not designed for a 170, it will turn slower
why bother, even bikes of yesteryear that had 190 are nowerdays 180
thats better, thanks

yorkie_chris 02-05-10 09:49 PM
Re: is bigger better
 
Quote:
Originally Posted by bald git (Post 2258745)
there is ample room to take a 170,
no there isn't

carternd 02-05-10 10:02 PM
Re: is bigger better
 
You don't pay any more for a 160 tyre, don't c*ck up your handling and risk invalidating your insurance! A 170 will curve more than it's meant to if crammed on a 160 rim.

bald git 03-05-10 06:01 AM
Re: is bigger better
 
http://www.avon-tyres.co.uk/motorcycle/storm-2-ultra not having a go at any one but check out this chart from avon. 99 sv has rear rim size of 17 x MT 4.5, 160 and 170 both fit this rim.[ 170 will fit rim size 4.25 to 5.5, recomended rim size 4.5 in ],so not crammed, aspect ratio of both tyres have 60, and total height of 6.8 in, so no height of bike increase or decrease. as to width, + 2mm. there is clearance of 20 mm + both sides of my current 160 avon storm at swing arm, 20mm + at torque arm, 15mm clearance at chain. so chris, i believe there is clearance, unless your seeing something i,m not.

BigBaddad 03-05-10 06:39 AM
Re: is bigger better
 
The Height of the profile i.e. in this case 60 is the % of the width. So 60% of 170mm is bigger than 60% of 160.

Fitting 170 tyre in place of a 160 would raise the height further as it is being pinched more.

In theory raising the rear of your bike can make it turn in quicker, but fitting a bigger would add more unsprung weight and increase the rotating mass (which is far greater than static mass), slowing turn in, will also need more energy the brake and accelerate.

In reality, you may not notice any difference. The sv runs well on a 160 so I wouldn't bother. As for your insurance, speak to them and at the least tell them about all the mods on your bike and make sure they put it on your policy schedule.

bald git 03-05-10 06:48 AM
Re: is bigger better
 
to be honest i have decided not to because there will be little gain, but good debate though. in conclusion bigger is not always better !

BigBaddad 03-05-10 07:21 AM
Re: is bigger better
 
You keep telling yourself that :smt046

bald git 03-05-10 07:26 AM
Re: is bigger better
 
hoh blu**dy hoh !

yorkie_chris 03-05-10 09:28 AM
Re: is bigger better
 
Thing is you won't get to the edge of a 160 anyway, Blue650S posted a pic on here of his tyre which was apparently a few 10ths of a second off minitwin lap record pace and there was still a small chicken strip.
170 will pinch more and you will leave even more unused, plus they are likely heavier.

BigBaddad 03-05-10 09:42 AM
Re: is bigger better
 
In that case, how about a 150?

mister c 03-05-10 09:45 AM
Re: is bigger better
 
I tried mine with a 170 & all I can say is that there is a slight difference in cornering, it tends to drop in a bit slower. As already said, I wouldnt bother.

yorkie_chris 03-05-10 09:47 AM
Re: is bigger better
 
Quote:
Originally Posted by BigBaddad (Post 2258972)
In that case, how about a 150?
There are million different things to fix before you start messing with different tyre size.

bald git 03-05-10 09:48 AM
Re: is bigger better
 
1 Attachment(s)
what like this

speedplay 03-05-10 10:04 AM
Re: is bigger better
 
Look at all that unused tyre!!



;)

bald git 03-05-10 04:48 PM
Re: is bigger better
 
Quote:
Originally Posted by mister c (Post 2258975)
I tried mine with a 170 & all I can say is that there is a slight difference in cornering, it tends to drop in a bit slower. As already said, I wouldnt bother.
raise the forks in the yoke by 5mm to get it all back.

mister c 03-05-10 06:23 PM
Re: is bigger better
 
Quote:
Originally Posted by bald git (Post 2259223)
raise the forks in the yoke by 5mm to get it all back.
Nah, drop them down & turn in faster ;)

bald git 03-05-10 07:53 PM
Re: Wider rear tyre?
 
raising the forks in the yokes, lowers front, decreases rake which in turn makes the steering quicker.....FIGHT !!!!

yorkie_chris 03-05-10 08:40 PM
Re: Wider rear tyre?
 
You both saying same thing.

Anyway it is all bollox. Until you fix the innate issues present IMO you chasing your tail with such shenanigans.

bald git 03-05-10 09:30 PM
Re: is bigger better
 
Quote:
Originally Posted by mister c (Post 2259324)
Nah, drop them down & turn in faster ;)
so in reality you drop your forks you increase the length of your bike, just like dennis hopper with his chopper, in easy rider which needed the whole of the freeway to turn in. i,m saying raise the forks, so how can that be the same. as you say chris its, bollox. a tyre with the same height, same aspect ratio but 10 mm wider is going to make that much difference, end of.:smt014

yorkie_chris 03-05-10 09:45 PM
Re: Wider rear tyre?
 
