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Evansc85 · 06-12-2010, 10:53 PM

Hey,

I'm trying to find tires that will fit on these rims:
Back: N17XMT2.50
Front: J19x1.85 or 1.85x19 1690 1407

The rims are on a 1980 Honda CB750K. Does this mean the back needs 17" rim that is 2.5" wide and the front is 19" rim that is 1.85" wide? That doesn't make sense to me and doesn't seem to match anything for sale. Any help would be greatly appreciated.

pplassm · 06-13-2010, 08:21 AM

No. The rear will probably take up to a 140 width tire. 130 is stock. The front will take a 90 or 100 width.

I am sure someone here can point out an online fitment guide that will tell exactly.

seruzawa · 06-13-2010, 09:01 AM

Google search "1980 Honda 750 tire size" and I bet you can find the answer pretty easily.

Evansc85 · 06-13-2010, 11:04 AM

Thanks! I tried to just use google before, but all the information I could find was on the F or the C series, and it looks like the different models have slightly different tire sizes... for example the C series has a 16" back instead of a 17"... so I wasn't sure if the width would be changing as well.

I did some more digging and found mention that someone used Cheng Shin tires with serials: Back: 4.50/85/H17 Front: 3.50-19 ML90-19.

From those numbers Im guessing pplassm was right on about the front being 90-19... but the back has me a little confused. What does 4.50/85 stand for? From what I have read and seen on retail sites the numbers don't seem to make much sense.

The_AirHawk · 06-13-2010, 03:11 PM

The whole dang tire industry don't make much sense - 4.50/85/H17 is the old designation, typically only used for bias-ply tires nowadays - it's a 4-1/2" tread width, 85% (of the tread width) aspect-ratio (that's the height of the tire from the bead to the outside of the tread) "H" Speed-rated (IIRC that's to 130mph) and the tire's for a 17"-rim. Some will have a numerical-designation (in inches, such as 28.6) of the outside-diameter of the tire, instead of the aspect-ratio.

Probably the closest Metric equivalent will be a 130/80-17, it may have an "H" or "V" speed-rating.

For the front rim; 3.50-19 ML90-19 - that's a "dual designation" that's giving both old-standard and Metric, as the sizes are essentially the same.

And then, you get into Race Tire sizes.............

Evansc85 · 06-13-2010, 05:53 PM

Its strange the sizing isn't more standardized. I'm new, so in time Ill get the hang of it. Thank you for all your help!

06-12-2010, 10:53 PM	#1
Evansc85 Registered Member Join Date: Jun 2010 Posts: 3	Help Interpret Wheel Serial Hey, I'm trying to find tires that will fit on these rims: Back: N17XMT2.50 Front: J19x1.85 or 1.85x19 1690 1407 The rims are on a 1980 Honda CB750K. Does this mean the back needs 17" rim that is 2.5" wide and the front is 19" rim that is 1.85" wide? That doesn't make sense to me and doesn't seem to match anything for sale. Any help would be greatly appreciated.

06-13-2010, 08:21 AM	#2
pplassm Founding Member Join Date: Nov 2001 Posts: 3,875	No. The rear will probably take up to a 140 width tire. 130 is stock. The front will take a 90 or 100 width. I am sure someone here can point out an online fitment guide that will tell exactly. __________________ Mongo just pawn in game of life.

06-13-2010, 09:01 AM	#3
seruzawa Robby Join Date: Nov 2001 Location: 8501 ft. Posts: 16,803	Google search "1980 Honda 750 tire size" and I bet you can find the answer pretty easily. __________________ I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion. I watched c-beams glitter in the dark near the Tanhauser Gate. All those moments will be lost in time, like tears in the rain.

06-13-2010, 03:11 PM	#5
The_AirHawk Founding Member Join Date: Jun 2007 Location: Livin' in a Van: down by the Mariana Trench Posts: 10,891	The whole dang tire industry don't make much sense - 4.50/85/H17 is the old designation, typically only used for bias-ply tires nowadays - it's a 4-1/2" tread width, 85% (of the tread width) aspect-ratio (that's the height of the tire from the bead to the outside of the tread) "H" Speed-rated (IIRC that's to 130mph) and the tire's for a 17"-rim. Some will have a numerical-designation (in inches, such as 28.6) of the outside-diameter of the tire, instead of the aspect-ratio. Probably the closest Metric equivalent will be a 130/80-17, it may have an "H" or "V" speed-rating. For the front rim; 3.50-19 ML90-19 - that's a "dual designation" that's giving both old-standard and Metric, as the sizes are essentially the same. And then, you get into Race Tire sizes............. __________________ *Parfois, on fait pas semblant* Sometimes, it's not pretend Oderint Dum Metuant Let them hate so long as they fear политики предпочитают безоружных крестьян Politicians Prefer Unarmed Peasants Nothing to see here, Citizen. Move along now... Last edited by The_AirHawk : 06-13-2010 at 03:15 PM.

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06-13-2010, 11:04 AM	#4
Evansc85 Registered Member Join Date: Jun 2010 Posts: 3	Thanks! I tried to just use google before, but all the information I could find was on the F or the C series, and it looks like the different models have slightly different tire sizes... for example the C series has a 16" back instead of a 17"... so I wasn't sure if the width would be changing as well. I did some more digging and found mention that someone used Cheng Shin tires with serials: Back: 4.50/85/H17 Front: 3.50-19 ML90-19. From those numbers Im guessing pplassm was right on about the front being 90-19... but the back has me a little confused. What does 4.50/85 stand for? From what I have read and seen on retail sites the numbers don't seem to make much sense.

06-13-2010, 05:53 PM	#6
Evansc85 Registered Member Join Date: Jun 2010 Posts: 3	Its strange the sizing isn't more standardized. I'm new, so in time Ill get the hang of it. Thank you for all your help!