Bicycle Mechanics - Proper tire pressure recommendation...

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cjbruin
03-28-08, 11:53 PM
Posted this in the Road forum but it occurred to me that this forum might be more appropriate...

I'm trying to figure out the right tire pressure for Ironman Arizona in two weeks.

Tires - Continental Grand Prix 4000 (tubular)
Wheels - Zipp 404's
Rider Weight - ~200 lbs
Likely temperature during the race 85-95F

Thanks!
-CJ

Bob Dopolina
03-29-08, 03:23 AM
Nice tires.

What kind of course is it? Are there other factors related to the course that should be considered? Do you know anything about the road surface?

You're going to get a thousand opinions about the right pressure and what is faster so forget finding a definitive answer.

Here's mine:

Continental sew-ups (sew-ups...that no longer applies here...I digress) generally like to run at a higher pressure than other brands. I base this on personal experience, conversations with other users and with Continental itself. I have no data to back up my assertion.

I have not ridden these tires. I am very familiar with the compounding (I ride the GP4000s clinchers) but I am curious to know how the fusing of the tube to the casing affects the sidewall. Perhaps someone who has can offer you some real world information about handling characteristics. Combine this with the characteristics of the course and you should be able to ballpark pressure from there.

The rest is personal preference and Voodoo.
Al1943
03-29-08, 09:02 AM
I think you should experiment and see what works best for you. My guess would be 120 psi rear, 110 psi front. I recommend pumping the tires shortly before each ride.

Al

operator
03-29-08, 09:47 AM
I'm going to say at least 100psi - more for the rear.
rodrigaj
03-29-08, 09:48 AM
I lived in Phoenix for 6 years, during the early '80's. Thorns from the saguaro cactus made road cycling a real PITA. I found that with higher tire pressures I got less flats - so I always went maximum sidewall pressure.

Good luck!
cjbruin
03-29-08, 12:33 PM
Mr. Dopolina - Thanks. The course is mostly fairly smooth asphalt with a few bumpy sections.

Al - Thanks. You're right on the experimentation...just looking for some real world experience. I think your recommendations might be a bit low given my weight but I'll give it a try.

rodrigal - Thanks. I don't think I want to go to 170 (max sidewall pressure) but good call on the thorns. I rode the course in December and didn't have that problem but I'm sure it's common.