have i made a major error?

[captaincaveman]

I got my bike back together with the new tyres, the old rear was a 140-70-18 and i wanted to reduce to a 130, which i did, both are pirelli demon sport, i realised that the front 100-90-19 and the 130-70-18 rear are different profiles

the original profiles were different before so assumed nothing wrong, now ive been looking at other gpz1100's and they run 90's front and rear

Have i just wasted my money on the rear tyre or will the different profiles be ok together?

What im trying to ask is how dodgy is it?

[tlc]

A 130/80 would have been better although my J has a 120 on.

[captaincaveman]

Is it ok to use or is it going to be risky?

[tlc]

A130/70 should be on a 3.5 inch rim to sit correctly.

The problem you will have is the profile of the tyre will be pinched. To see the effect of this take a tyre that is off a rim and simulate narrow and wide rims with your hands.

You will see what that does to the profile of the tyre and what effect it will have on the contact patch.

[Mark Tiller]

I would not use it, it would look strange on too

[captaincaveman]

Damn £100 wasted, so will a 130/80 be definitely ok?

[Mark Tiller]

i have always gone 120/90/18

[captaincaveman]

Yeah I'm kind of thinking that now, weird question but is it possible that a 120 would actually look wider than this 130 being pinched, because it looks really thin almost too domed

[captaincaveman]

i have always gone 120/90/18

Is that on a gpz1100 or a zed?

[Al]

Captain, just done 50 laps of Donnington on new Avon Roadriders.
Rear is 130 / 80 and the front 100 / 90.
Previously i had 130 / 80 rear BT45 and the Roadrider behaved itself exactly the same if not better for the same size tyre.
The rear wheel is a GPZ 1100 B like yours and this is on a J model.
The standard J1 wheel is narrower again at the back.
No wobbles, rear wheel steering, just the standard front understeer it has always had on the road.
Youre right, it does look narrow.

Hope this is of some use.

AL

[complete zedness]

I have run 130/80/18 rear with a 110/90/19 front on my Z1B for years and have not had any problems. That said, the wheel rims are Birrani's, the front is the same width as the standard front rim, but the rear rim is wider.

A narrower rim may change the profile as suggested by tlc

[captaincaveman]

it's confusing to a newbie, cause I'd assume that the profile wouldn't affect the rim, you'd think if the wheel could take a 130 then it could take any 130

See where my confusion lies, expensive lesson to learn lol

So it looks like quite a few people have used 130/80's without an issue, does tyre manufacturers make any difference, will a pirelli demon sport be ok if a bt45 is?

Sorry for being a pain, just can't afford another mistake lol

[Big Fluff]

it's confusing to a newbie, cause I'd assume that the profile wouldn't affect the rim, you'd think if the wheel could take a 130 then it could take any 130

See where my confusion lies, expensive lesson to learn lol

So it looks like quite a few people have used 130/80's without an issue, does tyre manufacturers make any difference, will a pirelli demon sport be ok if a bt45 is?

Sorry for being a pain, just can't afford another mistake lol

Captain - You have PM regarding the tyre you no longer need

[captaincaveman]

it's confusing to a newbie, cause I'd assume that the profile wouldn't affect the rim, you'd think if the wheel could take a 130 then it could take any 130

See where my confusion lies, expensive lesson to learn lol

So it looks like quite a few people have used 130/80's without an issue, does tyre manufacturers make any difference, will a pirelli demon sport be ok if a bt45 is?

Sorry for being a pain, just can't afford another mistake lol

Captain - You have PM regarding the tyre you no longer need

pmd back dude

[KWACKERZ1]

Have always ran a 130 on my zed no problems even though the tyre is oversized for the rim.

Save your money and run it , if you dont like it change it later.

Unless your Eddie Lawson you probably wont notice the difference.!!