Which tires for me and my 1978 GS750?

[titanfus]

First, let me say that I am a motorcycle newbie, so please don't leave out any detail in your replies because you think I may be offended.

I have a 1978 GS750 that I just revived from the dead and both the front and rear tires definitely need replacing.

I ride very conservatively and defensively. I do not need performance or speed tires. I need safe and comfortable tires that are suited for commuting and weekend cruising short distances.

Here is what it says on the bike for tire sizes:

Front: | Rear
3.25H19-4PR | 4.00H18-4PR
19x1.85RIM @ 25PSI | 18x2.15RIM @ 32PSI

Here is what is on the bike:

Front: | Rear
Nankang | Dunlop K391S
3.50H19-4PR | 130/90 V16
Max PSI: 40 | Max PSI: 42


Ok, here are my questions:

1. Can you give me a summary of what all of these numbers mean? I have googled many times and cannot find a definitive list.
2. I have what appear to be stock, spoked rims will I need tubed tires?
3. What type/brand/size do you recommend for my purposes? I would like to emphasize stability and safety over price and anything else.

Thanks in advance

[8trackmind]

Look like you need a 100/90/19 front, 120/90/18 rear (100mm is the width, 90 is the aspect ratio, 19" is the rim size)

You can use tubeless tires with tubes. (the only street tires that fit will be tubeless)

As far as the brand and model, you'll get an endorsement for every one if you watch this thread long enough. :-D
(I like Dunlops, the model depends on what I'm using the bike for)

[chuckycheese]

Good!

You happen to have the perfect attitude because I think you realize that your tires are "where the rubber meets the road" on a motorcycle.....it's amazing how some people overlook that fact. As the others have said, get a good tire in the right size, have it mounted properly, check for problems and check air pressure often...and you'll do just fine.!! OH,.....and, be careful!!!:-D

[titanfus]

Thanks for the quick reply and the clarification on the numbers.

I just thought of another question:

There is a PSI rating that is on the bike itself (Front: 25, Rear: 32).

I have always put in the maximum PSI when filling my car tires, should I match the value on the bike? or on the tire?

Should I get a tire that matches that PSI? or is it OK to inflate a tire with a max PSI of 40 PSI to only 25 as it says on the label on the bike?

Thanks again,

-Paul

[deves3000gt]

I have the same bike and am in the same position with tires. I shoped around and bike bandit has a set of tires that have gotten very good reviews on this site. They are a no name brand Ching something (you'll know what brand i am talking about when you see them) I got both front and rear tire delivered for $97. They are rated for the driving you are looking for. Good luck.

P.S. if anyone knows what tires i am talking about if you could help me out with the name. I'd run out and look but their in the locked shed.

[deves3000gt]

Ok, just checked bike bandit they are Chen Shin.

[titanfus]

I just happened to be on bikebandit.com when you replied. :-)

Like I said, I am more interested in stability/safety than price, so if a little more money will provide this then I'd like to know if this is the case.

On the other hand, since I do not need high-performance tires maybe these are just fine and spending more is just throwing money away?

Anybody else have some thoughts on this?

[8trackmind]

I just happened to be on bikebandit.com when you replied. :-)

Like I said, I am more interested in stability/safety than price, so if a little more money will provide this then I'd like to know if this is the case.

On the other hand, since I do not need high-performance tires maybe these are just fine and spending more is just throwing money away?

Anybody else have some thoughts on this?

The hardest part is finding the correct sizes. You don't have a whole lot of choices with the narrow tires that fit on our bikes.

[Billy Ricks]

One bit of advice for you, don't listen to the knuckleheads that tell you to run the maximum pressure stamped on the tire. They'll tell you that because of today's construction you need to run higher pressure, hogwash. Start out at what the bike specs call for and go from there. The maximum pressure stamped on the tire also has a carrying capacity that goes along with that pressure. In most cases you aren't carrying anywhere near that weight.

If you really want to know you are running the right pressure for your needs check the cold pressure before you start riding. Then after about 10 minutes of constant riding recheck the pressure. Ideally you should now have 3 lbs more pressure than when the tire was cold. Less and the tire is staying too cold. Like this you have less grip and will run the center out of the tire quicker than you should. If you have more than a 3 lb gain you are running too little air. The tire is going to run hotter than it should and wear out quicker.

[ironsheik]

Then after about 10 minutes of constant riding recheck the pressure. Ideally you should now have 3 lbs more pressure than when the tire was cold. Less and the tire is staying too cold. Like this you have less grip and will run the center out of the tire quicker than you should. If you have more than a 3 lb gain you are running too little air. The tire is going to run hotter than it should and wear out quicker.

I've never heard this before and it sounds like great advice. Is this a well known *trick* for the racers or am I just an ignorant dude?

Josh

[Billy Ricks]

I've never heard this before and it sounds like great advice. Is this a well known *trick* for the racers or am I just an ignorant dude?

Josh

Heard that from a BMW tech once.

[Greg O.]

I have been using Bridgestone S11 Spitfire Sport Touring tires on my 1979 GS 750L and they fit and look good, and I am happy with the way they handle. They are good tires for the older bikes and are reasonable priced. They have a dual tread.

http://www.motoxoutlet.com/index.asp?PageAction=VIEWPROD&ProdID=436

Also...

http://www-origin.motorcycle-superst...spx?style=4725#

Greg O

[Steve]

If you really want to know you are running the right pressure for your needs check the cold pressure before you start riding. Then after about 10 minutes of constant riding recheck the pressure. Ideally you should now have 3 lbs more pressure than when the tire was cold. Less and the tire is staying too cold... If you have more than a 3 lb gain you are running too little air. The tire is going to run hotter than it should and wear out quicker.

I heard something similar to this at a seminar that was presented at the Aspencade Rally in Ruidoso, NM back in 1981. What was presented to us was 3psi for the front, 5psi for the rear. On the GoldWing board that I visit frequently, their rule of thumb is 10%.

Titanfus,
Tires for bikes, cars, trucks, whatever have a maximum inflation pressure, as you have noted. They also have a maximum weight. In order to carry that weight, they need to be inflated to max pressure. If you are not carrying maximum weight on the tire, there is no need to run max pressure.

Car tires come in many more sizes than bike tires, and each size has a different weight rating. If the actual weight of the car is near the maximum load of the tire, it makes sense to run max pressure. I have always run more then the car manufacturer suggests, as they tend to go for maximum comfort. Since the edges of the tires wear out sooner on my cars, I run more pressure to help balance the wear.


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