Tire pressure

Wheels, hubs and tires
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awander
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Tire pressure

#1

Post by awander »

Wondering what other folks do about this.

My bike ('52 FL) original specs call for 12psi in front, and somewhere between 14-16psi rear(IIRC).

Obviously, those numbers are for the OE 5.00x16 tires.

i have been running modern Coker repros with those pressures,and the front tire gets worn excessively on the sides of the tread(not in the center), eventually leaving me with a plateau in the center of the tread pattern. If you run modern repros of the 5.00x16, what tire pressures do you use?

And what about "more modern" 5.10x16 tires? What pressures do you use, and how did you determine them?

Andy
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Re: Tire pressure

#2

Post by RUBONE »

Modern tires must be run with the current manufacturers pressure rating. The style of construction is totally different with the sidewalls being much softer. I imagine that thing handles like a pig with those low pressures! All manufacturers list suggested pressures on their sites, those are based on load and construction. I use Coker tires and run them at about 24 in the front and 26 in the rear.
Robbie
awander
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Re: Tire pressure

#3

Post by awander »

well, i guess my confusion comes from not knowing whether a repro tire is modern or not....

Where on the Coker site do they list recommended inflation pressures? I couldn't find it, for the Firestone Deluxe Champion Blackwalls in 500-16 size.

Funny thing, i think the bike handles great! Can;t wait to see how it does with more air in the tires....

Andy
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Re: Tire pressure

#4

Post by Hog54 »

I run 24 in front and 18 in rear with modern dunlops.If you put 30 pounds in your tires on a stock rigid pan,you will end up in the hospital.Especially if you dont run a pogo seat like I dont.:)
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Re: Tire pressure

#5

Post by RUBONE »

Andy,
If they are current production they are "modern". Tire makers don't use the old materials and techniques any more. They just use old tread patterns on modern carcases. Old style tires were so stiff they could run almost flat. And they were hard and slippery. Modern is good!
Robbie
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Re: Tire pressure

#6

Post by james »

Andy thanks for bringing up this topic, I've been doing the same thing your doing with pressures, going by the manual. I'll try Robbies formula and see how it goes, thanks Robbie.
By the way tires that wear on the outside are underinflated, center tread overinflated.

Jim :)
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Re: Tire pressure

#7

Post by awander »

RUBONE wrote:Andy,
If they are current production they are "modern". Tire makers don't use the old materials and techniques any more. They just use old tread patterns on modern carcases. Old style tires were so stiff they could run almost flat. And they were hard and slippery. Modern is good!
Robbie
Thanks, Robbie.

When you get a chance,see if you can find the inflation data on Coker's website; I couldn't.
john HD
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Re: Tire pressure

#8

Post by john HD »

andy,

i run the "old" tire pressures.

but be aware you need to add some more if you follow the guidelines in the riders handbook.

a couple of pounds if you are say a little "husky" a little if you have a passenger, extra equipment etc.

john
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Re: Tire pressure

#9

Post by Panacea »

I tried the higher pressure for a while on my 51 with Continentals, the Hydra-Glide front end didn't like it. After some trial and error I found around 23psi worked best for ride and handling...Mike
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Re: Tire pressure

#10

Post by Cotten »

Folks!

An engineer would tell you to weigh the machine and payload,
then determine the area of the tires' contact patches,
and by dividing the total weight into the total area,
you come up with the ideal psi.

A technician will feel the sidewall as he is filling it to assess if the book or sidewall spec is reasonable, and then adjust according to performance assessment on the street.

...Cotten
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Re: Tire pressure

#11

Post by rmcrh »

I remember reading that an ideal tire pressure should have a %10 percent increase between standing and riding temperature. I have always been to lazy to check this out although wondered if this was correct.
A rigid frame bike should not be ridden with tires hard nor low as it will cause the tube to heat and cause flats It does take trial and error for your area consideration ( elevation humidity ) and tire manufacture to find your best air pressure. A very good subject..
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Re: Tire pressure

#12

Post by azpaul50 »

I agree with the 22-24 or so PSI. I've had two sets of Cokers on my '63 bagger and started with the stock (low) pressures. Too much wear and even felt some wobble. Then I went to 28-30 thinking the weight of two riders plus running repops would require it. Nope... hit the brakes even a little hard and we went into skids/sliding. Exciting but not recommended. 22-24 just seems to work better at least for me. - azpaul
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