You contradict yourself there,
If tyre is same height but 10mm wider... it cannot by definition have same aspect ratio.

bald git 04-05-10 05:17 AM
Re: Wider rear tyre?
 
160 x 60 x17...... 170 x 60 x 17, same o/a tyre height, say 6 inches on both tyres,the height as in avon chart, 60 is aspect ratio or height of sidewall, surely these are same, its just width thats different.

cb1000rsteve 04-05-10 05:31 AM
Re: Wider rear tyre?
 
Its got something to do with percentages across the section of the tyre. Not like a car tyre where a 190 tyre is 19cm wide and a 205 is 20.5 cm wide. The 170 will be slightly taller, not enough that you'd notice. i'm fitting 170 rears as i just got 2 pairs of tyres for £160 delivered. 170's where cheaper than the 160's. I'll also be fitting 180's through summer as i get Pirelli BSB tyres for £60 a pair. yeah there may be a slight difference but for the price i can easily live with it.

lukemillar 04-05-10 06:09 AM
Re: is bigger better
 
Quote:
Originally Posted by yorkie_chris (Post 2258960)
Blue650S posted a pic on here of his tyre which was apparently a few 10ths of a second off minitwin lap record pace.
:lol: I don't think so

But you're right about not using the entire tyre.

However...

I have just stuck a 190 on my 675 for race next weekend. Apparently most of the supersport guys here run 190's on bikes that come with 180's as stock. Trade off is a slower turn in but you can get on the throttle earlier/with more lean without it spinning up.

Will see what it's like after raceday :)

That said, most people also acknowledge that it is a waste of time on the road.

BigBaddad 04-05-10 06:51 AM
Re: is bigger better
 
Quote:
Originally Posted by BigBaddad (Post 2258883)
The Height of the profile i.e. in this case 60 is the % of the width. So 60% of 170mm is bigger than 60% of 160.

as I explained on page1

yorkie_chris 04-05-10 07:58 AM
Re: is bigger better
 
Quote:
Originally Posted by lukemillar (Post 2259740)
:lol: I don't think so

But you're right about not using the entire tyre.
He did not in fact say it was his tyre, thinking about it

Suffice to say the thing was pretty well melted, except for a small band,

lukemillar 04-05-10 09:18 AM
Re: is bigger better
 
Quote:
Originally Posted by yorkie_chris (Post 2259769)
He did not in fact say it was his tyre, thinking about it

Suffice to say the thing was pretty well melted, except for a small band,
I meant the bit about 1/10th off the lap record!

If you look at pretty much any of the miniwtinners running supercorsas, they'll all have small bands as it is pretty much impossible to use the whole width without crashing on an SV rim.

yorkie_chris 04-05-10 09:38 AM
Re: Wider rear tyre?
 
What gets me more curious about SV is how it uses all front while leaving strip on back despite having really lazy geometry.

With much higher rear (actually longer than ohlins at full extension by 5mm or something like that) my chicken strips look more normal, using more of rear tyre and less of front. Counter-intuitive, though interesting.

I think those 160 SCs might be meant for a 5.0 rim and that's why, but I haven't tried fitting CBR rim to try it

-Ralph- 04-05-10 09:40 AM
Re: Wider rear tyre?
 
Just stick to the correct conclusion you came to in post 11!

yorkie_chris 04-05-10 09:43 AM
Re: Wider rear tyre?
 
Quote:
Originally Posted by bald git (Post 2259733)
60 is aspect ratio or height of sidewall, surely these are same, its just width thats different.
It cannot be both.

It is in fact ratio, and 0.60 x 170 is smaller than 0.60 x 160 ... get a calculator and try it :)

Then measure some tyres and find numbers on sidewall have a fairly loose relationship with reality :-P

bald git 04-05-10 04:19 PM
Re: is bigger better
 
Quote:
Originally Posted by BigBaddad (Post 2258883)
The Height of the profile i.e. in this case 60 is the % of the width. So 60% of 170mm is bigger than 60% of 160.

Fitting 170 tyre in place of a 160 would raise the height further as it is being pinched more.

In theory raising the rear of your bike can make it turn in quicker, but fitting a bigger would add more unsprung weight and increase the rotating mass (which is far greater than static mass), slowing turn in, will also need more energy the brake and accelerate.

In reality, you may not notice any difference. The sv runs well on a 160 so I wouldn't bother. As for your insurance, speak to them and at the least tell them about all the mods on your bike and make sure they put it on your policy schedule.
got most of that. extra mass increases gyroscopic force therefore the tyre will want to keep itself upright, so when turning, mass is forcing itself against the turn making steering slower. this can be counter acted on by decreasing angle of steering slightly, ie raising forks. its the pinching bit i dont get as both tyres have a recommended rim size of 4.5 inches.

bald git 04-05-10 04:23 PM
Re: Wider rear tyre?
 
Quote:
Originally Posted by -Ralph- (Post 2259853)
Just stick to the correct conclusion you came to in post 11!
i will, its carried on more than i expected.


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