tire designation

[Guest Ken8143]

One of these days I will get new tires. This is not a question about what brand of tire to get - it is about how the tire is described.

 

My manual for the 87 VR calls for 120/90-18 for the front and 140/90-16 for the rear. Currently there are 491 Elite II on the bike, and the front has MR90-18 71H. I think the rear has a MT or MU.

 

What the heck does MR or MT or MU or 71H mean? is a MT90-16 the same as a MU90-16? They are listed separately and have different prices.

[wisorac]

Hey,

I am not sure what MU, MT, or MR means, but the 71H is the load index and speed rating. The 71 is the load index which when you look the load index up it will let you know the max weight that tire can hold and certain psi amounts. The "H" is the speed/performance rating which lets you know what speeds that tire can travel without the tire heating up and busting. Sports bikes most likely have a "Z" rated wite which can withstand speed of 149mph+. The "H" rated can go up to speeds of 130mph.

 

On cars now days there are S, T, H, V, Z speed/performance ratings(There are others, but those are the basic). The lower the rating the harder the rubber and it gets softer as it goes up. The softer rubber tires give better handling and cornering(provided the car calls for it), but softer rubber tires also suffer from less mileage wear. I hope this helps some.

[Guest Popeye]

Perhaps this will help to clarify the 'metric vs. alpha' designations:

 

 

Front Tires				Rear Tires
metric	alpha	inch		metric	alpha	inch
80/90	MH90	2.50/2.75		110/90	MP85	4.00/4.75
90/90	MJ90	2.75/3.00		120/90	MR90	4.50/4.75
100/90	MM90	3.25/3.50		130/80		5.00/5.10
120/80		4.25/4.50		140/80		5.50/6.00
120/90	MR90	4.25/4.50		140/90	MU90	5.50/6.00
130/90	MT90	5.00/5.10		150/80	MV85	6.00/6.25
				150/90	MV85	6.00/6.25

Speed Ratings:

 

Maximum Design/Test Speed
J Type	62	100
N Type	87	140
P Type	94	150
S Type	112	180
H Type	130	210
V Type	149	240
Z Type	149+	240+
Tires with 2.00, 2.25 & 2.50 nominal section widths are rated for 75 mph.

Funny that the 'H' designation is out of sequence.

 

Load ratings:

 

LOAD INDEX (LI) RATING CHART
LI	lbs.	LI	lbs.	LI	lbs.	LI	lbs.	LI	lbs.
20	176	33	254	46	375	59	536	72	783
21	182	34	260	47	386	60	551	73	805
22	187	35	267	48	397	61	567	74	827
23	193	36	276	49	408	62	584	75	853
24	198	37	282	50	419	63	600	76	882
25	204	38	291	51	430	64	617	77	908
26	209	39	300	52	441	65	639	78	937
27	215	40	309	53	454	66	661	79	963
28	220	41	320	54	467	67	677	80	992
29	227	42	331	55	481	68	694	81	1019
30	234	43	342	56	494	69	716	82	1047
31	240	44	353	57	507	70	736	83	1074
32	247	45	364	58	520	71	761	84	1102

 

Hope this helps.

[dray]

hope this will help you out

 

http://www.phatperformanceparts.com/images/BasicTireInfo.html

 

 

[Guest Ken8143]

Thanks! That is exactly what I was looking for. Apparently there are different ways of "sizing" a tire.