wheel size info sought

[peanut]

My 79 SE 2F025155* import from the US has chrome rims/ wire spokes .
The front wheel is 19" with single brake rotor with 100/30/19 tyre ? and 16" rear wheel has 190/30/16 Rear ( drum brake)

Are these standard wheels and sizes for this year and model or have they been replaced? i'm looking to replace the tyres but haven't a clue if the tyres fitted are the correct size for the rims.

 

[XSLeo]

The front is a 100/30-19 up front and a 190/30-16 on the rear? I haven't ever seen those sizes before.
The 79 year had 3 models, the standard, with a 19 inch, 36 spoked flanged rim up front with a 18 inch 36 spoke flanged rim on the rear. The Special II used alloy rims on 36 spokes with a 19 front, 16 rear The Special used the mag wheels, 19 front, 16 rear. The mags had a disc brake.
If it has steel rims then they came off one of the first three years of production or the later 82 up years. The later spoke wheels had 48 spokes on the rear and 64 up front.
If you have the Haynes manual look on page 142, under wheels, brakes and tyres. The tyre specs are in inches, the metric sizes are 100/90-19 on the front, the rear is a 130/90-16. The 18 inch rear will get a 110/90-18
Leo

 

[jd750ace]

Looks like dyslexia. Happens to me all the time.

 

[peanut]

Looks like dyslexia. Happens to me all the time.

???

 

[peanut]

T
If you have the Haynes manual look on page 142, under wheels, brakes and tyres. The tyre specs are in inches, the metric sizes are 100/90-19 on the front, the rear is a 130/90-16. The 18 inch rear will get a 110/90-18
Leo

thanks Leo for taking the trouble to explain all that to me. Your knowledge is impressive .
This is my first XS650 and I bought it in bits . It was imported in 1997 but has been resored at least once since then so I imagine it is likely to have had a lot of replacement parts including maybe wheels.

I have a Haynes but as you say the measurements are in inches which was no help.

I was a bit concerned that if the wheels were a non original size it would effect the gearing and maybe the handling so rather than buy new tyres I might have considered new wheels as I would like to keep this bike stock for now at least .

I cannot get to the bike to check at the moment but I have found the original photos which show the rims are actually aluminium not steel ...apologies for the mistake.

Thanks for your help, much appreciated as always

 

[jd750ace]

???

Sorry man. Your tire sizes in your post both indicated a 30 in the second position which is the aspect ratio of the tire. If a tire is 100MM wide and the aspect ratio is 90, then it's 90MM tall at operating pressure, so if your tire was a 100/30, or even more radical, a 190/30, the sidewalls would not be much more than rim protectors. I assumed that the 3's and 9's got crossed, because if you transpose them in the first section of each of your size numbers indicated, then the tire sizes are standard. Hence my dyslexia comment. I, unfortunately, do that from time to time on aircraft part numbers. 6's and 7's are the worst, but when you try to look up a transposed part number, you come up with shit. Glad you found out that it's a proper Special II. My pics are a bone stock, with the exception of the seat cover, 79 Special II.

 

[peanut]

thats ok . I know my car tyres (,mine has 245x45x17 )but with early bike tyres I haven't a clue . I took the sizes off a photograph taken last year when I bought the bike. Snow is so bad I can't get into the garage at the moment.

I see now that by the time I wrote the post I'd forgotten the order of the numbers doh

 

[XSLeo]

Figuring out the metric size from an inch size is easy. 25.4 mm = 1 inch. Just multuiply the inch size by 25.4 as in 3.50 x 25.4 = 88.9 mm then round off to the nearest mm size. This would be a 90 wide tire. A 4.50 x 25.4 = 114.3, either a 110 or 120 will be close.
Leo

 

[peanut]

thanks leo I have a degree and am quite capable of basic math .

I can see that this embarrasing thread is not going to go away any time soon lol

I was just being a lazy basteward when I posted and didn't bother to check my facts before posting.

My principle interest is in whether or not these wheels are original spec and what tyre options I have available to me. Again I was just being lazy and avoiding searching for the answers myself.
Thanks for your help ......I'll be sure to read my posts twice in future to avoid looking an idiot again

 

[Newagerocker]

Yes those are the original size or more than likely the actual original wheels. The 18" rear wheel was last used in '78 on the XS650SE. The '79 XS650-2F had spoked rear 2.75-16" wide wheel; the '79 XS650-SF had cast wheels rear 3.00-16" wide rim.

In any case the tires would be the same size 100/90X19 front; 130/90X16 rear. TT for spokes.

 

[peanut]

thanks newagerocker you lot are so helpful it shames me for asking dumb questions that I could have checked myself.

 

[650Skull]

You are a bit unlucky if the rims are chrome, the 79F had the alloy spoke 19/16 rims and were for that year only, making them rare.