imperial tyre sizes

[Graeme77]

I need to get new tyres for my f1. Its pretending to be older than it is, ace bars, k rear mudguard, single seat etc so I was looking at maybe k81 dunlops for it but the sizes are confusing my.
Would 3.60x19 and 4.25/85x18 be right?
It currently has 100/80 and 120/80 on it so something this sort of size would be nice.

Ive looked at size conversions but why do these have a decimal point and is 4.21/85 a tyre wall ratio like metric tyres?

Im finding it hard to choose tyres but I think it will either be these k81s or ill have to go more modern with metzler/roadrider/bt45 or suchlike.

[Johnwebley]

tyre sizes can be confusing,

your front,3.60 - ? X 19,is normally a 3".60 inch wide and most cases a 90% profile ratio,X 19" diameter,

 try to figure,also check the overall diameter,http://www.avon-tyres.co.uk/motorcycle/roadrider

these are my personal favorite tyres,they grip very well,and help the bike to feel light and small,

what size is in the hand book?

[Trigger]

If you are looking for old style, Avon AM6 and AM7's are available at a good price. If you are on about F1 CB750 i have just put 3.25-19 on the front and 4.00-18 rear from Mytyres.

[Graeme77]

Yes, its a 750. Book is in the loft so just looked sizes up. As you say, 3.25 19 and 4.00 19.
Do they not look a little small?

I was going to get avons but ive read alot of bad opinions on the safety milage rear. Ive read good stuff too though.
I have a gsxr if I want all out handling, but I do like a nice sweeping corner

I found a thread on here recomending 4.10 19 and 4.25/85 18 if getting the k81's.

[Graeme77]

Does a k70 rear work ok with a speedmaster front?

[Trigger]

Yes, its a 750. Book is in the loft so just looked sizes up. As you say, 3.25 19 and 4.00 19.
Do they not look a little small?

I was going to get avons but ive read alot of bad opinions on the safety milage rear. Ive read good stuff too though.
I have a gsxr if I want all out handling, but I do like a nice sweeping corner

I found a thread on here recomending 4.10 19 and 4.25/85 18 if getting the k81's.

4.10-19 on the front? the forks are not that wide. You will find it very hard to find a 4.25-18 for the rear, or is it 4.10 ?  A GSXR is not a CB750

[Trigger]

Just noticed you have 80 wall tyres on, which is a low profile type for a CB750. The modern tyre should have a 90 wall.

[mick]

Hi Graeme I've just fitted Dunlop TT100's to my 750 and my Kettle , got my tyres from www.vintage-tyres.co.uk front is 4.10x19 rear is 4.25/85x18,

cheers Mick.

 

[Trigger]

Hi Graeme I've just fitted Dunlop TT100's to my 750 and my Kettle , got my tyres from www.vintage-tyres.co.uk front is 4.10x19 rear is 4.25/85x18,

cheers Mick.

 

It must be 4.10-18 that are hard to find these day Mick

[Graeme77]

Yes, its a 750. Book is in the loft so just looked sizes up. As you say, 3.25 19 and 4.00 19.
Do they not look a little small?

I was going to get avons but ive read alot of bad opinions on the safety milage rear. Ive read good stuff too though.
I have a gsxr if I want all out handling, but I do like a nice sweeping corner

I found a thread on here recomending 4.10 19 and 4.25/85 18 if getting the k81's.

4.10-19 on the front? the forks are not that wide. You will find it very hard to find a 4.25-18 for the rear, or is it 4.10 ?  A GSXR is not a CB750

people do seem to fit 4.10 19 and 4.25/85 18 on cb750's.
My comment about the gsxr was saying necausebibhave that im not after getting every last drop of ability out of the cb. The cb is for more relaxing journeys.

Oh, and I mistuped. The current tyres are 90 profile not 80.

[Graeme77]

Mick, have you got any photos of them fitted to the cb? I am still favouring tt100 just not sure in which sizes.
I think the 4.10/19 and 4.25/85/18 will be closer to whats on it now.

[Trigger]

A 4.10-19 on the front will not work on a CB750 unless the mudguard is removed and the forks widened. Look at the link that Mick has provided and enter CB750F for the tyres they recommend for the F1. Is this a cafe/custom F1? 

[mick]

Trigger both front tyres are 4.10 x19 got those off an ebay seller and got my 2 rear tyres from vintage tyres , I've been running TT100's on both my F1 and k model with no probs or modifications ? cheers Mick, 

[Graeme77]

Its slightly cafe/custom but apart from the rim the front end is all stock.

aparantly the 4.10/19 is 108mm wide. The 3.60/18 is 93mm wide.
I am not trying to go wider on the front for looks or anything, just trying to work out whats going to be best and nearest in size to my 100-90/19.

So if its 3.60/19 on the front would you put 4.10/18 or 4.25-85/18 on back?

[Graeme77]

Trigger both front tyres are 4.10 x19 got those off an ebay seller and got my 2 rear tyres from vintage tyres , I've been running TT100's on both my F1 and k model with no probs or modifications ? cheers Mick, 

So 4.10/19 does fit?
Have you tried the smaller sizes of tt100 and prefered the larger?

edit..
vintage tyres recomend 3.60/19 front and 4.25-85/18 rear.